Delayed Hypersensitivity to Trichinella Spiralis

[摘要] Guinea pigs were sensitized four times at 1-, 2- or 3-week intervals with crude saline extract of Trichinella spiralis larvae emulsified in Freund's complete adjuvant, then skin-tested 28, 56 or 84 days after the initial sensitization. The skin-test reaction was not typical of delayed hypersensitivity but was somewhat like the Arthus reaction. Electron microscopic examination of the lymphocytes from these animals showed structural changes that are generally associated with synthetic functions. In addition, passive cutaneous anaphylaxis (PCA) and precipitating antibodies were detected in their sera. The 2-week interval between sensitizations proved optimal for synthetic activity and for antibody production of both γ1 and γ2 classes. Correlation was noted between the degree of antigenic stimulus and proliferation of cellular organelles associated with protein synthesis in lymphocytes. Indeed, with the largest dose and optimal interval of antigenic stimulation, fine-structure studies indicated the production of lymphocytes very much like plasma cells. Lymph node cells from repeatedly sensitized donor animals transferred to normal recipients elicited negligible skin reactions, somewhat like the Arthus rather than the delayed hypersensitivity type. Even on day 1 after transfer of cells from repeatedly sensitized donors, antibody was detected by PCA in recipients, especially when the donors had been sensitized at 2-week intervals. Since PCA antibody was detected within 24 hr after transfer, it seems likely that the lymphocytes themselves produce antibody in recipients, at least until the lymphocytes possibly can develop into another type. Precipitating antibody was not detected in any of the recipients by either micro-immunoelectrophoresis or the ring test. In contrast, the transfer of delayed hypersensitivity was successful with lymphocytes from donors sensitized only once irrespective of dosage. The present findings suggest that animals repeatedly sensitized by the antigen apparently “lose” delayed hypersensitivity.

[学科分类] 生物科学（综合）