Early determination of B cell fate

Antibody responses by B cells become more specific over time in a process known as 'affinity maturation', but the role of antibody affinity for antigens in controlling B lymphocyte selection remains unclear. In 20 May Nature Immunology, Tien-An Yang Shih and colleagues from Rockefeller University, New York, show that strict selection for high-affinity B cell clones is imposed at an early stage of the T cell-dependent immune response in vivo (Nat Immunol 2002, DOI: 10.1038/ni803).

Shih et al. compared T cell-dependent immune responses to the hapten 4-hydroxyl-3-nitrophenyl acetyl (NP) in mice that carry targeted V_HB1-8 antibody genes with high or low antigen-binding affinity. They observed that high and low-affinity B cells were equally able to respond to antigen in the absence of competition. But when limiting numbers of high- and low-affinity B cells were mixed in wild type recipient mice, only the high-affinity B...