Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human papillomavirus type 16 (HPV-16) is strongly associated with the development of cervical cancer. Studies of model systems with animal papillomaviruses have demonstrated the importance of neutralizing antibodies in preventing papillomavirus-associated disease. The assessment of neutralizing antibody responses against HPV-16, previously hampered by the lack of a viral source, was enabled by the recent propagation of an HPV-16 stock in xenografted severe combined immunodeficiency (SCID) mice. HPV-16 infection of an immortalized human keratinocyte cell line was demonstrated by detection of an HPV-16-specific spliced mRNA amplified by reverse transcriptase PCR. Infection was blocked by preincubation of the virus with antiserum generated against HPV-16 virus-like particles (VLPs) composed of the major capsid protein, L1. To examine potential cross-neutralizing activity among the different genital HPV types, rabbit antisera to L1 VLPs corresponding to HPV-6, -11, -18, -31, -33, -35, -39, and -45 were assayed for the ability to block the HPV-16 infection of cultured cells. Antiserum raised against HPV-33 L1 VLPs was the only heterologous antiserum which inhibited HPV-16 infection. Thus, a neutralization assay for HPV-16 may help to characterize the components required to compose a broadly efficacious genital HPV vaccine.
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PMID:In vitro infection and type-restricted antibody-mediated neutralization of authentic human papillomavirus type 16. 944 88

Feline immunodeficiency virus (FIV) is a lentivirus of domestic cats that causes a spectrum of diseases remarkably similar to AIDS in HIV-infected humans. As part of this spectrum, both HIV-1 and FIV induce neurologic disorders. Because astrocytes are essential in maintaining the homeostasis of the central nervous system, we analyzed FIV for the ability to infect feline astrocytes. Through immunocytochemistry and reverse transcriptase activity, it was demonstrated that two molecular clones of FIV (FIV-34TF10 and FIV-PPR) produce a chronic low level productive infection of feline astrocyte cultures. To investigate the consequences of this infection, selected astrocyte functions were examined. Infection with FIV-34TF10 significantly decreased the ability of astrocytes to scavenge extracellular glutamate (with a peak inhibition of 74%). The effects of the infection did not appear to be a result of toxicity but rather were more selective in nature because the glucose uptake function of the infected astrocyte cultures was not altered. Our data demonstrate that FIV productively infected, at a low level, feline astrocyte cultures, and as a consequence of this infection, an important astroglial function was altered. These findings suggest that a chronic low grade infection of astrocytes may impair the ability of these cells to maintain homeostasis of the central nervous system that, in turn, may contribute to a neurodegenerative disease process that is often associated with lentivirus infections.
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PMID:Effects of feline immunodeficiency virus on astrocyte glutamate uptake: implications for lentivirus-induced central nervous system diseases. 948 37

Infections with high-risk human papillomaviruses (e.g., HPV-16) play an important role in the development of cervical intraepithelial neoplasia (CIN) and invasive cervical cancer (IC). Continued expression of the viral E6 and E7 genes is believed to be a key factor for oncogenic transformation of infected cells. Two spliced transcripts of the E6/E7 oncogenes, termed E6*I and E6*II, can be detected by reverse transcriptase polymerase chain reaction (RT-PCR). To increase the sensitivity of detecting E6/E7 transcripts in cervical scrapes we took advantage of a nested RT-PCR (nRT-PCR) protocol. In a series of 30 HPV-16-positive patients with histologic diagnoses ranging from nondysplastic epithelium to IC, the application of nRT-PCR significantly improved the detection of E6/E7 transcripts compared to conventional RT-PCR. The prevalence of E6/E7 spliced transcripts correlated with lesion severity and the nRT-PCR protocol allowed detection of these transcripts even in nondysplastic epithelium and CIN I lesions. Therefore, in epidemiologic follow-up studies, detection of E6/E7 transcripts by nRT-PCR should prove to be a useful diagnostic tool for risk evaluations regarding the development of CIN and its progression to cervical cancer, especially in high-risk HPV-type-infected patients with CIN 0 and CIN I.
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PMID:Detection of human papillomavirus type 16 E6/E7 oncogene transcripts in dysplastic and nondysplastic cervical scrapes by nested RT-PCR. 960 Aug 17

The development of policies to prevent nosocomial transmission of hepatitis C virus (HCV) infection in hemodialysis units is critically dependent on the understanding of the relationship between tests for anti-HCV, HCV RNA, and HCV genotype and the patients' clinical characteristics. We tested sera from all patients on the renal transplant waiting list at the New England Organ Bank between November 1986 and June 1990 for anti-HCV by a third-generation enzyme-linked immunosorbent assay (ELISA3) and a third-generation recombinant immunoblot assay (RIBA3). All ELISA3-positive sera were tested for HCV RNA by reverse transcriptase "nested" polymerase chain reaction, and the genotype was characterized by restriction fragment length polymorphism. Sera were available in 1,544 of 3,243 (48%) patients on the waiting list, of whom 287 (19%) tested positive for anti-HCV by ELISA3. Two hundred eighty-six randomly selected, anti-HCV-negative patients served as controls. Compared with anti-HCV-negative controls, anti-HCV-positive patients had a longer duration since initiation of renal replacement therapy, higher number of previous kidney transplants and blood transfusions, higher proportion of patients with anti-HBc, history of liver disease, history of non-A, non-B hepatitis, and elevated serum alanine aminotransferase, and lower serum albumin concentrations. Of the 287 anti-HCV-positive sera, 261 (91%) were reactive by RIBA3, 21 (7%) were indeterminate, and five (2%) were nonreactive. HCV RNA was detected in 224 of 275 (81%) ELISA3-positive patients, in whom additional sera were available. There were no significant differences in clinical or laboratory characteristics between ELISA3-positive patients with and without HCV RNA. Genotypes 1a, 1b, 2a, 2b, 3a, and 4 were present in 53%, 23%, 8%, 10%, 4%, and 2% of patients, respectively. Infection with one, two, or three different HCV genotypes was present in 92%, 7%, and 1%, respectively. There was no significant association between the type or number of HCV genotypes and RIBA3 reactivity. There were no major differences in clinical or laboratory characteristics between genotypes or between single and mixed infection. In summary, this study provides detailed information regarding the relationship between tests for anti-HCV, HCV RNA, and HCV genotypes and the clinical and laboratory characteristics of a large, well-characterized cohort of patients referred for renal transplant.
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PMID:Serologic and virologic profiles of hepatitis C infection in renal transplant candidates. New England Organ Bank Hepatitis C Study Group. 963 34

An experimental oral infection of neonatal (< 2 weeks old) lambs with a cervine isolate of Mycobacterium avium subspecies paratuberculosis (M.a. paratuberculosis), the causal agent of ruminant paratuberculosis (Johne's disease) was used to investigate bacteriological, histopathological and immunological changes during the early (up to 8 weeks) post-infection phase. In vitro culture for mycobacteria was positive in one faecal and three mesenteric lymph node (MLN) samples from the eight infected lambs. All mycobacterial isolates from MLN were identified as M.a. paratuberculosis by polymerase chain reaction (PCR). Small-to-medium sized focal granulomata were observed in jejunal (JPP) and ileal Peyer's patches (IPP) from four of the eight infected lambs. Compared with controls, JPP from all infected lambs had significantly (p < 0.05) higher proportions of CD8+ and CD2+ lymphocytes, and there were significantly (p < 0.05) fewer cells expressing B lymphocyte-associated markers in IPP and MLN. The T/B cell ratio was significantly (p < 0.05) increased in both JPP and MLN from infected lambs. The expression of a range of genes for cytokines was examined using specific reverse transcriptase PCR (RT-PCR) amplification of messenger RNA (mRNA) template isolated from MLN, JPP and IPP from both groups of animals. Densitometric analyses indicated that, in infected animals, MLN expressed significantly (p < 0.05) more mRNA for TNF-alpha: JPP had significantly increased (p < 0.05) mRNA for GM-CSF and significantly decreased (p < 0.05) mRNA for IL-4 and IFN-gamma. Infected lambs had significantly (p < 0.05) decreased titres of both circulating IgG and gut mycobacteria-associated IgG antibody. Infection was not associated with any consistent changes in lymphocyte reactivity to specific mycobacterial antigens, IFN-gamma release into supernatants from in vitro intestinal lymphocyte cultures or gut IgA antibody levels.
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PMID:Early immunopathological events in experimental ovine paratuberculosis. 965 60

Infection with HIV leads to AIDS and death in about 90% of patients within ten years. The first generation of anti-HIV drugs inhibited the viral enzyme reverse transcriptase (RT); but long-term studies have revealed side-effects and a high rate of emergence of drug-resistant HIV mutants. The more recent combination of two anti-RT drugs and a protease inhibitor appears to be more promising: approximately 75% of AIDS patients benefit. However, increasing numbers of treatment failures from toxicity and drug-resistant mutants are emerging. Passive immunotherapy (PIT) is a non-toxic form of treatment based on the neutralization of HIV with antibody-rich plasma from healthy HIV-positive individuals. Studies show it can benefit AIDS patients. Here, we suggest that, in combination with anti-HIV drugs, PIT could reduce some of the toxicity of the latter and limit the emergence of drug-resistant HIV strains. In addition, regular plasma donation seems to be beneficial to the donors.
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PMID:How to prolong the effects of combination therapy for HIV. 967 42

The maedi-visna virus (MVV) is classified as a lentivirus of the retroviridae family. The genome of MVV includes three genes: gag, which encodes for group-specific antigens; pol, which encodes for reverse transcriptase, integrase, RNAse H, protease and dUTPase and env, the gene encoding for the surface glycoprotein responsible for receptor binding and entry of the virus into its host cell. In addition, analogous to other lentiviruses, the genome contains genes for regulatory proteins, i.e. vif, rev and tat. The coding regions of the genome are flanked by long terminal repeats (LTR) which play a crucial role in the replication of the viral genome and provide binding sites for cellular transcription factors. The organs targeted by MVV are, in descending order of importance, the lungs, mammary glands, joints and the brain. In these organs, the virus replicates in mature macrophages and induces slowly progressing inflammatory lesions containing B and T lymphocytes. The clinical signs of MVV infection, i.e. dyspnea, loss of weight, mastitis and arthritis, are related to the location of these lesions. Infection with MVV induces the formation of antibodies which can be detected by agar gel immunodiffusion, ELISA and the serum neutralization assay. As neither antiviral treatment nor vaccination is available, diagnostic tests are the backbone of most of the schemes implemented to prevent the spread of MVV. However, since current serological assays are still lacking in sensitivity and specificity, molecular biological methods are being developed permitting the detection of virus in peripheral blood, milk and tissue samples. Future research will have to focus on both the development of new diagnostic tests and a better understanding of the pathogenesis of MVV infection.
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PMID:Maedi-visna virus infection in sheep: a review. 968 46

Interleukin-12 (IL-12) is an important cytokine for Th1 response which stimulates the T-cell population to produce cytokines for cellular immunity. Interleukin-10 (IL-10) is a pleiotropic cytokine capable of suppressing cytokine production from macrophages and T-cells and participants in Th2 immune response. The present study was carried out to examine the effect of these cytokines on virus replication and apoptosis in T-cells infected with feline immunodeficiency virus (FIV). Infection of a feline T-lymphoid cell line (Fel-039) resulted in an increase of the reverse transcriptase (RT) activity in the culture supernatant accompanied by cell death from apoptosis. Addition of human recombinant IL-12 significantly inhibited the virus replication and apoptosis in Fel-039 cells in a dose dependent manner. Furthermore, the antiviral activity of IL-12 was associated with the expression of IFN-gamma in the FIV-infected Fel-039 cells. In contrast, human recombinant IL-10 did not show any inhibitory effect on the virus replication and apoptosis in the Fel-039 cells infected with FIV. These results suggest that the inhibitory effect of IL-12 on both virus replication and apoptosis has potential implications for the design of immunotherapy strategies using IL-12 in FIV infection.
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PMID:Effect of interleukin-12 and interleukin-10 on the virus replication and apoptosis in T-cells infected with feline immunodeficiency virus. 985 97

Infection with human parvovirus B19 causes fifth disease, acute and chronic red cell aplasia, fetal hydrops, arthropathy, and other disorders. Antiviral antibodies limit B19 infection in vivo; however, the identification of serologic markers of protection has been hampered by the lack of a quantitative assay for parvovirus neutralization. A novel in vitro test for parvovirus neutralization has been developed using reverse transcriptase-polymerase chain reaction to detect viral transcripts in a B19-permissive cell line. Parvovirus neutralizing activity was measured in sera from naturally infected individuals, and common features of sera with high neutralizing capacity were identified as protection correlates. Sera that suppressed B19 replication in vitro demonstrated IgG reactivity with capsid proteins VP1 and VP2, but no linear relationship between antibody titer and neutralizing capacity was observed. Sera from experimental animals and human volunteers immunized with a virus-like particle vaccine candidate exhibited B19 neutralizing titers equal to or greater than those observed in natural infections.
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PMID:Quantitative analysis of neutralizing immune responses to human parvovirus B19 using a novel reverse transcriptase-polymerase chain reaction-based assay. 995 68

Seven ponies were infected with the virulent wild-type Wyoming strain of equine infectious anaemia virus (EIAV). Infection status was monitored by serum reverse transcriptase activity, rectal temperature, and complete blood count. Preinfection serum and serum obtained during the initial febrile episode following infection were assayed for interleukin 6 (IL-6) activity. Postinfection IL-6 activity was significantly increased as compared to preinfection values. The magnitude of increase in IL-6 was positively correlated with reverse transcriptase activity (an indirect measure of viraemia) but was not correlated with rectal temperature. IL-6 production in response to EIAV infection may play a role in pathogenesis of disease, especially the hyperglobulinaemia and apparent polyclonal B cell activation in these horses.
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PMID:Increased interleukin-6 activity in the serum of ponies acutely infected with equine infectious anaemia virus. 1008 17


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