The potential of the human immune system to develop broadly neutralizing HIV-1 antibodies: implications for vaccine...

Developing an effective HIV-1 vaccine that elicits broadly neutralizing HIV-1 human antibodies (bnAbs) remains a challenging goal. Extensive studies on HIV-1 have revealed various strategies employed by the virus to escape host immune surveillance. Here, we investigated the human antibody gene repertoires of uninfected and HIV-1-infected individuals at genomic DNA (gDNA) and cDNA levels by deep sequencing followed by high-throughput sequence analysis to determine the frequencies of putative germline antibody genes of known HIV-1 monoclonal bnAbs (bnmAbs).

Combinatorial gDNA and cDNA antibody libraries were constructed using the gDNAs and mRNAs isolated from uninfected and HIV-1-infected human peripheral blood mononuclear cells (PBMCs). All libraries were deep sequenced and sequences analysed using IMGT/HighV-QUEST software (http://imgt.org/HighV-QUEST/index.action). The frequencies of putative germline antibodies of known bnmAbs in the gDNA and cDNA libraries were determined.

The human gDNA antibody libraries were more diverse in heavy and light chain V-gene lineage usage than the cDNA libraries, indicating that the human gDNA antibody gene repertoires may have more potential than the cDNA repertoires to develop HIV-1 bnAbs. The frequencies of the heavy and kappa and lambda light chain variable regions with identical V(D)J recombinations to known HIV-1 bnmAbs were extremely low in human antibody gene repertoires. However, we found relatively high frequencies of the heavy and kappa and lambda light chain variable regions that used the same V-genes and had the same CDR3 lengths as known HIV-1 bnmAbs regardless of (D)J-gene usage. B-cells bearing B-cell receptors of such heavy and kappa and lambda light chain variable regions may be stimulated to induce HIV-1 bnAbs.