Transplantation Tolerance at the T-Lymphocyte Receptor Level II.

Abstract

CBA T lymphocytes deprived temporarily of receptors for alloantigens A[RS(A)] cultivated <i>in vitro </i>for 30 h with anti-receptor antibody-forming (AxCBA)F<sub>1</sub> spleen cells were capable of resynthesizing RS(A) if primed F<sub>1</sub> cells exceeded parental T cells by a factor of 25 or less, but not if the excess was 50-fold or more. This indicated that resynthesis of CBA T-cell RS(A) was successful if primed F<sub>1</sub> cells formed insufficient amounts of anti-CBA T-cell RS(A) antibody. Abortive or successful receptor resynthesis was measured by two parameters, (a) reappearing RS(A) formed PAR together with A alloantigens of (A×CBA)F<sub>1</sub> spleen cells and (b) budding receptors bound anti-receptor antibody. CBA B lymphocytes did not interfere with these reactions. A search for putative T suppressor cells in the F<sub>1</sub>cell population was unsuccessful. PAR formation and anti-RS antibody consumption by reappearing receptors differed temporally: receptors forming PAR were present after a delay lasting 8 h; receptor structures fixed anti-RS antibody as early as 5 h after being cultivated. With due caution, these results might reflect processes operating in maintenance of transplantation tolerance, suggesting that this condition is a serum-mediated suppression of long duration. The suppression would encompass continued neutralisation of receptors for the alloantigen to be tolerated by anti-T-cell receptor antibody formed by the F<sub>1</sub> chimeric cells within an animal with acquired transplantation tolerance.