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R C Gallo

Publications and source records attributed to R C Gallo.

At least 19 recordsLinked to original sources
PubMed1979

Characterization of an RNA-directed DNA-polymerase from a cell line derived from a radiation-induced lymphoma in mice.

An RNA-directed DNA polymerase was purified from a cell line derived from a radiation-induced lymphoma in NIH Swiss mice which produced non-infectious type C virus particles. The enzyme was isolated from a high speed particulate fraction which bands at a density of 1.16--1.19 g/ml in a sucrose gradient, and purified by successive chromatography on DEAE-cellulose, phosphocellulose and hydroxyapatite. The purified DNA polymerase has a molecular weight of 68 000, a pH optimum of 7.5, a KCl optimum of 50 mM, and a Mn2+ optimum of 0.25 mM. It prefers (dT)15 . (A)n to (dT)15 . (dA)n as the primer template and transcribes the poly(C) strand of (dG)15 .(C)n and (dG)15 . (OMeC)n. It transcribes heteropolymeric regions of avian myeloblastosis virus 70 S RNA, and is inhibited by antiserum to Rauscher murine leukemia virus DNA polymerase. Comparison of the properties of DNA polymerase purified from radiation-induced lymphoma cells with the DNA polymerase purified from non-defective murine type C RNA tumor viruses shows that the mouse lymphoma enzyme is both biochemically and immunologically related to murine leukemia virus DNA polymerases.

Animals↗
PubMed1979

Normal functional characteristics of cultured human promyelocytic leukemia cells (HL-60) after induction of differentiation by dimethylsulfoxide.

The HL-60 human promyelocytic leukemia cell line can be induced to terminally differentiate to mature myeloid cells sharing a number of functional characteristics with normal granulocytes including response to chemoattractants, development of complement receptors, phagocytosis, superoxide production, and nitroblue tetrazolium dye reduction. Hence the Me2SO-induced HL-60 cells provide a unique in vitro model for studying various important aspects of human myeloid cell differentiation.

Binding Sites↗
PubMed1979

Placenta-bound immunoglobulins.

Low pH eluates were prepared from trophoblasts derived from 8 term human placentas. A qualitative analysis for immunoglobulins revealed the presence of IgG, IgA, and IgM in these eluates. IgC-rich fractions were obtained by DEAE-cellulose chromatography of ammonium sulfate-concentrated eluates. These fractions were able to neutralize, in vitro, the catalytic activity of reverse transcriptases (RT) from several retroviruses. RT from baboon endogenous virus (BEV) seemed to be more susceptible to the neutralizing activity of some eluates. This was in contrast to RT from feline leukemia virus (FeLV) which were neutralized by eluates of leukocytes from chronic myelogenous leukemia. In contrast to previous and present results with purified IgG from leukemic leukocytes, the purified IgG from placenta eluates was incapable of RT neutralization. However, such purified IgG fractions inhibited mixed lymphocyte reactions.

Female↗
PubMed1979

Characterization of a type-C virus produced by co-cultures of human leukemic bone-marrow and fetal canine thymus cells.

The putative human helper virus SKA-21/A204V, isolated by Nooter et al. in 1977 from human leukemic bone-marrow cells following co-culture with normal fetal canine thymus cells, Cf2th, has been characterized with respect to its major viral core protein, reverse transcriptase, and nucleic acid sequences. The results of these analyses show that this virus is not distinguishable from the woolly monkey type-C virus, SSAV-1, by the techniques employed.

Animals↗
PubMed1979

Cellular and virological studies directed to the pathogenesis of the human myelogenous leukemias.

1. Work over the past years and especially results of the past few years indicate that type-C viral or viral related genetic information exists in humans. 2. We do not know how this information entered humans or whether it causes disease, but it is of interest that the probes from the viruses used to detect this information are from the very same viruses which we find can affect growth and differentiation of some human hematopoietic cells. 3. The status of actual virus isolates from humans, though encouraging because of similarities of isolates from five different laboratories, remain very perplexing and so far have not been especially informative to human leukemogenesis. 4. In the near future we hope to clone in bacteria the viral related sequences detected in human DNA in order to more precisely determine their chemical and biological properties. The HL-60 system may also afford an opportunity to purify receptors for CSF. When CSF and other, perhaps more important, regulatory factors are purified, we would like to determine if they bind differently to leukemic and normal cells.

Animals↗
PubMed1979

Chromatin conformation during cell differentiation of human myeloid leukemia cells.

A novel human promyelocytic leukemia cell line (HL-60) has been shown to form terminally differentiated granulocytes in the presence of dimethyl-sulfoxide (DMSO), some other chemicals, or colony stimulating factor. Compared to chromatin from HL-60 cells, chromatin from DMSO treated HL-60 cells showed an enrichment in low temperature melting material. The decrease in thermostability of chromatin from HL-60 cells after DMSO treatment is similar to the shift in thermostability of chromatin from human lymphocytes after stimulation with phytohemagglutinin (PHA). These results suggest that changes in the thermostability of chromatin may not be specific for cell differentiation or PHA stimulation.

Adult↗
PubMed1979

Retrovirus sequences in a leukemic gibbon and its contact: evidence for partial provirus in the nonleukemic gibbon.

Integrated viral DNA sequences were detected in tissues from two gibbon apes, a leukemic gibbon (6G-1) from whose leukocytes a distinct strain of gibbon ape leukemia virus (GaLVH) was isolated, and gibbon 6G-4, a contact of 6G-1 from the same colony that had uremia and cachexia of unknown origin. Although 6G-4 had no detectable neoplasia or viral proteins, its serum contained persistent antibody against GaLV antigens. Whereas DNA from most of the tissues of 6G-1 contained GaLV provirus, DNA from only three tissues (kidney, spleen, and liver) from 6G-4 showed detectable viral sequences, and the extent of hybridization in each case was lower than with 6G-1. After cleavage with BamHI, two virus-specific DNA fragments were detected in tissues of 6G-1. Only one of these fragments was detected in the positive tissues of 6G-4. The results indicate that: (i) 6G-4 was exposed to and infected by GaLV; (ii) early target sites for infection of gibbon by GaLV may be limited to a few tissues; and (iii) infection can be contained by integration of only partial provirus in a few tissues.

Animals↗
PubMed1979

Type-specific binding antibody to baboon endogenous virus (M7) reverse transcriptase.

A type-specific binding antibody to the baboon endogenous virus, M7, reverse transcriptase was developed and characterized using a double antibody immunoprecipitation assay. This assay allows the analysis of non-enzyme neutralizing binding antibody, as well as the detection of early antibody production before high titre enzyme neutralizing antibodies appear. The antibody described is unique among hyperimmune antisera to DNA polymerases in that it recognizes only type-specific determinants on the enzyme molecule. Analysis of the enzymes of several BaEV isolates indicated a grouping of those from Papio cynocephalus, P. anubis and the HL23VBab isolate. The RD-114 enzyme was in a separate class, and the P. papio and P. hamadryas DNA polymerases were distinguished from all the other BaEV enzymes but not from each other.

Animals↗
PubMed1979

Gibbon ape leukemia virus-Hall's Island: new strain of gibbon ape leukemia virus.

Gibbon ape leukemia virus-Hall's Island (GaLV-H), a type C virus related to previous isolates of GaLV and simian sarcoma virus, was isolated from a gibbon ape with lymphocytic leukemia from a small colony of free-ranging gibbon apes on Hall's Island near Bermuda. We show here by molecular hybridization experiments that GaLV-H is approximately 60% related to three previous isolates of GaLV (GaLV-SF, GaLV-SEATO, and GaLV-Br) and is less closely related to simian sarcoma virus. The oligopyrimidine pattern of a transcript of the terminal 135 +/- 5 nucleotides of the viral RNA of GaLV-H is similar to that of GALV-Br but distinct from that of GaLV-SF and simian sarcoma virus. GaLV-H thus represents a fifth distinct strain of the infectious primate type C viruses, which among the previously described isolates of GaLV is most closely related to GaLV-Br.

Animals↗
PubMed1979

Detection of virus-specific RNA in simian sarcoma-leukemia virus-infected cells in in situ hybridization to viral complementary DNA.

An in situ molecular hybridization system which will detect retrovirus RNA in the cytoplasm of individual virus-infected cells has been developed. The technique was applied to cells infected with simian sarcoma-leukemia virus, where the virus-specific RNA was detected by hybridization to simian sarcoma-leukemia virus 3H-labeled complementary DNA. The system is useful for detecting viral RNA-containing cells in the presence of an excess of virus-negative cells and for determining which type of cell in a heterogenous population is expressing viral RNA.

Cell Line↗
PubMed1978

Surface antibodies of human myelogenous leukaemia leukocytes reactive with specific type-C viral reverse transcriptases.

Purified immunoglobin G (IgG) from patients with chronic myelogenous leukaemia specifically neutralised RT from feline leukaemia virus while purified IgG from other types of leukaemias and from normal blood cells were less reactive and in some cases preferentially reacted with RT from horizontally transmitted primate type-C viruses (simian sarcoma virus-gibbon ape leukaemia virus group). This indicates the presence of a heterogeneous immune response to RT or to an RT-like molecule in humans.

Antibodies, Neoplasm↗
PubMed1978

Antigenic characterization of a new gibbon ape leukemia virus isolate: seroepidemiologic assessment of an outbreak of gibbon leukemia.

A type-C virus recently isolated from a leukemic gibbon in a colony located on Hall's Island, Bermuda, was characterized with respect to the antigenic properties of its gag and env gene-coded proteins. This virus, designated GaLV-H, was found to be closely related immunologically to type-C viruses previously isolated from gibbons (GaLV-SF, GaLV-SEATO, GaLV-Br) and from woolly monkey (SSAV). However, GaLV-H was readily differentiated from these isolates in a radioimmunoassay for its env gene product, gp70. Seroepidemiology established that GaLV-H was horizontally transmitted among gibbons within the colony. There was no evidence of exposure leading to an immune response to the virus or viral antigenemia in humans working in association with these animals.

Animals↗