Regulation of CD28 and CD154 (CD40L) expression on CD4⁺ cells by MIP-1α and MIP-1β.

Spleen cells from DO11.10 mice were incubated with 0, 1, 10, 100, or 1000 ng/mL MIP-1α (triangles) or MIP-1β (squares) in plates containing 0 (open symbols) or 500 (filled symbols) μg/mL OVA. The percent increase (or decrease) of the costimulatory molecule expression by resting (open symbols) or OVA-activated (filled symbols) T cells was calculated as the percent of double-positive CD4⁺ and CD28⁺ or CD154⁺ cells in cultures containing MIP-1α or MIP-1β minus the percent gated of double-positive cells in cultures without these chemokines, divided by the latter. Studies were repeated 3 times, and the data presented are the mean percent changes ± SEMs of these experiments.