FIG. 2.

Dose-dependent, antigen-specific proliferative responses of PBMC from MSP-2-immunized calves. PBMC were obtained at 2 (calves 57, 60, 61, 63, and 65) or 3 (calf 59) weeks following the fifth antigen inoculation and tested for proliferation against 0 to 25 μg of membrane antigen prepared from A. marginale or URBC per ml. Cells were cultured for 6 days, radiolabeled, harvested, and counted on a scintillation counter. Data are the means ± the SEM of triplicate cultures. For the response to 25 μg of A. marginale per ml, SI values are also indicated.