Presentation Title

Recombining Antibody’s CDRs to Create a More Potent HIV-1 Monoclonal Antibody

Faculty Mentor

Peter Kim

Start Date

23-11-2019 9:45 AM

End Date

23-11-2019 10:00 AM

Location

Markstein 102

Session

oral 1

Type of Presentation

Oral Talk

Subject Area

biological_agricultural_sciences

Abstract

An obstacle in the development of a universal HIV-1 vaccine is the inability to target the breadth of HIV strains given the highly-mutable envelope glycoprotein (Env). Identifying broadly neutralizing antibody (bNAb) responses that target epitopes conserved across the various mutants of HIV-1 will allow the field to design more effective vaccines. One conserved region with the potential for stimulating bNAbs is the gp41 pre-hairpin intermediate (PHI), which is exposed during viral membrane fusion to host cells. The few antibodies that target the PHI demonstrate modest neutralization potency. The best characterized of these is a monoclonal antibody, D5, which was discovered from a phage display library. D5 was recently affinity matured using phage display by randomizing complementarity determing regions (CDRs), regions that contribute to the binding of the antibody to its antigen. These mutants only demonstrated a 1.5-fold neutralization enhancement when compared to wildtype. Interestingly, each mutant tested was limited by having only one CDR mutated at a time. We hypothesize that by recombining multiple CDR mutations, we could achieve an even more potent antibody. Through antibody engineering and expression via mammalian cells, we have created a panel of 11 different CDR combinations. Using in vitro HIV-1 neutralization assays, we have found that some of these mutant antibodies enhance neutralization while some are less neutralizing than wildtype. In particular, we have identified one mutant, D5 AR, that demonstrates around a 6-fold enhancement. With D5 AR being identified as the best enhanced neutralizer, we further tested the neutralization breadth against a panel of HIV-1 strains. Crystallographic studies are currently being completed to further understand the binding contacts of the mutant with its antigen. Further investigating these enhanced mutants can potentially lead to identifying a more potent D5 mutant which will be instrumental in further developing possible vaccine efforts to prevent HIV-1 transmission.

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Nov 23rd, 9:45 AM Nov 23rd, 10:00 AM

Recombining Antibody’s CDRs to Create a More Potent HIV-1 Monoclonal Antibody

Markstein 102

An obstacle in the development of a universal HIV-1 vaccine is the inability to target the breadth of HIV strains given the highly-mutable envelope glycoprotein (Env). Identifying broadly neutralizing antibody (bNAb) responses that target epitopes conserved across the various mutants of HIV-1 will allow the field to design more effective vaccines. One conserved region with the potential for stimulating bNAbs is the gp41 pre-hairpin intermediate (PHI), which is exposed during viral membrane fusion to host cells. The few antibodies that target the PHI demonstrate modest neutralization potency. The best characterized of these is a monoclonal antibody, D5, which was discovered from a phage display library. D5 was recently affinity matured using phage display by randomizing complementarity determing regions (CDRs), regions that contribute to the binding of the antibody to its antigen. These mutants only demonstrated a 1.5-fold neutralization enhancement when compared to wildtype. Interestingly, each mutant tested was limited by having only one CDR mutated at a time. We hypothesize that by recombining multiple CDR mutations, we could achieve an even more potent antibody. Through antibody engineering and expression via mammalian cells, we have created a panel of 11 different CDR combinations. Using in vitro HIV-1 neutralization assays, we have found that some of these mutant antibodies enhance neutralization while some are less neutralizing than wildtype. In particular, we have identified one mutant, D5 AR, that demonstrates around a 6-fold enhancement. With D5 AR being identified as the best enhanced neutralizer, we further tested the neutralization breadth against a panel of HIV-1 strains. Crystallographic studies are currently being completed to further understand the binding contacts of the mutant with its antigen. Further investigating these enhanced mutants can potentially lead to identifying a more potent D5 mutant which will be instrumental in further developing possible vaccine efforts to prevent HIV-1 transmission.