Figure 4

SP-A has a significant inhibitory effect on antigen specific lymphocyte proliferation from mice sensitized and challenged with Af. (A): Baseline (unstimulated) proliferation of splenic lymphocytes. Endotoxin in concentration equivalent to the endotoxin content of the 10 μg/ml SP-A samples did not affect cell proliferation. (B): In vitro Af stimulated proliferation of cells from mice sensitized and challenged with Af was inhibited by presence of SP-A, in a dose-dependent manner. (C): The Af dose-response curve of sensitized lymphocytes was abrogated in the presence of SP-A (10 μg/ml). (D) Presence of SP-A inhibited murine lymphocytes stimulated with PMA (2 ng/ml) and ionomycin (100 ng/ml). Background cpm (from wells that contain no cells): 0–16. Mean ± SEM of n = 4 independent experiments presented, each performed in triplicates. * p < 0.05: 0 vs. 10 μg/ml