MECHANISMS OF PROTECTIVE IMMUNITY IN EXPERIMENTAL CUTANEOUS LEISHMANIASIS OF GUINEA-PIG .3. INHIBITION OF LEISHMANIAL LESION IN GUINEA-PIG BY DELAYED-HYPERSENSITIVITY REACTION TO UNRELATED ANTIGENS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 29  (2) , 320-325
Abstract
This investigation was done to determine whether prior induction of a nonspecific delayed reaction at a site of leishmanial infection could modify the couse of infection. Groups of animals were made hypersensitive to DNCB [dinitrochlorobenzene] or BCG, and a delayed reaction was elicited by corresponding antigen in 1 or both ears where an infective dose of Leishmania enriettii was inoculated. With various experimental designs the following results were obtained: induction of delayed reaction by DNCB or BCG inhibited the development of leishmanial lesions; the protection was effective only when delayed reaction occurred at the site of infection; to be effective, the reaction had to be continuously present at the site of infection for at least 3-4 wk; lesions developed normally, in the absence of delayed reaction, in DNCB-tolerant animals treated with DNCB; a protective delayed reaction did not completely eliminate the parasites from the host tissues, since metastatic lesions appeared later at ectopic areas and the suppressed development of a lesion did not confer resistance to reinfection with the usual infective dose of the parasite. Cell-mediated immunity apparently palsy an important role in healing leishmanial lesions in the guinea-pig. The final effector mechanism may be sought in the nonspecific microbicidal capacity of activated macrophages. The relevance of leishmania-specific delayed reaction in the course of the disease is discussed.