FIG 4.

Conformation-dependent immunoreactivity of 22 E. chaffeensis proteins by ELISA. (A) Immunoreactivity of the denatured IVTT-expressed E. chaffeensis proteins compared with TRP120 by ELISA using a panel of eight HME sera. (B) Immunoreactivity of overlapping synthetic peptides spanning three E. chaffeensis immunoreactive proteins, as determined by ELISA with pooled HME sera. Positive control, a TRP120 epitope peptide. OD₆₅₀ values represent the mean optical density reading from three wells (± standard deviations) after background subtraction. A sample OD₆₅₀ of ≥0.2 was considered positive and ≥0.5 a strong positive after subtracting negative-control (IVTT reaction with empty plasmid template in panel A; negative peptide in panel B) reading.