The influence of dissolved oxygen on the mitogen responses of mouse lymphocytes

Mouse spleen cells incubated at either 30 mm Hg dissolved oxygen partial pressure (pO2) or 160 mm Hg did not differ significantly in their survival or in their proliferative response to the mitogens concanavalin A, phytohemagglutinin or bacterial endotoxin in a subsequent static culture. If the mitogen was added prior to exposing the cells to the controlled dissolved oxygen environment the incorporation of thymidine was always substanstially lower in cells held at 160 mm Hg pO2. This toxic effect of oxygen increased with the time of incubation and was not reversed by the inclusion of 2-mercaptoethanol in the medium. Incubation of cells with mitogen in the absence of oxygen had no deleterious effect on the proliferative response. A comparison of DNA, RNA and protein synthesis in Con A stimulated cells indicated that the predominant effect of oxygen was on DNA synthesis.