CD4(+) T cell activation and tolerance induction in B cell knockout mice

B cell knockout mice mu MT/mu MT were used to examine the requirement for B cell antigen (Ag) presentation in the establishment of CD4(+) T cell tolerance. CD4(+) T cells from mu MT mice injected with exogenous protein Ag in adjuvant responded to in vitro challenge by transcription of cytokine mRNA, cytokine secretion, and proliferation. Peripheral tolerance could be established in mu MT mice with a single dose of deaggragated protein. This tolerance was manifested by a loss of T cell proliferation and cytokine production (including both T helper cell type 1 [Th1]- and Th2-related cytokines), indicating that B cells are not required for the induction of peripheral T cell tolerance and suggesting that the dual zone tolerance theory is not applicable to all protein Ags and is not mediated through Ag presentation by B cells.