Primed allogeneic reactions to leukocytes and epithelial cells in the bicolor damselfish.

ABSTRACT

The studies presented here describe allogeneic reactions in the bicolor damselfish, Pomacentrus partitus, a tropical marine teleost. Damselfish were immunized twice at 2-week intervals either by placement of reciprocal allografts or with primary cultures of epithelial cells. Two weeks after the second immunization, recipient splenocytes were tested for alloreactivity toward donor and third-party pronephros cells. For those animals immunized with cultured cells, reactivity toward donor and third-party epithelial cells was also examined. Unprimed animals responded to allogeneic pronephros between days 8 and 10 (28 degrees C). Fish immunized with epithelial cells showed accelerated mixed leukocyte reactions, with optimal responses occurring between days 4 and 6. Moreover, responses to the immunogen preceded responses to donor pronephros tissue by 2 days, occurring on day 2 or day 4. In addition, primed responses were of significantly greater magnitude than primary reactions. Reactivity toward third-party pronephros tissue paralleled responses of naive animals, indicating the specificity of response. No reactivity toward epithelial cells was observed in the absence of immunization, suggesting that accessory cell functions of damselfish pronephros and epithelial cells differ.