An in vitro method of detecting a cell-mediated immune response to a specific antigen in a human or animal comprises (a) incubating a whole blood sample from the human or animal with the specific antigen and (b) detecting the presence of gamma interferon (gamma IFN) released by sensitised lymphocytes in the whole blood sample to indicate a cell-mediated immune response to the specific antigen. Pref. the gamma IFN is detected using an emxyme-linked immunosorbent assay or a radioimmunoassay. 
IN-VITRO-TESTVERFAHREN ZUM NACHWEIS ZELLULAERER IMMUNRESPONSEN.