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)

Genes coding for human antibody Fab fragments specific for Entamoeba histolytica were cloned and expressed in Escherichia coli. Lymphocytes were separated from the peripheral blood of a patient with an amebic liver abscess. Poly(A)+ RNA was isolated from the lymphocytes, and then genes coding for the light chain and Fd region of the heavy chain were amplified by a reverse transcriptase PCR. The amplified DNA fragments were ligated with a plasmid vector and were introduced into Escherichia coli. Three thousand colonies were screened for the production of antibodies to E. histolytica HM-1:IMSS by an indirect fluorescence-antibody (IFA) test. Lysates from five Escherichia coli clones were positive. Analysis of the DNA sequences of the five clones showed that three of the five heavy-chain sequences and four of the five light-chain sequences differed from each other. When the reactivities of the Escherichia coli lysates to nine reference strains of E. histolytica were examined by the IFA test, three Fab fragments with different DNA sequences were found to react with all nine strains and another Fab fragment was found to react with seven strains. None of the four human monoclonal antibody Fab fragments reacted with Entamoeba dispar reference strains or with other enteric protozoan parasites. These results indicate that the bacterial expression system reported here is effective for the production of human monoclonal antibodies specific for E. histolytica. The recombinant human monoclonal antibody Fab fragments may be applicable for distinguishing E. histolytica from E. dispar and for use in the serodiagnosis of amebiasis.
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PMID:Preparation of recombinant human monoclonal antibody Fab fragments specific for Entamoeba histolytica. 1022 40

The cysteine-rich region of the 170-kDa subunit galactose-adherence lectin (Gal-lectin) of Entamoeba histolytica is a subunit vaccine candidate and a protective antigen in the gerbil model of amebiasis. Macrophage-mediated immunity is important for protection against E. histolytica and is activated by Th1 cytokines. As Th1 differentiation is promoted by IL-12, we investigated what portion of the Gal-lectin could stimulate IL-12 in human THP-1 macrophages. Native Gal-lactin stimulated IL-12 p40 / p35 mRNA expression in a dose- and time-dependent manner as measured by reverse transcriptase-PCR. Human immune serum and Gal-lectin mAb inhibition studies identified amino acids (aa) 596 - 998 as immunogenic and containing the IL-12 inducing domain. IFN-gamma priming augmented Gal-lectin-induced IL-12 mRNA expression independent of TNF-alpha and IL-1beta, and was required for IL-12 p70 protein production from macrophages and human peripheral blood mononuclear cells. Gal-lectin plus IFN-gamma stimulated IL-12 p40 and p35 gene transcription with stable mRNA transcripts and a differential requirement for protein synthesis. These results suggest that aa 596 - 998 of the Gal-lectin can confer Th1-mediated protection against amebiasis through IL-12 induction.
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PMID:A subunit vaccine candidate region of the Entamoeba histolytica galactose-adherence lectin promotes interleukin-12 gene transcription and protein production in human macrophages. 1067 Nov 97

Entamoeba histolytica, a protozoan parasite, is an important cause of diarrhea and colitis in the developing world. Amebic colitis is characterized by ulceration of the intestinal mucosa. We performed microarray analysis of intestinal biopsies during acute and convalescent amebiasis in order to identify genes potentially involved in tissue injury or repair. Colonic biopsy samples were obtained from 8 patients during acute E. histolytica colitis and again 60 days after recovery. Gene expression in the biopsies was evaluated using microarray, and confirmed by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). REG 1A and REG 1B were the most up-regulated of all genes in the human intestine in acute versus convalescent E. histolytica disease: as determined by microarray, the levels of induction were 7.4-fold and 10.7 fold for REG 1A and B; p=0.003 and p=0.006 respectively. Increased expression of REG 1A and REG 1B protein in the colonic crypt epithelial cells during acute amebiasis was similarly observed by immunohistochemistry. Because REG 1 protein is anti-apoptotic and pro-proliferative, and since E. histolytica induces apoptosis of the intestinal epithelium as part of its disease process, we next tested if REG 1 might be protective during amebiasis by preventing parasite-induced apoptosis. Intestinal epithelial cells from REG 1-/- mice were found to be more susceptible to spontaneous, and parasite-induced, apoptosis in vitro (p=0.03). We concluded that REG 1A and REG 1B were upregulated during amebiasis and may function to protect the intestinal epithelium from parasite-induced apoptosis.
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PMID:The expression of REG 1A and REG 1B is increased during acute amebic colitis. 2158 35