To explore the function of mannose-binding lectin(MBL) during the process that sheep mucosal epithelial cells against Mycoplasma ovipneumoniae infection. Natural MBL was extracted from sheep serum. The sheep mucosal epithelial cells were divided into 4 groups. Operation as fallow: added MBL in cell culture before inoculation of MO; added MBL in cell culture after inoculation of MO; cultured cells after inoculation of MO; cultured normally. The genes expression levels of MBL,C3, ICAM-1, IL-6, SBD-1 was detec...