Conglutinin,
collectin-43 (CL-43) and collectin-46 (CL-46) are
serum proteins characteristic for Bovidae. They belong to
collectins--family of oligomeric
proteins composed of trimeric subunits containing
collagen-like sequences joined to
C-type lectin domains. The genes encoding
conglutinin,
CL-43 and CL-46 are located on the bovine chromosome 28, and phylogenetic analysis indicates their common origin--from the lung
surfactant protein D gene. Northern blot or immunocytochemical analysis confirm biosynthesis of bovine
collectins mainly in the liver (conglutinin, CL-43) and in the thymus (CL-46). The level of
conglutinin in the serum of dairy cows depends on many factors such as breeding, the season of the year, the stage of the reproductive cycle and
infection. The
collectins are involved in the innate immune defense. They bind to microbial surface
carbohydrates inducing aggregation and, thereby, impeding infectivity. On the other hand the destruction of pathogens occurs due to stimulation of effector cells.
CL-43 as well as
conglutinin, binds to the
collectin receptor (C1qR) localized on many types of cells identified as a surface variant of
calreticulin.
Conglutinin and
CL-43 show
antiviral activities towards influenza A virus and rotaviruses.
Conglutinin also displays protective activity against
bacterial infections.