Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The UL18 open reading frame of human cytomegalovirus (HCMV) (which encodes a product homologous to major histocompatibility complex class I heavy chains) has been disrupted by insertion of the beta-galactosidase gene under control of the major HCMV early promoter. The recombinant virus delta UL18 showed no phenotypic differences from wild-type HCMV in terms of single-step growth curves or particle/infectivity ratios, indicating that the UL18 gene product is dispensable for the growth of HCMV in human fibroblasts in vitro. The synthesis of the mature cellular class I heterodimer is shut down in cells infected at a high multiplicity with wild-type HCMV, and a similar effect was seen in delta UL18-infected fibroblasts, suggesting that although the UL18 gene product can associate with beta 2 microglobulin, it is not directly involved in the disruption of class I assembly.
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PMID:Construction and characterization of a human cytomegalovirus mutant with the UL18 (class I homolog) gene deleted. 132 89

We report that injecting an E1-deleted, non-replicating, human adenovirus type 5 vector into the brain leads to an inflammatory response. Much of this inflammation is induced directly by the virion particles themselves rather than through the expression of new proteins from the vector. The severity of inflammation was found to depend on the strain of inbred rat used: PVG rats have less inflammation than AO rats in response to a vector injection. Twelve hours after injection of adenovirus vectors into the striatum of AO rats, leukocytes were seen marginating to the walls of nearby blood vessels. By two days there was a large increase in major histocompatibility complex class I expression and a heavy infiltration of leukocytes, mainly macrophages and T cells. Retrograde transport of adenovirus to neurons of the substantia nigra was associated with a delayed and less intense inflammation at this distant site. Although AO and PVG rats showed comparable responses in the striatum up to six days, at later times PVG rats had less intense inflammation. In spite of the inflammatory response, vector-driven expression of the marker protein beta-galactosidase and an adenovirus early protein was seen for at least two months following the injection, although expression declined with time. The observation that adenovirus gene transfer leads to an inflammatory response in the brain must be taken into account when planning and interpreting experiments with these vectors. Furthermore, we conclude that using an appropriate strain of rat can diminish some aspects of the inflammation.
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PMID:Adenovirus gene transfer causes inflammation in the brain. 765 6

The question is addressed whether antigens of Leishmania, a parasite residing in the endosomal compartment of macrophages, can be presented in the context of major histocompatibility complex class I molecules. We used E. coli beta-galactosidase as a model antigen which can be expressed in high levels in L. mexicana promastigotes (L. mexicana-gal). Infection of BALB/c mice with L. mexicana-gal induces beta-galactosidase-specific cytotoxic T cells (CTL), which can be isolated using a beta-galactosidase-expressing mastocytoma line as an antigen-presenting cell. These CTL recognize epitopes of beta-galactosidase in the context of H-2Kd; however, they do not recognize L. mexicana-gal-infected macrophages even after killing of the intracellular amastigotes by drug treatment or macrophage activation by lymphokines, although class I-peptide interaction and the presentation of endogenously produced antigens is normal. It is concluded that parasite antigens can induce a CTL response in vivo but that these CTL cannot recognize infected macrophages because the relevant epitopes cannot gain access to class I molecules. The effect of priming in vivo may be explained by the well-known but ill-understood phenomenon of cross-priming.
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PMID:Leishmania mexicana promastigotes induce cytotoxic T lymphocytes in vivo that do not recognize infected macrophages. 841 75

The priming of an immune response against a major histocompatibility complex class I-restricted antigen expressed by nonhematopoietic cells involves the transfer of that antigen to a host bone marrow-derived antigen presenting cell (APC) for presentation to CD8+ T lymphocytes. Dendritic cells (DC), as bone marrow-derived APC, are first candidates for presentation of tumor-associated antigens (TAA). The aim of this study was to see whether DC are able to prime in vivo antigen-specific cytotoxic T lymphocytes after exposure to a soluble protein antigen in vitro. Lacking a well-defined murine TAA, we took advantage of beta-galactosidase (beta-gal)-transduced tumor cell lines as a model in which beta-gal operationally functions as TAA. For in vivo priming both a DC line, transduced or not transduced with the gene coding for murine GM-CSF, and fresh bone marrow-derived DC (bm-DC), loaded in vitro with soluble beta-gal, were used. Priming with either granulocyte macrophage colony-stimulating factor-transduced DC line or fresh bm-DC but not with untransduced DC line generated CTL able to lyse beta-gal-transfected target cells. Furthermore, GM-CSF was necessary for the DC line to efficiently present soluble beta-gal as an H-2Ld-restricted peptide to a beta-gal-specific CTL clone. Data also show that a long-lasting immunity against tumor challenge can be induced using beta-gal-pulsed bm-DC as vaccine. These results indicate that effector cells can be recruited and activated in vivo by antigen-pulsed DC, providing an efficient immune reaction against tumors.
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PMID:Murine dendritic cells loaded in vitro with soluble protein prime cytotoxic T lymphocytes against tumor antigen in vivo. 855 Dec 46

Dendritic cells (DCs) are bone marrow-derived leukocytes that function as potent antigen presenting cells capable of initiating T cell-dependent responses from quiescent lymphocytes. DC pulsed with tumor-associated antigen (TAA) peptide or protein have recently been demonstrated to elicit antigen-specific protective antitumor immunity in a number of murine models. Transduction of DCs with TAA genes may allow stable, prolonged antigen expression as well as the potential for presentation of multiple, or unidentified, epitopes in association with major histocompatibility complex class I and/or class II molecules. To evaluate the potential efficacy of retrovirally transduced DCs, bone marrow cells harvested from BALB/c mice were transduced with either a model antigen gene encoding beta-galactosidase (beta-gal) or a control gene encoding rat HER-2/neu (Neu) by coculture with irradiated ecotropic retroviral producer lines. Bone marrow cells were differentiated into DC in vitro using granulocyte/macrophage colony-stimulating factor and interleukin-4. After 7 d in culture, cells were 45-78% double positive for DC phenotypic cell surface markers by FACS(R) analysis, and DC transduced with beta-gal were 41-72% positive for beta-gal expression by X-gal staining. In addition, coculture of beta-gal transduced DC with a beta-gal-specific T cell line (CTLx) resulted in the production of large amounts of interferon-gamma, demonstrating that transduced DCs could process and present endogenously expressed beta-gal. DC transduced with beta-gal and control rat HER-2/neu were then used to treat 3-d lung metastases in mice bearing an experimental murine tumor CT26.CL25, expressing the model antigen, beta-gal. Treatment with beta-gal-transduced DC significantly reduced the number of pulmonary metastatic nodules compared with treatment with Hank's balanced salt solution or DCs transduced with rat HER-2/neu. In addition, immunization with beta-gal-transduced DCs resulted in the generation of antigen-specific cytotoxic T lymphocytes (CTLs), which were significantly more reactive against relevant tumor targets than CTLs generated from mice immunized with DCs pulsed with the Ld-restricted beta-gal peptide. The results observed in this rapidly lethal tumor model suggest that DCs transduced with TAA may be a useful treatment modality in tumor immunotherapy.
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PMID:Dendritic cells retrovirally transduced with a model antigen gene are therapeutically effective against established pulmonary metastases. 933 60

Mice were immunized i.p. with soluble or heat-denatured protein antigens [ovalbumin, beta-galactosidase, or recombinant E7 protein of human papilloma virus type 16 (HBV)]. Heat-denatured (100 degrees C) preparations of these proteins were able to induce cytotoxic T lymphocytes (CTL) that recognize cells expressing the respective genes, whereas native protein was either inefficient or required up to 30-fold higher doses. If the heat-treated proteins were separated into aggregated and soluble fractions by ultracentrifugation, only the aggregated fractions were able to induce specific CTL; this is probably because of the easier access to one of the major histocompatibility complex class I loading pathways for exogenous antigen. Addition of the adjuvant aluminium hydroxide (alum) to aggregated proteins abolished their ability to induce CTL; thus, a condition leading to a strong antibody response appeared to inhibit CTL induction. Interestingly, immunization with heat-denatured ovalbumin plus alum increased the IgM/IgG1 ratio compared to immunization with native ovalbumin and alum. Immunization of B6 mice transgenic for an HLA-A2/H-2K(b) hybrid gene with heat-denatured, recombinant HPV 16-E7 protein induced D(b)-restricted CTL specific for the peptide 49-57 of E7, indicating that this epitope is immunodominant over any A2-restricted E7 epitope in these mice. A whole influenza virus preparation heated to 100 degrees C or even autoclaved was still able to induce virus-specific CTL and BALB/c spleen cells heated to 100 degrees C could still cross-prime minor H-specific CTL in B6 mice, although with lower efficiency than fresh spleen cells. Thus, aggregated proteins can be considered as components for future vaccines.
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PMID:Priming of cytotoxic T lymphocytes by five heat-aggregated antigens in vivo: conditions, efficiency, and relation to antibody responses. 934 85

Recombinant adenovirus (AdV) vectors are highly efficient at in vitro and in vivo gene delivery. VKCK is a murine myeloma cell line expressing the light chain of the fusion protein RM4/tumor necrosis factor (TNF)-alpha. The in vitro transfection of VKCK cells with the AdV AdV5LacZ, which contains the marker gene beta-galactosidase, can reach a maximal 75% at a multiplicity of infection of 1000. Intratumoral injections of AdV5LacZ (2 x 10(9) plaque-forming units) resulted in substantial gene transfer in nearly 50% of VKCK tumors. The AdV pLpA/M4-TNF-alpha, which contains a fused gene M4-TNF-alpha that codes for the heavy chain of fusion protein RM4/TNF-alpha, was constructed. After the in vitro transfection of pLpA/M4-TNF-alpha at a multiplicity of infection of 1000, transfected VKCK cells showed significant secretion of RM4/TNF-alpha (36 ng/mL/10(6) cells) containing the functional TNF-alpha moiety in tissue culture. The secretion peaks at day 3 and is diminished at day 6 following the viral infection. These transfected VKCK cells also became more immunogenic with enhanced expression of major histocompatibility complex class I antigen. Intratumoral injections of 2 x 10(9) plaque-forming units of pLpA/M4-TNF-alpha virus with a repeated booster resulted in significant VKCK tumor regression in immune-competent mice, but not in athymic nude mice with a mean tumor weight of 0.07 g that were compared with 1.58 g and 1.70 g for tumors injected with AdV5LacZ and phosphate-buffered saline, respectively (P < .01). The tumor regression also results in protective immunity against a second challenge with parental tumor cells, which is mainly mediated by VKCK tumor-specific CD8+ T cells. These results indicate that AdV-mediated cytokine gene therapy may be a useful approach in the clinical management of solid human tumors.
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PMID:Intratumoral vaccination of adenoviruses expressing fusion protein RM4/tumor necrosis factor (TNF)-alpha induces significant tumor regression. 991 92

The potential use as vaccine delivery system of Salmonella typhimurium strains harboring defined mutations in the sseC (HH104) and sseD (MvP101) genes, which encode putative effector proteins of the type III secretion system of Salmonella pathogenicity island 2, was evaluated and compared with that of the well-characterized aroA mutant strain SL7207 by using beta-galactosidase (beta-Gal) as a model antigen. When orally administered to immune-competent or gamma interferon-deficient (IFN-gamma-/-) BALB/c mice, both mutants were found to be highly attenuated (50% lethal dose, >10(9) bacteria). Both strains were also able to efficiently colonize and persist in Peyer's patches. Immunization with HH104 and MvP101 triggered beta-Gal-specific serum and mucosal antibody responses equivalent to or stronger than those observed in SL7207-immunized mice. Although immunoglobulin G2 (IgG2) serum antibodies were dominant in all groups, IgG1 was also significantly increased in mice vaccinated with MvP101 and SL7207. Comparable beta-Gal-specific IgA and IgG antibodies were detected in intestinal lavages from mice immunized with the different strains. Antigen-specific CD4(+) T-helper cells were generated after vaccination with all vaccine prototypes; however, responses were significantly more efficient when HH104 and MvP101 were used (P < 0.05). Significantly higher levels of IFN-gamma were produced by restimulated spleen cells from mice immunized with HH104 than from those vaccinated with the MvP101 or SL7207 derivatives (P </= 0.05). Interestingly, the three strains induced major histocompatibility complex class I-restricted CD8(+) cytotoxic T cells against beta-Gal; however, cytotoxic T-lymphocyte responses were significantly stronger after immunization with HH104 (P < 0.05). These novel S. typhimurium attenuated strains constitute promising delivery systems for vaccine antigens. The qualitative differences observed in the obtained responses with different carriers may be useful for those applications in which a targeted immunomodulation is required.
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PMID:Pathogenicity island 2 mutants of Salmonella typhimurium are efficient carriers for heterologous antigens and enable modulation of immune responses. 1002 48

The development of mucosal adjuvants is still a critical need in vaccinology. In the present work, we show that bis(3',5')-cyclic dimeric GMP (cdiGMP), a second messenger that modulates cell surface properties of several microorganisms, exerts potent activity as a mucosal adjuvant. BALB/c mice were immunized intranasally with the model antigen beta-galactosidase (beta-Gal) coadministered with cdiGMP. Animals receiving cdiGMP as an adjuvant showed significantly higher anti-beta-Gal immunoglobulin G (IgG) titers in sera than controls (i.e., 512-fold [P < 0.05]). Coadministration of cdiGMP also stimulated efficient beta-Gal-specific secretory IgA production in the lung (P < 0.016) and vagina (P < 0.036). Cellular immune responses were observed in response to both the beta-Gal protein and a peptide encompassing its major histocompatibility complex class I-restricted epitope. The IgG1-to-IgG2a ratio of anti-beta-Gal antibodies and the observed profiles of secreted cytokines suggest that a dominant Th1 response pattern is promoted by mucosal coadministration of cdiGMP. Finally, the use of cdiGMP as a mucosal adjuvant also led to the stimulation of in vivo cytotoxic T-lymphocyte responses in C57BL/6 mice intranasally immunized with ovalbumin and cdiGMP (up to 30% of specific lysis). The results obtained indicate that cdiGMP is a promising tool for the development of mucosal vaccines.
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PMID:The bacterial second messenger cdiGMP exhibits promising activity as a mucosal adjuvant. 1756 66