Evaluation of the Enzygnost Measles Enzyme-Linked Immuno-Sorbent Assay kit (Behring) performance to detect specific immunoglobulin M (IgM) was carried out with 3,297 single serum samples and 898 paired serum samples collected during a measles epidemic (10,184 reported cases) in Quebec, Canada. Anti-measles IgM and IgG were detected by using the Enzygnost kit with the appropriate conjugates. Complement-fixing (CF) antibody (Ab) titers were assessed by the laboratory branch complement fixation micromethod. The Centers for Disease Control's clinical measles case definition was used. A modification of the manufacturer's optical density interpretation algorithm was introduced to allow for equivocal results, in addition to positive and negative ones. These three categories differed as to their association with a significant increase in CF Ab titer and the time between the onset of symptoms and phlebotomy. The IgM positivity rate for complement fixation-confirmed measles cases was 96.6% for vaccinated subjects and 100% for nonvaccinated subjects. The daily percentage of IgM seropositivity that was detected for subjects who became IgM positive within 30 days increased gradually from 40 to 90% for sera taken 1 to 7 days after the onset of symptoms, and it plateaued at 100% for sera taken 16 to 30 days after the onset of symptoms. IgM seropositivity was strongly associated with IgG seroconversion, CF Ab titer increase, and clinical measles (P less than 0.0001). Reproducibility was 100% for nonreactive sera and 99.1% for reactive sera. In conclusion, the Enzygnost Measles Enzyme-Linked Immuno-Sorbent Assay kit performed adequately to confirm measles virus infection during this epidemic. A second serum sample should be tested when an early-acute-phase serum sample is IgM negative.
A 20-year-old girl developed a subacute neurological illness characterized by seizures and epilepsia partialis continua, which resulted in her death within 10 weeks of her first symptom. Although she had a history of unusual reactions to viral infections, there was no evidence of any underlying disorder resulting in immunosuppression. Histopathology demonstrated the presence of dense infection with measles virus. The unusual clinical features of this cases suggest that measles virus may be responsible for a wide spectrum of neurological disease ranging from measles inclusion body encephalitis on the one hand to subacute sclerosing panencephalitis on the other.
Subacute sclerosing panencephalitis (SSPE) is a fatal disease in children and young adults that is caused by persistent infection of the central nervous system (CNS) by a nonproductive, cell-associated form of measles virus. Using an experimental model for SSPE (LEC viral strain in newborn hamsters), we have shown previously that establishment of such CNS infections involves selective elimination from the CNS of productively infected cells by host defensive mechanisms, coupled with the selective sparing of cells carrying nonproductive viral forms. That interferon (IFN) may play a role in this process was suggested by the disappearance of productively infected cells from the CNS tissues prior to the appearance of antiviral antibodies and by the demonstration of cell-associated, IFN-resistant viral variants in the virus stocks that were used. Results of this study support these conclusions by showing that similar IFN-resistant viral variants are present in the HBS strain of SSPE-derived measles virus and that these variants, in the presence of IFN, have properties that are similar to those of naturally occurring cell-associated strains of SSPE viruses, e.g., DR, IP3, and Biken. These IFN-resistant forms of HBS virus were isolated and were shown to maintain their resistance to inhibition by IFN after cloning. However, on removal of IFN, they reverted to productive forms similar to the parental HBS virus. The potential role of such viral forms in the pathogenesis of SSPE is discussed.
The role of the immune response to measles virus in acute infection or in disease states associated with this virus is of major interest. The viral genome-specified surface antigens of measles, the hemagglutinin and fusion proteins, are likely to be of paramount importance with respect to the host immune response to the virus. This report describes initial studies aimed at assessing the immune response to the major surface glycoprotein, the hemagglutinin. This antigen was purified by affinity chromatography, using a monoclonal anti-hemagglutinin immobilized on Sepharose. The purified protein retained biological activity in hemagglutination assays. This activity could be specifically inhibited with a human antimeasles serum and with monoclonal antibody to the hemagglutinin. Lymphocytes from individuals known to proliferate to measles-infected monolayers also proliferated to the purified hemagglutinin. Thus, the immune-response to measles virus is, in part, directed to this surface antigen.
Measles virus (MV) rarely induces lethal diseases of the human central nervous system characterized by reduced expression of the viral envelope proteins and by lack of viral budding. The MV envelope contains two integral membrane proteins, termed fusion (F) protein and hemagglutinin (H) protein, and a membrane-associated matrix (M) protein. Previously, analysis of MV genes from autopsy material indicated that the M protein and the F protein intracellular domain are often drastically altered by mutations. Here, we present evidence that truncation of the F protein intracellular domain does not impair fusion function, and we suggest that this alteration interferes with viral budding. Unexpectedly, certain combinations of functional F and H proteins were unable to induce syncytium formation, an observation suggesting that specific F-H protein interactions are required for cell fusion. We also found that three of four H proteins of persistent MVs are defective in intracellular transport, oligosaccharide modification, dimerization, and fusion helper function. Thus, MVs replicating in the brain at the terminal stage of infection are typically defective in M protein and in the two integral membrane proteins. Whereas the M protein appears dispensable altogether, partial preservation of F-protein function and H-protein function seems to be required, presumably to allow local cell fusion. Certain subtle alterations of the F and H proteins may be instrumental for disease development.
Vaccine and laboratory adapted strains of measles virus can use CD46 as a receptor to infect many human cell lines. However, wild type isolates of measles virus cannot use CD46, and they infect activated lymphocytes, dendritic cells, and macrophages via the receptor CD150/SLAM. Wild type virus can also infect epithelial cells of the respiratory tract through an unidentified receptor. We demonstrate that wild type measles virus infects primary airway epithelial cells grown in fetal calf serum and many adenocarcinoma cell lines of the lung, breast, and colon. Transfection of non-infectable adenocarcinoma cell lines with an expression vector encoding CD150/SLAM rendered them susceptible to measles virus, indicating that they were virus replication competent, but lacked a receptor for virus attachment and entry. Microarray analysis of susceptible versus non-susceptible cell lines was performed, and comparison of membrane protein gene transcripts produced a list of 11 candidate receptors. Of these, only the human tumor cell marker PVRL4 (Nectin 4) rendered cells amenable to measles virus infections. Flow cytometry confirmed that PVRL4 is highly expressed on the surfaces of susceptible lung, breast, and colon adenocarcinoma cell lines. Measles virus preferentially infected adenocarcinoma cell lines from the apical surface, although basolateral infection was observed with reduced kinetics. Confocal immune fluorescence microscopy and surface biotinylation experiments revealed that PVRL4 was expressed on both the apical and basolateral surfaces of these cell lines. Antibodies and siRNA directed against PVRL4 were able to block measles virus infections in MCF7 and NCI-H358 cancer cells. A virus binding assay indicated that PVRL4 was a bona fide receptor that supported virus attachment to the host cell. Several strains of measles virus were also shown to use PVRL4 as a receptor. Measles virus infection reduced PVRL4 surface expression in MCF7 cells, a property that is characteristic of receptor-associated viral infections.
Measles virus is a primate-specific virus that causes acute respiratory disease and can also lead to short term immune suppression resulting in secondary infections by bacteria or parasites. Wild type measles virus attaches to and infects lymphocytes using the receptor CD150 (signaling lymphocyte activation molecule, SLAM). Measles virus is also known to infect epithelial cells of the upper respiratory system and lungs. However, the viral receptor on these cells was previously unknown. Adenocarcinomas are derived from glandular epithelial cells of organs including the lung, breast, or colon. We showed that wild type isolates of measles virus can infect human airway epithelial cells and many adenocarcinoma cell lines. A comparative analysis of membrane genes expressed in cells susceptible and non-susceptible for measles virus infections revealed candidate receptor proteins. Only PVRL4 (Nectin 4) converted cells that were resistant to measles viral infections, to cells that could support virus infections. PVRL4 is a tumor cell marker that is highly expressed on embryonic cells such as those of the placenta, but it is also expressed at lower levels in the trachea, oral mucosa, nasopharynx, and lungs. It is highly expressed on many lung, breast, colon, and ovarian tumors suggesting that they could be targeted with oncolytic measles virus.
The pathogenesis of two rodent-adapted strains of measles virus was studied in 1- to 2-day-old suckling and 4-week-old weanling BALB/c mice. Both the mouse-adapted Edmonston (MAEd) strain and the hamster-neurotropic (HNT) strain caused necrotizing giant-cell encephalitis with a 90 to 100% mortality after intracerebral inoculation into suckling mice. After intracerebral inoculation into weanling mice, MAEd virus caused fatal disease in 20% of the mice; HNT virus caused fatal disease in 30%, but an additional 35% of these mice developed disease and then recovered. Even when mice were moribund there was little histological evidence of disease in weanling mice inoculated intracerebrally with either strain of virus. Fluorescent-antibody staining showed extensive measles virus antigen in the suckling mouse brain and focal areas of measles virus antigen in the weanling mouse brain. Infectious virus was recovered easily from the brains of suckling mice by plaquing on Vero cells, but no infectious virus could be recovered similarly from weanling mice. However, virus could be recovered by intracerebral inoculation of weanling mouse tissue homogenates into suckling animals. The immune response appeared to play no role in the recovery from infection or in these age-related differences in disease. It appears that maturation of the cells of the mouse central nervous system converted the production of measles virus from the infectious form in the suckling mouse to a primarily defective infection in the weanling mouse.
BACKGROUND: There is evidence that measles virus infection in early life may predispose to Crohn's disease. AIMS: To examine using serological methods a potential association between measles virus infection in early life and predisposition to Crohn's disease. SUBJECTS: Forty five patients with Crohn's disease and forty five healthy controls were studied prospectively. METHODS: Clinical data were recorded and serum was analysed for measles virus, cytomegalovirus (CMV), adenovirus and herpes simplex virus (HSV) antibody titres by a complement fixation test (CFT), and for measles virus IgM by enzyme linked immunosorbent assay (ELISA). RESULTS: Reciprocal CFT titres for measles virus were lower in patients with Crohn's disease compared with controls (p < 0.05); there was no significant difference in titres for other viruses. None of the subjects studied had a level of measles virus IgM suggestive of acute infection, and there was no significant difference in measles virus IgM levels between patients and controls. The measles virus CFT titres and IgM levels in the patients with Crohn's disease did not correlate with any of the clinical features recorded. CONCLUSION: This study does not provide supportive evidence for a role for measles virus in the aetiology of Crohn's disease.
Rapp, Fred (Baylor University College of Medicine, Houston, Tex.). Plaque differentiation and replication of virulent and attenuated strains of measles virus. J. Bacteriol. 88:1448–1458. 1964.—Plaque formation by strains of measles virus in a stable line of African green monkey kidney cells (BSC-1) is characterized by development of large plaques (>1 mm) within 4 days after inoculation of the cultures with the virulent Edmonston strain or by small plaques (<1 mm) after inoculation with the attenuated Edmonston strain of virus. Plaque formation by measles virus is not influenced by iododeoxyuridine, cytosine arabinoside, isatinthiosemicarbazone, streptonigrin, actinomycin D, or mitomycin C. The predominant cytopathic effect observed with both strains is the formation of large, multinucleated giant cells. Development of the giant cells is correlated with development of virus antigen and synthesis of infectious virus. Synthesis of virus is similar at 34 and at 37 C. Appearance of intracellular virus precedes release, and is later in the attenuated virus-infected cells than in cells infected with the virulent strain. With the virulent strain, equal concentrations of intra- and extracellular virus are found but, with attenuated virus, only a small fraction reaches the extracellular fluids, and more than 95% of the newly synthesized virus remains cell-associated.
To assess whether an virus-specific immune defect may be associated with multiple sclerosis (MS), we have examined the ability to generate measles virus-and influenza virus-specific cytotoxic T cells (CTL) in patients with MS, normal individuals, and other disease controls (ODC). The mean (+/- SEM) measles virus-specific CTL response for normal individuals and ODC was 26.9 +/- 2.9% (N = 17) and 26.7 +/- 2.8% (N = 13) specific lysis, respectively. In contrast, the capacity of MS patients to generate measles virus-specific CTL was markedly diminished. Peripheral blood lymphocytes from MS patients stimulated with measles virus lysed their measles virus-infected autologous B cell line at a group mean level of 6.0 +/- 1.4% (N = 16) specific lysis. MS patients had significantly lower measles virus-specific CTL responses than normal individuals (p less than 0.00001) or ODC (p less than 0.0001). Importantly, this lowered response did not reflect a generalized depressed cytolytic activity of MS patients, since influenza virus-specific CTL and NK activity from these patients were comparable to normals and ODC. Thus, in MS there is a significant depression of measles virus-specific CTL which suggests that this virus- specific immune dysfunction may play a role in the pathogenesis of this disorder.
Measles virus (MV) is hypothesized to enter the host by infecting epithelial cells of the respiratory tract, followed by viremia mediated by infected monocytes. However, neither of these cell types express signaling lymphocyte activation molecule (CD150), which has been identified as the receptor for wild-type MV. We have infected rhesus and cynomolgus macaques with a recombinant MV strain expressing enhanced green fluorescent protein (EGFP); thus bringing together the optimal animal model for measles and a virus that can be detected with unprecedented sensitivity. Blood samples and broncho-alveolar lavages were collected every 3 d, and necropsies were performed upon euthanasia 9 or 15 d after infection. EGFP production by MV-infected cells was visualized macroscopically, in both living and sacrificed animals, and microscopically by confocal microscopy and FACS analysis. At the peak of viremia, EGFP fluorescence was detected in skin, respiratory and digestive tract, but most intensely in all lymphoid tissues. B- and T-lymphocytes expressing CD150 were the major target cells for MV infection. Highest percentages (up to 30%) of infected lymphocytes were detected in lymphoid tissues, and the virus preferentially targeted cells with a memory phenotype. Unexpectedly, circulating monocytes did not sustain productive MV infection. In peripheral tissues, large numbers of MV-infected CD11c+ MHC class-II+ myeloid dendritic cells were detected in conjunction with infected T-lymphocytes, suggesting transmission of MV between these cell types. Fluorescent imaging of MV infection in non-human primates demonstrated a crucial role for lymphocytes and dendritic cells in the pathogenesis of measles and measles-associated immunosuppression.
Measles remains one of the most important causes of childhood mortality in developing countries. The virus is highly infectious and is spread via the respiratory route. According to textbook descriptions, measles virus first infects respiratory epithelial cells, followed by viremia mediated by infected monocytes. However, this order of events is inconsistent with current knowledge about receptor usage by measles virus strains. In this paper we have revisited the pathogenesis of measles by infecting non-human primates with a recombinant measles virus expressing enhanced green fluorescent protein. An important advantage of this system is that infected cells become fluorescent and can be detected with high sensitivity in living animals as well as tissue samples. Strikingly, at the peak of virus replication all lymphoid tissues were strongly fluorescent, and up to 10% of T-lymphocytes and 30% of B-lymphocytes were infected. In peripheral tissues the virus predominantly infected lymphocytes and dendritic cells, although to a lesser extent respiratory epithelial cells were also infected. We hypothesize that measles virus, like human immunodeficiency virus, utilizes dendritic cells as a vehicle to establish infection of the lymphoid system and cause immunosuppression. This study reshapes our basic view of measles pathogenesis.
Hamster embryo fibroblasts persistently infected with a derivative of the Schwarz vaccine strain of measles virus spontaneously released virus particles with an average buoyant density considerably lower than that of the parental virus. The released virus contained all of the measles virus structural proteins and interfered with replication of standard virus. All of the virus structural proteins were associated with a membrane-free cytoplasmic extract from the persistently infected cells. Membrane-free cytoplasmic extracts prepared from Vero cells lytically infected with Schwarz strain measles contained little or no virus envelope structural protein. Maintenance of persistent infection may involve both the presence of virus variants and a defect in the ability of the infected cell to replicate the virus efficiently.
Measles virus-directed protein synthesis was examined in two HeLa cell lines (K11 and K11A) that are persistently infected with wild-type measles virus. Four viral proteins (H, hemagglutination protein; P, nucleocapsid-associated protein; NP, the major nucleocapsid protein; and M, the matrix protein) were readily detected in both cell lines by immune precipitation of [35S]methionine-labeled cell extracts followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. When analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, three (H, NP, and M) of the four viral proteins in both K11 and K11A cells differed from the corresponding viral proteins synthesized in HeLa cells acutely infected with the parental wild-type virus. In addition, the M protein from K11A cells migrated significantly more slowly on sodium dodecyl sulfate-polyacrylamide gel electrophoresis than the M protein from K11 cells, and there appeared to be slight differences in the H and NP proteins between these two persistently infected cell lines. The altered viral proteins detected in K11 and K11A cells appeared to be the result of viral mutations rather than changes in the host cell, since virus recovered from these cells directed the synthesis of similar aberrant viral proteins in HeLa cells. Virus recovered from K11 cells and virus recovered from K11A cells were both temperature sensitive and grew more slowly than wild-type virus. HeLa cells infected with virus recovered from K11 cells readily became persistently infected, resembling the original persistently infected K11 cells. Thus, viral mutations are associated with persistent measles virus infections in cell cultures.
B cells and humoral immune responses play an important role in the pathogenesis and diagnosis of multiple sclerosis (MS). A characteristic finding in patients with MS is a polyspecific intrathecal B cell response against neurotropic viruses, specifically against measles virus, rubella virus, and varicella zoster virus, also known as an MRZ reaction (MRZR). Here, we correlated from the routine clinical diagnostics individual IgG antibody indices (AIs) of MRZR with magnetic resonance imaging (MRI) findings in patients with first MS diagnosis.
MRZR was determined in 68 patients with a clinically isolated syndrome (CIS) or early relapsing-remitting MS (RRMS). Absolute AI values for measles virus, rubella virus, and varicella zoster virus were correlated with T2 lesion load and gadolinium enhancing lesions on cerebral MRI (cMRI) and cMRI combined with spinal MRI (sMRI). Measles virus AI correlated significantly with T2 lesion load on cMRI (p = 0.0312, Mann-Whitney U test) and the sum of lesions on cMRI and sMRI (p = 0.0413). Varicella zoster virus AI also showed a correlation with T2 lesion load on cMRI but did not reach statistical significance (p = 0.2893).
The results confirm MRZR as part of the polyspecific immune reaction in MS with possible prognostic impact on MRI and clinical parameters.
Furthermore, the data indicate that intrathecal measles virus IgG production correlates with disease activity on cMRI and sMRI in patients with early MS.
Rustigian, Robert (Tufts University School of Medicine, Boston, Mass.). Persistent infection of cells in culture by measles virus. II. Effect of measles antibody on persistently infected HeLa clonal line persistently infected with incomplete virus. J. Bacteriol. 92:1805–1811. 1966.—The effect of viral antibody on persistent infection of HeLa cells by the Edmonston strain of measles virus was investigated by culturing cells from three persistently infected clones in medium supplemented with human immune globulin. The three infected HeLa clones were isolated from a persistently infected parent line. Two sublines which were grown in the presence of measles antibody developed a nonyielder state, wherein there is no detectable virus infectious for normal HeLa cultures. There is, however, continued synthesis of intracellular viral antigen and formation of viral intracytoplasmic inclusion bodies. The development of a nonyielder state was associated with a marked decrease in the degree of hemadsorption in cultures of both sublines. Further studies of the viral properties of non-yielder HeLa cell populations were made with a clone obtained from one of these sublines by plating under antibody. Persistent infection in this line was characterized by synthesis of incomplete virus even when the cells were cultured thereafter in anti-body-free medium. This was evidenced by (i) failure to recover infectious virus from the clonal population despite continued formation of intracellular viral antigen and viral intracytoplasmic inclusion bodies in a majority of the cells, (ii) the presence of only a few cells with surface viral antigen(s) including hemagglutinin, and (iii) the relatively weak antibody response to viral envelope antigen(s) after injection of cells into guinea pigs.
Measles is a highly contagious childhood disease associated with an immunological paradox: although a strong virus-specific immune response results in virus clearance and the establishment of a life-long immunity, measles infection is followed by an acute and profound immunosuppression leading to an increased susceptibility to secondary infections and high infant mortality. In certain cases, measles is followed by fatal neurological complications. To elucidate measles immunopathology, we have analyzed the immune response to measles virus in mice transgenic for the measles virus receptor, human CD150. These animals are highly susceptible to intranasal infection with wild-type measles strains. Similarly to what has been observed in children with measles, infection of suckling transgenic mice leads to a robust activation of both T and B lymphocytes, generation of virus-specific cytotoxic T cells and antibody responses. Interestingly, Foxp3+CD25+CD4+ regulatory T cells are highly enriched following infection, both in the periphery and in the brain, where the virus intensively replicates. Although specific anti-viral responses develop in spite of increased frequency of regulatory T cells, the capability of T lymphocytes to respond to virus-unrelated antigens was strongly suppressed. Infected adult CD150 transgenic mice crossed in an interferon receptor type I-deficient background develop generalized immunosuppression with an increased frequency of CD4+CD25+Foxp3+ T cells and strong reduction of the hypersensitivity response. These results show that measles virus affects regulatory T-cell homeostasis and suggest that an interplay between virus-specific effector responses and regulatory T cells plays an important role in measles immunopathogenesis. A better understanding of the balance between measles-induced effector and regulatory T cells, both in the periphery and in the brain, may be of critical importance in the design of novel approaches for the prevention and treatment of measles pathology.
B95-8, an Epstein-Barr virus-transformed marmoset B-lymphoblastoid cell line, and its derivative B95a, capable of attachment to a substrate surface, were 10,000-fold more sensitive to measles virus present in clinical specimens than were Vero cells. B95-8 and B95a cells were thus thought to be useful host cells for the isolation of measles virus. Quantitation of measles virus present in clinical specimens showed that a large quantity of virus, exceeding 10(6) 50% tissue culture infective doses per ml of a nasal-swab eluate, is shed into secretions by patients with acute measles, consistent with the contagiousness of the disease. Measles viruses isolated in B95a cells differed in some biological properties from those adapted to Vero cells. First, the viruses isolated in B95a cells did replicate in Vero cells, but release into the fluid phase was less efficient than that of Vero cell-adapted viruses. Second, minor antigenic differences were found between virus strains isolated in B95a cells and those isolated in Vero cells from the same clinical specimens. Third, the viruses isolated and propagated in B95a cells caused clinical signs in experimentally infected monkeys resembling those of human measles. It was suspected that measles virus is subject to host cell-mediated selection and that the viruses grown in B95a cells are more representative of measles virus circulating among humans than are the viruses selected in Vero cells.
Identification of stimulatory T-cell epitopes recognized by CD4+ T lymphocytes is important for vaccine development. Our previous studies using mass spectrometry identified a naturally processed HLA class II restricted DRB1*0301 T cell epitope in the measles virus phosphoprotein, MV-P1 (residues 179-197). Here we provide lymphocyte proliferation data from peripheral blood mononuclear cells (PBMC) obtained from 131 HLA-DRB1*0301-positive and HLA-DRB1*0301-negative (HLA discordant) individuals previously immunized against measles and report that a single amino acid substitution in the MV-P1 T cell epitope can reduce T cell proliferation and CD4+ T-cell recognition. Measles virus and measles peptide-specific lymphoproliferative responses and HLA-DRB1 allele associations reveal that the DRB1*0701 allele provided suggestive evidence of association with both measles virus (p = 0.03) and MV-P1 peptide (p = 0.06) lymphoproliferation. A marginally significant increase in the frequency of the *0301 allele (p = 0.10) was found among subjects who demonstrated low cellular responses to the measles virus. We found no associations between proliferation levels to the MV-P1 and MV-P2 peptides with *0301 alleles. We speculate that the glutamic acid at position 192 of the measles phosphoprotein is a critical immunogenicity factor and may influence the antigenicity of the naturally processed HLA class II MV-P1 epitope.
measles; HLA class II epitopes; cellular immunity; measles peptides; T-cell recognition
Two cellular proteins, membrane cofactor protein (MCP) and moesin, were reported recently to be functionally associated with the initiation of a measles virus infection. We have analyzed the interaction of measles virus with cell surface proteins, using an overlay binding assay with cellular proteins immobilized on nitrocellulose. Among surface-biotinylated proteins from a human rectal tumor cell line (HRT), measles virus was able to bind only to a 67-kDa protein that was identified as MCP. The virus recognized different isoforms of MCP expressed from human (HRT and HeLa) and simian (Vero) cell lines. The binding of measles virus to MCP was abolished after cleavage of the disulfide bonds by reducing agents as well as after enzymatic release of N-linked oligosaccharides. By contrast, removal of sialic acid or O-linked oligosaccharides did not affect the recognition of MCP measles virus. These data indicate that the receptor determinant of MCP is dependent on a conformation of the protein that is maintained by disulfide bonds and N-glycans present in the complement binding domains. Our results are consistent with a role of MCP as primary attachment site for measles virus in the initial stage of an infection. The functional relationship between MCP and moesin in a measles virus infection is discussed.
The biological activity of monoclonal antibodies specific for the hemagglutinin protein of measles virus strain CAM recognizing six epitope groups according to their binding properties to measles virus strain CAM/R401 was investigated in vivo in our rat model of measles encephalitis. When injected intraperitoneally into measles virus-infected suckling rats, some monoclonal antibodies modified the disease process and prevented the necrotizing encephalopathy seen in untreated animals. The analysis of measles virus brain isolates revealed emergence of variants that resisted neutralization with the passively transferred selecting monoclonal antibody but not with other monoclonal antibodies. Monoclonal antibody escape mutants were also isolated in vitro, and their neurovirulence varied in the animal model. Sequence data from the hemagglutinin gene of measles virus localize a major antigenic surface determinant of the hemagglutinin protein between amino acid residues 368 and 396, which may be functionally important for neurovirulence. The data indicate that the interaction of antibodies with the measles virus H protein plays an important role in the selection of neurovirulent variants. These variants have biological properties different from those of the parent CAM virus.
Background. In 2010, Zambia had a large measles outbreak, providing an opportunity to measure changes in measles serostatus following highly active antiretroviral therapy (HAART), exposure to measles virus, and revaccination among children infected with human immunodeficiency virus (HIV).
Methods. A prospective cohort study of 169 HIV-infected Zambian children aged 9–60 months with a history of measles vaccination was conducted to characterize the effects of HAART and revaccination on measles immunoglobulin G (IgG) serostatus by enzyme immunoassay.
Results. Prior to the measles outbreak, only 23% of HIV-infected children were measles IgG seropositive at HAART initiation. After adjusting for 6-month changes in baseline age and 5% changes in nadir CD4+ T-cell percentage, HAART was not associated with measles IgG seroconversion. However, 18 of 19 children seroconverted after revaccination. Eight children seroconverted during the outbreak without revaccination and were likely exposed to wild-type measles virus, but none were reported to have had clinical measles.
Conclusions. Immune reconstitution after HAART initiation did not restore protective levels of measles IgG antibodies, but almost all children developed protective antibody levels after revaccination. Some previously vaccinated HIV-infected children had serological evidence of exposure to wild-type measles virus without a reported history of measles.
measles; HIV; antiretroviral therapy; immune reconstitution; antibody; outbreak
Despite the availability of measles vaccines, infants continue to die from measles. Measles vaccine responses vary between individuals, and poor immunogenicity is likely to preclude protection against measles. CD46 is a ubiquitously expressed specific receptor for vaccine strains of measles virus. CD46 polymorphisms have not been functionally investigated but may affect CD46 protein expression, which in turn may mediate primary measles antibody responses in infants. In a cohort of children aged 12 to 14 months from Perth, Australia (n = 137), after their first dose of measles-mumps-rubella (MMR) vaccine, CD46 polymorphisms were genotyped, and postvaccination measles IgG and CD46 protein expression before and after measles lysate stimulation of cells were measured. Three CD46 variants (rs7144, rs11118580, and rs2724384) were significantly associated with measles virus-specific IgG levels (P = 0.008, P = 0.026, and P = 0.018, respectively). There were significant differences between CD46 rs7144 genotypes and CD46 protein expression on T cells, as well as the downregulation of CD46 and T-cell frequency after measles lysate stimulation. We show that CD46 polymorphisms were associated with primary measles antibody responses in naive infants. We also report the first association of a measles virus receptor polymorphism with functional effects on the receptor, suggesting a possible mechanism through which antibody responses are altered. Elucidating all of the interconnecting genetic factors that alter primary measles vaccine responses may be important for identifying children at risk of poor immunogenicity or vaccine failure and for the future design of vaccine strategies to help these children.
AIMS: To determine the specificity of persistent measles virus infection in intestinal samples from Crohn's disease patients using quantitative immunogold electron microscopy. To compare the results with samples from ulcerative colitis, a granulomatous inflammatory control (tuberculous lymphadenitis), and a positive control. METHODS: Formalin fixed, paraffin embedded intestinal tissue from patients with Crohn's disease was reprocessed and stained with antimeasles nucleocaspid protein primary antibody followed by 10 nm gold conjugated secondary antibody. Tissue samples were taken from granulomatous and non-granulomatous areas of the intestine. Intestinal samples from patients with ulcerative colitis, tuberculous lymphadenitis, or acute mesenteric ischaemia were similarly processed. Brain tissue from a patient with subacute sclerosing panencephalitis (SSPE) was used as the positive control. Duplicate sections of all tissues were processed without the primary antibody. Stained specimens were examined by electron microscopy. RESULTS: In Crohn's disease patients, 8/9 foci of granulomatous inflammation and 0/4 foci of non-specific inflammation were positive for measles virus. Of controls, 0/5 non-inflamed intestinal tissues, 1/8 tuberculous tissues, 1/5 ulcerative colitis tissues, and 1/1 SSPE tissues were positive. Gold grain counts per nuclear field-of-view in both Crohn's disease granulomas (43.29) and SSPE (36.94) were significantly higher than in tissues from patients with ulcerative colitis (13.52) or tuberculous lymphadenitis (15.875), and nongranulomatous areas of Crohn's disease (4.89) (p < 0.001, p < 0.001, p = 0.0006, respectively), with no significant difference between Crohn's disease and SSPE (p > 0.1). In both SSPE and Crohn's disease staining was confined to a small population of cells exhibiting characteristic cytopathology. CONCLUSION: These data support a role for measles virus in the aetiology of Crohn's disease.
Measles virus (MV) infection of U937 cell or peripheral blood leukocyte cultures was shown to induce changes in the expression of leukocyte function antigen 1 (LFA-1) and cause marked aggregation of these cells. Addition of selected monoclonal antibodies specific for LFA-1 epitopes that did not neutralize MV in standard neutralization assays were found to block both virus-induced leukocyte aggregation and virus dissemination. These data suggest that MV modulation of LFA-1 expression on leukocytes may be an important step in MV pathogenesis.
Pre-existing antiviral antibodies in cancer patients can quickly neutralize oncolytic measles virus (MV) and decrease its anti-tumor potency. In contrast to `naked' viruses, cell-associated viruses are protected from antibody neutralization. Hence, we hypothesized that measles virotherapy of ovarian cancer in measles immune mice might be superior if MV infected mesenchymal stem cell (MSC) carriers are used.
Antimeasles antibodies titers in ovarian cancer patients were determined. The protection of MV by MSC from antimeasles antibodies, the in vivo biodistribution profiles and tumor infiltration capability of MSC were determined. Measles naïve or immune tumor-bearing mice were treated with naked virus or MSC-associated virus and mice survivals were compared.
MSC transferred MV infection to target cells via cell-to-cell heterofusion and induced syncytia formation in the presence of high titers of antimeasles antibody; at levels which completely inactivated naked virus. Athymic mice bearing intraperitoneal human SKOV3ip.1 ovarian tumor xenografts passively immunized with measles immune human serum were treated with saline, naked MV or MV infected MSC. Bioluminescent and fluorescent imaging data indicated that intraperitoneally administered MSC localized to peritoneal tumors, infiltrated into the tumor parenchyma and transferred virus infection to tumors in measles naïve and passively immunized mice. Survival of the measles immune mice was significantly enhanced by treatment with MV-infected MSC. In contrast, survivals of passively immunized mice were not prolonged by treatment with naked virus or uninfected MSC.
MSC should be used as carriers of MV for intraperitoneal virotherapy in measles-immune ovarian cancer patients.
Mesenchymal stem cells; oncolytic measles virus; ovarian cancer; virus neutralizing antibodies