Responding kinetic of B-cell receptor repertoire to the Toll-like receptor 7/8 stimulation in non-human primates

TLR7 and 8 regulate B cell immunity, but the precise details of the mechanism are still unclear. Here, we studied the kinetics of both heavy and light chains (IgKL) of B-cell receptor (BCR) repertoire responding to the TLR7/8 stimulation in two geniuses of non-human primates (NHPs), African green monkeys (AGMs) and rhesus macaques (RMs). We evaluated the activation of lymphocytes by flow cytometry, and studied characteristics of BCR repertoire in terms of gene usage, repertoire diversity, and the number of lineages. Although AGMs had a weaker activation than RMs, and a different responding kinetic, both AGMs and RMs presented an increased IgKL repertoire diversity and lineages expansion. It suggested that the responding time rather than initiation of TLR7/8-induced IgKL repertoire response related to B cell activation. Expanded IgKL lineages with frequency from 0.001% to 1% had an elevated mutation rate and expanded IgH lineages used more IgA/G/E, suggesting that the TLR7/8 stimulation expanded low-frequent but high-mutated lineages. Besides, most of expanded IgKL lineages were {lambda} isotype. In conclusion, TLR7/8 selectively expands IgKL lineages with a high mutation rate, low frequency, and {lambda} isotype. The selective effect of TLR7/8 on BCR repertoire allows TLR7/8 agonists to be adjuvant for selectively accelerating antibody maturation.