Impaired cell-mediated immunity in experimental abdominal sepsis and the effect of interleukin 2.

A murine model of experimental sepsis, ie, cecal ligation and puncture, was used to determine the potential effects of infection on in vitro cell-mediated immunity. Following cecal ligation and puncture, in vitro responses of mouse splenocytes to mitogens (phytohemagglutinin and concanavalin A), the effects of in vitro interleukin 2 on these responses, and the impact of in vivo interleukin 2 on survival were studied. Compared with controls (sham cecal ligation and puncture), phytohemagglutinin responses 1 day after cecal ligation and puncture were enhanced (43% +/- 17%, n = 9), phytohemagglutinin and concanavalin A responses at day 4 were suppressed (45.5% +/- 4.4% and 57.5% +/- 5.6%), and, by day 7, phytohemagglutinin and concanavalin A responses were approaching values in mice treated by sham cecal ligation and puncture. Suppressed phytohemagglutinin responses at day 4 after cecal ligation and puncture were restored to normal with in vitro interleukin 2 (61,052 +/- 3407 cpm for cecal ligation and puncture and 64,643 +/- 4727 cpm for sham cecal ligation and puncture). Mortalities following cecal ligation and puncture were identical at day 1 after cecal ligation and puncture (6/20) for both interleukin 2- and vehicle-treated groups; thereafter, interleukin 2-treated groups fared better. At day 1 after cecal ligation and puncture, the mean spleen cell phytohemagglutinin response was enhanced (43.8% +/- 17%, n = 9) compared with sham cecal ligation and puncture (= 10). By day 4, the responses to both concanavalin A and phytohemagglutinin were suppressed (45.5% +/- 4.4% and 57.5% +/- 5.6%, respectively). Responses at day 7 approached those of controls given sham cecal ligation and puncture. Sepsis causing a temporary impairment of cell-mediated immunity may be a factor in the frequent coexistence of altered cell-mediated immunity and sepsis, and interleukin 2 may have a role in limiting the adverse effects of sepsis.