Blood type AB in the feline AB blood group system.

OBJECTIVE: To assess the genetics, frequency, and biochemistry of the AB blood type in cats. ANIMALS: Domestic shorthair and purebred cats in a breeding colony and privately owned catteries and blood samples from a large feline blood typing laboratory. PROCEDURES: Samples from cats with blood type AB were selected from the feline blood typing laboratory at the university. Breeding experiments and family studies were used for the genetic analysis of cats with blood type AB. Simple slide hemagglutination assays were used to type cats. Hemagglutination assays, flow cytometry, and ganglioside analysis by high-performance thin layer chromatography were applied to characterize the AB antigens. RESULTS: Type AB was rare (13/9,239 cats; 0.14% frequency) in cats of the United States and Canada. Type AB occurred only in breeds in which type B was also detected. Cats with type-AB blood express biochemical features of type-A and type-B antigens. Genetic analyses of families with blood type-AB cats are consistent with the hypothesis of 3 alleles: A, B, and AB. The AB allele is recessive to the A allele, but dominant over the B allele. There may be an additional genetic mechanism responsible for the inheritance of blood type AB in cats. CONCLUSION: Blood type AE is an extremely rare and separately inherited type in the feline AB blood group system. CLINICAL RELEVANCE: Kittens with type-AB blood born to queens with type-B blood are at similar risk for neonatal isoerythrolysis as kittens with type-A blood because anti-A alloantiserum from blood type-B queens recognizes AB red blood cells. Furthermore, cats with type-AB blood are best transfused with type-AB or type-A blood.

Biochemical characterization of the feline AB blood group system.

The biochemical nature of the feline AB blood group system was characterized by analysing red blood cells from homozygous (genotype A/A) and heterozygous (A/B) type A, type B (B/B), and type AB cats. High performance thin layer chromatography (HPTLC) of red cell glycolipids revealed that specific neuraminic acids (NA) on gangliosides, containing ceramide dihexoside (CDH) as a backbone, correlated with the feline AB blood group antigens. Although disialogangliosides predominated, mono- and trisialogangliosides were also isolated. B cats expressed solely N-acetyl-NA (NeuNAc) on these gangliosides. In addition to expressing N-glycolyl-NA (NeuNGc) containing gangliosides, A red cells have gangliosides with only NeuNAc or mixtures of both NA. HPTLC profiles of disialogangliosides from homozygous and heterozygous A cats differed slightly in the quantity of disialogangliosides. Equal amounts of NeuNAc and NeuNGc containing disialogangliosides, as well as two intermediary forms, were recovered from AB erythrocytes. Analysing disialogangliosides from red cells belonging to 17 genetically related cats, we consistently obtained the expected disialoganglioside profile, based on blood typing and pedigree information. SDS-PAGE of red cell membrane proteins and blotting with Triticum vulgaris, a lectin recognizing NeuNAc, revealed glycoproteins of approximately 51, 53, and 80 kD in B and AB cats but only a faint band of approximately 53 kD in A cats. By haemagglutination, Triticum vulgaris could also distinguish different blood types by specifically binding to B and AB cells.(ABSTRACT TRUNCATED AT 250 WORDS)