PRESENCE OF INOSINE MONOPHOSPHATE DURING CELL MEDIATED IMMUNITY IN GUINEA PIGS (IMP).

Abstract

The presence of the purine nucleotide inosine monophosphate (IMP) was studied in direct relationship to the development and expression of cell mediated immunity in guinea pigs using DNCB or Histoplasma capsulatum as sensitizing antigens. The IMP content of T-cell enriched lymphocytic lysates was measured by isocratic high pressure liquid chromatography (HPLC). Intracellular IMP levels of cells from homologously skin tested sensitized animals were significantly increased one day after skin testing when compared to the concentrations found in these cells during the period following sensitization. Concurrent with these observations were the findings that the absolute lymphocyte counts and histoplasmin stimulated in vitro blastogenic responses increased following sensitization while the PHA-induced proliferative response decreased slightly. One day after skin testing, when IMP levels had increased, there was a slight decrease in lymphocyte numbers and a marked decrease in the PHA response. Cells collected at this time and cultured in vitro with histoplasmin responded with increased levels of protein production and increased IMP levels. These data suggest (1) the proliferative response of cells from sensitized animals appears to be associated with lower levels of intracellular IMP, and (2) sensitized cells stimulated in vivo with antigen appear to have characteristically higher IMP concentrations.