HIV-1 Vaccine-elicited Antibodies Reverted to Their Inferred Naive Germline Reveal Associations between Binding Affinity and in vivo Activation

Sci Rep. 2016 Feb 16;6:20987. doi: 10.1038/srep20987.

Abstract

The elicitation of HIV-1 broadly neutralizing antibodies following envelope glycoprotein (Env) vaccination is exceedingly difficult. Suboptimal engagement of naïve B cells is suggested to limit these low frequency events, especially at the conserved CD4bs. Here, we analyzed CD4bs-directed monoclonal antibodies (mAbs) elicited by YU2 gp140-foldon trimers in a non-human primate by selective sorting using CD4bs "knock out" trimers. Following two inoculations, the CD4bs-directed mAbs efficiently recognized the eliciting immunogen in their affinity-maturing state but did not recognize CD4bs-defective probes. We reverted these mAbs to their most likely inferred germline (igL) state, leaving the HCDR3 unaltered, to establish correlates of in vitro affinity to in vivo activation. Most igL-reverted mAbs bound the eliciting gp140 immunogen, indicating that CD4bs-directed B cells possessing reasonable affinity existed in the naïve repertoire. We detected relatively high affinities for the majority of the igL mAbs to gp120 and of Fabs to gp140, which, as expected, increased when the antibodies 'matured' following vaccination. Affinity increases were associated with slower off-rates as well as with acquisition of neutralizing capacity. These data reveal in vitro binding properties associated with in vivo activation that result in functional archiving of antigen-specific B cells elicited by a complex glycoprotein antigen following immunization.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • AIDS Vaccines / administration & dosage
  • AIDS Vaccines / immunology*
  • Animals
  • Antibodies, Monoclonal / chemistry
  • Antibodies, Monoclonal / immunology
  • Antibodies, Neutralizing / immunology
  • Antibody Specificity / immunology
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism
  • CD4 Antigens / metabolism
  • Complementarity Determining Regions / chemistry
  • Complementarity Determining Regions / immunology
  • Enzyme-Linked Immunosorbent Assay
  • HIV Antibodies / chemistry
  • HIV Antibodies / genetics
  • HIV Antibodies / immunology*
  • HIV-1 / immunology*
  • Humans
  • Immunization
  • Kinetics
  • Macaca mulatta
  • Models, Molecular
  • Neutralization Tests
  • Protein Binding / immunology
  • Protein Conformation
  • Surface Plasmon Resonance
  • env Gene Products, Human Immunodeficiency Virus / chemistry
  • env Gene Products, Human Immunodeficiency Virus / immunology

Substances

  • AIDS Vaccines
  • Antibodies, Monoclonal
  • Antibodies, Neutralizing
  • CD4 Antigens
  • Complementarity Determining Regions
  • HIV Antibodies
  • env Gene Products, Human Immunodeficiency Virus