Maturational characteristics of HIV-specific antibodies in viremic individuals.

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TitleMaturational characteristics of HIV-specific antibodies in viremic individuals.
Publication TypeJournal Article
Year of Publication2016
AuthorsMeffre, E, Louie, A, Bannock, J, J Y Kim, L, Ho, J, Frear, CC, Kardava, L, Wang, W, Buckner, CM, Wang, Y, Fankuchen, OR, Gittens, KR, Chun, T-W, Li, Y, Fauci, AS, Moir, S
JournalJCI Insight
Date Published2016

Despite the rare appearance of potent HIV-neutralizing mAbs in infected individuals requiring prolonged affinity maturation, little is known regarding this process in the majority of viremic individuals. HIV-infected individuals with chronic HIV viremia have elevated numbers of nonconventional tissue-like memory (TLM) B cells that predominate in blood over conventional resting memory (RM) B cells. Accordingly, we investigated affinity maturation in these 2 memory B cell populations. Analysis of IgG-expressing TLM B cells revealed a higher number of cell divisions compared with RM B cells; however, TLM B cells paradoxically displayed significantly lower frequencies of somatic hypermutation (SHM). To assess Ab reactivity in TLM and RM B cells, single-cell cloning was performed on HIV envelope CD4-binding site-sorted (CD4bs-sorted) B cells from 3 individuals with chronic HIV viremia. Several clonal families were present among the 127 cloned recombinant mAbs, with evidence of crosstalk between TLM and RM B cell populations that was largely restricted to non-VH4 families. Despite evidence of common origins, SHM frequencies were significantly decreased in TLM-derived mAbs compared with SHM frequencies in RM-derived mAbs. However, both cell populations had lower frequencies of SHMs than did broadly neutralizing CD4bs-specific mAbs. There was a significant correlation between SHM frequencies and the HIV-neutralizing capacities of the mAbs. Furthermore, HIV neutralization was significantly higher in the RM-derived mAbs compared with that seen in the TLM-derived mAbs, and both SHM frequencies and neutralizing capacity were lowest in TLM-derived mAbs with high polyreactivity. Thus, deficiencies in memory B cells that arise during chronic HIV viremia provide insight into the inadequacy of the Ab response in viremic individuals.

Alternate JournalJCI Insight
PubMed ID27152362
PubMed Central IDPMC4854302
Grant ListR01 AI102766 / AI / NIAID NIH HHS / United States