No abstract

The fusion of NS-1 myeloma cells with spleen cells from mice chronically infected with Leishmania tropica resulted in nine clones of hybridomas producing monospecific antibodies to membrane antigens of L. tropica. One of the antibodies (L-5-85) bound specifically to the promastigote form of the parasite, and the remaining eight recognized antigens shared by the promastigote and amastigote of L. tropica. Four of the antibodies (L-5-16, L-5-34, L-5-44, and L-2-3F11) detected parasite antigens on the surface of L. tropica-infected macrophages. Common antigens shared by L. tropica, L. mexicana, and L. donovani were identified as well as one antigen apparent on most Leishmania spp. and present also in Crithidiafasciculata. Two monoclonal antibodies (L-5-27 and L-5-41) were found to bind only to strains of L. tropica from simple cutaneous leishmaniasis. A special property shared by these two antibodies was the inhibition of parasite growth in macrophages in vitro.

Summary The radioisotopic assay for acute granulomatous hypersensitivity (AGH) to eggs of Schistosoma japonicum in mice sensitized with eggs in adjuvant has been examined in the high responder strain. C57BL/6. Responsiveness is expressed as the lung‐kidney ratio of radioactivity in mice challenged intravenously with eggs and injected with 123I‐iododeoxyuridine, Eggs vary in their AGH sensitizing and eliciting potency; eggs proven to be superior in the circumoval precipitation (COP) test for detection of human serum anti‐S. japonicum antibodies are superior in the C57BL/6 AGH assay. CBA/H are non responders and BALB/c are low to intermediate responders and are thus different from C57BL/6 mice. Short‐term infected CBA/H mice are low COP antibody responders relative to infected C57BL/6 and titres of IgM anti‐egg antibodies are low in the CRA/H strain as determined in a solid‐phase radioimmunoassay (RIA). Following egg sensitization. CBA/H mice are also lower responders than C57BL/6 mice in terms of antibodies with the specificity of a COP‐positive IgM hybridoma‐derived antibody, P.41, measured in a competitive RIA. No evidence has been obtained that alteration of the response to the target epitope of P.41 alters the responsiveness of C57BL/6 mice to S. japonicum eggs. Thus, large amounts of injected P.41 antibody do not alter lung AGH and induced anti‐idiotype responses to the P.41 protein do not influence AGH in egg‐sensitized C57BL/6 mice. However, immunization of C57BL/6 mice with another IgM anti‐schistosome hybridoma antibody, 1.39, results in partial inhibition of lung AGH responsiveness. The nature of the effect of 1.39 immunization on AGH to eggs remains unknown, but further analysis of the phenomenon may lead to novel approaches to the control of granulomatous inflammatory disease in high responders.

SUMMARYMice experimentally infected with the hydatid parasite Echinococcus granulosus (secondary echinococcosis), were used as spleen cell donors for hybridoma production. Two hybridomas were produced which secreted antibody with anti-E. granulosus cyst fluid (EgCF) activity. Radio-immunoassays comparing the binding of these hybridoma-derived antibodies to E. granulosus versus several other antigen preparations from sheep parasites showed that the antibodies had a high degree of specificity for the hydatid parasite. However, using a panel of clinically defined sheep sera in a competitive radio-immunoassay, the binding of the hybridoma-derived antibodies to EgCF was inhibited strongly by sera from sheep infected with the common parasites Fasciola hepatica and Taenia hydatigena. When the hybridoma-derived antibodies were conjugated to CNBr-activated Sepharose and the crude EgCF applied to the affinity column, the ‘run through’ antigen preparation showed a significant increase in specificity for experimental E. granulosus infection. A useful means of applying the hybridoma technology in the development of new immunodiagnostic reagents may be to select those murine hybridomas which produce high-affinity, cross-reacting antibodies and to use these antibodies in the processing of homologous antigen by affinity chromatography.