The Hoeppli phenomenon in schistosomiasis. II. Histochemistry

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An electron microscopic study of leukocyte emigration and vascular permeability in tuberculin sensitivity

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In vitro demonstration of cellular sensitivity in allergic encephalomyelitis

Peritoneal cells obtained from animals exhibiting delayed hypersensitivity are inhibited from migrating in vitro by specific sensitizing antigen. This test for the detection of delayed hypersensitivity was applied to the problem of cellular sensitivity in allergic encephalomyelitis (AE). The migration of peritoneal cells obtained from guinea pigs with AE was inhibited specifically by nervous tissue antigens. The specificity of this reaction was further studied. Neonatal rat nervous tissue, which was shown to lack the encephalitogenic antigen, i.e. did not produce AE when injected with complete adjuvant into guinea pigs and rats, did not inhibit the migration of cells from animals with AE. Adult rat nervous tissue, which readily produces AE, and thus contains the encephalitogenic antigen did inhibit the migration of such cells. The finding that cells from animals with AE display hypersensitivity which appears to be directed specifically to the encephalitogenic antigen strongly supports the view that such cells could play an important role in the pathogenesis of this disease.

A cellular study of tuberculin sensitivity

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The effect of irradiation on the fever of delayed hypersensitivity

The effect of total body irradiation on the development of delayed hypersensitivity and on the febrile response to specific antigen has been studied in guinea-pigs with the following results:

1. 200 R. whole body irradiation in guinea-pigs, while suppressing circulating antibody response, did not prevent the development of delayed hypersensitivity.

2. Irradiated and non-irradiated hypersensitive animals had an equal febrile response to systemic challenge with specific antigen.

3. Serum from antigen-challenged, irradiated, hypersensitive animals contained a pyrogenic factor of the endogenous serum type capable of producing fever in normal recipients.

These results support the conclusion that production of circulating specific antibody is not essential either for development of delayed hypersensitivity or for the febrile response of the hypersensitive animal to specific antigen.