In vitro reactivities of blood lymphocytes from symptomatic and asymptomatic pigeon breeders to antigen and mitogens.

The proliferation of blood lymphocytes in response to pigeon gammaglobulin in the presence or absence of IL2 was measured in 9 symptomatic and 12 asymptomatic pigeon breeders and 24 controls. The symptomatic breeders exhibited spontaneous lymphocyte proliferation (p less than 0.001) when compared with controls whilst lymphocytes from asymptomatic breeders required the simultaneous addition of IL2 in order to proliferate (p less than 0.001). IL2 alone did not induce cellular proliferation. Both patient groups had abnormal T-cell functions and response to lectins and, in the symptomatic group, there existed an inverse correlation (r = -0.70, p less than 0.001) between specific antibody titres to pigeon gammaglobulin and the Con A response. We conclude that both patient groups have circulating, presensitized antigen-specific lymphocytes but these require different stimulatory signals at the cellular level.