Effect of temperature on polymorphonuclear leukocyte function.

The effect of temperature on the function of polymorphonuclear leukocytes (PMN) has been investigated in vitro. Increases in temperature from 37 degrees C to 40 degrees C progressively increased chemiluminescence (CL) responses by PMN after stimulation by Staphylococcus aureus, zymosan or phorbol myristate acetate (PMA) while increases above 40 degrees C decreased these functions. Temperature increases from 37 degrees C to 40 degrees C also produced increased PMN bactericidal activity against S. aureus. In contrast, similar increases in temperature did not change superoxide production by PMN stimulated by PMA. Incubation of PMN at the various temperatures did not cause release of LDH indicating that damage to PMN was not the cause of reduced PMN chemiluminescence and bactericidal activity seen within the temperature range studied. The discrepancy between the influence of temperature on PMN chemiluminescence and bactericidal activity of PMN compared to superoxide anion production by PMN suggests that superoxide anion production may not be solely, or at least directly, responsible for killing of bacteria. Careful temperature control is needed when assaying PMN function. Febrile responses up to 40 degrees C may play a beneficial role in host defense.