BIOLOGICAL EFFECTS OF ESCHERICHIA-COLI LIPOPOLYSACCHARIDE (LPS) INVIVO .2. SELECTION IN MOUSE THYMUS OF PHA-RESPONSIVE AND CON A-RESPONSIVE CELLS

Abstract

The effect of LPS injection on mouse thymocytes [T cells] was examined by in vitro stimulation with PHA [phytohemagglutinin] and Con A [concanavalin A]. Thymocytes from LPS treated mice were more responsive than normal thymocytes to PHA and Con A. The increase of responsiveness was different for PHA and Con A and dependent on the dose of LPS injected. This dose dependency suggests that LPS in vivo modifies the thymocyte population by progressively eliminating T1 cells and selecting T2 cells. These effects seem to be mediated by corticosteroids because they were prevented by adrenalectomy, a finding in agreement with the notion that the injection of cortisone induces similar cell changes in the thymus.