IMMUNOLOGY AND MOLECULAR BIOLOGY Serum Levels of Mannan-Binding Lectin in Chickens Prior to and During Experimental Infection with Avian Infectious Bronchitis Virus

Mannan-binding lectin (MBL) is a glyco- protein and a member of the C-type lectin super family, the collectin family, and the acute phase protein family. The MBL exerts its function by directly binding to micro- bial surfaces through its carbohydrate recognition do- mains, followed by direct opsonization or complement activation via MBL-associated serine proteases (MASP) −1 and −2. Thus, MBL plays a major role in the first-line innate defense against pathogens. We investigated the MBL concentrations in serum during experimental infec- tious bronchitis virus (IBV) infections in chickens. The results showed that the acute phase MBL response to infection with IBV was, to a degree (P < 0.0068), depen- dent on whether the chickens were inoculated after 12 h of rest (dark) or after 12 h of activity (light). The acute phase response in chickens challenged after 12 h of activ-