Figure 3

Microarray evaluation with sera from cows and calves with C. pecorum infections. Six IncA (Inclusion membrane protein A) peptides of five C. pecorum strains are shown in the top panel along with percent sequence identities among the peptide sequences. Sequence identities of 50% or more are shown in red font to indicate potential for cross-reactivity. These C-terminus IncA peptides were chosen to cover known sequence variants in C. pecorum⁵⁵. Reactivity of the 6 IncA peptides with 10 calf and 5 cow sera in the microarray assay are shown in the middle panel. Reactivity of the sera with peptides from any other chlamydial species is indicated in the bottom panel. Also shown separately in the bottom panel are 5 of the calves that were 0 to 53 days old and had been less exposed to C. pecorum than 5 older calves and the 5 cows, consistent with IgG and IgM antibody levels against C. pecorum- peptide and elementary body (EB) lysate ELISAs, and by Chlamydia 23SrRNA gene PCR. The difference in average anti-peptide IgG antibody levels between low and highly exposed animals is highly significant (P < 0.001, Mann Whitney U test). The 7 PCR-positive calves and cows infected with C. pecorum were also confirmed with ompA gene sequencing^37,38.