T cell-independent B cell memory.

Despite being unable to mount a bona fide recall antibody (Ab) response to secondary immunization, T cell-independent antigens (TI Ag) such as pneumococcal capsular polysaccharides (PS) can generate protective humoral immunity in adults. The concept of TI B cell memory after being iconoclastic for decades has now received experimental support from several laboratories. TI B cell memory comprises two components: i) memory B lymphocytes that differ phenotypically and functionally from their T cell-dependent counterparts, ii) memory bone marrow plasma cells that play a crucial role in the immune protection conferred by TI polysaccharidic vaccines. B-1b cells constitute the major source of both TI memory lymphocytes and plasma cells. This conceptual shift should lead to rehabilitate the TI arm of the immune system for vaccination purposes.
(Copyright © 2011 Elsevier Ltd. All rights reserved.)