Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 60,000-dalton polypeptide (p60) has been identified in the feline leukemia virus (FeLV) pseudotype of Moloney sarcoma virus [MSV(FeLV)]. This polypeptide is present in the purified virus complex in concentrations greater than either the murine p30 or the feline p27. Purified p60 crossreacts immunologically with murine p30 group antiserum and contains several interspecies determinants, whereas the group specific determinant of FeLV p27 is not detected. Comparison of peptide fingerprints of p60 and murine p30 show many peptides in common. Limited digestion of p60 with either trypsin or chymotrypsin produced p30-35 and p20 peptides which retain the MuLV p30 group and interspecies antigenic activities. The p30 produced by both enzymes comigrates in polyacrylamide gels with the murine p30 of MSV(FeLV), thus suggesting that p60 may be an uncleaved precursor to p30.
 ...
PMID:A p60 polypeptide in the feline leukemia virus pseudotype of Moloney sarcoma virus with murine leukemia virus p30 antigenic determinants. 4 60

Using the Ouchterlony immunodiffusion method and indirect immunofluorescence tests on tissue slices the antigenic structure of iAp of mouse mammary tumour origin has further been investigated. Antisera against iAp, MTV-B particles, B particle polypeptide p27 and glycoprotein gp52, and leukemia C-type particles were used in these studies. The most prominent antigen of iAp in mammary tumours was found to be identical to the p27 antigen of B particles. This finding was not unexpected in view of recently published data by other authors showing the presence of p27 in iAp of leukemia cells and Leydig cell tumours. The p27 polypeptide is considered to be a group-specific antigen of mouse mammary tumour viruses associated with iAp of different tissue sources and inner structural components of mature B particles. On the other hand, the gp52 antigen and leukemia virus antigens were shown to be absent from iAp of mammary carcinomas. Therefore, the assumption is confirmed that the gp52 glycoprotein represents a group-specific antigen of B type viruses, presumably located at the virion surface. The failure to demonstrate leukemia virus antigens in iAp supports the suggestion that this kind of particles is not related to C type viruses.
 ...
PMID:Presence of the p27 antigenicity and absence of the gp52 antigenicity and leukemia virus antigens in intracytoplasmic A particles (iAp) of mouse mammary tumour origin. 6 45

A quantitative estimation of retrovirus associated cell membrane antigens of murine and feline cells infected with their respective type C leukosis virus is presented. Using a radio-immune assay with three broadly reactive antisera, the minimum estimated number of retrovirus associated antigenic determinants on YAC [Moloney leukaemia virus (MuLV) infected murine] and FL-74 [feline leukaemia virus (FeLV) infected feline] cells was 1.3 x 10(6) and 1.6 x10(6) determinants per cell respectively. The virus structural proteins p27-30 and gp70 were detected by three component specific antisera on murine and feline cell surfaces in amounts which varied between cell isolates. MuLV infected cells produced as many as 1.9 x 10(5) p30 antigenic determinants and 7.5 x 10(5) gp70 determinants on infected cells. FeLV infected cells (FL-74) expressed 5.6 x 10(5) p27 and 7.5 x 10(5) gp70 antigenic determinants per single cell surface. The major core protein (p27-30) and the major envelope glycoprotein (gp70) antigens are sufficiently physically separated on cell surfaces so that binding of either of the membrane antigens with component specific antibodies does not interfere with binding of antibodies specific for the other. Despite the expression of interspecies determinants for p30, gp70, and other retrovirus associated antigens detected by antibody procedures, interspecies determinants of cell mediated immunity could not be demonstrated in immune mice bearing Moloney sarcoma virus (MSV) induced tumours. Furthermore, xenogeneic immunization of mice with FL-74 cells failed to protect mice against the growth of MSV induced lymphoma or sarcoma.
 ...
PMID:Deposition of retrovirus associated antigens (p30 and gp70) on cell membranes of feline and murine leukaemia virus infected cells. 7 45

An immunofluorescence technique was developed for the major group-specific (gs) p27 antigen of avian type C viruses. The localization of this antigen virus-infected in chick embryo fibroblasts was perinuclear, intracytoplasmic and at the cell surface in the majority of the cells, while it was at the cell surface only in some of the cells. No antigen was found in the nucleus. When chickens were experimentally infected with RAV-1 or a wild-strain avian leukosis virus (of subgroup A), the viral gs antigen was detected in lymphocytes of bursa of Fabricius and the spleen. Distinct specific staining was seen in the medulla of germinal centers in bursas of Fabricius and in the white pulp of the spleen where B lymphocytes are thought to be located. This is consistent with the possibility that B lymphocytes are the target cells in the infection of chickens with avian leukemia viruses.
 ...
PMID:Localization of the major group-specific protein (p27) of avian tumor viruses by immunofluorescence in chicken cells and tissues. 17 23

The major structural polypeptides, p30 of reticuloendotheliosis virus (REV) (strain T) and p27 of avian sarcoma virus B77, have been compared with regard to amino acid composition. NH2-terminal amino acid sequence, and immunological crossreactions. The amino acid composition of the two polypeptides is distinct, and a comparison of the first 30 NH2-terminal amino acids of REV p30 with that for the first 25 of B77 p27 yields only three homologous residues. In competition radioimmunoassays the polypeptides show no crossreactivity. A comparison of the amino acid composition and NH2-terminal amino acid sequence of REV p30 with those reported for several mammalian retrovirus p30s shows remarkable similarities. Both REV and mammalian p30s contain a large number of polar residues in their amino acid composition and show approximately 40% homology in the first 30 NH2-terminal amino acids. No crossreactivity could be observed, however, in competition radioimmunoassays between Rauscher murine leukemia virus p30 and that of REV. The observations reported here suggest a close evolutionary relationship between REV and the mammalian retroviruses.
 ...
PMID:Amino-terminal amino acid sequence of the major structural polypeptides of avian retroviruses: sequence homology between reticuloendotheliosis virus p30 and p30s of mammalian retroviruses. 20 72

The amino acid composition, the COOH-terminal amino acid, and the NH2-terminal amino acid sequence of the first 55 residues of the major internal structural protein, p24, of bovine leukemia virus (BLV) were determined. The compositional data and the results of end-group analysis revealed that, although BLV p24 is chemically distinct, it more closely resembles the p30 structural proteins than the other gag gene products of mammalian retroviruses. It was found that BLV p24 shares the common NH2-terminal proline and COOH-terminal leucine but lacks the common prolylleucylarginine tripeptide and the larger conserved region found near the NH2 terminus of all mammalian type C viral p30s. Alignment of the amino acid sequence of BLV p24 with the previously determined sequence of feline leukemia virus p27 revealed a statistically significant sequence homology. A more distant relationship was found between BLV p24 and other mammalian p30s. The finding of a definite sequence homology between BLV p24 and mammalian type C virus p30s clearly establishes the origin of these contemporary viral proteins from common progenitor genes.
 ...
PMID:Amino-terminal sequence of bovine leukemia virus major internal protein: homology with mammalian type C virus p30 structural proteins. 22 66

Serum samples from 224 Norwegian cats were analyzed for the presence of feline leukemia virus (FeLV) p27 common core antigen, and for antibodies to feline immunodeficiency virus (FIV). Ninety specimens originated from the serum bank at the central referral clinic at the Norwegian College of Veterinary Medicine, which had been collected during the years 1983-1989; 67 sera were submitted from veterinarian practitioners; while 67 sera originated from cats presented for euthanasia. The cats were classified into one "healthy" and one "sick" group. Only 2.2% of sick cats and 1.2% of healthy cats showed FeLV antigenemia, a finding which is lower than which has been reported from many other countries. The prevalence of FIV antibodies was 10.1% in sick cats and 5.9% in healthy cats. Antibodies to FIV was most prevalent in male cats (14.7%) than in female cats (2.1%), and more prevalent among domestic cats (12.0%) compared to pedigree cats (2.4%). Antibodies to FIV in the cats demonstrated increasing prevalence with increasing age. It may be concluded that FeLV causes minor problems in Norwegian cats, while FIV is present in a similar prevalence to what is reported from other countries.
 ...
PMID:Prevalence of feline leukemia virus and antibodies to feline immunodeficiency virus in cats in Norway. 131 24

Feline leukemia viruses (FeLVs) belonging to interference subgroup C induce fatal anemia resembling human pure red cell aplasia (PRCA). Subgroup A FeLVs, although closely related genetically to FeLVs of subgroup C, do not induce PRCA. The determinants for PRCA induction by a molecularly cloned prototype subgroup C virus (FeLV-Sarma-C [FSC]) have been localized to the N-terminal 241 amino acids of the surface glycoprotein (SU) gp70. To investigate whether the anemogenic activity of FSC reflects a unique capacity to infect erythroid progenitor cells, we used correlative immunogold, immunofluorescence, and cytological staining to study prospectively the hemopoietic cell populations infected by either FSC or FeLV-FAIDS-61E-A (F6A), a prototype of subgroup A virus. The results demonstrated that although only FSC-infected animals developed erythrocyte aplasia, the env SU and the major core protein (p27) were expressed in a surprisingly large fraction of the lymphoid, erythroid, and myeloid lineage marrow cells in both FSC- and F6A-infected cats. Between days 8 and 17 postinoculation, gp70 and p27 were detected in 43 to 73% of erythroid, 25 to 75% of lymphoid, and 35 to 50% of myeloid lineage cells, regardless of whether the cats were infected with FSC or F6A. Thus, anemogenic subgroup C and nonanemogenic subgroup A FeLVs have similar hemopoietic cell tropism and infection kinetics, despite their divergent effects on erythroid progenitor cell function. Acute anemia induction by subgroup C FeLV, therefore, does not reflect a unique tropism for marrow erythroid cells but rather indicates a unique cytopathic effect of the SU on erythroid progenitor cells.
 ...
PMID:Hematopoietic target cells of anemogenic subgroup C versus nonanemogenic subgroup A feline leukemia virus. 132 10

An African lioness from the Zoo of Zurich had to be euthanized because of an inoperable tumor. The serum tested negative for feline leukemia virus (FeLV) p27 antigen by enzyme-linked immunosorbent assay (ELISA) but was strongly positive for feline immunodeficiency virus (FIV) antibodies by ELISA and Western blot. When her only offspring and mate were tested for FIV, high antibody titers to FIV were also found in their serum. Lymphocytes were prepared from these two lions on different occasions and co-cultivated with specific pathogen free (SPF) cat lymphocytes in the presence of concanavalin A and recombinant human interleukin-2 (IL-2) for 6 weeks. The cell culture supernatants tested negative for Mg(2+)-dependent reverse transcriptase and FIV p24 by a double antibody sandwich ELISA throughout the culture period. Whole blood and buffy coat cells collected from these two lions were transmitted by intraperitoneal injection into two SPF cats. The two cats did not seroconvert for a period of 11 months nor could reverse transcriptase activity and FIV p24 antigen be demonstrated in the supernatant of several lymphocyte cultures. To determine the importance of lentivirus infections in zoo-kept wild felids, 124 serum samples were obtained from African lions, Indian and Siberian tigers, snow leopards, panthers, cheetahs and other wild cats from nine European zoos. In addition, serum samples collected from 12 Asiatic lions originating from Gir forest in the Indian State of Gujarat were included in this study. The sera were tested for antibodies to FIV, FeLV and feline syncytium-forming virus (FeSFV) by ELISA and Western blot using the respective viruses after gradient purification. In addition, some of the sera were also tested for antibodies to equine infectious anemia virus (EIAV) and Visna-Maedi virus (VMV). Antibodies to FIV were found in 30/53 (57%) of African lions, one of 18 tigers and one of four panthers. All other sera including those collected from the 12 Asiatic lions were negative for FIV antibodies. Some of the FIV positive lion sera had high antibody titers producing strong bands on Western blot strips even in dilutions of >> 1:1000. The Western blot pattern of the lion sera differed from that of domestic cats in that primarily p24 and to a lesser degree p17 was recognized. Antibodies to FeSFV were found in 14 animals (seven with strong, seven with intermediate, reaction). No correlation was found between FIV and FeSFV infection. Antibodies to FeLV were found in two cheetahs which later turned out to have been vaccinated with Leukocell, a FeLV vaccine.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Retrovirus infections in non-domestic felids: serological studies and attempts to isolate a lentivirus. 133 98

A cell line (BsT) established from neoplastic embryonal tissues of the platyfish (Xiphophorus maculatus) released spontaneously retrovirus-like particles. The particles have a buoyant density of 1.16 g/ml, a mean diameter of 100 nm and the morphology of immature retroviruses. The particle-associated proteins p70, p65, and p28 react with an antiserum directed against the major internal feline leukemia virus structural protein p27. The particles are associated with a reverse transcriptase. The purified enzyme has a molecular weight of about 70 kDa and prefers the template primers poly(rA):oligo(dT), poly(dC):oligo(dG), and poly(rC):oligo(dG) in the presence of Mn2+. The enzyme activity is inhibited by antibodies directed against the reverse transcriptase of feline leukemia virus and simian sarcoma virus. The particles contain a ribonucleic acid of about 70 S. In an endogenous reverse transcriptase reaction nucleic acids in the range of 0.2 to 0.4 kb were synthesized. In Northern blots with these nucleic acids as probe, three transcripts of about 8.5, 4.2, and 1.5 kb were detected in BsT cells. Southern blot analysis with the same probe demonstrates related sequences in the DNA of BsT cells and the platyfish and swordtail (Xiphophorus helleri). Hybridization experiments with the LTR-gag region of the feline leukemia virus show homologous sequences in the Xiphophorus genome.
 ...
PMID:Isolation and characterization of a retrovirus from the fish genus Xiphophorus. 137 84


1 2 3 4 5 6 7 8 9 10 Next >>