Refractoriness to Pyrogens. Effects of Incubation of Pyrogen With Plasma From Normal and Refractory Donors on the Responses of Refractory Recipients

Abstract

Refractoriness to pyrogens resulting from daily injns. involves increased latency and diminished febrile reaction. Incubation of the pyrogen with plasma or serum from non-refractory rabbits before injn. into refractory test rabbits resulted in abolition of the increased latency and partial restoration of febrile responses (40 tests on 22 rabbits). Incubation of pyrogen with plasma from refractory rabbits had no such effects (17 tests on 12 rabbits). These differences are statistically strongly significant. It is suggested that pyrogen fever involves initial reaction of the injected pyrogen with plasma to form an "endogenous" pyrogen, that refractoriness involves loss of ability to carry out this plasma-pyrogen reaction and that it may involve no other changes.