Fig. 1.

Immunization with 3K peptide and LPS generates memory CD4 T cells but injection of 3K into naive animals leads to antigen-specific T-cell tolerance. Naive B6 mice were injected with 3K peptide or 3K peptide and LPS i.v. and the percentages of live CD4⁺ dump negative cells that were IA^b/3K tetramer⁺ CD44^hi in the spleen examined 46 d later (Upper row). Alternatively, 40 d following immunization, these mice and naive controls were immunized with 3K-OVA delivered with alum i.p. and the percentages of IA^b/3K tetramer⁺ CD44^hi out of live CD4⁺ dump negative cells examined in the spleen after a further 6 d (Lower row). The data are representative plots from two experiments with four mice per group. The cells are gated on CD4⁺ live lymphocytes that do not express CD8, F4/80, MHC II, and B220. The numbers indicate the percentages of gated CD4 T cells that are CD44^hi IA^b/3K tetramer⁺.