Numbers of interleukin-12 (IL-12)-producing cells were quantitated in
the peripheral blood of healthy donors and tuberculosis patients by th
e ELISPOT assay. We observed that (i) stimulation with mycobacteria in
creases numbers of IL-12 producers from healthy donors and (ii) tuberc
ulosis patients have larger numbers of IL-12 producers than healthy do
nors. Our data emphasize the importance of IL-12 in immunity to tuberc
ulosis.