Conglutinin is not specific to cattle

Conglutinin is a high-molecular-weight mammalian lectin which binds in a calcium-dependent manner to cell-surface-bound complement fragment iC3b, yeast cell-wall extract and terminal non-reducing N-acetyl-dglucosamine, mannose and fucose residues. This protein, originally detected in bovine serum, belongs to the family of collectins, which are effector molecules in innate immunity. Conglutinin appears to play an important role in defence mechanisms, showing antiviral and antibacterial activity. We have characterized the electrophoresis profile of bovine serum conglutinin and used Western blotting to compare profiles of this lectin derived from the sera of different breeds of cattle. The profile of non-reduced conglutinin is characterised by many bands with molecular masses ranging from 34 to 630 kDa. Reduced lectin takes the form of three main bands with molecular masses of 41, 47 and 96 kDa. We show that conglutinin is present not only in adult bovine serum, but also in foetal bovine serum, colostrum and milk. The sera of sheep, goats, gnu antelopes and deer, as well as some non-ruminant species such as llamas, horses, boars, pigs and humans, contain proteins which have similar antigenicity to that of bovine conglutinin. These reacted with monoclonal and polyclonal antibodies specific for bovine conglutinin under reducing and non-reducing conditions in Western blotting. The protein profiles of bison and swine lectin were observed to be particularly similar to bovine conglutinin.