The effect of adult thymectomy upon helper function in Xenopus laevis, the South African clawed toad.

Carrier-primed helper activity enhancing anti-hapten (TNP-) responses in young adult Xenopus laevis reached peak levels 2-4 days after a low dose challenge (0.005% RBC) of unconjugated carrier. It fell quickly to negligible levels by 10 days. Adult thymectomized (ATx) animals were consistently unable to generate substantial levels of hapten-specific antigen-binding spleen cell (ABC) activity. Since ATx does not severely reduce splenic ABC responses to the high dose (10% RBC) of carrier used for hapten challenge, the results suggested a role for Xenopus adult thymus in carrier-specific enhancement of an anti-hapten response.