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 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.     

Frequency and inheritance of A and B blood types in feline breeds of the United States

Using a simple hemagglutination assay to determine A and B blood types, we surveyed 1,072 domestic short- and longhair (DSH/DLH) cats and 1,100 purebred cats in the United States. Data from 234 matings with 552 offspring were consistent with the hypothesis that feline blood types A and B are due to the action of two different alleles at the same gene locus and that A is completely dominant over B. Neither an AB nor an O type cat was encountered. No type B cats were found in the Siamese and related breeds or in American Shorthair and Norwegian Forest cats. Among the breeds with type B blood, the proportion was lowest in DSH/DLH cats (0.0028) and variably higher in Abyssinian, Birman, British Shorthair, Devon Rex, Himalayan, Persian, Scottish Fold, and Somali, ranging from 0.15 to 0.59. Since all type B cats have strong, naturally occurring anti-A alloantibodies, fatal neonatal isoerythrolyses occur in type A offspring of type B mothers bred to type A males. The gene frequency of the B allele and the proportion of mating at risk of neonatal isoerythrolysis were estimated in a number of breeds. In most breeds, the frequency of the B allele was less than 0.5. Since the kittens at risk for neonatal isoerythrolysis always have the genotype AB, there is constant natural selection against heterozygotes. Heterozygote disadvantage in the cat AB system represents an unusual form of negative selection, similar to that in Rh blood group incompatibility in humans.     

Distribution of Feline Blood Types Detected in the Copenhagen Area of Denmark

The purpose of the present study was to make the first survey of the distribution of feline AB blood types in the Copenhagen area of Denmark. A total of 244 cats (139 purebred cats and 105 Domestic Shorthair cats) were tested. 93% of all tested cats had blood type A. Neither an AB nor an O type cat was detected and thus, the frequency of blood type B among all tested cats was 7%. Most type B cats were purebred cats (Birman, British Shorthair and Persian cats). No association between sex and blood type could be demonstrated among British Shorthair and Persian cats. Thus, the present study indicates that cats in Denmark predominantly have blood type A, and that blood type B cats are rare, except for certain breeds such as Birman and British Shorthair cats.     

The occurrence of the feline A blood group antigen on lymphocytes

Sera from 300 cats were tested for the presence of anti-lymphocytic antibodies. One hundred and nineteen sera showed some activity with the majority (79) reacting only with lymphocytes from blood group A cats. Absorption of two such sera with A, AB and B erythrocytes and absorption of AB system reagents with lymphocytes from A and B blood group cats demonstrated that the A antigen is expressed on both erythrocytes and lymphocytes. Blood group and lymphocyte typing tests of foetuses indicated that the A antigen is present on these tissues as early as 46 days gestation. The erythrocytic B antigen could not be demonstrated on lymphocytes although a single antiserum, which reacted against lymphocytes from group B cats, was found. Several sera containing anti-lymphocytic antibodies which were not related to the AB type were also detected.     

The occurrence of the feline A blood group antigen on lymphocytes

Sera from 300 cats were tested for the presence of anti-lymphocytic antibodies. One hundred and nineteen sera showed some activity with the majority (79) reacting only with lymphocytes from blood group A cats. Absorption of two such sera with A, AB and B erythrocytes and absorption of AB system reagents with lymphocytes from A and B blood group cats demonstrated that the A antigen is expressed on both erythrocytes and lymphocytes. Blood group and lymphocyte typing tests of foetuses indicated that the A antigen is present on these tissues as early as 46 days gestation. The erythrocytic B antigen could not be demonstrated on lymphocytes although a single antiserum, which reacted against lymphocytes from group B cats, was found. Several sera containing anti-lymphocytic antibodies which were not related to the AB type were also detected.     

The AB blood group system in wild felids

The blood type of 131 non-domesticated felids belonging to 26 felid species was surveyed in this study. Based upon a tube hemagglutination assay established for domestic cats, 80% of felids had type-A, 18% type-B, and 2% type-AB blood. Felids in the Puma group and African and Asian golden cats had blood type B, whereas all other species were found to have blood type A. Two cheetahs and one bobcat had type-AB blood. Red cell glycolipids analysed by high performance thin layer chromatography revealed a similar ganglioside pattern in wild cats as reported in domestic cats. Independent of the AB blood group system, incompatible blood crossmatch reactions were detected between different felid groups. In conclusion, wild felids display the same AB-erythrocyte antigens as domestic cats, and the same blood typing procedures can be applied for wild and domestic felids.     

ABO blood groups in the primate species of Cebidae from the Amazon region

The ABO blood groups were determined in blood and saliva collected from 40 Aotus infulatus, 74 Saimiri sciureus, and 96 Cebus apella from the Amazonian region along the Tocantins river. Saliva samples were tested for human ABH antigens by a standard hemagglutination inhibition test. Aotus infulatus showed monomorphism, exhibiting only the B blood group. Saimiri sciureus exhibited the A (67) and AB (7) phenotypes. All four phenotypes have been found in C. apella: O (8), A (52), B (19) and AB (17). The observed distribution was as expected assuming Hardy-Weinberg equilibrium. The titers of ABH substances varied among the species and phenotypes. The B-like agglutinogen, common to all New World monkey species tested, was detected in the red blood cells. Sera were used to detect naturally occurring antibodies and the results showed discrepancies between serum and saliva phenotypes in all species studied.     

Prevalence of Bartonella henselae in stray and domestic cats in different Italian areas: evaluation of the potential risk of transmission of Bartonella to humans

Bartonella henselae is the major etiological agent of Cat Scratch Disease in humans. Cats act as the natural reservoir of B. henselae and can transmit the infection to humans by bite or scratch. The diffusion of B. henselae was evaluated by seroprevalence and bacteremic status in different stray cat populations located in nine areas of Northern Italy. A total of 1585 cats were tested by blood culture and 361 (23%) resulted bacteremic; 1416 out off 1585 cats were also tested for Bartonella henselae antibodies and 553 (39%) resulted seropositive. The molecular typing of the isolates showed that 26% of bacteremic cats were infected with B. henselae type I, 52% with B. henselae type II, 16% were co-infected with both and 5% infected with B. Clarridgeiae. Moreover 165 domestic cats were tested by blood culture and serological test (IFA test cut-off: 1:64). 35 cats (21%) resulted bacteremic and 49 (43.5%) were seropositive. The molecular typing of the Bartonella isolates of the domestic cats showed that 45% of bacteremic cats were infected with B. henselae type I, 36.5% with B. henselae type II, 12% were coinfected with both and 6% infected with B. Clarridgeiae. For a completely evaluation of health status of the cat for B. henselae infection, the authors suggest both blood culture and serological tests. Nevertheless a nonbacteremic cat with positive serology result should be reevaluated for possible recurrent bacteremia.     

Lymphocytotoxic antibodies against cattle J antigen

The J substance is unique compared to all other known red cell antigenic characters of cattle blood because it is detected by naturally occurring antibodies and occurs dissolved in body fluids. Also it could be demonstrated by absorption techniques on the lymphocytes and platelets of the J-positive animals (Eyquem et al., 1956). The presence of the J antigen on these tissues raises the question whether cytotoxic antibodies exist against it. This question has been studied and the first results are presented.     

Seroepidemiological investigation of feline chlamydiosis in cats and humans in Japan

The prevalence of chlamydia antibodies in Japan was investigated in 215 cat sera, consisting of 88 sera of stray cats and 127 sera of pet cats, and 2,184 human sera, taken from 2,003 general persons and 181 small animal clinic veterinarians, by microimmunofluorescence (MIF) testing with Chlamydia psittaci Fe/Pn1 of feline origin and Prk/6BC of avian origin as antigens. The prevalence rates of anti-Fe/Pn1 antibodies were 45.5% in stray cats, 17.3% in pet cats, 1.7% in general persons and 8.8% in small animal clinic veterinarians. The prevalence rates of anti-Prk/6BC antibodies were 51.1% in stray cats, 15.0% in pet cats, 3.1% in general persons and 5.0% in small animal clinic veterinarians. These results suggested that feline chlamydia infection is widely spread in cats especially in stray cats in Japan, and suggested that feline chlamydiosis could be transmitted to people who are in close contact with infected cats.     

Serological survey of feline leukemia virus infection and the outcome of antibody-positive cats

A serological survey was carried out to examine the presence of antibodies against feline leukemia virus (FeLV) and feline oncornavirus-associated cell membrane antigen (FOCMA) in 208 cat sera collected at Teikyo University School of Medicine. Seven cats (3.4%) were positive for FeLV antibodies by enzyme-linked immunosorbent assay whereas no cat was positive for FOCMA antibody by indirect membrane immunofluorescent test. Anemia, leukemia and/or lymphoma formation were not observed in these FeLV antibody-positive cats. But among these seven cats, three were positive for toxoplasma antibodies. One of them was also positive for Chlamydia psittaci antibody and it died in pneumonia. Among the four toxoplasma antibody negative cats, one was died in eosinophilic granuloma. Furthermore, two of three cats, which were used for experiments, had cold and took therapy.     

Strong sequence conservation among horizontally transmissible, minimally pathogenic feline leukemia viruses.

We report the first complete nucleotide sequence (8,440 base pairs) of a biologically active feline leukemia virus (FeLV), designated FeLV-61E (or F6A), and the molecular cloning, biological activity, and env-long terminal repeat (LTR) sequence of another FeLV isolate, FeLV-3281 (or F3A). F6A corresponds to the non-disease-specific common-form component of the immunodeficiency disease-inducing strain of FeLV, FeLV-FAIDS, and was isolated from tissue DNA of a cat following experimental transmission of naturally occurring feline acquired immunodeficiency syndrome. F3A clones were derived from a subgroup-A-virus-producing feline tumor cell line. Both are unusual relative to other molecularly cloned FeLVs studied to date in their ability to induce viremia in weanling (8-week-old) cats and in their failure to induce acute disease. The F6A provirus is organized into 5'-LTR-gag-pol-env-LTR-3' regions; the gag and pol open reading frames are separated by an amber codon, and env is in a different reading frame. The deduced extracellular glycoproteins of F6A, F3A, and the Glasgow-1 subgroup A isolate of FeLV (M. Stewart, M. Warnock, A. Wheeler, N. Wilkie, J. Mullins, D. Onions, and J. Neil, J. Virol. 58:825-834, 1986) are 98% homologous, despite having been isolated from naturally infected cats 6 to 13 years apart and from widely different geographic locations. As a group, their envelope gene sequences differ markedly from those of the disease-associated subgroup B and acutely pathogenic subgroup C viruses. Thus, F6A and F3A correspond to members of a highly conserved family and represent prototypes of the horizontally transmitted, minimally pathogenic FeLV present in all naturally occurring infections.     

Serosurvey for selected virus infections of wild carnivores in Taiwan and Vietnam.

Serum samples from two leopard cats (Felis bengalensis) and four Formosan gem-faced civets (Paguma larvata taivana) in Taiwan, September 1995, and nine leopard cats in Vietnam, August and December 1997, were examined for the prevalence of antibodies against feline parvovirus, feline herpesvirus type 1, feline calicivirus and feline immunodeficiency virus. All civets and nine of 11 leopard cats were shown to have antibodies against feline parvovirus (FPV), and FPV's were isolated from mononuclear cells in the peripheral blood of the six leopard cats.     

Identification of capillaries in sections from skeletal muscle by use of lectins and monoclonal antibodies reacting with histo-blood group ABH antigens

This study was performed to evaluate the application of different lectins and monoclonal antibodies against ABH antigens to detect and characterize carbohydrate structures in capillaries of skeletal muscle from humans and laboratory animals. Blood group specific lectins (Griffonia simplicifolia, Griffonia simplicifolia isolectin B4,Lotus tetragonlobus, Ulex europaeus, andDolichos biflorus) and monoclonal antibodies reacting with histo-blood group carbohydrate antigens belonging to type 1 (Le^a) and type 2 (H, A and Le^y) chains were used as histological markers for capillaries in sections from skeletal muscle. The material consisted of 20 human masseter muscle biopsies from individuals with known blood types: (eight blood group O, nine blood group A, two blood group B, and one blood group AB) and masseter muscles specimens from different laboratory animals (mouse, rat, rabbit, cat, dog, pig, cow, and macaca monkey). Unfixed sections and an avidin alkaline phosphatase method were used to visualize the specific reaction.Ulex lectin stained capillaries in all human biopsies either strongly or moderately. Strong muscle capillary reaction was observed in biopsies from O, B and AB individuals while capillaries from A individuals were only moderately stained.Griffonia simplicifolia marked capillaries in A, B, and AB individuals andGriffonia simplicifolia isolectin B4 stained capillaries in muscle biopsies from B and AB donors.Dolichos biflorus was a weak marker of muscle capillaries from A individuals. Only capillaries from O individuals were stained with the antibody against H type 2. Capillary reaction was not observed with the other antibodies used.Girffonia simplicifolia was an excellent marker for capillaries in mouse muscle whileGriffonia simplicifolia isolectin B4 is recommended for rat muscles. Periodic acid treatment and subsequentLotus tetragonolobus staining is suitable to visualize capillaries in mouse, rat and pig muscle. Using a sensitive histochemical technique for staining with lectins and monoclonal antibodies reacting with blood group related antigens the microvascular density in human skeletal muscle may be estimated. Further, the carbohydrate compounds in the muscle capillaries reflect the individual blood type. A selection of lectins is suitable for demonstration of capillaries in animal skeletal muscle.     

Subcellular localization of blood group substances ABH in human salivary glands

We investigated the subcellular localization of ABH antigens in human submandibular, sublingual, and buccal glands by applying a post-embedding immunogold method using monoclonal antibodies specific for A, B, and H antigens. In most glands the immunoreactivity was usually restricted to mucous cells, in which only secretory granules and sometimes Golgi cisternae were specifically labeled. A and B antigens were demonstrated only in the glands of type A, B, and AB subjects, while H antigen was visualized in glands from individuals of all blood types. Moreover, differences were observed in the relative distribution of ABH antigens, depending on the type of gland.     

Distribution of blood-group-related carbohydrate antigens on oral endothelial cells

Summary Recent studies indicate that carbohydrate structures are involved in various endothelial functions such as inflammatory processes, adhesion of metastatic cells to endothelium and endothelial differentiation. In this paper we report the endothelial expression of various blood-group-related carbohydrate structures in normal oral mucosa using 15 different monoclonal antibodies reacting with type 1, 2 or 3 carbohydrate chains. Twenty biopsies, including normal oral mucosa, from secretor individuals comprised nine blood group O, nine A, one B and one AB. Endothelial staining was compared with epithelial staining in the same biopsies. Five blood-group-related carbohydrate antigens were detected on endothelial cells. The H type 2 antigen, which is the precursor of A, B and AB antigens, has previously been believed to be a universal marker for endothelial cells. All blood group O individuals (n = 9) showed strong H antigen staining in the endothelium of most vessels. However, of blood group A, B and AB individuals (n = 11), four showed heterogenous H antigen staining. In addition, we found that six out of ten blood group A or AB individuals, who expressed A or A and B antigens on spinous squamous cells and glandular epithelium, showed either heterogenous or no staining for these structures on their endothelial cells. It is concluded that there are differences between the biosynthesis of blood-group-related carbohydrate antigens in oral endothelium and epithelium.     

Does Coinfection of Bartonella henselae and FIV Induce Clinical Disorders in Cats?

It was found that Bartonella henselae (B. henselae) may induce clinical disorders in cats in natural conditions from a comparison of the serological status for B. henselae with the serostatus for feline immunodeficiency virus (FIV) and several clinical characteristics in 170 domestic cats. Seropositivity for B. henselae was not significantly different between FIV antibody-positive and -negative cats (18.4% vs 16.0%). The incidence of clinical characteristics were compared among four cat groups distinguished by the reactivity of sera against B. henselae and FIV. The incidence of lymph node swelling was lower in only FIV antibody-positive cats (3.0%), but higher in B. henselae antibody-positive cats (13.6%) and significantly higher in both B. henselae and FIV antibody-positive cats (42.9%) compared with the incidence of lymph node swelling in cats which were negative for both antibodies (5.5%). The same relation was also observed for the incidence of gingivitis among the 4 cat groups, suggesting that coinfection of B. henselae and FIV may be associated with gingivitis and lymphadenopathy in cats.     

Vaccination protects against in vivo-grown feline immunodeficiency virus even in the absence of detectable neutralizing antibodies.

So far, vaccination experiments against feline immunodeficiency virus have used in vitro-grown virus to challenge the vaccinated hosts. In this study, cats were vaccinated with fixed feline immunodeficiency virus-infected cells and challenged with plasma obtained from cats infected with the homologous virus diluted to contain 10 cat 50% infectious doses. As judged by virus culture, PCRs, and serological analyses performed over an 18-month period after the challenge, all of the vaccinated cats were clearly protected. Interestingly, prior to challenge most vaccines lacked antibodies capable of neutralizing a fresh isolate of the homologous virus.     

Canine plasma alkaline phosphatase polymorphism and its relationship with the canine Tr blood group system

A canine blood group antigen, QN, which was detected by a naturally occurring alloantibody in the antiglobulin test, was shown to be antigenically related to the human A and cattle J antigens by absorption experiments. Family studies supported a dominant mode of inheritance with the gene controlling the production of QN being dominant to the gene responsible for its absence. Frequencies of the QN and Tr antigens and serological data strongly suggested that the two antigens are identical. Two canine plasma alkaline phosphatase variants, F and S, were detected by starch gel electrophoresis, pH 8.65. Assuming genetic control of two codominant alleles, ALPF and ALPS, the distributions of types in families differed significantly from expectation. A relationship between the ALP and Tr(QN) systems was demonstrated with Tr-positive animals having a significant deficiency of S alkaline phosphatase types.     

P26-based serodiagnosis for Bartonella spp. infection in cats

Bartonella henselae P26 has been identified as an immunodominant antigen expressed during feline infection. We used antisera from cats experimentally infected with B. henselae (n = 6), B. clarridgeiae (n = 4), or B. koehlerae (n = 2) and from a sample of naturally infected cats (B. henselae, n = 34; B. clarridgeiae, n = 1) to evaluate recombinant P26 (rP26) as a serodiagnostic antigen. Immunoblots using antisera from cats infected with B. henselae and B. clarridgeiae reacted strongly with rP26, whereas B. koehlerae antisera did not. A capture ELISA was designed to evaluate the kinetics of rP26 IgG in sera from experimentally infected cats. For B. henselae and B. clarridgeiae antisera, the kinetic profiles of reactivity were similar for rP26 capture ELISA and Bartonella spp. indirect fluorescence assay. However, for B. koehlerae antisera, reactivity in rP26 capture ELISA was consistently low. The serodiagnostic potential of rP26 capture ELISA was evaluated using sera from cats with known Bartonella sp. exposure histories. All 24 (100%) uninfected cats were seronegative, and 33 of 35 (94.3%) cats bacteremic for Bartonella spp. were seropositive. We propose that rP26-based serology can serve as a useful adjunct tool for the diagnosis of feline infection with B. henselae and B. clarridgeiae, but it may not be useful for feline infection with B. koehlerae.