AN INTERFERON-GAMMA (IFN-GAMMA) BASED WHOLE-BLOOD ASSAY TO DETECT T-CELL RESPONSE TO ANTIGENS IN HIV-1-INFECTED PATIENTS

Recently it has been reported that cytokine production by T cells in r esponse to antigens may be more sensitive test than lymphoproliferatio n. T cell reactivities to antigens is usually performed on isolated PB MCs, however whole blood is being used frequently for cytokine product ion studies. A whole blood assay is described to measure T cell mediat ed immune responses to HIV-1 and recall antigens. The cultures were pe rformed in 96-well plates in which only 25 mu l of whole blood was req uired. We studied the production of IFN gamma in short term culture (2 4 hours) of 1/10 diluted heparinized whole blood (HWB) from 22 HIV-1 ( +) patients grouped according to the 1993 classification of the CDC. I FN gamma was measured with an immunoassay in supernatants of HWB cultu red in parallel experiments in the presence of supernatant of HIV-1(LA I) infected CD4 + T cells, p24 HIV antigen, PPD, tetanus toroid (TET) and PHA. We found no production of IFN gamma in response to HIV-1 anti gens in 15 HIV-1 (-) subjects; whereas a specific IFN gamma production in the presence of HIV-1 antigen was obtained in all of the 9 group A patients, in 7 of 8 group B patients and in 2 of 5 group C patients. In response to recall antigens (TET, PPD), we obtained IFN gamma produ ction in 6 of 9 group A patients, 5 of 8 group B patients and in 1 of 5 group C patients, the response to PHA decreased but remained preserv ed until late in the disease. The HWR assay is a quick and simple pote ntially valuable tool for assessing cellular immune function in HIV-1 + patients.