The ability of T helper (TH) precursor cells to differentiate into T effector populations confers the adaptive immune system with a means to protect the host from microbes and react to “foreign” antigenic tissues. T-cell immunoglobulin and mucin domain (TIM) proteins have recently been shown to be novel and critical regulators of T cell subset-driven dependent immune responsiveness. A dichotomy is emerging as to how Tim-3– and Tim-2– related signals respectively impact TH1 and TH2 responses. By comparison, the influence of the Tim-1 pathway seems to be broader and is probably not restricted to a specific type of T helper response. Beyond the mere control of the TH1/TH2 balance, Tim proteins are likely to target other regulatory components of the T cell response. Likewise, it is tempting to speculate that Tim proteins might also modulate the function of other T helper cell subsets such as TH3, TR1 and TH17 cells, among others.
Immunity; T cell; T-cell immunoglobulin mucin proteins
Although permanent engraftment is often achieved with new therapeutics, chronic rejection and graft failure still occur. As the importance of CD8+ cells in rejection processes has been underlined in various transplant models, and as interleukin (IL)-15 is involved in the activation of CD8+ T cells, we hypothesize that CD8+ T cell "escape" from costimulation blockade might be a IL-15/IL-15R dependent process.
In a murine islet allograft model employing a fully major histocompatibility complex-mismatched strain combination of Balb/c donors to CD4−/− C57BL/6 recipients, a monotherapy with the IL-15 antagonist, IL-15 mutant/ Fcγ2a, or the costimulatory blockade molecule, CTLA4/Fc, was used. In addition to monitoring graft survival, infiltration of alloreactive immune cells was analyzed by histology and immunohistochemistry, and alloimmune response of proliferative CD8+ T cells was measured in vivo.
Sixty percent of the recipients treated with CTLA4/Fc acutely rejected their islet allograft, comparable to untreated control animals (50% survival). In contrast, the IL-15 antagonist proved to be highly effective, with 100% of recipients accepting their allograft. Immunohistology study demonstrated a remarkable decrease of CD8+ T-Cell intragraft infiltration in IL-15 mutant/Fcγ2a treated animals with well-preserved islet architecture and a reduced frequency of proliferating alloreactive CD8+ T cells in comparison with that of untreated and CTLA4/Fc treated groups.
In this study, we determined the efficacy and potential therapeutic benefit of the IL-15 antagonist on CD4-independent CD8+ T-cell responses to alloantigens. Targeting the IL-15/IL-15R pathway represents a potent strategy to prevent rejection driven by CD8+ T cells resistant to costimulation blockade.
Tolerance; Suppression; T-lymphocytes; Cytokines; Immunotherapy
IL-27 promotes the differentiation of monocytes to HIV-resistant macrophages by down-regulating host factor SPTBN1.
The susceptibility of macrophages to HIV-1 infection is modulated during monocyte differentiation. IL-27 is an anti-HIV cytokine that also modulates monocyte activation. In this study, we present new evidence that IL-27 promotes monocyte differentiation into macrophages that are nonpermissive for HIV-1 infection. Although IL-27 treatment does not affect expression of macrophage differentiation markers or macrophage biological functions, it confers HIV resistance by down-regulating spectrin β nonerythrocyte 1 (SPTBN1), a required host factor for HIV-1 infection. IL-27 down-regulates SPTBN1 through a TAK-1–mediated MAPK signaling pathway. Knockdown of SPTBN1 strongly inhibits HIV-1 infection of macrophages; conversely, overexpression of SPTBN1 markedly increases HIV susceptibility of IL-27–treated macrophages. Moreover, we demonstrate that SPTBN1 associates with HIV-1 gag proteins. Collectively, our results underscore the ability of IL-27 to protect macrophages from HIV-1 infection by down-regulating SPTBN1, thus indicating that SPTBN1 is an important host target to reduce HIV-1 replication in one major element of the viral reservoir.
Differentiation and clonal expansion of Ag-activated naive T cells play a pivotal role in the adaptive immune response. T cell Ig mucin (Tim) proteins influence the activation and differentiation of T cells. Tim-3 and Tim-2 clearly regulate Th1 and Th2 responses, respectively, but the precise influence of Tim-1 on T cell activation remains to be determined. We now show that Tim-1 stimulation in vivo and in vitro induces polyclonal activation of T cells despite absence of a conventional TCR-dependent signal 1. In this model, Tim-1-induced proliferation is dependent on strong signal 2 costimulation provided by mature dendritic cells. Ligation of Tim-1 upon CD4+ T cells with an agonist anti-Tim-1 mAb elicits a rise in free cytosolic calcium, calcineurin-dependent nuclear translocation of NF-AT, and transcription of IL-2. Because Tim-4, the Tim-1 ligand, is expressed by mature dendritic cells, we propose that interaction between Tim-1+ T cells and Tim-4+ dendritic cells might ensure optimal stimulation of T cells, when TCR-derived signals originating within an inflamed environment are weak or waning.
The critical roles of TGF-β in the reciprocal differentiation of tolerance-promoting CD4+Foxp3+ regulatory T cells (Treg) and pro-inflammatory Th17 effector cells impact alloimmune reactivity and transplant outcome. We reasoned that a strategy that harnessed TGF-β and blocked pro-inflammatory cytokines would inhibit the differentiation of Th17 cells and strengthen the cadre of Treg to promote tolerance induction and long-term allograft survival. Herein we report the development of a novel, long-lasting auto-active human mutant TGF-β1/Fc fusion protein that acts in conjunction with rapamycin to inhibit T cell proliferation and induce the de novo generation of Foxp3+ Treg in the periphery, while at the same time inhibiting IL-6-mediated Th17 cell differentiation. Short-term combined treatment with TGF-β1/Fc and rapamycin achieved long-term pancreatic islet allograft survival and donor-specific tolerance in a mouse model. This effect was accompanied by expansion of Foxp3+ Treg, enhanced alloantigen-specific Treg function, and modulation of transcript levels of Foxp3, IL-6 and IL-17. Our strategy of combined TGF-β1/Fc and rapamycin to target the IL-6-related Treg and Th17 signaling pathways provides a promising approach for inducing transplant tolerance and its clinical application.
Resistance to cytotoxic agents has long been known to be a major limitation in the treatment of human cancers. Although many mechanisms of drug resistance have been identified, chemotherapies targeting known mechanisms have failed to lead to effective reversal of drug resistance, suggesting that alternative mechanisms remain undiscovered. Previous work identified midkine (MK) as a novel putative survival molecule responsible for cytoprotective signaling between drug-resistant and drug-sensitive neuroblastoma, osteosarcoma and breast carcinoma cells in vitro. In the present study, we provide further in vitro and in vivo studies supporting the role of MK in neuroblastoma cytoprotection. MK overexpressing wild type neuroblastoma cells exhibit a cytoprotective effect on wild type cells when grown in a co-culture system, similar to that seen with doxorubicin resistant cells. siRNA knockdown of MK expression in doxorubicin resistant neuroblastoma and osteosarcoma cells ameliorates this protective effect. Overexpression of MK in wild type neuroblastoma cells leads to acquired drug resistance to doxorubicin and to the related drug etoposide. Mouse studies injecting various ratios of doxorubicin resistant or MK transfected cells with GFP transfected wild type cells confirm this cytoprotective effect in vivo. These findings provide additional evidence for the existence of intercellular cytoprotective signals mediated by MK which contribute to chemotherapy resistance in neuroblastoma.
To tilt the immunologic balance towards tolerance and away from rejection, nonhuman primate recipients of cardiac allografts were treated with IL-2/Fc, mutant antagonist type (m) IL-15/Fc and sirolimus.
Heterotopic heart transplants were performed on fully mismatched cynomolgus macaques (n=8). An untreated control recipient rejected its graft by postoperative day 6. The remaining seven animals received immunosuppression with sirolimus, administered either orally or intramuscularly. A recipient treated with sirolimus alone rejected at the end of a 28 day course of immunosuppression. The remaining six monkeys also received IL-2/Fc and mIL-15/Fc intramuscularly until 28 days after transplant. In one animal, a second 28-day course of fusion protein was given starting at day 50. In these six animals, sirolimus was continued for either 28 days (n=4) or until protein levels were low (n=2).
In the four monkeys treated with a 28-day course of sirolimus and fusion proteins, mean graft survival was 51.5 (range 28-76) days. The animal receiving a second course of fusion protein rejected its graft on day 177 despite detectable levels of the fusion proteins and sirolimus. The central memory, effector memory and naïve CD4+ and CD8+ T-cell populations in peripheral blood did not change significantly during the period of fusion protein administration. However, a 2.5-fold expansion in CD4+CD25+ lymphocytes occurred in recipients treated with fusion proteins and sirolimus which was not observed in the recipient treated with sirolimus alone.
Although IL-2/Fc, mIL-15/Fc and sirolimus administered in this manner permits modest prolongation of graft survival and expansion of CD4+CD25+ T cells, tolerance was not achieved.
heart; transplantation; IL-15; primates; rejection
Nonstructural protein 3 (NS3) of hepatitis C virus (HCV), codes for protease and helicase carrying NTPase enzymatic activities, plays a crucial role in viral replication and an ideal target for diagnosis, antiviral therapy and vaccine development. In this study, monoclonal antibodies (mAbs) to NS3 helicase were characterized by epitope mapping and biological function test. A total of 29 monoclonal antibodies were produced to the truncated NS3 helicase of HCV-1b (T1b-rNS3, aa1192–1459). Six mAbs recognized 8/29 16mer peptides, which contributed to identify 5 linear and 1 discontinuous putative epitope sequences. Seven mAbs reacted with HCV-2a JFH-1 infected Huh-7.5.1 cells by immunofluorescent staining, of which 2E12 and 3E5 strongly bound to the exposed linear epitope 1231PTGSGKSTK1239 (EP05) or core motif 1373IPFYGKAI1380 (EP21), respectively. Five other mAbs recognized semi-conformational or conformational epitopes of HCV helicase. MAb 2E12 binds to epitope EP05 at the ATP binding site of motif I in domain 1, while mAb 3E5 reacts with epitope EP21 close to helicase nucleotide binding region of domain 2. Epitope EP05 is totally conserved and EP21 highly conserved across HCV genotypes. These two epitope peptides reacted strongly with 59–79% chronic and weakly with 30–58% resolved HCV infected blood donors, suggesting that these epitopes were dominant in HCV infection. MAb 2E12 inhibited 50% of unwinding activity of NS3 helicase in vitro. Novel monoclonal antibodies recognize highly conserved epitopes at crucial functional sites within NS3 helicase, which may become important antibodies for diagnosis and antiviral therapy in chronic HCV infection.
Streptococcus suis (S.suis) is an important emerging worldwide pig pathogen and zoonotic agent with rapid evolution of virulence and drug resistance. In this study, we wanted to investigate the effect of licochalcone A on growth and properties of Streptococcus suis. The antimicrobial activity of licochalcone A was tested by growth inhibition assay and the minimal inhibitory concentrations (MICs) also were determined. The effect of licochalcone A on S.suis biofilm formation was characterized by crystal violet staining. The effect of licochalcone A on suilysin secretion was evaluated by titration of hemolytic activity. To understand the antimicrobial effect, gene expression profile of S.suis treated by licochalcone A was analyzed by DNA microarray. Our results demonstrated that licochalcone A showed antimicrobial activity on S.suis with MICs of 4 µg/ml for S.suis serotype 2 strains and 8 µg/ml for S.suis serotype 7 strains. Biofilm formation was inhibited by 30–40% in the presence of licochalcone A (3 µg/ml) and suilysin secretion was also significantly inhibited in the presence of licochalcone A (1.5 µg/ml). The gene expression profile of S.suis in the presence of licochalcone A showed that 132 genes were differentially regulated, and we analyzed the regulated genes in the aspect of the bacterial cell cycle control. Among the deregulated genes, the genes responsible for the mass doubling was increased expression, but the genes responsible for DNA replication and cell division were inhibited the expression. So, we think the regulation of the cell cycle genes might provide a mechanistic understanding of licochalcone A mediated antimicrobial effect against S.suis.
F-box and WD repeat domain-containing 7 (Fbxw7/hAgo/hCdc4/Fbw7) is a p53-dependent tumor suppressor and leads to ubiquitination-mediated suppression of several oncoproteins including c-Myc, cyclin E, Notch, c-Jun and others. Our previous study has indicated that low expression of Fbxw7 was negatively correlated with c-Myc, cyclin E and mutant-p53 in hepatocellular carcinoma (HCC) tissues. But the role and mechanisms of Fbxw7 in HCC are still unknown. Here, we investigated the function of Fbxw7 in HCC cell lines and the anti-tumor activity of recombinant human adenovirus-p53 injection (rAd-p53, Gendicine) administration in vitro and in vivo. Fbxw7-specific siRNA enhanced expression of c-Myc and cyclin E proteins and increased proliferation in cell culture. rAd-p53 inhibited tumor cell growth with Fbxw7 upregulation and c-Myc and cyclin E downregulation in vitro and a murine HCC model. This effect could be partially reverted using Fbxw7-specific siRNA. Here, we suggest that the activation of Fbxw7 by adenoviral delivery of p53 leads to increased proteasomal degradation of c-Myc and cyclin E enabling growth arrest and apoptosis. Addressing this pathway, we identified that rAd-p53 could be a potential therapeutic agent for HCC.
It has been suggested that different hepatitis B virus (HBV) genotypes may have distinct virological characteristics that correlate with clinical outcomes during antiviral therapy and the natural course of infection. Hydrodynamic injection (HI) of HBV in the mouse model is a useful tool for study of HBV replication in vivo. However, only HBV genotype A has been used for studies with HI.
We constructed 3 replication-competent clones containing 1.1, 1.2 and 1.3 fold overlength of a HBV genotype B genome and tested them both in vitro and in vivo. Moreover, A HBV genotype B clone based on the pAAV-MCS vector was constructed with the 1.3 fold HBV genome, resulting in the plasmid pAAV-HBV1.3B and tested by HI in C57BL/6 mice. Application of siRNA against HBx gene was tested in HBV genotype B HI mouse model.
The 1.3 fold HBV clone showed higher replication and gene expression than the 1.1 and 1.2 fold HBV clones. Compared with pAAV-HBV1.2 (genotype A), the mice HI with pAAV-HBV1.3B showed higher HBsAg and HBeAg expression as well as HBV DNA replication level but a higher clearance rate. Application of two plasmids pSB-HBxi285 and pSR-HBxi285 expressing a small/short interfering RNA (siRNA) to the HBx gene in HBV genotype B HI mouse model, leading to an inhibition of HBV gene expression and replication. However, HBV gene expression may resume in some mice despite an initial delay, suggesting that transient suppression of HBV replication by siRNA may be insufficient to prevent viral spread, particularly if the gene silencing is not highly effective.
Taken together, the HI mouse model with a HBV genotype B genome was successfully established and showed different characteristics in vivo compared with the genotype A genome. The effectiveness of gene silencing against HBx gene determines whether HBV replication may be sustainably inhibited by siRNA in vivo.
Hydrodynamic injection; HBV mouse model; HBV genotype B; HBx gene silencing; Antiviral research
An ‘anomalous' negative flux, in which carbon dioxide (CO2) enters rather than is released from the ground, was studied in a saline/alkaline soil. Soil sterilization disclosed an inorganic process of CO2 dissolution into (during the night) and out of (during the day) the soil solution, driven by variation in soil temperature. Experimental and modeling analysis revealed that pH and soil moisture were the most important determinants of the magnitude of this inorganic CO2 flux. In the extreme cases of air-dried saline/alkaline soils, this inorganic process was predominant. While the diurnal flux measured was zero sum, leaching of the dissolved inorganic carbon in the soil solution could potentially effect net carbon ecosystem exchange. This finding implies that an inorganic module should be incorporated when dealing with the CO2 flux of saline/alkaline land. Neglecting this inorganic flux may induce erroneous or misleading conclusions in interpreting CO2 fluxes of these ecosystems.
The ulnar styloid is an important supportive structure for the triangular fibrocartilage complex. However, it remains inconclusive whether or not a fractured ulnar styloid should be fixed in an unstable distal radius fracture (DRF) with a stable distal radioulnar joint (DRUJ). The purpose of this study is to evaluate the effect of an untreated ulnar styloid fracture on the outcome of unstable DRF treated with transarticular external fixation when the DRUJ is stable.
106 patients with an unstable DRF and a stable DRUJ were included in this study following external fixation. The patients were divided into the non-fracture, the tip-fracture and the base-fracture groups according to the location of the ulnar styloid fracture at the time of injury. Postoperative evaluation included the range of wrist motion, the radiological index, the grip strength, the PRWE-HK scores, the wrist pain scores, and the instability of DRUJ at the external fixator removal time, three months postoperatively and the final follow-up visit.
The patients were followed for 12 to 24 months (15 months in average). Sixty-two of 106 patients (58%) had ulnar styloid fracture and 16 patients (26%) showed radiographic evidence of union of ulnar styloid fractures at the final follow-up visit. No significant difference in the radiological findings, the range of wrist motion, the grip strength, the PRWE-HK scores, and the wrist pain scores among three patient groups was detected at the external fixator removal time, three months postoperatively, or the final follow-up visit. Six of the 106 patients (5.7%) complained of persistent ulnar-side wrist pain during daily activities. One patient (0.9%) showed a positive sign in a stress-test, three patients (2.8%) showed a positive sign in a provocative-test, and five patients (4.7%) showed a positive sign in a press-test. There was no significant difference in the percentages of patients who complained of persistent ulnar-side wrist pain or showed a positive sign in the physical examination of the distal radioulnar joint among the three groups at the final follow-up time points.
When the DRUJ is stable, an untreated ulnar styloid fracture does not affect the wrist outcome of the patient with an unstable DRF treated with external fixation.
Distal radius fracture; Ulnar styloid fracture; External fixation
Summary of background data
The curve pattern of idiopathic scoliosis is important for making decisions concerning bracing. However, whether the curve pattern changes during brace treatment have not been fully documented. The aim of this study was to investigate the changes of curve pattern during brace treatment in skeletally immature patients with adolescent idiopathic scoliosis (AIS).
From January 2002 to January 2011, AIS patients treated with a Boston or Milwaukee brace were recruited after meeting the following inclusion criteria: older than 10 years of age at initiation of bracing; having a Cobb angle of 25°–40°; with a Risser sign 0–2; being regularly followed until the weaning of brace or the necessity of surgical treatment; and without history of previous treatment. A total of 130 female and 11 male AIS patients were included. The mean age was 12.9 years at initiation of bracing, and the female patients were, on average, 2.7 months past menarche. The mean follow-up period was 2.6 years (range 1.0–5.5 years). The definitions of changes in curve patterns were divided into four categories as follows: (1) shift of the apex of the main curve; (2) change in the curve span of more than two vertebrae; (3) change in the main curve type with regard to the apex location; and (4) change of curve direction. The patients were divided into two groups. Group A was comprised of patients who had experienced one or more categories of curve pattern changes, and Group B was comprised of those who had not.
Of these 39 patients, 14 had apex shifting, 2 underwent curve span changes, 22 experienced changes in the main curve type, and one female had both changes in the apex and curve span. At the initiation of bracing, patients in Group A demonstrated significantly lower menarchal status (P = 0.018) and lower Risser grade (P = 0.025) than those in Group B. The difference in the percentage of patients who underwent Boston bracing between the two groups was statistically significant (41.5 % for Group A vs. 24.0 % for Group B, P = 0.023).
Changes in curve pattern can occur during brace treatment. Patients with less skeletal maturity and those treated with a Boston brace are more susceptible to this phenomenon.
Adolescent idiopathic scoliosis; Brace treatment; Curve pattern
Description of syrinx resolution after posterior fossa decompression (PFD) in patients with scoliosis secondary to Chiari malformation type I (CMI) and syringomyelia (SM) has been rarely reported in the literature. This study was performed to investigate the outcome of PFD in patients with scoliosis secondary to CMI and to identify potential predictive factors for better outcome after PFD.
Material and methods
Patients with scoliosis secondary to CMI and SM, who had undergone PFD during the period 2000 through 2009, were recruited. Inclusion criteria were (1) age ≤ 18 years, (2) diagnosis of SM associated with CMI, (3) scoliosis as the first complaint, (4) having undergone preoperative and follow-up magnetic resonance imaging (MRI). Patients with acquired CMI anomalies or who had received syringosubarachnoid shunting were excluded. The maximal S/C ratio and syrinx length were measured to evaluate syrinx resolution after PFD. A 20% decrease in S/C ratio or length at the latest follow-up was defined as a significant radiographic improvement and complete resolution was used to describe the syrinx disappearing after PFD.
44 patients were recruited. Follow-up MRI was conducted for all 44 patients at 6 ± 3 months postoperatively, for 37 patients at 2 years ± 3 months, for 26 patients at 4 years ± 3 months, and for 15 patients at 6 years ± 3 months. 97.7% (43 of 44) of patients showed significant radiographic improvement by MRI. The distance of tonsillar descent (mm) was correlated significantly with the surgical outcome (r = 0.116, P = 0.013). Significant improvement was observed within 6 months postoperatively, with continued slow improvement after that.
Syringes showed significant improvement after PFD in most patients with scoliosis secondary to CMI. Resolution generally occurred within 6 months follow-up and continued at a slow rate for several years. In addition, the severity of tonsillar descent is a potential predictor for better improvement after standard PFD.
Resolution; Syrinx; Chiari malformation type I; Syringomyelia; Scoliosis; Posterior fossa decompression
A novel route was introduced to synthesize dense polyacrylamide (PAM) onto the glass slide surface. To investigate the surface chemistry of the PAM on the glass slides, X-ray photoelectron spectroscopy (XPS) was utilized to obtain detailed chemical state information on the PAM layer constituents. The XPS peak data were consistent with the presented model of the PAM on the glass slide surface. Scanning electron microscopy and atomic force microscope data indicated the presence of PAM on the glass slides, which consist of nodules. The results showed that PAM was successfully immobilized onto glass slides with a two-tier structure under aqueous condition and a monolayer structure under anhydrous condition. Compared with those under aqueous condition, the controllability of the molecular layer on glass slides and the reproducibility under anhydrous condition were much better, which makes anhydrous condition an advisable condition for the study of the reaction mechanisms of glass slides modified by PAM.
Glass slide; Polyacrylamide; Surface analysis; XPS; SEM; AFM
Bioactive peptides, either derived from nature resources or synthesized by rational design, have been demonstrated potential for therapeutic agents against numerous human diseases, including cancer. However, the mechanism of therapeutic peptides against cancer has not been well elucidated. Here we show that PGPIPN, a hexapeptide derived from bovine β-casein, inhibited the proliferation of human ovarian cancer cells line SKOV3 as well as the primary ovarian cancer cells in vitro. Consistently, PGPIPIN also decreased tumor growth rate in xenograft ovarian cancer model mice in a dose-dependent manner. Further study demonstrated that the anti-tumor effect of PGPIPN is partially through promoting cell apoptosis by inhibiting BCL2 pathway. Thus, our study suggests that PGPIPN is a potential therapeutic agent for the treatment of ovarian cancer or other types of cancer.
Novel magnetic-antimicrobial-fluorescent multifunctional hybrid microspheres with well-defined nanostructure were synthesized by the aid of a poly(glycidyl methacrylate) (PGMA) template. The hybrid microspheres were fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD) and digital fluorescence microscope. The as-synthesized microspheres PGMA, amino-modified PGMA (NH2-PGMA) and magnetic PGMA (M-PGMA) have a spherical shape with a smooth surface and fine monodispersity. M-PGMA microspheres are super-paramagnetic, and their saturated magnetic field is 4.608 emu·g−1, which made M-PGMA efficiently separable from aqueous solution by an external magnetic field. After poly(haxemethylene guanidine hydrochloride) (PHGH) functionalization, the resultant microspheres exhibit excellent antibacterial performance against both Gram-positive and Gram-negative bacteria. The fluorescence feature originating from the quantum dot CdTe endowed the hybrid microspheres with biological functions, such as targeted localization and biological monitoring functions. Combination of magnetism, antibiosis and fluorescence into one single hybrid microsphere opens up the possibility of the extensive study of multifunctional materials and widens the potential applications.
poly(glycidyl methacrylate); magnetic; antibacterial; fluorescent; multifunctional; hybrid microspheres
Organ/tissue transplantation has become an effective therapy for end-stage diseases. However, immunosuppression after transplantation may cause severe side effects. Donor-specific transplant tolerance was proposed to solve this problem. In this study, we report a novel method for inducing and maintaining heart allograft tolerance rats. First, we induced indefinite vascularized hind-limb allograft survival with a short-term antilymphocyte serum + Cyclosporine A treatment. Peripheral blood chimerism disappeared 6-7 weeks after immunosuppression was withdrawn. Then the recipients accepted secondary donor-strain skin and heart transplantation 200 days following vascularized hind-limb transplantation without any immunosuppression, but rejected third party skin allografts, a status of donor-specific tolerance. The ELISPOT results suggested a mechanism of clone deletion. These findings open new perspectives for the role of vascularized hind-limb transplant in the induction and maintenance of organ transplantation tolerance.
The emerging field of vascular composite allotransplantation (VCA) has become a clinical reality. Building upon cutting edge understandings of transplant surgery and immunology, complex grafts such as hands and faces can now be transplanted with success. Many of the challenges that have historically been limiting factors in transplantation, such as rejection and the morbidity of immunosuppression, remain challenges in VCA. Because of the accessibility of most VCA grafts, and the highly immunogenic nature of the skin in particular, VCA has become the focal point for cross-disciplinary approaches to developing novel approaches for some of the most challenging immunological problems in transplantation, particularly the early diagnoses and assessment of rejection. This paper provides a historically oriented introduction to the field of organ transplantation and the evolution of VCA.
Skin is the most immunogenic component of a vascularized composite allograft (VCA) and is the primary trigger and target of rejection.
The skin is directly accessible for visual monitoring of acute rejection (AR) and for directed biopsy, timely therapeutic intervention, and management of AR.
Logically, antirejection drugs, biologics, or other agents delivered locally to the VCA may reduce the need for systemic immunosuppression with its adverse effects.
Topical FK 506 (tacrolimus) and steroids have been used in clinical VCA as an adjunct to systemic therapy with unclear beneficial effects. However, there are no commercially available topical formulations for other widely used systemic immunosuppressive drugs such as mycophenolic acid, sirolimus, and everolimus. Investigating the site-specific therapeutic effects and efficacy of systemically active agents may enable optimizing the dosing, frequency, and duration of overall immunosuppression in VCA with minimization or elimination of long-term drug-related toxicity.
Immunotherapy has been used to improve patient immune function, inhibit tumor growth and has become a highly promising method of cancer treatment. Highly agglutinative staphylococcin (HAS), a mixture of Staphylococcus aureus culture filtrates, which include staphylococcal enterotoxin (SE) C as the active ingredient, has been used clinically as an immunomodifier in the treatment of a number of tumors for many years. However, the use of HAS has been associated with some unavoidable side-effects such as fever. Previous studies have shown that SEB stimulates a more potent activation of T lymphocytes than SEC3, and mutations of the histidine residues eliminated the toxicity of SEB. SE mutants with decreased side-effects and/or more potent antitumor activities are required.
We built a structural model of the MHC II-SEB-TCR complex and found that a mutation of SEB at Lys173 might decrease the repulsion force between the SEB-TCR, which would facilitate their interaction. From the above results, we designed SEB-H32Q/K173E (mSEB). Analysis of in vitro stimulation of the proliferation of human peripheral blood mononuclear cells (PBMCs), IFN-γ secretion and inhibition of the growth of various tumor cell lines demonstrated that mSEB exhibited higher antitumor activity compared with wild-type SEB (wtSEB). Notably, mSEB inhibited the growth of various tumors at an extremely low concentration with little cytotoxicity against normal cells. Three animal tumor models (C57BL/6 mouse, New Zealand rabbit and a humanized NOD/SCID mouse) were used to evaluate the in vivo immunotherapeutic effects. Compared with wtSEB, mSEB significantly enhanced antitumor effect in more than one animal model with reduced pyrexia toxicity and prolonged the survival of tumor-bearing mice.
Our results suggest that SEB-H32Q/K173E retains superantigen (SAg) characteristics and enhances the host immune response to neoplastic diseases while reducing associated pyrogenic toxicity.
Japanese encephalitis (JE) was once epidemic in most areas of China, including Wuhan, a city located in the central part of China. The incidence of JE dramatically decreased due to nationwide immunization with the live attenuated JE virus (JEV) vaccine, and no JE cases were reported during 2005–2008 in Wuhan. In 2009 and 2010, 31 JE cases reoccurred in this area. In this study, we investigated the causes of JE recurrence.
Methods and Findings
All JE cases were laboratory-confirmed by detecting the JEV-specific IgM antibody with an IgM-capture enzyme-linked immunosorbent assay (ELISA). All patients were children between 2 months and 9 years of age with a median age of 2 years. Of the 31 cases, 9 had received one or two doses of the JEV vaccine, 11 had not been immunized previously with the JEV vaccine, and 11 had an unclear immunization history. Through reverse transcription polymerase chain reaction (RT-PCR), sequencing, and phylogenetic analysis, two new strains of JEV were isolated from Culex tritaeniorhynchus and identified as genotype 1 JEV, rather than genotype 3, which circulated in this area previously.
Vaccine failure or missed vaccination may have caused JE recurrence. Local centers for disease control and prevention need to improve immunization coverage, and the efficacy of the JE vaccine needs to be reevaluated in a population at risk for disease.
Reconstructive transplantation has emerged as clinical reality over the past decade. Long-term graft acceptance has been feasible in extremity and facial vascularized composite allotransplantation (VCA) under standard immunosuppression. Minimizing overall burden of lifelong immunosuppression is key to wider application of these non-life saving grafts. Allograft tolerance is the holy grail of many cell-based immunomodulatory strategies. Recent protocols using mesenchymal stem cells from bone marrow and adipose tissue offer promise and potential in VCA. This article provides an overview of the experimental basis, the scientific background and clinical applications of stem cell-based therapies in the field of reconstructive allotransplantation.
adipose stem cells; cell-based therapy; immunomodulation; composite tissue allotransplantation; tolerance