FIG. 1.

C3H/HeN and BALB/c mice develop inflammatory lesions that are more severe than do C57BL/6 mice after mycoplasma infection. Mice were inoculated with either M. pulmonis or sterile broth, and 14 days later the lungs were collected for histological examination. There were no cellular infiltrates in the lungs of C3H/HeN mice inoculated with sterile broth, whereas severe lesions developed in these mice after mycoplasma infection. The lungs of BALB/c mice were very similar to those of the C3H/HeN mice (not shown). In contrast, C57BL/6 mice did not have any evidence of inflammatory disease in their lungs.