Cellular Immunology · Jul 11, 2017

The properties of the unique age-associated B cell subset reveal a shift in strategy of immune response with age

By Swain SL, Kugler-Umana O, Kuang Y et al.

In aged mice, conventional naive B cells decrease and a new population of age-associated B cells (ABC)³ develops. When aged unprimed mice are infected with influenza virus, there is a reduced generation of helper CD4 T cell subsets and germinal center B cells, leading to limited production of IgG Ab and less generation of conventional long-lived plasma cells, compared to young. However, we find an enhanced non-follicular (GL7⁻) ABC response that is helper T cell-independent, but requires high viral dose and pathogen recognition pathways. The infection-induced ABC (iABC) include IAV-specific Ab-secreting cells, some of which relocate to the bone marrow and lung, and persist for >4wk., suggesting they may provide significant protection. We also speculate there is a shift with increased age to dependence on TLR-mediated pathogen-recognition in both B and CD4 T cell responses.

doi.org/10.1016/j.cellimm.2017.05.009PubMed 28712455Mechanisms