STUDIES ON IMMUNOLOGICAL UNRESPONSIVENESS DURING SECONDARY DISEASE III. Effect of Donor Strain on Acquisition of Mutual Tolerance

Colony Inhibition of Fibroblasts from Chimeric Dogs Mediated by the Dogs' Own Lymphocytes and Specifically Abrogated by Their Serum

“…The most common explanation is that those lymphoid cell clones that would have been reactive against the foreign alloantigens of the host have been made "tolerant," i.e., specifically nonreactive.8-13 Alternatively, it has been suggested that a phenomenon analogous to immunological enhancement may be involved, by which a chimeric individual's serum can protect against such cellular immune reactions that would otherwise lead to destruction of its own cells. [14][15][16] Hellstrom et al have employed an in vitro test, colony inhibition, to demonstrate specific cellular immunity to tumor antigens. "7 18 Inhibition of colony formation of plated target tumor cells was seen in both animal and human systems after exposure of the target cells to lymphocytes from animals or human patients with tumors.…”