Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rapid advances have occurred in the characterization of human papilloma virus (HPV) types applying the new advanced techniques of restriction endonuclease analysis and molecular hybridization to human wart virus. Human papilloma virus can no longer be viewed as a single, homogeneous virus producing all varieties of clinical warts. At least three antigenically heterogeneous HPV types have been associated with common and plantar warts. Two additional HPV types have been found in patients with epidermodysplasia verruciformis. Condylomata acuminata and laryngeal papillomas contain viruses which are also distinct from the preceding viruses and may represent additional HPV types. This antigenic heterogeneity of HPV has important implications concerning the immunology of human warts which have not been taken into account in most previously published studies. Both antibody and cell-mediated responses may be seen in patients with active warts, but many patients with warts have no demonstrable immune reactions. The role of immunity in wart regression remains poorly understood. Nevertheless, the increased frequency of warts in patients receiving immunosuppressive drugs and with immune deficiency states and the immunologic alterations which occur in patients with regressing or cured warts compared to patients with active warts, particularly the increased frequency of cell-mediated responses and antibodies specific for viral antigens, support a possible role for immunity in the resolution of warts. The evidence to date, however, does not prove that immune mechanisms are directly responsible for the elimination of warts.
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PMID:Immunology of human warts. 22 34

Human herpesvirus type 6 (HHV-6), a newly recognized human herpesvirus first described in 1986, is morphologically similar to other herpesviruses but is distinguishable from all of them by some unique in vitro biological effects, specific antigenic analysis, and patterns of endonuclease restriction digests of DNA. In vitro HHV-6 exhibits tropism mainly for T lymphocytes, but it also infects other cells, including B lymphocytes, monocytes-macrophages, glial cells, and fibroblasts. Because HHV-6 causes frequent infection in infants and children, a seroprevalence rate of antibody to this virus of up to 80% has been reported in the United States. Infection in infancy develops as levels of maternal antibody wane, thus resulting in either subclinical infection or an acute febrile illness termed exanthema subitum. Primary infection acquired later in life causes a disease resembling acute infectious mononucleosis. Since HHV-6 shares the capacity to establish latent infection with other herpesviruses, frequent viral reactivation is probably the explanation for the high incidence of serologically proven active HHV-6 infection found simultaneously with active infection due to other herpesviruses as well as in the presence of various immune deficiency conditions.
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PMID:Human herpesvirus type 6: review. 131 2

Several different genital and non-genital HSV isolates were obtained from a patient with an acquired immune deficiency of unknown aetiology. The patient was initially treated with topical acyclovir (ACV) and later with topical and intravenous ACV. In spite of treatment with antiviral drugs the patient continued to shed virus and to have extensive genital ulcerations. Restriction endonuclease (RE) analyses of the viral DNA revealed that all the isolates had characteristic HSV-2 patterns and that there were three genetically distinct virus groups among the ten isolates tested. Three post-therapy isolates, with the same RE pattern, were found to be devoid of thymidine kinase activity (TKD), highly resistant to ACV in cell culture, but sensitive to vidarabine (ara-A), phosphonoacetate and phosphonoformate. Two of these TKD isolates were obtained during and after topical ACV therapy and before intravenous treatment. Mice inoculated intracerebrally with a lethal dose of each of the three TKD viruses were refractory to ACV, but responded to vidarabine or a combination of ACV and ara-A. Mice inoculated with the TK+ viruses (including the pre-therapy isolate) responded to ACV and/or ara-A treatment. The results indicate that: (i) TKD variants may be produced in humans after topical ACV therapy; (ii) different ACV-resistant or sensitive HSV-2 variants can establish latency at different body sites and reactivate; and (iii) when drug-resistant viruses are isolated from patients with multiple reactivations, the drug in question should not be discontinued, since the patients may also be shedding drug-sensitive virus at a different body site.
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PMID:Characterization of acyclovir-resistant and -sensitive herpes simplex viruses isolated from a patient with an acquired immune deficiency. 302 53

Several papillomas from a single patient who exhibited an unusual immune deficiency syndrome were analyzed for the presence of specific human papillomavirus (HPV) types. Preliminary analysis indicated that the HPV DNA species present in each of these tissues was quite unlike any of the previously characterized HPV types. In order to more rigorously analyze the HPV from this patient we have isolated the HPV DNA by molecularly cloning it into a bacteriophage lambda vector and have constructed a detailed restriction endonuclease map. Comparative hybridization studies using S1 nuclease analyses showed 6% or less nucleotide sequence homology of this viral DNA with HPV types 1, 2, 3, 4, 5, 6, or an HPV-11, molecularly cloned in this laboratory. Moreover, Southern blot analyses under stringent hybridization conditions revealed little, if any, hybridization to HPV types 1, 2, 4, 5, 7, 8, 10, 11, HPV-EV isolated from a patient with epidermodysplasia verruciformis (EV), or 2 previously described HPVs (HPV-P and HPV-PW) related to HPV-3. There was, however, a very weak sequence homology detected with HPV-6 and an extremely weak homology to HPV-3. No filter hybridization was observed with the recently characterized HPVs 9 or -12 to -24. These data accumulatively indicate that the HPV species from this immunosuppressed patient represents a new, hitherto unidentified HPV type.
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PMID:Molecular cloning and characterization of a unique type of human papillomavirus from an immune deficient patient. 632 88

Human dermatitis-involving cytotoxic interaction between effector lymphocytes and epithelial target cells has thus far been documented in vivo only as naturally occurring disease or as an iatrogenic complication of organ engraftment. In this report, we reproduce human cytotoxic dermatitis via local microinjection of heterologous human lymphocytes into human skin xenografted to mice with severe combined immune deficiency syndrome. Injection sites develop progressive T cell epidermotropism culminating in cytotoxic dermatitis resembling human lichen planus within 4 weeks. Effector T cells express a CD8+, TIA-1+ phenotype, proliferate locally, express interleukin-2 surface receptors, and demonstrate interferon-gamma mRNA induction after microinjection. Migration of these T cells into the epidermis is closely linked to experimental induction and coincident expression of intercellular adhesion molecule by keratinocytes. T cell apposition to keratinocytes is associated with endonuclease-mediated DNA fragmentation (apoptosis) in the latter cell type. Intraepidermal T cell migration and related lesion formation is partially abrogated by systemic administration of antisense oligonucleotide to ICAM-1 mRNA. These findings demonstrate that human cytotoxic tissue injury directed against epithelial targets can be produced and modulated in chimeric mice.
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PMID:Experimental production and modulation of human cytotoxic dermatitis in human-murine chimeras. 903 76