IgA deficiency in wolves

► Low levels of serum IgA and an increased frequency of IgAD in selected dog breeds. ► Is it a breeding-enriched phenomenon or heredity? ► Serum IgA concentrations of wolves were found to be markedly lower than in dogs. ► Identity of the amino acid sequence was proven for the IGHA gene. ► Double immunodiffusion ascertained identity between dog and wolf IgA. Low mean concentrations of serum immunoglobulin A (IgA) and an increased frequency of overt IgA deficiency (IgAD) in certain dog breeds raises the question whether it is a breeding-enriched phenomenon or a legacy from the dog’s ancestor, the gray wolf (Canis lupus). The IgA concentration in 99 serum samples from 58 free-ranging and 13 captive Scandinavian wolves, was therefore measured by capture ELISA. The concentrations were markedly lower in the wolf serum samples than in the dog controls. Potential differences in the IgA molecule between dogs and wolves were addressed by sequencing the wolf IgA heavy chain constant region encoding gene (IGHA). Complete amino acid sequence homology was found. Detection of wolf and dog IgA was ascertained by showing identity using double immunodiffusion. We suggest that the vast majority of wolves, the ancestor of the dog, are IgA deficient.