Cutaneous hypersensitivity responses in chickens divergently selected for antibody responses to sheep red blood cells.

Cellular immunity in vivo of chickens selected for high and low antibody responses to SRBC was evaluated by primary and secondary cutaneous hypersensitivity reactions to BSA and phytohemagglutinin (PHA)-induced delayed-type hypersensitivity (DTH). Similar to PHA-induced DTH, primary and secondary cutaneous hypersensitivity to BSA comprised acute (1- and 2-h), intermediate (4- and 6-h), and late (24-h) wing web swelling responses. Primary and secondary hypersensitivity to BSA revealed line differences between the High (H) line and a randombred Control (C) line on the one hand, and the Low (L) line on the other hand. Hypersensitivity to BSA was almost absent or decreased in the L line. The late phase of PHA-induced DTH was significantly elevated in the H line as compared with the L line. Naive recipients sensitized systematically with either serum from chickens sensitized with BSA, or with BSA-binding IgG, developed an antigen-specific early wing web swelling response following local challenge with BSA. It is suggested that the acute component of cutaneous hypersensitivity is mediated by Ig. The acute response may be a prerequisite for the development of classical (late) cutaneous DTH responses or may be initiated simultaneously with DTH. The current results indicate that the selection did not result in a higher hypersensitivity response to another T cell-dependent antigen and a mitogen in the H line, but in a lower response in the L line.