Principal Investigator
Abstract
A successful prophylactic HIV vaccine will likely need to elicit both T-cell responses and broadly neutralizing antibodies (bNAbs). Yet, the elicitation of anti-HIV bNAbs has been elusive, partly because they require unusual structural features that are rare in the human naive B-cell repertoire. Further, most germline-reverted versions of bNAbs do not bind known HIV envelope glycoproteins, suggesting that conventional immunogens would be poor at activating them to initiate the development of bNAb-like lineages. To overcome these limitations, engineered germline-targeting (GT) immunogens have been designed to activate the rare bNAb-like naive B cells. A series of carefully selected booster immunogens that have increasing complexities will be then used to drive the lineages to breadth. The development of a successful GT regimen will be reiterative and could therefore take long. As such, it will be beneficial to have readily available animal models for rapid evaluation at each step, to guide timely immunogen re-design and re-evaluation. An ideal animal model will have germline immunoglobulin genes and B-cell repertoires that mimic those in humans. Non-human primates (NHPs) are attractive models because they are genetically close to humans. Indeed, Rhesus macaques (RMS) are well-described, and have successfully contributed to the preclinical evaluation of upcoming GT immunogens. But they have become relatively inaccessible and expensive due to increased global demand and reduced supply. Other more readily available NHPs, such as the African green monkeys (AGMs), Bonnet macaques (BMs) and marmosets, could bridge this gap, but their germline immunoglobulin genes and B-cell repertoires are poorly understood. The overall goal of this joint proposal between India and Africa is to assess the suitability of AGMs, RMs, BMs and marmosets for evaluation of HIV vaccines. We propose to adapt techniques that have been established in our laboratories to characterize the germline immunoglobulin genes and B-cell repertoires of AGMs, RMs, BMs and marmosets. First, we will use Illumina sequencing and IgDiscover to determine germline immunoglobulin genes of the NHP models. To confirm that the NHPs can indeed respond to GT immunogens, we will further quantify bNAb-like naïve B cells that bind GT immunogens in AGMs repertoires by using a combination of FACS sorting and a 10X Genomics V(D)J sequencing pipelines. Our laboratories have established pipelines for Illumina sequencing, IgDiscover analyses, FACS sorting and 10X Genomics analyses that are being used for similar work in humans. This
work will provide crucial information on the suitability of these NHPs for evaluation of HIV vaccines, especially with regard to GT vaccines that have strict immunoglobulin genes requirements. Information gathered from the detailed characterization of these NHPs will strengthen the knowledge base necessary to support rational design of HIV vaccines. Implementing this work will also enable us to assemble, coordinate and develop research capacity, reagents, assays, and resources needed for rapid testing and evaluation of HIV vaccine candidates. In addition, we will generate comprehensive databases of germline immunoglobulin genes, thus creating a general resource for the study of B-cell responses in these NHPs even in the context of other diseases and vaccines.
