Fig. 2.

The IBV-specific IgG and IgA response in tears. Endpoint titers of IBV-specific IgG (A) and IgA (B) on day 14 of the immune response were measured by ELISA. Chickens were vaccinated on day 1, 7, 14, 21 or 28 of age. Unvaccinated chickens of the different age groups served as negative control. Depicted are the means and standard error of each age group and the control group, and different age groups are as described in Fig. 1 (n = 10–14 per group). The data was analyzed by one way ANOVA with the Newman–Keuls post-test. Differences were considered significant at P < 0.05 and are indicated by different letters.