The Src-homology 2 (SH2) domain of Csk-family protein tyrosine kinases acts as a conformational switch to regulate their catalytic activity, which in turn promotes the inhibition of their proto-oncogenic targets, the Src-family kinases. Here, the expression, purification, small-angle X-ray scattering and preliminary diffraction analysis of the SH2 domain of the Csk-homologous kinase is reported.

The C-terminal Src kinase (Csk) and Csk-homologous kinase (CHK) are endogenous inhibitors of the proto-oncogenic Src family of protein tyrosine kinases (SFKs). Phosphotyrosyl peptide binding to their Src-homology 2 (SH2) domains activates Csk and CHK, enhancing their ability to suppress SFK signalling; however, the detailed mechanistic basis of this activation event is unclear. The CHK SH2 was expressed in Escherichia coli and the purified protein was characterized as monomeric by synchrotron small-angle X-ray scattering in-line with size-exclusion chromatography. The CHK SH2 crystallized in 0.2 M sodium bromide, 0.1 M bis-Tris propane pH 6.5 and 20% polyethylene glycol 3350 and the best crystals diffracted to ∼1.6 Å resolution. The crystals belonged to space group P2, with unit-cell parameters a = 25.8, b = 34.6, c = 63.2 Å, β = 99.4°.

Background

This study examined the effects of religiosity on the trajectories of depressive symptoms in a sample of community-dwelling older adults over a four-year period in a Southern state in the U.S.

Method

Data from the University of Alabama at Birmingham Study (UAB) of Aging were analyzed using a hierarchical linear modeling (HLM) method. This study involved 1,000 participants aged 65 and older (M age = 75 at baseline, SD = 5.97) and data were collected annually from 1999 through 2003. The Geriatric Depression Scale measured depressive symptoms; the Duke University Religion Index measured religious service attendance, prayer, and intrinsic religiosity; and control variables included sociodemographics, health, and social and economic factors.

Results

The HLM analysis indicated a curvilinear trajectory of depressive symptoms over time. At baseline, participants who attended religious services more frequently tended to report fewer depressive symptoms. Participants with the highest levels of intrinsic religiosity at baseline experienced a steady decline in the number of depressive symptoms over the four-year period, while those with lower levels of intrinsic religiosity experienced a short-term decline followed by an increase in the number of depressive symptoms.

Implications

In addition to facilitating access to health, social support and financial resources for older adults, service professionals might consider culturally-appropriate, patient-centered interventions that boost the salutary effects of intrinsic religiosity on depressive symptoms.

Bapineuzumab is a humanized antibody developed by Pfizer and Johnson & Johnson targeting the amyloid (Aβ) plaques that underlie Alzheimer's disease neuropathology. Here we report the crystal structure of a Fab-Aβ peptide complex that reveals Bapineuzumab surprisingly captures Aβ in a monomeric helical conformation at the N-terminus. Microscale thermophoresis suggests that the Fab binds soluble Aβ(1–40) with a KD of 89 (±9) nM. The structure explains the antibody's exquisite selectivity for particular Aβ species and why it cannot recognize N-terminally modified or truncated Aβ peptides.

Intestinal fatty-acid binding proteins from human and rat have been crystallized in complex with the fluorescent probe 11-(dansylamino)undecanoic acid. Diffraction data for the crystals were collected to 1.8 Å resolution (human) and 1.6 Å resolution (rat).

Fatty-acid binding proteins (FABPs) are abundantly expressed proteins that bind a range of lipophilic molecules. They have been implicated in the import and intracellular distribution of their ligands and have been linked with metabolic and inflammatory responses in the cells in which they are expressed. Despite their high sequence identity, human intestinal FABP (hIFABP) and rat intestinal FABP (rIFABP) bind some ligands with different affinities. In order to address the structural basis of this differential binding, diffraction-quality crystals have been obtained of hIFABP and rIFABP in complex with the fluorescent fatty-acid analogue 11-(dansylamino)undecanoic acid.

Dihydrodipicolinate synthase (DHDPS) is an essential oligomeric enzyme of interest to antibiotic discovery research and studies probing the importance of quaternary structure to protein function, stability and dynamics. The cloning, expression, purification and crystallization of DHDPS from the psychrophilic (cold-dwelling) bacterium Shewanella benthica are described.

Dihydrodipicolinate synthase (DHDPS) is an oligomeric enzyme that catalyzes the first committed step of the lysine-biosynthesis pathway in plants and bacteria, which yields essential building blocks for cell-wall and protein synthesis. DHDPS is therefore of interest to drug-discovery research as well as to studies that probe the importance of quaternary structure to protein function, stability and dynamics. Accordingly, DHDPS from the psychrophilic (cold-dwelling) organism Shewanella benthica (Sb-DHDPS) was cloned, expressed, purified and crystallized. The best crystals of Sb-DHDPS were grown in 200 mM ammonium sulfate, 100 mM bis-tris pH 5.0–6.0, 23–26%(w/v) PEG 3350, 0.02%(w/v) sodium azide and diffracted to beyond 2.5 Å resolution. Processing of diffraction data to 2.5 Å resolution resulted in a unit cell with space group P212121 and dimensions a = 73.1, b = 84.0, c = 143.7 Å. These studies of the first DHDPS enzyme to be characterized from a bacterial psychrophile will provide insight into the molecular evolution of enzyme structure and dynamics.

We report the rational design and in vivo testing of mosaic proteins for a polyvalent pan-filoviral vaccine using a computational strategy designed for the Human Immunodeficiency Virus type 1 (HIV-1) but also appropriate for Hepatitis C virus (HCV) and potentially other diverse viruses. Mosaics are sets of artificial recombinant proteins that are based on natural proteins. The recombinants are computationally selected using a genetic algorithm to optimize the coverage of potential cytotoxic T lymphocyte (CTL) epitopes. Because evolutionary history differs markedly between HIV-1 and filoviruses, we devised an adapted computational technique that is effective for sparsely sampled taxa; our first significant result is that the mosaic technique is effective in creating high-quality mosaic filovirus proteins. The resulting coverage of potential epitopes across filovirus species is superior to coverage by any natural variants, including current vaccine strains with demonstrated cross-reactivity. The mosaic cocktails are also robust: mosaics substantially outperformed natural strains when computationally tested against poorly sampled species and more variable genes. Furthermore, in a computational comparison of cross-reactive potential a design constructed prior to the Bundibugyo outbreak performed nearly as well against all species as an updated design that included Bundibugyo. These points suggest that the mosaic designs would be more resilient than natural-variant vaccines against future Ebola outbreaks dominated by novel viral variants. We demonstrate in vivo immunogenicity and protection against a heterologous challenge in a mouse model. This design work delineates the likely requirements and limitations on broadly-protective filoviral CTL vaccines.

Community engagement is increasingly promoted in developing countries, especially in international health research, but there is little published experience. The Shoklo Malaria Research Unit (SMRU) conducts research with refugees, migrant workers, displaced people, and day migrants on the Thai-Burmese border, and has recently facilitated the set up of the Tak Province Border Community Ethics Advisory Board (T-CAB). Valuable lessons have been learnt from consultation with the T-CAB especially in the area of participant recruitment and the informed consent process. A lot of new research questions have emerged from consultation with the T-CAB. This paper describes our experience, lessons learnt and the unique challenges faced working with the T-CAB from its initial conception to date. We conclude that consultation with the T-CAB has made improvements in our research in particular operational and ethical aspects of our studies.

Background

Seeking consent for genetic and genomic research can be challenging, particularly in populations with low literacy levels, and in emergency situations. All of these factors were relevant to the MalariaGEN study of genetic factors influencing immune responses to malaria in northern rural Ghana. This study sought to identify issues arising in practice during the enrolment of paediatric cases with severe malaria and matched healthy controls into the MalariaGEN study.

Methods

The study used a rapid assessment incorporating multiple qualitative methods including in depth interviews, focus group discussions and observations of consent processes. Differences between verbal information provided during community engagement processes, and consent processes during the enrolment of cases and controls were identified, as well as the factors influencing the tailoring of such information.

Results

MalariaGEN participants and field staff seeking consent were generally satisfied with their understanding of the project and were familiar with aspects of the study relating to malaria. Some genetic aspects of the study were also well understood. Participants and staff seeking consent were less aware of the methodologies employed during genomic research and their implications, such as the breadth of data generated and the potential for future secondary research.

Moreover, trust in and previous experience with the Navrongo Health Research Centre which was conducting the research influenced beliefs about the benefits of participating in the MalariaGEN study and subsequent decision-making about research participation.

Conclusions

It is important to recognise that some aspects of complex genomic research may be of less interest to and less well understood by research participants and that such gaps in understanding may not be entirely addressed by best practice in the design and conduct of consent processes. In such circumstances consideration needs to be given to additional protections for participants that may need to be implemented in such research, and how best to provide such protections.

Capacity building for research ethics committees with limited familiarity with genetic and genomic research, and appropriate engagement with communities to elicit opinions of the ethical issues arising and acceptability of downstream uses of genome wide association data are likely to be important.

The TRIM family of proteins is distinguished by its tripartite motif (TRIM). Typically, TRIM proteins contain a RING finger domain, one or two B-box domains, a coiled-coil domain and the more variable C-terminal domains. TRIM16 does not have a RING domain but does harbour two B-box domains. Here we showed that TRIM16 homodimerized through its coiled-coil domain and heterodimerized with other TRIM family members; TRIM24, Promyelocytic leukaemia (PML) protein and Midline-1 (MID1). Although, TRIM16 has no classic RING domain, three-dimensional modelling of TRIM16 suggested that its B-box domains adopts RING-like folds leading to the hypothesis that TRIM16 acts as an ubiquitin ligase. Consistent with this hypothesis, we demonstrated that TRIM16, devoid of a classical RING domain had auto-polyubiquitination activity and acted as an E3 ubiquitin ligase in vivo and in vitro assays. Thus via its unique structure, TRIM16 possesses both heterodimerization function with other TRIM proteins and also has E3 ubiquitin ligase activity.

Amiloride and its derivative 5-(N-ethyl-N-isopropyl)amiloride (EIPA) were previously shown to inhibit coxsackievirus B3 (CVB3) RNA replication in cell culture, with two amino acid substitutions in the viral RNA-dependent RNA polymerase 3Dpol conferring partial resistance of CVB3 to these compounds (D. N. Harrison, E. V. Gazina, D. F. Purcell, D. A. Anderson, and S. Petrou, J. Virol. 82:1465–1473, 2008). Here we demonstrate that amiloride and EIPA inhibit the enzymatic activity of CVB3 3Dpol in vitro, affecting both VPg uridylylation and RNA elongation. Examination of the mechanism of inhibition of 3Dpol by amiloride showed that the compound acts as a competitive inhibitor, competing with incoming nucleoside triphosphates (NTPs) and Mg2+. Docking analysis suggested a binding site for amiloride and EIPA in 3Dpol, located in close proximity to one of the Mg2+ ions and overlapping the nucleotide binding site, thus explaining the observed competition. This is the first report of a molecular mechanism of action of nonnucleoside inhibitors against a picornaviral RNA-dependent RNA polymerase.

Background

Increase in global health research undertaken in resource poor settings in the last decade though a positive development has raised ethical concerns relating to potential for exploitation. Some of the suggested strategies to address these concerns include calls for providing universal standards of care, reasonable availability of proven interventions and more recently, promoting the overall social value of research especially in clinical research. Promoting the social value of research has been closely associated with providing fair benefits to various stakeholders involved in research. The debate over what constitutes fair benefits; whether those that addresses micro level issues of justice or those focusing on the key determinants of health at the macro level has continued. This debate has however not benefited from empirical work on what stakeholders consider fair benefits. This study explores practical experiences of stakeholders involved in global health research in Kenya, over what benefits are fair within a developing world context.

Methods and results

We conducted in-depth interviews with key informants drawn from within the broader health research system in Kenya including researchers from the mainstream health research institutions, networks and universities, teaching hospitals, policy makers, institutional review boards, civil society organisations and community representative groups.

The range of benefits articulated by stakeholders addresses both micro and macro level concerns for justice by for instance, seeking to engage with interests of those facilitating research, and the broader systemic issues that make resource poor settings vulnerable to exploitation. We interpret these views to suggest a need for global health research to engage with current crises that face people in these settings as well as the broader systemic issues that produce them.

Conclusion

Global health research should provide benefits that address both the micro and macro level issues of justice in order to forestall exploitation. Embracing the two is however challenging in terms of how the various competing interests/needs should be balanced ethically, especially in the absence of structures to guide the process. This challenge should point to the need for greater dialogue to facilitate value clarification among stakeholders.

The emergence of drug-resistant bacteria highlights the importance of identifying potential drug targets. Dihydrodipicolinate synthase (DHDPS) is a valid but as yet unexploited antimicrobial target that functions in the biosynthesis of (S)-lysine. In this study, the cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of DHDPS from S. pneumoniae are described.

Dihydrodipicolinate synthase (DHDPS; EC 4.2.1.52) catalyzes the rate-limiting step in the (S)-lysine biosynthesis pathway of bacteria and plants. Here, the cloning of the DHDPS gene from a clinical isolate of Streptococcus pneumoniae (OXC141 strain) and the strategy used to express, purify and crystallize the recombinant enzyme are described. Diffracting crystals were grown in high-molecular-weight PEG precipitants using the hanging-drop vapour-diffusion method. The best crystal, from which data were collected, diffracted to beyond 2.0 Å resolution. Initially, the crystals were thought to belong to space group P42212, with unit-cell parameters a = 105.5, b = 105.5, c = 62.4 Å. However, the R factors remained high following initial processing of the data. It was subsequently shown that the data set was twinned and it was thus reprocessed in space group P2, resulting in a significant reduction in the R factors. Determination of the structure will provide insight into the design of novel antimicrobial agents targeting this important enzyme from S. pneumoniae.

Given the recent rise in antimicrobial resistance, there is an urgent need to identify and characterize new antibiotic drug targets. One such target is dihydrodipicolinate reductase (DHDPR), which is an essential bacterial enzyme that catalyzes the second step in the lysine-biosynthesis pathway. In this paper, the cloning, expression, purification and crystallization of DHDPR from methicillin-resistant S. aureus are presented.

Dihydrodipicolinate reductase (DHDPR; EC 1.3.1.26) catalyzes the nucleotide (NADH/NADPH) dependent second step of the lysine-biosynthesis pathway in bacteria and plants. Here, the cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of DHDPR from methicillin-resistant Staphylococcus aureus (MRSA-DHDPR) are presented. The enzyme was crystallized in a number of forms, predominantly with ammonium sulfate as a precipitant, with the best crystal form diffracting to beyond 3.65 Å resolution. Crystal structures of the apo form as well as of cofactor (NADPH) bound and inhibitor (2,6-pyridinedicarboxylate) bound forms of MRSA-DHDPR will provide insight into the structure and function of this essential enzyme and valid drug target.

The cholesterol-dependent cytolysins (CDCs) attack cells by punching large holes in their membranes. Lectinolysin from Streptococcus mitis is unique among CDCs due to the presence of an N-terminal lectin domain that enhances the pore-forming activity of the toxin. We recently determined the crystal structures of the lectin domain in complex with various glycans. These structures revealed the molecular basis for the Lewis antigen specificity of the toxin. Based on this information we have used in silico molecular modeling to design a mutant toxin, which we predicted would increase its specificity for Lewis y, an antigen found on the surface of cancer cells. Surprisingly, we found by surface plasmon resonance binding experiments that the resultant mutant lectin domain exhibited higher specificity for Lewis b antigens instead. We then undertook comparative crystallographic and molecular dynamics simulation studies of the wild-type and mutant lectin domains to understand the molecular basis for the disparity between the theoretical and experimental results. The crystallographic results revealed that the net number of interactions between Lewis y and wild-type versus mutant was unchanged whereas there was a loss of a hydrogen bond between mutant and Lewis b compared to wild-type. In contrast, the molecular dynamics studies revealed that the Lewis b antigen spent more time in the binding pocket of the mutant compared to wild-type and the reverse was true for Lewis y. The results of these simulation studies are consistent with the conclusions drawn from the surface plasmon resonance studies. This work is part of a program to engineer lectinolysin so that it will target and kill specific cells in human diseases.

Background

The concept of benefit sharing to enhance the social value of global health research in resource poor settings is now a key strategy for addressing moral issues of relevance to individuals, communities and host countries in resource poor settings when they participate in international collaborative health research.

The influence of benefit sharing framework on the conduct of collaborative health research is for instance evidenced by the number of publications and research ethics guidelines that require prior engagement between stakeholders to determine the social value of research to the host communities. While such efforts as the production of international guidance on how to promote the social value of research through such strategies as benefit sharing have been made, the extent to which these ideas and guidelines have been absorbed by those engaged in global health research especially in resource poor settings remains unclear. We examine this awareness among stakeholders involved in health related research in Kenya.

Methods

We conducted in-depth interviews with key informants drawn from within the broader health research system in Kenya including researchers from the mainstream health research institutions, networks and universities, teaching hospitals, policy makers, institutional review boards, civil society organisations and community representative groups.

Results

Our study suggests that although people have a sense of justice and the moral aspects of research, this was not articulated in terms used in the literature and the guidelines on the ethics of global health research.

Conclusion

This study demonstrates that while in theory several efforts can be made to address the moral issues of concern to research participants and their communities in resource poor settings, quick fixes such as benefit sharing are not going to be straightforward. We suggest a need to pay closer attention to the processes through which ethical principles are enacted in practice and distil lessons on how best to involve individuals and communities in promoting ethical conduct of global health research in resource poor settings.

Six monoclonal antibodies were isolated that exhibited specificity for a furin cleavage site deletion mutant (V3526) of Venezuelan equine encephalitis virus (VEEV). These antibodies comprise a single competition group and bound the E3 glycoprotein of VEEV subtype I viruses but failed to bind the E3 glycoprotein of other alphaviruses. These antibodies neutralized V3526 virus infectivity but did not neutralize the parental strain of Trinidad donkey (TrD) VEEV. However, the E3-specific antibodies did inhibit the production of virus from VEEV TrD-infected cells. In addition, passive immunization of mice demonstrated that antibody to the E3 glycoprotein provided protection against lethal VEEV TrD challenge. This is the first recognition of a protective epitope in the E3 glycoprotein. Furthermore, these results indicate that E3 plays a critical role late in the morphogenesis of progeny virus after E3 appears on the surfaces of infected cells.

Glutathione S-transferases (GSTs) are a group of detoxifying enzymes that are found in animals, plants and microorganisms. Here, the crystallizations of two cyanobacterial GSTs are reported with the aim of determining their atomic structures.

Glutathione S-transferases (GSTs) are a group of multifunctional enzymes that are found in animals, plants and microorganisms. Their primary function is to remove toxins derived from exogenous sources or the products of metabolism from the cell. Mammalian GSTs have been extensively studied, in contrast to bacterial GSTs which have received relatively scant attention. A new class of GSTs called Chi has recently been identified in cyanobacteria. Chi GSTs exhibit a high glutathionylation activity towards isothiocyanates, compounds that are normally found in plants. Here, the crystallization of two GSTs are presented: TeGST produced by Thermosynechococcus elongates BP-1 and SeGST from Synechococcus elongates PCC 6301. Both enzymes formed crystals that diffracted to high resolution and appeared to be suitable for further X-ray diffraction studies. The structures of these GSTs may shed further light on the evolution of GST catalytic activity and in particular why these enzymes possess catalytic activity towards plant antimicrobial compounds.

A Fab fragment of a monoclonal anti-parathyroid hormone-related protein antibody was prepared and its complex with parathyroid hormone-related protein was crystallized. X-ray diffraction data were collected to 2.0 Å resolution.

Parathyroid hormone-related protein (PTHrP) plays an important role in regulating embryonic skeletal development and is abnormally regulated in the pathogenesis of skeletal complications observed with many cancers and osteoporosis. It exerts its action through binding to a G-protein-coupled seven-transmembrane cell-surface receptor (GPCR). Structurally, GPCRs are very difficult to study by X-ray crystallography. In this study, a monoclonal antibody Fab fragment which recognizes the same region of PTHrP as its receptor, PTH1R, was used to aid in the crystallization of PTHrP. The resultant protein complex was crystallized using the hanging-drop vapour-diffusion method with polyethylene glycol as a precipitant. The crystals belonged to the orthorhombic space group P21212, with unit-cell parameters a = 72.6, b = 96.3, c = 88.5 Å, and diffracted to 2.0 Å resolution using synchrotron radiation. The crystal structure will shed light on the nature of the key residues of PTHrP that interact with the antibody and will provide insights into how the antibody is able to discriminate between PTHrP and the related molecule parathyroid homone.

Background

Genome-wide association studies (GWAS) provide a powerful means of identifying genetic variants that play a role in common diseases. Such studies present important ethical challenges. An increasing number of GWAS is taking place in lower income countries and there is a pressing need to identify the particular ethical challenges arising in such contexts. In this paper, we draw upon the experiences of the MalariaGEN Consortium to identify specific ethical issues raised by such research in Africa, Asia and Oceania.

Discussion

We explore ethical issues in three key areas: protecting the interests of research participants, regulation of international collaborative genomics research and protecting the interests of scientists in low income countries. With regard to participants, important challenges are raised about community consultation and consent. Genomics research raises ethical and governance issues about sample export and ownership, about the use of archived samples and about the complexity of reviewing such large international projects. In the context of protecting the interests of researchers in low income countries, we discuss aspects of data sharing and capacity building that need to be considered for sustainable and mutually beneficial collaborations.

Summary

Many ethical issues are raised when genomics research is conducted on populations that are characterised by lower average income and literacy levels, such as the populations included in MalariaGEN. It is important that such issues are appropriately addressed in such research. Our experience suggests that the ethical issues in genomics research can best be identified, analysed and addressed where ethics is embedded in the design and implementation of such research projects.

Dihydrodipicolinate synthase (DHDPS) catalyzes an important step in lysine biosynthesis. Here, the crystallization and preliminary diffraction analysis to 1.2 Å resolution of DHDPS from C. botulinum in the presence of its substrate pyruvate is reported.

In this paper, the crystallization and preliminary X-ray diffraction analysis to near-atomic resolution of DHDPS from Clostridium botulinum crystallized in the presence of its substrate pyruvate are presented. The enzyme crystallized in a number of forms using a variety of PEG precipitants, with the best crystal diffracting to 1.2 Å resolution and belonging to space group C2, in contrast to the unbound form, which had trigonal symmetry. The unit-cell parameters were a = 143.4, b = 54.8, c = 94.3 Å, β = 126.3°. The crystal volume per protein weight (V M) was 2.3 Å3 Da−1 (based on the presence of two monomers in the asymmetric unit), with an estimated solvent content of 46%. The high-resolution structure of the pyruvate-bound form of C. botulinum DHDPS will provide insight into the function and stability of this essential bacterial enzyme.

Dihydrodipicolinate synthase (DHDPS) catalyses an important step in lysine biosynthesis. Here, the expression, purification, crystallization and preliminary diffraction analysis to 2.15 Å resolution of DHDPS from B. anthracis soaked with the substrate pyruvate are reported.

Dihydrodipicolinate synthase (DHDPS) catalyses the first committed step in the lysine-biosynthesis pathway in bacteria, plants and some fungi. In this study, the expression of DHDPS from Bacillus anthracis (Ba-DHDPS) and the purification of the recombinant enzyme in the absence and presence of the substrate pyruvate are described. It is shown that DHDPS from B. anthracis purified in the presence of pyruvate yields greater amounts of recombinant enzyme with more than 20-fold greater specific activity compared with the enzyme purified in the absence of substrate. It was therefore sought to crystallize Ba-DHDPS in the presence of the substrate. Pyruvate was soaked into crystals of Ba-DHDPS prepared in 0.2 M sodium fluoride, 20%(w/v) PEG 3350 and 0.1 M bis-tris propane pH 8.0. Preliminary X-ray diffraction data of the recombinant enzyme soaked with pyruvate at a resolution of 2.15 Å are presented. The pending crystal structure of the pyruvate-bound form of Ba-DHDPS will provide insight into the function and stability of this essential bacterial enzyme.

A multisystem approach was used to assess the efficiency of several methods for inactivation of Venezuelan equine encephalitis virus (VEEV) vaccine candidates. A combination of diverse assays (plaque, in vitro cytopathology and mouse neurovirulence) was used to verify virus inactivation, along with the use of a specific ELISA to measure retention of VEEV envelope glycoprotein epitopes in the development of several inactivated VEEV candidate vaccines derived from an attenuated strain of VEEV (V3526). Incubation of V3526 aliquots at temperatures in excess of 64°C for periods >30 minutes inactivated the virus, but substantially reduced VEEV specific monoclonal antibody binding of the inactivated material. In contrast, V3526 treated either with formalin at concentrations of 0.1% or 0.5% v/v for 4 or 24 hours, or irradiated with 50 kilogray gamma radiation rendered the virus non-infectious while retaining significant levels of monoclonal antibody binding. Loss of infectivity of both the formalin inactivated (fV3526) and gamma irradiated (gV3526) preparations was confirmed via five successive blind passages on BHK-21 cells. Similarly, loss of neurovirulence for fV3526 and gV3526 was demonstrated via intracerebral inoculation of suckling BALB/c mice. Excellent protection against subcutaneous challenge with VEEV IA/B Trinidad donkey strain was demonstrated using a two dose immunization regimen with either fV3526 or gV3526. The combination of in vitro and in vivo assays provides a practical approach to optimize manufacturing process parameters for development of other inactivated viral vaccines.