Project Grant F31AI197981

EFFECTS OF AUTOLOGOUS CD4 BINDING SITE ANTIBODIES ON HIV BROADLY NEUTRALIZING ANTIBODIES - PROJECT SUMMARY HUMAN IMMUNODEFICIENCY VIRUS (HIV) REMAINS A GLOBAL HEALTH BURDEN DESPITE EFFECTIVE ANTIRETROVIRAL THERAPY (ART), WHICH SUPPRESSES VIRAL REPLICATION BUT DOES NOT ELIMINATE LATENT VIRAL RESERVOIRS. THESE RESERVOIRS CAUSE VIRAL REBOUND UPON TREATMENT INTERRUPTION, UNDERSCORING THE NEED FOR CURATIVE STRATEGIES. ONE CURRENT STRATEGY IS THE CLINICAL ADMINISTRATION OF BROADLY NEUTRALIZING ANTIBODIES (BNABS) THAT TARGET CONSERVED REGIONS OF THE HIV ENVELOPE (ENV) PROTEIN. BNABS ARE CAPABLE OF NEUTRALIZING DIVERSE VIRAL STRAINS. HOWEVER, HIV'S HIGH MUTATION RATE ALLOWS IT TO RAPIDLY DEVELOP ESCAPE MUTATIONS, LIMITING THE DURABILITY OF BNAB-MEDIATED VIRAL SUPPRESSION. AUTOLOGOUS NEUTRALIZING ANTIBODIES (ANABS), WHICH ARISE DURING EARLY INFECTION, ALSO CAUSE THE SELECTION OF ESCAPE MUTATIONS AND OFTEN TARGET THE SAME REGIONS AS BNABS, PARTICULARLY THE CD4 BINDING SITE (CD4BS). WHILE CD4BS ANABS ARE PREVALENT IN MOST INDIVIDUALS WITH HIV, THEIR ROLE IN MODULATING VIRAL SENSITIVITY TO BNABS REMAINS UNCLEAR. ESCAPE MUTATIONS SELECTED BY THESE AUTOLOGOUS ANTIBODIES MAY ALTER BNAB SENSITIVITY, REPRESENTING AN UNDERSTUDIED FACTOR IN OPTIMIZING BNAB-BASED THERAPIES. WE HYPOTHESIZE THAT MUTATIONS SELECTED FOR BECAUSE OF AUTOLOGOUS CD4BS ANTIBODIES WOULD NEGATIVELY IMPACT BNAB SENSITIVITY BY DRIVING VIRAL RESISTANCE RENDERING THE VIRUS RESISTANT TO BNABS. THE PROPOSED RESEARCH AIMS TO ELUCIDATE THE IMPACT OF CD4BS-TARGETING ANABS ON BNAB SENSITIVITY. AIM 1 WILL ISOLATE CD4BS ANABS FROM DONOR PLASMA, THEN THE ISOLATED ANTIBODIES WILL BE USED TO CAUSE THE SELECTION OF ESCAPE MUTATIONS AGAINST AN INFECTIOUS MOLECULAR CLONE IN AN IN VITRO ESCAPE ASSAY. ONCE THE VIRUS HAS ESCAPED FROM THESE ANTIBODIES, VIRUS CULTURES WILL BE SEQUENCED TO IDENTIFY AMINO ACID SUBSTITUTIONS ASSOCIATED WITH RESISTANCE TO AUTOLOGOUS CD4BS-DIRECTED ANTIBODIES. AIM 2 WILL ASSESS HOW THESE MUTATIONS INFLUENCE BNAB SENSITIVITY BY INTRODUCING ESCAPE MUTATIONS INTO MATCHED ENV PLASMIDS THROUGH SITE-DIRECTED MUTAGENESIS, GENERATING PSUEDOVIRUSES WITH THESE PLASMIDS, AND THEN PERFORMING NEUTRALIZATION ASSAYS WITH A PANEL OF BNABS TARGETING DIVERSE ENV EPITOPES AGAINST THE PSEUDOVIRUSES. THIS STUDY WILL ADVANCE THE UNDERSTANDING OF HOW PRE-EXISTING IMMUNE RESPONSES SHAPE VIRAL EVOLUTION AND INFLUENCE THE EFFECTIVENESS OF BNAB THERAPY. THE FINDINGS HAVE POTENTIAL TO INFORM THE RATIONAL SELECTION OF BNABS FOR THERAPEUTIC USE IN PEOPLE LIVING WITH HIV, CONTRIBUTING TO THE DEVELOPMENT OF MORE EFFECTIVE STRATEGIES AIMED AT VIRAL CURE.