Release of interleukin-2 induced by a major antigenic outer membrane protein of Shigella dysenteriae type 1 in natural infection.

An antigen specific modulation of peripheral blood lymphocyte function was examined in a patient-based study of Shigella dysenteriae type 1 infection. Interleukin-2 (IL-2) production by the peripheral blood mononuclear cells (PBMC) from Shigella-infected patients was correlated with the expression of host cellular immune responses. To evaluate the role of a 57 kD major antigenic outer membrane protein of S. dysenteriae 1 in the proliferation of PBMC and the production of IL-2, the in vitro blastogenic transformation assay was employed. The magnitude of the response was monitored morphologically as well as by the proliferation of the IL-2 dependent CTLL-2 cell line. The proliferation of the IL-2 dependent CTLL-2 cell line against PBMC culture fluids after exposure to the major antigen reflected the participation of functionally active T-lymphocytes in shigellosis patients. The precise quantitation of IL-2 concentration in such lymphocyte culture supernatants by immunoassay showed substantial production of IL-2.