The substitution of carrier priming of helper function in the common American newt, Notophthalmus viridescens by lectins and human lymphokines.

There is no clear evidence that helper function is thymus dependent in the Common American newt, Notophthalmus viridescens. Here we test the capacity of concanavalin A, wheat germ agglutinin, human rIL-1 and rIL-2, reagents which stimulate T cell activities in other species, to substitute for carrier priming in the newt. Cytofluorimetric analyses have been used to demonstrate specific IL-2 receptor binding sites on newt splenocytes. Competitive pre-binding with rIL-2 tested whether anti-IL-2 receptor antibody binding sites would bind rIL-2. While Con A can substitute for carrier priming in the newt only when it is presented on Sepharose or agarose particles, wheat germ agglutinin cannot, even when it is injected in particulate form. Additionally, human rIL-1 can serve as an effective substitute for carrier priming, but rIL-2 cannot. The cytofluorimetric data are in agreement with the functional data in that they suggest that human rIL-2 may not bind newt splenocytes. Our data which show shared lectin specificities with T cell regulated helper function in another amphibian species are consistant with the possibility that T-like cells are responsible for helper function in this species.