FIG. 4.

Reduced CD62L expression on secondary memory cells compared to primary memory cells. BALB/c mice were immunized i.p. either once or twice (21 days after the first immunization [D21]) with 30 pmol of LT-NP. Splenocytes were harvested 28 days later, enriched for T cells, and analyzed by flow cytometry. (A) Representative dot plots from individual mice demonstrating the distribution of CD62L^high and CD62L^low cells. Plots were gated on CD8⁺ L^dNP⁺ cells. (B) Percentages of CD62L^high and CD62L^low cells among CD8⁺ L^dNP⁺ cells from 10 to 16 mice per group compiled from three independent experiments. CD62L^high and CD62L^low were defined based on the gates indicated in panel A. (C) Calculated percent increases in the numbers of CD62L^high and CD62L^low cells 28 days after a second LT-NP immunization compared to the numbers 28 days after a first immunization.