Serum levels of chicken mannan-binding lectin (MBL) during virus infections; indication that chicken MBL is an acute phase reactant

Mannan-binding lectin (MBL) is a serum collectin which is believed to be an opsonin of the innate immune defence against various microorganisms. MBL is a minor acute phase reactant in man. We investigated the concentration of serum MBL in chickens infected with infectious bronchitis virus (IBV) and infectious laryngotracheitis virus (ILTV). The concentration of serum MBL increased about twofold (from approximately 6 to 12 μg/ml) due to these viral infections. The concentration peaked 3–7 days after infection with IBV, and 3–5 days after ILTV infection, depending on the ILTV strain used. The increased levels returned to normal values 6–10 days after infection. The results indicated that MBL is a minor acute phase reactant in chickens.