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Antigenic competition in the induction of contact sensitivity in mice
Abstract:
Antigenic competition in contact sensitivity was found to occur between DNFB and PCl and also between some other pairs of non-cross reacting sensitizers. When mice were painted with DNFB 0-7 days before the sensitization with PCl, the responsiveness to PCl was suppressed completely, whereas when DNFB was painted after sensitization with PCl, the responsiveness to PCl was affected. The prior application of DNFB resulted in the reduction of DNA synthesis in the draining lymph nodes of PCl-sensitization. This indicated that the suppression by painting with DNFB was not attributable to the inactivation of PCl-specific effector T cells which had already been generated by the sensitization with PCl, but to the inhibition of the generation of PCl-specific effector T cells. The antigenic competition occurred even when two contact sensitizing agents were applied to different lymphoid regions of mice. The suppressive effect of DNFB on the PCl-sensitization was observed also in the mice which had been made tolerant to DNFB. These results seem to imply that the antigenic competition in the present experimental system is the phenomenon which may not be mediated by effector T cells but rather by other cells, possibly suppressor cells.
Insights
Antigenic competition suppresses immune responses to sensitizing agents like DNFB and PCl. Prior application of one sensitizer inhibits the generation of responses to the other, suggesting a role for suppressor cells rather than effector T cells.
Area of Science:
- Immunology
- Dermatology
- Cellular Biology
Background:
- Contact sensitivity involves immune responses to chemical sensitizers.
- Antigenic competition describes the phenomenon where exposure to one antigen can suppress the immune response to another.
- Understanding the mechanisms of antigenic competition is crucial for immune modulation.
Purpose of the Study:
- To investigate the phenomenon of antigenic competition between different contact sensitizing agents, specifically DNFB and PCl.
- To elucidate the underlying cellular mechanisms responsible for this suppressive effect.
- To determine whether effector T cells or other cell types mediate antigenic competition.
Main Methods:
- Mice were sensitized with 2,4-dinitrofluorobenzene (DNFB) and picryl chloride (PCl) at varying time points.
- Contact sensitivity responses were assessed.
- DNA synthesis in draining lymph nodes was measured.
- Experiments were conducted in DNFB-tolerant mice.
Main Results:
- Prior application of DNFB significantly suppressed the sensitization response to PCl, indicating antigenic competition.
- This suppression was linked to reduced DNA synthesis in lymph nodes, suggesting inhibition of effector T cell generation.
- Antigenic competition occurred even when sensitizers were applied to different sites and in tolerant mice.
- Results suggest suppressor cells, not effector T cells, may mediate this competition.
Conclusions:
- Antigenic competition between contact sensitizers like DNFB and PCl inhibits the generation of immune responses.
- The mechanism appears to involve suppression of effector T cell generation, potentially mediated by suppressor cells.
- These findings have implications for understanding immune regulation and developing strategies for immune modulation.