Francisella tularensis-specific T-cell clones are human leukocyte antigen class II restricted, secrete interleukin-2 and gamma interferon, and induce immunoglobulin production.

T-cell clones (TLC) were established from a Francisella tularensis-vaccinated subject in order to study the cells responsive for cell-mediated immunity against F. tularensis. All the clones were human leukocyte antigen (HLA) class II restricted to one of the HLA-DR specificities of the original donor. The TLC cells were CD4+ and produced interleukin-2 and gamma interferon after stimulation with specific antigen. Seven of the eight clones tested assisted in the production of immunoglobulin G (IgG), IgA, and IgM antibodies.