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Biomedical subjects

M Lipman

Publications and source records attributed to M Lipman.

51 records · Page 3Linked to original sources
PubMed1973

Comparison of the yield of infectious virus from clones of human and simian lymphoblastoid lines transformed by Epstein-Barr virus.

Three lymphoblastoid cell lines, of human, squirrel monkey, and marmoset origin, all transformed by the same strain of Epstein-Barr virus (EBV), differed markedly in their content of infectious virus. Single cell clones were obtained from each line to learn whether these differences were dependent upon factors shared by all cells in each line or upon factors present only in a proportion of the total cell population. A total of 17 primary clones were examined: 6 human, 6 squirrel monkey, and 5 marmoset. Cloning efficiency on human placental cell feeder layers varied from 16 to 24%. EBV antiserum, present in the cloning suspension, was shown to neutralize all extracellular virus. 15 of the 17 clones released EBV as measured by the transformation assay. Titers of infectious virus released by daughter clones paralleled titers of virus in the parent line. The median virus titers from human, squirrel monkey, and marmoset clones were respectively 10(1.5), 10(3.0), and 10(4.3) 50% transforming doses per 0.2 ml. The median yield of virus from clones of the three species was, respectively, 4, 96, and 786 transforming units per 1,000 cells containing viral capsid antigen. Two nonproducer clones (one human and one squirrel monkey) did not release infectious virus after treatment with 5'-bromodeoxyuridine, or with X ray followed by co-cultivation with marmoset leukocytes. The nonproducer clones could not be superinfected by biologically active EBV. These results show that differences in production of infectious EBV among the lines tested are reflected in the majority of cells of these lines. The data imply that the mechanism for regulation of the expression of the EBV genome is cellular rather than viral in origin. There are presumably genetic differences among primate species in this regulatory process.

Animals↗
PubMed1973

Release of infectious Epstein-Barr virus by transformed marmoset leukocytes.

Marmoset blood leukocytes transformed in vitro by Epstein-Barr virus regularly release extracellular infectious Epstein-Barr virus with high titers of transforming activity. By comparison, human umbilical cord leukocytes and adult human leukocytes transformed by Epstein-Barr virus release either no extracellular infectious virus or small amounts, irregularly.

Animals↗
PubMed1972

Epstein-Barr virus: transformation, cytopathic changes, and viral antigens in squirrel monkey and marmoset leukocytes.

Blood leukocytes of two species of new world primates, other than human, transform following exposure to Epstein-Barr virus. The transformed simian cells produce Epstein-Barr virus antigens and infectious (transforming) virus. The simian lymphoblastoid cells form multinucleate giant cells that appear to be selective sites for the production of Epstein-Barr virus. Multinucleate cells reveal intranuclear inclusions; in both species, a large proportion of giant cells contain Epstein-Barr virus antigen detectable by immunofluorescence.

Animals↗