FIG. 2.

A. marginale-specific antibody and proliferative responses of PBMCs and splenocytes over the course of infection with A. marginale Florida strain. (A and B) Animals 33875 and 33901 were infected intravenously with A. marginale Florida strain-infected erythrocytes, and A. marginale-specific antibody was measured weekly with C-ELISA; (C to F) A. marginale-specific lymphocyte proliferation was performed with fresh PBMCs (C and D) or splenocytes (E and F). Cells were collected every 3 to 7 days during acute infection and in general weekly thereafter. Asterisks denote significant responses compared with those on the URBC membrane, where P is <0.05. (G and H) Proliferation specific for an unrelated vaccine antigen, Clostridium sp. vaccine antigen, was determined using fresh PBMCs and splenocytes, and responses were significant at all time points (although they are not indicated by asterisks). All graphs are superimposed over levels of bacteremia, presented as log₁₀ number of organisms/ml of blood, for 110 days following infection. (I) Cryopreserved lymphocytes from selected time points with significant A. marginale-specific proliferation were depleted of either CD4⁺ cells or CD8⁺cells and γδ T cells, and proliferation assays were performed. Significant decreases in proliferation compared to that of the nondepleted cell line are denoted with asterisks, where P is <0.05.