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Biomedical subjects

W D Hardy

Publications and source records attributed to W D Hardy.

At least 127 records · Page 7Linked to original sources
PubMed1975

Feline oncornavirus-associated cell membrane antigen. II. Antibody titers in healthy cats from household and laboratory colony environments.

Antibody titers to the feline oncornavirusassociated cell membrane antigen (FOCMA) were determined for 447 healthy cats from laboratory colony and household environments. Only 2.7 percent of 221 cats from colony environments were antibody positive as compared to 50.4 percent of 256 cats from household environments. Incidence of FOCMA antibody and geometric mean antibody titer for pet cats from New York City representing single cat apartment habitats were substantially lower than values for unscreened cats from the Boston, Glasgow, and Detroit suburban environments. Geometric mean antibody titer for young adults in the Boston population was significantly higher than titers for kittens or aged cats. This may be due to greater mobility resulting in increased exposure to other cats. In contrast to the high frequency of FOCMA antibody positivity in pet-cat populations, less than 2 percent of the same groups were positive for virus group-specific antigen in peripheral blood leukocytes and platelets. This was interpreted as an indication that many more cats became infected with feline leukemia virus under natural conditions that the number developing persistent virus infection and/or clinical leukemia.

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PubMed1975

Feline oncornavirus-associated cell membrane antigen. III. Antibody titers in cats from leukemia cluster households.

Serum samples from 182 healthy cats residing in environments known to have a natural exposure to feline leukemia virus (FeLV) were examined for the presence of antibody to the feline oncornavirus-associated cell membrane antigen. The number included 138 cats from leukemia-"cluster" households. Such cats previously showed greatly increased frequencies of FeLV infection, as determined by the virus group-specific antigen (gasa) in peripheral blood leukocytes and platelets. The geometric mean antibody titer for all 182 cats with known exposure to FeLV was 4.69, more than four times higher than the mean titer for healthy pet cats from the same geographic areas but with no known FeLV exposure. About 92 percent of the cats in exposure environments were positive for FeLV gsa or feline oncornavirus-associated cell membrane antigen (FOCMA) antibody, and gsa-positive cats had lower FOCMA antibody geometric mean titers than gsa-negative cats. In the exposure environments, no differences were seen for cats of different sexes, but a higher geometric mean antibody titer was observed for cats 5 years and over when compared to younger groups. These results prove that previous reports of increased incidences of leukemia in cluster households were not due to chance alone, but rather to increased infection rates of cats in the FeLV environment. Also, they suggest that horizontal transmission of FeLV is highly efficient under crowded conditions, and that most cats naturally exposed to virus elicit an active immune response.

Age Factors↗
PubMed1975

Feline oncornavirus-associated cell membrane antigen. IV. Antibody titers in cats with naturally occurring leukemia, lymphoma, and other diseases.

Cats with naturally occurring leukemia and lymphoma had low or negative humoral antibody titers to the feline oncornavirus-associated cell membrane antigen (FOCMA). Geographic differences were seen in the relative frequencies of various forms of lymphoproliferative neoplasms. Lymphatic leukemia and thymic lymphoma were most common in Boston, whereas alimentary lymphoma was most frequent in Glasgow. No significant differences were found in geometric mean FOCMA antibody titers for the various forms of leukemia-lymphoma or for feline leukemia virus (FeLV)-positive as compared to FeLV-negative cats. Approximately 70% of 76 Boston cats with nonregenerative anemias were FeLV gs antigen (gsa) positive; this was similar to the percentage with leukemia-lymphoma from the same population that was positive. Fifty-five to 62% of the Boston cats with other infectious diseases, such as peritonitis and septicemia, were gsa positive. We postulate that this is due to a predisposition to infectious diseases by the immunosuppressive action of FeLV. Young cats from the Boston population that developed lymphoma, infectious peritonitis, and certain other diseases were more likely to be FeLV gsa positive than older cats with the same diseases.

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PubMed1974

Common cell surface antigen associated with mammalian C-type RNA viruses. Cell membrane-bound gs antigen.

The indirect membrane immunofluorescence test and the absorption analysis of rabbit anti-FeLV, rabbit anti-FeLVp 30, and rabbit anti-MuLVp 30 antisera yielded the following conclusions. An antigen shared by mammalian (murine and feline) C-type RNA leukemia and sarcoma viruses was detected on the surface of cells infected or transformed by C-type viruses. The antigen was characterized as membrane-bound gs antigen bearing two determinants, membrane-bound gs-1, intraspecies-specific antigenic determinant, and membrane-bound gs-3, interspecies-specific antigenic determinant. Membrane-bound gs antigen was located on the cell surface, frequently near the site of virus budding but not on the envelope of murine C-type RNA virus.

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PubMed1973

Serum-mediated leukemia cell destruction in AKR mice.

AKR mice with spontaneous leukemia were infused with normal serum from a variety of species. Leukemia cell destruction was produced by serum from strains of mice possessing the full spectrum of complement components, but not by serum from strains with a genetically determined deficiency of C5. Serum from guinea pigs, horses, and humans also causes destruction of leukemia cells. The antileukemic factor in normal serum was heat labile (56 degrees C for 35 min) and could be inactivated by cobra venom factor (CVF). Tests of individual complement factors from guinea pig serum and from human serum suggest that C5 is the antileukemic complement component in normal serum. Evidence was obtained that complement also plays a role in the antileukemic effect of interferon and endotoxin.

Animals↗
PubMed1973

Common cell-surface antigen associated with murine and feline C-type RNA leukemia viruses.

A new common cell-surface antigen associated with murine and feline C-type RNA leukemia viruses was demonstrated by the use of rabbit antiserum against feline leukemia virus and the indirect membrane immunofluorescence test. Common cell-surface antigen was found in all leukemias of all strains of mice tested, in normal lymphoid tissues of Gross-positive (high incidence of leukemia) mouse strains AKR, AKR.H-2(b), C58, and NZB, in cultured rat fibroblasts infected with Rauscher virus, in cultured feline fibroblasts infected with feline leukemia virus, and in spontaneous feline lymphosarcoma. The antigen was not demonstrable in normal adult and fetal tissues of Gross-negative mouse strains or in tissues and cultured fibroblasts derived from normal rats and normal cats. The immunoferritin study of murine leukemia cells revealed that the antigen was located on the cell surface in discrete areas; budding and C-type RNA viral envelope was not labeled as antigen site. The distribution of common cell-surface antigen on murine and feline leukemias, as well as on normal lymphoid tissues of Gross-positive mouse strains, indicates the presence of an antigen distinct from any cell-surface antigen heretofore shown to be associated with, or specified by, mammalian C-type RNA viruses.

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