Immunity. 2018 Jan 16; 48(1):133-146.e6.

PubMed ID: 29287996

Precursor frequency and affinity determine B Cell competitive fitness in germinal centers, tested with germline-targeting HIV vaccine immunogens

Abbott RK, Lee JH, Menis S, Skog P, Rossi M, Ota T, Kulp DW, Bhullar D, Kalyuzhniy O, Havenar-Daughton C, Schief WR, Nemazee D, Crotty S

How precursor frequencies and antigen affinities impact interclonal B cell competition is a particularly relevant issue for candidate germline-targeting HIV vaccine designs because of the in vivo rarity of naive B cells that recognize broadly neutralizing epitopes. Knowing the frequencies and affinities of HIV-specific VRC01-class naive human B cells, we transferred B cells with germline VRC01 B cell receptors into congenic recipients to elucidate the roles of precursor frequency, antigen affinity, and avidity on B cell responses following immunization. All three factors were interdependently limiting for competitive success of VRC01-class B cells. In physiological high-affinity conditions using a multivalent immunogen, rare VRC01-class B cells successfully competed in germinal centers (GC), underwent extensive somatic hypermutation, and differentiated into memory B cells. The data reveal dominant influences of precursor frequency, affinity, and avidity for interclonal GC competition and indicate that germline-targeting immunogens can overcome these challenges with high-affinity multimeric designs.