Analysis of B microti–specific IgG responses. Plasma was collected from mice on day10 (A) and day 17 (B) in Townes (AA, AS, SS) mice following B microti infection and the levels of Babesia-specific IgG antibody were determined by ELISA using recombinant B microti proteins as listed in supplemental Table 1 (n = 2-3). Error bars indicate the mean ± SEM. *P < .05; **P < .01; by unpaired 2-tailed Student t test.