FIG. 4.
Reduced borreliacidal activity in the serum of CD18 hypomorph mice. (Top) The percentages of viable B. burgdorferi cells after incubation in serum from infected WT (circles; n = 10) and CD18 hypomorph mice (squares; n = 11) at 3 weeks postinfection are shown. Each symbol represents the serum from one infected mouse, with the average of each experimental group depicted as a horizontal line (the average was 55.99% for WT and 76.31% for CD18 hypomorph mice sera). Samples from four independent experiments were included in this analysis. The asterisk indicates that the difference is statistically significant (P = 0.02). The difference was also statistically significant when the nonparametric Mann-Whitney U test was used. (Bottom) Anti-OspC IgG level in B. burgdorferi-infected WT (circles) and CD18 hypomorph (squares) sera at 3 weeks postinfection. Each symbol corresponds to serum from one mouse. The samples were combined from four independent experiments, as in the top panel. Average optical density (OD) values for B. burgdorferi-infected WT (n = 9) and CD18 hypomorph (n = 10) sera were 0.183 and 0.109, respectively, and are depicted as horizontal lines. The asterisk indicates that the difference is statistically significant (P = 0.008). The difference was also statistically significant when the nonparametric Mann-Whitney U test was used. No anti-OspC IgG was detected in sera from uninfected mice. Bb, B. burgdorferi; CD18hypo, CD18 hypomorph.