Vaccination with M41K-Beau(S) and M41R-Beau(S) induces a robust antibody response.

Serum was harvested from chickens on day 14 post-vaccination (A) and days 4 (B) and 14 post-challenge (C) and diluted 1/80 for ELISA using the commercial BioChek IBV ELISA kit. Samples from each bird in a group harvested on day 14 post-vaccinated were pooled together due to the limited quantities of serum able to be collected. Samples were run in triplicate, and the average S/P ratio was calculated for each bird. S/P ratios for each independent repeat (A) or for each bird (B and C) are displayed with error bars representing the SD. (D) To assess the levels of neutralizing antibody, serum from day 14 post-challenge was serially diluted and incubated with 10³ PFU of M41-CK, followed by a plaque assay on CK cells to determine the plaque reduction neutralization titer (PRNT₅₀). The PRNT₅₀ values were calculated for each group using the Reed-Muench method. Average PRNT₅₀ values for each bird are displayed, with error bars representing the SD. Statistical differences were assessed by one-way ANOVA, followed by Tukey’s test for multiple comparisons and are highlighted by * (p<0.05), *** (p< 0.0005) and **** (p<0.0001).