Nonspecific entry of thoracic duct immunoblasts into intradermal foci of antigens

Abstract

Lymph borne immunoblasts were obtained by collecting thoracic duct lymph from inbred rats 3–5 days after either killed C. parvum, B. abortus or B.C.G. organisms had been injected subcutaneously into the hindquarter regions to stimulate the caudal lymph nodes. By incubating the lymph cells with a radioactive precursor of DNA, 5-iodo-2-deoxyuridine- 125I, the immunoblasts became labelled but the small lymphocytes did not. The labelled cells were washed and injected intravenously into syngeneic recipients which had had intradermal injections of various antigens at various previous times. The entry of labelled cells into these injection sites was monitored by counting the radioactivity that they contained up to 24 hr later. It was found that the accumulation of radioactivity in the skin lesions was maximal 12 hr after the donor cells had been injected, but the immunological specificity of the donor immunoblasts did not affect significantly the extent to which they entered lesions which contained the same or unrelated antigens. It was found also that the sites of intradermal injections of B.C.G. or C. parvum always attracted more immunoblasts than sites containing other antigens; this was a non-specific effect, thought to be related to the adjuvant properties of these organisms.