The cell-mediated response to schistosomal antigens at the clonal level: development and characterization of a panel of egg antigen-specific murine T cell clones.

The cellular basis of the immune response underlying the granulomatous hypersensitivity in experimental murine schistosomiasis caused by Schistosoma mansoni was investigated by examining a panel of 16 egg antigen-specific T cell clones. The clones were derived from a sensitized T cell line by limiting dilution, and were selected on the basis of their strong responses against schistosomal egg antigens. By cytofluorographic analysis, it was determined that all clones were T helper cells and expressed the CD3+CD4+CD8- phenotype. Lymphokine analysis revealed that some clones secreted either interleukin (IL)-2 or IL-4, but a surprisingly large number were double producers. Southern blot analysis verified the clonality of these T cells and indicated that the clones examined included at least five independent clones by the criterion of T cell receptor beta gene rearrangements. Despite their diversity, the clones responded strongly, and virtually exclusively, to egg antigen components with isoelectric points in the limited range of 4.7 to 5.2. The relevant antigenic egg molecules were shown to require processing by accessory cells for presentation to, and stimulation of, the T cell clones.