Immune responses to bovine serum albumin in chicken lines divergently selected for antibody responses to sheep red blood cells.

Primary antibody and cutaneous hypersensitivity responses to BSA revealed differences between two lines of chickens that had been selected during 12 generations for either high (H) or low (L) antibody responses to SRBC. Levels of total and IgM BSA-binding antibodies at Day 8 postsensitization were significantly lower in the L line than in the H line and in a randombred control (C) line that originated from the same parental stock as the selected lines. Both the early and the late classical wing-web responses to BSA were absent in the L line. In contrast, peripheral blood leukocytes from all three lines proliferated equally well in vitro in the presence of BSA. Line by treatment effects were found for mitogen-induced lymphoproliferation in vitro. Peripheral blood leukocytes obtained from BSA-sensitized H line chickens exhibited lower proliferative responses to concanavalin A than peripheral blood leukocytes from C and L line chickens. These results suggest that differences in immune responses in vivo between the present chicken lines are expressed as antibody (-mediated immune) responses to T cell-dependent antigens. The similarity in immune responses to BSA of the H and C lines after 12 generations of divergent selection indicate that selection for an enhanced immune response to one (multiantigenic) antigen (SRBC) may not necessarily implicate improvement of immunity to another antigen (BSA).