125I-labelled ovalbumin (OVA) antigen did not sensitize guinea-pigs and anaphylaxis did not develop after native OVA challenge. The radiolabelled antigen was fixed by lymphocytes with highly specific receptors for 125I-OVA and this condition produced a continuous radiation damage leading to inactivation of the cells. As the proliferative response of lymphocytes did not occur, no antibody production was detected. This was demonstrated by passive haemagglutination techniques. However, the immune response to a simultaneously given non-radioactive antigen remained intact. It is supposed that radiation damage depended on specific activity of antigen destroying the antigen-specific lymphocyte clone selectively. The mechanism and the practical importance of the in vivo lsquo;antigen suicidersquo; is discussed.
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