ENUMERATION OF LYMPHOKINE-SECRETING CELLS AS A QUANTITATIVE MEASURE FOR CELLULAR IMMUNE-RESPONSES IN RHESUS MACAQUES

We investigated whether enumeration of lymphokine-secreting T cells ca n be used as a quantitative measure to determine the immunogenicity of foreign proteins in rhesus monkeys. In addition, it was assessed whet her this approach can supplement and/or substitute for the well-establ ished lymphoproliferation assay. Two candidate vaccine proteins (e.g., HIV-1 gp120 and HSV-2gD) were used as model antigens for immunization , PBMCs from immunized animals were antigenically stimulated and evalu ated on their proliferative capacity and lymphokine release at the sin gle cell level. The experiments showed a close quantitative correlatio n between antigen-triggered proliferative responses and the antigen-in duced generation of Il-2 and IFN-gamma producing cells (pc). Il-4pc we re found to appear relatively late after the initiation of antigen exp osure. The data indicate that ELISPOT assays provide valuable tools fo r the assessment of the antigenicity of foreign proteins in vivo.