Cell collaboration in a marine teleost. A demonstration of specificity in the carrier effect

Abstract

The possible role of helper cells for the antibody response was studied in a marine teleost, the winter flounder ( Pseudopleuronectes americanus). The fish were injected with either fowl gamma-globulin (FGG), bovine gamma-globulin (BGG), or bovine serum albumin (BSA). Three weeks later they were immunized with a hapten conjugate, either NIP-FGG or NIP-BGG, and bled after another 3 weeks. A specific carrier priming effect was observed: animals immunized with NIP-FGG produced 10 times higher anti-NIP titres when they had been primed by FGG than when primed with BGG or BSA. The specific priming effect also held true for animals immunized with NIP-BGG; BGG priming was associated with 10 times higher anti-NIP titres than FGG priming. Sera of unimmunized winter flounders had higher natural anti-NIP titres than the sera of other animals tested, and immunization by NIP-FGG or NIP-BGG without carrier priming did not increase the background titre within 3 weeks. An 8-fold increase was observed in carrier-primed animals (average of 3 experiments) and a 100-fold increase in one group that was primed with whole hapten—carrier conjugate (a true secondary response, one experiment).