Figure 3.

Host responses to infections. (A) Peritonitis. DH5α Escherichia coli bacteria (1 × 10⁸) containing an ampicillin-resistance plasmid were injected into the peritoneum. The following day exudate cells were recovered by lavage of the peritoneal cavity with 5 ml of PBS. White blood cells were collected by centrifugation and treated with 0.1% Triton X-100 to release ingested bacteria. Recovered bacteria were diluted and plated on an ampicillin-containing plate, and the number of colonies was counted. (B) Viral infection. Friend leukemia viruses (FLV; 1 × 10³ virons per mouse) or PBS was injected intraperitoneally. Spleen size was assessed by weight after 14 days. The data were presented as mean ± SEM. The P value was calculated from comparison of the two genotypes by a nonparametric analysis of variance for unrelated samples (Mann–Whitney test).