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

A novel immunoassay is described based on the agglutination by antigens of antibody-coated ferric oxide (Fe2O3) particles. The procedure for attachment of antibodies to the ferric oxide particles is simple and fast. The assay was used for identification and quantification of gamma-globulin in human serum and in chromatographic fractions as well as of gp70 (an envelope protein from feline leukemia virus) in the culture medium and for identification of the thyroid-stimulating hormone (TSH).
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PMID:Protein immunoassay based on agglutination of antibody-coated ferric oxide particles. 284 2

Cats exposed to the feline leukemia virus (FeLV) may mount an effective immune response and eliminate the virus, develop a non-viremic, latent infection or become persistently infected and shed the virus. Persistently infected cats commonly die of secondary opportunistic infections that result from FeLV-induced immunosuppression. The acquired immunosuppression is the most frequent and most devastating consequence of FeLV infection in the cat. Immunosuppression is targeted primarily to the cell-mediated immune system and has been attributed to the viral p15e envelope protein. The decreased IgG response and proliferative response to T cell mitogens is thought to be due to a defect in the helper cell function. As a result of T helper cell immunosuppression, infected cats may also have defective cytotoxic lymphocyte and activated macrophage functions which are regulated by their lymphokines. Research has shown that the virus causes a general suppression in the production of T cell-derived lymphokines, including gamma interferon and interleukin 2. A decrease in the function of polymorphonuclear leukocytes has also been reported and may contribute to deaths due to opportunistic infections in FeLV-positive cats. There are numerous parallels between the acquired immunodeficiency syndrome (AIDS) in man and the FeLV-induced immunodeficiency syndrome in cats. Frequent deaths due to opportunistic infections, lymphopenia, depressed cell-mediated immune responses to T cell-dependent antigens despite hypergammaglobulinemia and the presence of a long period of time between infection and the onset of clinical signs are just a few of the syndromes that are similar between the 2 retroviral diseases. A new strain of FeLV, FeLV-FAIDS has been associated with a naturally occurring immunosuppressive syndrome that is strikingly similar to AIDS in man. In addition, a T-lymphotropic retrovirus has recently been identified from cats with an immunodeficiency-like syndrome; this feline lentivirus disease is morphologically similar, but antigenically distinct from the human immunodeficiency virus, the cause of AIDS. Treatment for FeLV immunosuppression is primarily supportive. The development of a soluble tumor cell antigen vaccine has been shown to be efficacious in preventing FeLV infections.
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PMID:Clinical and immunologic aspects of FeLV-induced immunosuppression. 284 93

Serum containing antibodies to the human T-lymphotropic virus type I (HTLV-I) has been observed at a higher than expected frequency in patients with B-cell chronic lymphocytic leukemia (CLL) in an area endemic for HTLV-I. An attempt was made to determine whether the cells from patients with this leukemia were HTLV-I antigen-committed B cells that had undergone malignant transformation. Cells from two HTLV-I seropositive Jamaican patients with CLL were fused with a human B-lymphoblastoid cell line. The hybridoma cells that resulted from the fusion of CLL cells from patient I.C. produced an immunoglobulin (IgM) that reacted with the p24 gag protein from HTLV-I, HTLV-II, and HTLV-III (now referred to as HIV), but showed preferential reactivity with HTLV-I. The specific immunoglobulin gene rearrangement (IgM, kappa) in the CLL cell was demonstrated in the hybridoma cell line, indicating that the captured immunoglobulin was from the CLL cells. The IgM secreted by the fusion of CLL cells from patient L.L. reacted only with HTLV-I-infected cells and with the HTLV-I large envelope protein (gp61) on Western blots. The CLL cells from these patients appear to be a malignant transformation of an antigen-committed B cell responding to HTLV-I infection, suggesting an indirect role for this retrovirus in leukemogenesis.
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PMID:HTLV-I--associated B-cell CLL: indirect role for retrovirus in leukemogenesis. 288 31

Protection against human T-cell leukemia virus type-I (HTLV-I) infection in cynomolgus monkeys, achieved by immunizing the animals with env gene products of HTLV-I produced in Escherichia coli, was evaluated. Four monkeys that had been immunized with the env product produced antibody against HTLV-I gp68 and gp46, and their sera were found to cause strong inhibition of syncytium formation of a cat fibroblast cell line induced by HTLV-I. Immunized and non-immunized monkeys were challenged with live MT-2 cells, a high HTLV-I-producer cell line. After challenge, all the control non-immunized monkeys were infected with HTLV-I, as judged by the frequent detection of HTLV-I-antigens in cultures of their peripheral blood mononuclear cells (PBMC), whereas no antigens were recovered from PBMC of immunized monkeys. These results indicate that humoral immunity against HTLV-I-envelope protein elicited by immunization with the polypeptides synthesized in bacteria protected the monkeys against primary infection with HTLV-I.
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PMID:Protection of cynomolgus monkeys against infection by human T-cell leukemia virus type-I by immunization with viral env gene products produced in Escherichia coli. 288 18

Human retroviruses, or RNA viruses, including the 2 HIV agents associated with AIDS, and the 2 HTLV agents causing leukemia, are described from the viewpoint of history, detection, serology, transformation mechanism, disease pathophysiology, genetic function, associated disease, and related viruses. Both HTLV and HIV infect the human T-lymphocytes, also known as CD4 or helper cells. Both can now be grown in culture, and their genomes are well characterized. HTLV, an acronym for human T-lymphotropic leukemia virus, causes the fulminating adult T-cell leukemia-lymphoma (ATLL), 1st described in 1977. It is prevalent in population clusters, notably in the Caribbean and in southwestern Japan, and is spread by sexual, blood and perinatal routes, as is HIV. It is thought to promote transformation of target cells by release of growth promoting, soluble factor, perhaps a product of the viral "tat" gene. Besides leukemia, HTLV-1 causes a myelopathy sometimes called tropical spastic paraparesis. HIV, formerly known as HTLV-III, causes depletion of the T-cells, and also infects the brain and nervous system. IT has also been isolated from semen, cervical secretions, saliva, monocytes, milk, endothelial cells, tears and cornea. HIV has 5 more genes than HTLV, which regulate transcription, mRNA processing and virus maturation. Parts of the HIV genome are highly heterogeneous, and mutate rapidly, notable sections of the envelope protein. Thus, HIV has 2 main subtypes, but others are known and probably exist. Approaches toward developing AIDS therapeutic agents as of 1987 are outlined: an effective drug should cross the blood-brain barrier. Several anti-viral drugs that block the enzyme reverse transcriptase area being investigated. Possible mechanisms for growth of Kaposi's sarcoma, activation of herpes type viruses, and animal viruses related to HTLV and HIV are discussed.
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PMID:Retroviruses: new viral infections in man. 289 67

Interference to superinfection by murine leukemia viruses (MuLV) was analyzed in cells chronically infected with other MuLVs. A new sensitive focal immunofluorescence assay employing monoclonal antibodies was used to detect foci of virus infection in live cell monolayers. Monoclonal antibodies were chosen which reacted with the challenge virus but not with the interfering virus. The results obtained confirmed some of the findings of previous workers using Moloney sarcoma virus pseudotypes as challenge viruses on mouse and nonmouse cells. In addition, SC-1 mouse cells nonproductively infected with defective spleen focus-forming virus were found to be resistant to superinfection by recombinant dual-tropic viruses. Furthermore, results indicated that interference patterns between some pairs of viruses differed in different cell types. Thus, xenotropic MuLV blocked superinfection by recombinant dual-tropic viruses in SC-1 feral mouse cells, but not in two lines of NZB mouse cells. Also, in a Mus dunii tail fibroblast cell line some unique patterns of interference were observed. One ecotropic MuLV blocked infection by two xenotropic viruses and three recombinant dual-tropic viruses. Two other ecotropic viruses blocked infection by only one of the two xenotropic viruses tested. These two ecotropic viruses also differed from each other in their ability to block the three recombinant viruses. In addition, two strains of amphotropic MuLV also differed in their interference capacity. As expected, strain 1504A did not block any viruses tested, whereas strain 4070A surprisingly blocked one xenotropic and one ecotropic MuLV. The lack of homogeneity in interference patterns seen in the Mus dunii cells suggested either that a large number of heterogeneous virus receptors were present on this cell line or that interference in these cells might operate through a mechanism other than blocking of virus receptors by the envelope protein of the interfering virus.
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PMID:Different murine cell lines manifest unique patterns of interference to superinfection by murine leukemia viruses. 298 94

Ultraviolet light-inactivated feline leukemia virus (FeLV) and its 15,000 dalton envelope protein (p15E) inhibited concanavalin A receptor motility of feline peripheral lymphocytes (PBL). In contrast, the virus had no effect on immunoglobulin capping of feline PBL. The inhibitory action of FeLV and FeLV p15E was reversed by the addition of indomethacin. The indomethacin effect was titratable and gave significant reversal between 1 X 10(-5) and 1 X 10(-10) M. The indomethacin inhibition of the prostaglandin synthesis does not appear to be the mechanism of action in its ability to reverse FeLV suppression of Con A receptor mobility. Since the addition of prostaglandin E2 (PGE2) (1.0 microM) was also able to reverse the FeLV-induced inhibition and neither indomethacin nor PGE2 had an observable effect on Con A receptor mobility of normal PBL without FeLV present. PBL from FeLV-infected cats were sensitive to indomethacin (1.0-10.0 microM) and an indomethacin-related increase in cap formation was observed. Since both indomethacin and PGE2 were able to reverse the FeLV-induced suppression it was concluded that their mechanism of action may be through a common site. In addition, indomethacin may prove useful as an immune response modifier for therapy in FeLV-infected cats.
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PMID:The reversal of feline retroviral-induced suppression of lymphocyte Con A receptor mobility by indomethacin and PGE2. 299 19

The immunosuppressive effect of feline leukemia virus (FeLV) and its 15,000 dalton envelope protein (p15E) were studied to determine if the mechanism of action was due to an increase in prostaglandin production. We examined the effects of exogenous PGE1 and PGE2 on the normal Con A response of feline peripheral blood lymphocytes (PBL) and found them to be inhibitory. The addition of the cyclooxygenase inhibitor indomethacin to cells incubated with FeLV or FeLV p15E and Con A completely abrogated the viral suppressive effects. This reversal was titratable and time-dependent. Other non-steroidal anti-inflammatory (NSAI) drugs were found to have similar actions. Indomethacin was also able to increase the suppressed Con A response of PBL from FeLV-infected cats. Upon measurement of PGE2 levels from PBL cultured with FeLV, we found a decrease in PGE2 accumulation associated with FeLV presence during the first 24 h of culture. These findings indicate that FeLV does not cause its immunosuppressive effects by increasing PG production and suggests that indomethacin and the other tested NSAI drugs do not produce their effect by PG inhibition.
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PMID:Reversal of feline retroviral suppression by indomethacin. 300 36

In an attempt to express the small (transmembrane) envelope protein p21e of type 1 human T-cell leukemia (lymphotrophic) virus (HTLV-1) exclusive of other viral gene products, we have constructed a recombinant plasmid clone (pMBE-1) in a bovine papillomavirus-derived mammalian expression vector. Mouse C127 cells transfected with the pMBE-1 plasmid expressed the introduced HTLV-1 viral gene(s) as demonstrated by Northern blot and indirect immunofluorescence with natural human antisera. The transfected mouse cells were injected into BALB/c mice, and a monoclonal antibody was recovered which specifically recognizes a 21-kilodalton protein present in HTLV-1 virions, indicating that the pMBE-1 plasmid encodes the small envelope protein.
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PMID:Type 1 human T-cell leukemia virus small envelope protein expressed in mouse cells by using a bovine papilloma virus-derived shuttle vector. 301 17

We have constructed a recombinant vaccinia virus encoding the expression of the feline leukemia virus (FeLV) envelope gene of the Gardner-Arnstein strain of FeLV subgroup B. Human cells infected with the recombinant virus (vFeLVenv) express and process the FeLV envelope protein similarly to cells infected with authentic FeLV. The mature gp 70 protein is transported to and accumulates on the surface of vFeLVenv-infected cells. Vaccinia virus replication and FeLV gp70 accumulation was also observed in cells of feline and murine origin, albeit at levels somewhat reduced from those in human cells. Toward the goal of developing a recombinant vaccinia virus as a live vaccine for feline leukemia disease in cats, immunogenicity studies were performed in cats and mice. These experiments yielded surprising results: although animals mounted a typical virus-neutralizing antibody response to the vaccinia virus vector, we were unable to detect antibodies against FeLV gp70 in any of the vaccinated animals. A subsequent 'booster' immunization with killed FeLV was unable to elicit evidence of immunologic 'priming' by the recombinant virus. We are presently unable to explain the apparent lack of immunogenicity. These results may point to complexities involved in the development of vaccines to protect against retrovirus infection.
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PMID:Feline leukemia virus envelope protein expression encoded by a recombinant vaccinia virus: apparent lack of immunogenicity in vaccinated animals. 303 95


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