Figure 7.

Challenge with “persister” C. jejuni 81-176 has no effect on vaccine performance. (A) Colonization of 35-day-old broiler birds. C. jejuni levels [expressed as colony forming units (CFU) per gram of chicken cecal contents] after vaccination (with 1×10⁸ live E. coli vaccine on day 7 and 21) and challenge. Birds were challenged with either 1×10⁶ “standard” C. jejuni 81-176 (standard-Cj, n=8) or with 1×10⁶ C. jejuni 81-176 recovered from vaccinated bird that were still colonized (persister-Cj, n=8) on day 28. Standard-Cj and persister-Cj groups (n=8) were not vaccinated, but challenged on day 28. No statistical difference in CFU (Fisher’s exact test) was observed between the standard and persister groups. (B) The N-glycan-specific immune responses. ELISA results using a 1:10 dilution of chicken sera from bleeds taken before challenge (day 28, upper panel) and at the day of euthanasia (day 35, lower panel). Each point represents the N-glycan-specific IgY antibody response measured at OD₄₅₀ for each individual chicken. Black bars represent the median for each group. ^*statistically significant; two-tailed t-test, p<0.05.