FIG. 4.

B. burgdorferi-specific antibody titers in infected IFN-γR^−/− (RKO) and 129SvEv (WT) mice. There was a slight increase in IgG1 and a decrease in IgG2a in IFN-γR^−/− mice compared with 129SvEv mice. Serum from mice sacrificed 5 weeks postinfection was diluted and used to detect B. burgdorferi antigen. The titer was calculated from the linear regression of three dilutions using as a cutoff the mean plus three standard deviations of the results for the negative controls. Each symbol represents one mouse.