Biochemical characterization of the feline AB blood group system

Abstract

SummaryThe 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 gly‐colipids 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 disialoganglio‐side 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. Flow cytometry showed that more anti‐B bound to B cells than anti‐A bound to A cells. Although AB cells had a broad range of fluorescence when compared to the profiles seen with A and B cells, the mean fluorescence with AB cells was half of that seen with A or B. These results further characterize the antigens determining the feline AB blood group system illustrating differences between A, B and AB cats, and between homozygous and heterozygous A cats.

Cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) mutations associated with the domestic cat AB blood group

“…The common types are allelic, with type A dominant to type B. A rare type AB, which shows agglutination with both anti-A and anti-B, has not been as clearly defined, but is suspected to be allelic to types A and B [6,7]. Several studies have shown familial segregation for cat blood types A and B.…”

“…However, families segregating for type AB are limited and the parentage of the matings was not confirmed. Therefore, the inheritance of the third type AB allele was not clearly resolved [6,7], although it appears to be recessive to type A and dominant to type B [8]. …”

Blood Typing and Cross‐Matching

“…15,16 Feline blood type A or B is determined by the pres ence of certain RBC membrane glycolipids; type AB contains a mixture of both types. [17][18][19][20] Unlike dogs, by 1-2 months of age, cats produce alloantibodies against RBC antigens they lack without prior sensitization from a blood transfusion. 21 Because blood transfusion is not required for the production of these antibodies, they are referred to as "naturally occurring" alloantibodies.…”

“…Necessary reagents for the slide test include serum from a type B cat, used as the antiA solution, and a prepared solution of Triticum vulgaris lectin (Sigma Chemical Co., Product L9640, St. Louis, MO), used as the antiB solution. 17,19,27 Triticum vulgaris, a wheat germ lectin, when prepared at a specific concentration, pref erentially causes agglutination of type B feline RBCs. A stock solution is prepared: 25 mg of lyophilized Triticum vulgaris lectin powder is resuspended in 12.5 mL of 0.9% saline and kept frozen.…”

“…Whereas the tube crossmatch requires a minimum amount of equipment, gel column as needed. 19,27 The slide test allows for rapid determina tion of blood type as long as all reagents are readily available; it also evaluates for autoagglutination.…”