FIG. 1.

Dose- and time-dependent expression of IFN-γ following E. coli challenge. (A) Mice (two per group) were injected i.p. with the indicated quantities of E. coli O111:B4 bacteria or LPS, and serum IFN-γ concentrations were measured 6 h later. This experiment was repeated with similar results. (B) Mice (three per group) were challenged i.p. with 100 μg of LPS, and their sera were collected at the indicated times. The serum IFN-γ concentration was measured by enzyme-linked immunosorbent assay. A similar time course was obtained with mice challenged with viable E. coli bacteria.