Functional analysis of human memory B-cell subpopulations: IgD+CD27+ B cells are crucial in secondary immune response by producing high affinity IgM.

摘要: The number of memory B cells in peripheral blood has been assayed various diseases by using CD27 as a B-cell marker. However, the defining differences characteristic and function between two subpopulations separated immunoglobulin (Ig)D expression remain to be clearly elucidated. We analyzed here IgD(+)CD27(+) (circulating 2, cB2) IgD(-)CD27(+) (cB3) comparison with IgD(+)CD27(-) naive (cB1). cB2 were found morphologically similar cB3 abundant cytoplasm, whereas expressed CD80, CD86, CD95 on their surface more predominantly than cB2. A majority both IgD IgM, IgA or IgG. Mature gamma1 gamma2 transcripts cB3, but at very low levels cB2, activation-induced cytidine deaminase (AID) mRNA was recognized only cB3. frequencies somatic hypermutation comparable studied VH5. did not shift vitro stimuli such via receptor CD40. produced large amounts IgM promptly, which is accordance known characteristics cells. Taken together, although are unclass-switched, have functions process transition from switched cells, playing crucial role secondary immune response producing high-affinity early phase infections.