Montefiori Antibody Vaccine Immune Monitoring Consortium  

OVERVIEW:

The Comprehensive Antibody Vaccine Immune Monitoring Consortium (Ab VIMC) provides global access to key reference reagents, validated assays and high throughput assay capacity for standardized assessments of antibody responses in preclinical and clinical HIV/AIDS vaccine studies, with a major focus on neutralizing antibodies.

RESEARCH OBJECTIVES:

1. Establish a Central Reference Laboratory for assay validation, training and proficiency testing aimed at harmonizing the types of assays and standard operating procedures (SOPs) used between laboratories,
2. Establish a Quality Assurance Unit (QAU) that will provide Good Clinical Laboratory Practice (GCLP) training and oversight for laboratories that perform antibody assays for vaccine clinical trials,
3. Create an international network of Core and Regional Laboratories that will meet the growing demand for routine assay performance, with an emphasis on serving the needs of the CAVD Vaccine Discovery Consortia and other clinical trials programs,
4. Organize a Standard Virus Panel Consortium (SVPC) and Neutralization Serotype Discovery Project (NSDP) that will develop key reference reagents in coordination with Core and Regional Laboratories,
5. Assemble a research and development team of investigators who will work to improve existing assays and technology sophistication, and will help develop new assays that will better inform vaccine design, and
6. Provide new scientific findings that will help bridge the gap between preclinical vaccine discovery and human clinical trials.

PROGRESS:

• The Ab VIMC offers highly standardized and validated assays for binding antibodies and neutralizing antibodies with high throughput capacity and GCLP compliance. 
• The capacity for assessing antiviral antibody effector functions includes antibody-dependent cell-mediated viral inhibition studies and new technologies for measuring antibody-dependent cellular cytotoxicity and inhibition of cell-cell transmission.
• A new assay technology for studying peripheral blood mononuclear cells (PBMCs) with high throughput capacity for neutralizing antibodies will soon be available.
• The consortium has created and characterized IMC-rLuc viruses for clades B and C with progress made toward development of IMCs for SIV.
• The ability to assess vaccine-elicited neutralizing antibodies and to study broadly neutralizing antibodies has been enhanced by the creation and characterization of over 400 unique Env clones of multiple genetic subtypes from diverse geographic locations. 
• A successful collaboration between the Ab VIMC and HIV Specimen Cryorepository (Dr. Hagen von Briesen) has been made to provide centrally prepared stocks of Env-pseudotyped viruses which promises to enhance the quality and reproducibility of neutralizing antibody assay results across laboratories. 
• The Ab VIMC has implemented a formal proficiency testing program for the TZM-bl neutralizing antibody assay that will be used to qualify GCLP laboratories and to monitor proficiency at other laboratories. 
• Substantial progress had been made at Ab VIMC Regional Laboratories towards achieving and maintaining GCLP-compliance in performing the neutralizing antibody assay for HIV-1 in TZM-bl cells. 
• The consortium has initiated projects utilizing high throughput overlapping peptide microarrays for mapping of binding epitopes (collaboration with JPT Peptide Technologies).
• The Ab VIMC continues to make progress in understanding the antigenic diversity of HIV-1 as it relates to neutralizing antibodies and vaccine development. Recent progress includes the completion of an extensive investigation of the epitope specificity of broadly neutralizing antibodies in serum from clade B and clade C HIV-1-infected individuals (J. Virology, 82:11651-11668, 2008).
• Researchers at the Ab VIMC, in collaboration with CAVD Vaccine Immunology Statistical Center, have identified clade-related neutralization phenotypes and associated genetic signatures (Virology, 385:505-520, 2009) and have completed a study that refines the tier classification of 109 molecularly cloned Env-pseudotyped viruses (manuscript submitted). 
• The Ab VIMC has recently generated additional large datasets that will be analyzed by agglomerative hierarchical clustering analysis (heat maps) and other statistical methods that will provide new insights for vaccine design and testing. 
• The Ab VIMC has recently accomplished the computational identification of amino acid signatures in the CD4-induced co-receptor binding domain of gp120 that associate with broadly NAb responses in HIV-1-infected individuals (manuscript in preparation). 
• Full implementation of the Neutralization Serotype Discovery Program (NSDP) including the performance of 40,000 neutralization assays to be completed in early 2010 with over 200 HIV-1 Env-pseudotyped viruses and serum from 200 HIV-1 infected individuals representing all major genetic subtypes of the virus. These data will be analyzed to decide the optimal choice of reference strains for neutralizing antibody assays and to seek additional information to inform vaccine design.