PubMed Health⌕ Search

Biomedical subjects

D S Yohn

Publications and source records attributed to D S Yohn.

At least 37 records · Page 2Linked to original sources
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.

Age Factors↗
PubMed1975

Antibody in cats to mammalian RNA tumor virus interspecies antigens.

The studies were undertaken to determine whether the cat, a mammalian species that carries xenotropic endogenous C-type virus(es) and in addition undergoes horizontally transmitted oncogenic C-type RNA tumor virus infections, responds immunologically to the mammalian C-type virus interspecies antigens. Sera from normal cats and from cats with spontaneous or virus-induced neoplasms were examined for antibodies to interspecies antigen antigen by complement-fixation inhibition, by inhibition of the paired radioiodine-labeled antibody technique (PRILAT inhibition), and by two-step radioimmunoelectrophoresis. Using three separate complement-fixation inhibition systems designed to detect antibodies to interspecies antigen(s), 23 of 23 sera from tumor-bearing cats and 24 of 31 sera from normal cats were positive in both systems. The negative sera were from germ-free cats. Among the 49 positive sera, 47 yielded titers of 1:16 or greater by one or more complement-fixation inhibition tests. Of these 47 sera, 42 were positive by the paired radioiodine-labeled antibody technique inhibition test; the 5 paired radioiodine-labeled antibody technique-negative sera were from normal specific-pathogen-free cats. Direct reaction with the interspecies determinant on the p30 protein from Rauscher murine leukemia virus by immunoglobulin from cats immunized with feline leukemia virus was shown by two-step radioimmunoelectrophoresis. The feline antibody was also identified as an immunoglobulin by column chromatography and two-step radioimmunoelectrophoresis. These antibodies did not fix guinea pig complement during reaction with the interspecies antigen. That other mammals may produce similar noncomplement-fixing (guinea pig) antibodies to RNA tumor virus antigens is likely.

Animals↗
PubMed1974

Differences in acute and convalescent-phase antibodies of cats infected with feline picornaviruses.

Complement fixation inhibiting and complement-fixing antibodies were demonstrated in sera from cats during the acute and convalescent stages, respectively, of feline picornavirus infections. Complement-fixing antibody activity was present in 19S and 7S globulins, whereas complement fixation inhibiting antibody activity was confined to the 7S globulins. Sera with complement-fixing antibody and sera with complement fixation inhibiting antibody were also shown to have neutralizing and precipitating antibodies. In a study of antibody responses to homotypic and heterotypic strains of feline picornavirus, less serological cross-reactions were observed between strains of feline picornavirus in sera from cats in the acute phase of feline picornavirus infection than in the convalescent phase. The temporal relationship of complement fixation inhibiting and complement-fixing antibody responses of cats after acute viral respiratory infections is contrasted with previously observed antibody response in cats to feline leukemia virus.

Animals↗
PubMed1974

Transformation potentials of the noninfectious (defective) component in pools of adenoviruses type 12 and simian adenovirus 7.

Pools of adenovirus 12 and simian adenovirus 7 were separated into four or five fractions by density gradient centrifugation in cesium chloride. Each fraction was analyzed for total in vitro infectivity units, total transformation activity, and for total virus particle (VP) content. Two major subpopulations were separated with mean densities of 1.30 +/- 0.02 and 1.34 +/- 0.02 g/ml, respectively. Virions in the 1.34 g/ml range were highly infectious (10(2) to 10(3) VP per infectivity unit) in contrast to virions at 1.30 g/ml density (10(4) to 10(5) VP per infectivity units). Transformation capacity was evenly distributed throughout fractions of both viruses, indicating that genetically incomplete or defective virus particles were not deficient in their ability to induce transformation. The average VP per transformation unit for adenovirus 12 (2.85 x 10(6)) and for simian adenovirus 7 (4.00 x 10(6)) did not vary significantly from fraction to fraction. These values were obtained with optimal input multiplicities of 16 to 64 VP per cell. At higher multiplicities the apparent increase in VP per transformation unit was attributable to the viral cytocidal effect on hamster cells. These studies revealed that quantitation of in vitro transformation based on VP multiplicities was more reliable than on the basis of infectious units. These estimates were independent of method of virus production, extraction, and purification.

Adenoviridae↗
PubMed1973

Differences in clinical and convalescent-phase antibodies of Rhesus monkeys infected with monkey pox, tanapox, and Yaba poxviruses.

Complement-fixing and complement-fixing inhibiting (CFI) antibodies were demonstrated in the clinical and convalescent stages, respectively, of rhesus monkeys infected with either monkey poxvirus, Tanapoxvirus, or Yaba poxvirus. Specificity of the CFI antibody was confirmed by its failure to cross-react with heterologous poxvirus antigens and by experiments demonstrating the CFI test as being antigen dependent. Serum containing CFI antibody neutralized homologous poxvirus but failed to agglutinate antigen-coated, tanned red blood cells. The application of CFI test as a seroepidemiologic tool for studies of poxvirus infection of man and simian monkeys and the biologic role of CFI antibody in pathogenesis were discussed.

Animals↗
PubMed1972

Detection and assay of avian tumor virus group-specific antigen and antibody by the paired radioiodine-labeled antibody technique.

The paired radioiodine-labeled antibody technique (PRILAT) was applied to the detection and quantitation of avian tumor virus group-specific (gs) antigens and antibody. The technique proved to be specific, repeatable, and appreciably more sensitive than the microcomplement-fixation test for avian leukosis (COFAL). The PRILAT facilitated direct measurement of comparative antigen content of several types of transformed, neoplastic, or virus-infected cells and the magnitude of nonspecific antibody binding by appropriate control cells. The versatility of the technique was illustrated by application to the detection and quantitation of gs antibody content of chicken, turkey, pigeon, and hamster sera. Antibodies were detected in COFAL-negative sera from hamsters bearing tumors induced by the Schmidt-Ruppin strain of Rous sarcoma virus. Sera from chickens bearing similar tumors were not positive for gs antibodies, although sera from turkeys and chickens immunized with avian leukosis virus did contain gs antibodies.

Animals↗