FIG. 3.

Overexpression of the E. chaffeensis p28 gene (A) and Western blot analysis with convalescent-phase serum from a human ehrlichiosis patient (B) and with a rabbit anti-rP28 antibody (C). Lanes: M, molecular size markers; C, pET29a-transformed E. coli (negative control); R, pET29p28-transformed E. coli (recombinant) (arrowhead, rP28); Eca, purified E. canis; Ech, purified E. chaffeensis. Dominant protein antigens with the molecular masses of P25 to P30, and rP28 (31 kDa), are schematically shown. Numbers indicate molecular masses in kilodaltons.