Hapten-Specific, Carrier Dependent Cells in the Newt, Notophthalmus Viridescens

Abstract

We have investigated whether a primitive vertebrate possesses subsets of antigen reactive cells specific for the same hapten but activated by different carriers. Our data from co-immuniza tion protocols suggest that the newt, Notophthalmus viridescens may possess the same kind of heterogeneity recently described for mammals. The hapten, trinitrophenyl (TNP) was tested as conjugates of horse erythrocytes (HRBC), Ficoll or LPS. All TNPspecific responses were monitored in pooled spleens by immunocytoadherence. TNP-Ficoll and TNP-HRBC appear to activate separate reactive populations, since their co-immunization response is additive when compared to optimal responses with each immunogen alone. On the other hand, TNP-HRBC and TNP-LPS produce co-immunization responses no greater than one of the immunogens alone. The response to co-immunization with TNP-Ficoll and TNP-LPS shows a degree of overlapping indicating that some, but not all, of the reactive populations can respond to both. This heterogeneity, related to protection from bacterial pathogens, may be fundamental to vertebrate immunity.