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M F Gurish

Publications and source records attributed to M F Gurish.

At least 37 records · Page 2Linked to original sources
PubMed1993

A closely linked complex of mouse mast cell-specific chymase genes on chromosome 14.

Mouse mast cells differentially express at least four chymases (mouse mast cell protease (mMCP) 1, mMCP-2, mMCP-4, and mMCP-5), a tryptase (mMCP-6), and an exopeptidase (mouse mast cell carboxypeptidase A (mMC-CPA)). The previously uncharacterized 2.5-kilobase mMCP-2 gene was isolated and found to consist of 5 exons. The 5'-flanking region of this gene is 89, 93, and 42% similar to that of the mMCP-1, mMCP-4, and mMCP-5 genes, respectively. Inheritance patterns of restriction-enzyme fragment length polymorphisms of these six mast cell protease genes in recombinant inbred mouse strains and interspecific backcrosses were used to determine their chromosomal locations. The mMCP-6 and mMC-CPA genes are located on chromosomes 17 and 3, respectively, whereas the four mast cell chymase genes all reside on chromosome 14 linked to a gene complex that encodes four cytotoxic T lymphocyte granzymes. Pulsed-field gel electrophoresis of genomic DNA digests demonstrated that the mMCP-1, mMCP-2, and mMCP-5 genes are within 850 kilobases of each other. Although clustering of the serine protease genes on chromosome 14 may be important at a higher level of genomic organization, the ability to independently induce or suppress the steady-state levels of the four chymase transcripts by treatment of mast cells with cytokines suggests that gene clustering is not the most critical factor for coordinate expression of these proteases. Because of the unique features of their tertiary structures, the substrate specificities of the serine proteases encoded by genes at the chromosome 14 complex are predicted to be more limited than those of pancreatic chymotrypsin and pancreatic trypsin, whose genes reside on chromosomes 8 and 6, respectively. Based on present day genomic distribution and sequence similarities, we propose that a primordial gene that encoded a serine protease with restricted substrate specificity underwent extensive duplication and divergence to form a family of cytokine-regulated transcripts from genes on chromosome 14.

Amino Acid Sequence↗
PubMed1992

Expression of murine beta 7, alpha 4, and beta 1 integrin genes by rodent mast cells.

The screening of a rat mast cell cDNA library with a probe selected to recognize those genes preferentially or exclusively expressed by mast cells identified a rat gene sequence, RF-17, that shared homology with the beta-integrins. This integrin was expressed in rat tissues enriched for mast cells and T cells. The rat RF-17 sequence was used to isolate the murine homologue from a spleen cDNA library. The murine gene encodes a protein of 806 amino acids that is the probable homologue to the human beta 7 chain. Transcripts specific for the murine gene are found in the thymus, spleen, and lung. To attempt to identify the gene product for this new integrin chain, we examined the murine T cell line TK-1, which expresses a novel integrin heterodimer, lymphocyte Peyer's patch high endothelial venule adhesion molecule (LPAM-1), of a known alpha 4 chain and an unknown beta P chain, for expression of murine beta 7 (RF-17). This cell line expresses high levels of RF-17 transcripts, suggesting that beta P is encoded by the beta 7 gene. Bone marrow cells induced to differentiate into mast cells via IL-3 express the beta 7 gene as well as the genes encoding the murine integrin alpha 4 and beta 1 proteins. Surface staining analysis indicates that these cells express an alpha 4-containing integrin complex throughout the differentiation process. These data suggest that the Peyer's patch homing LPAM-1 receptor expressed by a subset of T cells consists of the beta 7 gene product and the alpha 4 chain, and that this integrin chain complex is also found on the surface of maturing mast cells. The presence of beta 1 transcripts also suggests that these maturing mast cells possess the LPAM-2 integrin complex (alpha 4/beta 1) as well. The experimental strategy described in this manuscript has, thus, identified a novel murine beta-integrin chain that is expressed by rodent T cells and mast cells.

Amino Acid Sequence↗
PubMed1992

IL-10 induces transcription of the gene for mouse mast cell protease-1, a serine protease preferentially expressed in mucosal mast cells of Trichinella spiralis-infected mice.

Mouse bone marrow-derived mast cells (BMMC) obtained by culturing progenitor cells with rIL-3 express mouse mast cell protease (MMCP)-5 mRNA but not MMCP-1 mRNA or MMCP-4 mRNA. In terms of mast cell differentiation, these transcripts encode one early-expressed and two late-expressed chymases, respectively. cDNA and cRNA probes were used in RNase protection assays and RNA blot analyses to study the expression of these three homologous protease genes in cultured mast cells and in helminth-infected mice. Intestinal tissue from Trichinella spiralis-infected mice, containing high numbers of mucosal mast cells, had abundant amounts of MMCP-1 mRNA but only minimal amounts of the serosal mast cell transcript that encodes MMCP-4. Exposure of mouse BMMC to rIL-10-induced transcription of the MMCP-1 gene but not the MMCP-4 gene, and a cDNA encoding MMCP-1 was obtained from these rIL-10-treated cells. The expression of MMCP-1 mRNA in BMMC depended on the continuous exposure of these cells to rIL-10, and the level of MMCP-1 mRNA (but not MMCP-5 mRNA) was substantially higher in BMMC maintained in rIL-4 and rIL-10 than in rIL-3 and rIL-10 or in rIL-3, rIL-4, and rIL-10. Thus, whereas rIL-3 elicits transcription of early expressed genes in cultured mast cells, it suppresses the transcription of late-expressed genes. These in vitro and in vivo transcription studies also indicate that rIL-10 preferentially induces differentiation of mouse progenitor cells in a mucosal mast cell-specific lineage, and that expression of granule serine protease genes is regulated in a subclass-specific manner in mouse mucosal mast cells and serosal mast cells.

Amino Acid Sequence↗
PubMed1992

Transcriptional regulation of the mucosal mast cell-specific protease gene, MMCP-2, by interleukin 10 and interleukin 3.

Although transcription of mast cell (MC) secretory granule neutral protease genes has been shown to distinguish MC subclasses in mucosal and serosal environments, the specific cytokines that regulate the expression of these genes have not been determined. To examine cytokine-mediated gene regulation, bone marrow-derived MC (BMMC) differentiated in vitro were obtained by culturing mouse bone marrow progenitor cells in the presence of WEHI-3 cell-conditioned medium, concanavalin A-stimulated splenocyte-conditioned medium (BMMCC), or recombinant (r) interleukin (IL)-3 (BMMCIL-3). All three populations of BMMC expressed the serosal MC-specific transcripts that encode mouse MC serine protease (MMCP)-5, MMCP-6, and MC carboxypeptidase A. However, only BMMCC contained MMCP-2 mRNA, a late expressed gene selectively transcribed by intestinal mucosal MC that proliferate during helminthic infestation in response to the T cell-derived cytokines IL-3, IL-4, and IL-10. When BMMCIL-3 were exposed to rIL-10 in the presence of either rIL-3 or rIL-4, they expressed MMCP-2 mRNA. Not only was the transcription of the MMCP-2 gene in BMMC dependent on continuous exposure of the cells to rIL-10, but the level of MMCP-2 mRNA in these cells could be down-regulated by rIL-3. These studies comparing the effects of two cytokines on the transcriptional regulation of secretory granule protease genes in MC demonstrate that rIL-10 induces BMMCIL-3 to express the mucosal MC protease MMCP-2, that rIL-3 attenuates the rIL-10-induced expression of this gene, and that transcription of the MMCP-2 gene is reversed in the absence of rIL-10.

Animals↗
PubMed1992

Differential expression of secretory granule proteases in mouse mast cells exposed to interleukin 3 and c-kit ligand.

It is now established that the subclasses of mast cells (MC) that reside in mucosal and serosal environments can be distinguished from one another in terms of their expression of specific secretory granule-localized proteases and proteoglycans. Further, the hematopoietic- and connective tissue-derived cytokines that regulate expression of the genes that encode these constituents of the granule can now be identified using recently developed gene-specific probes and recombinant cytokines. When bone marrow-derived MC (BMMC) were developed with recombinant interleukin 3 (rIL-3) and maintained with this cytokine in the absence or presence of recombinant c-kit ligand (rKL), they remained safranin-, produced almost no 35S-labeled heparin proteoglycans, and contained greater levels of mouse MC protease (MMCP) -5 mRNA and mast cell carboxypeptidase A (MC-CPA) mRNA than MMCP-6 mRNA. They did not contain MMCP-4 or -2 mRNA, genes expressed late in the differentiation of progenitor cells into serosal and mucosal MCs, respectively. In contrast, BMMC developed with rKL alone or by sequential culture in medium containing rIL-3 followed by rKL expressed high levels of MMCP-4 and -6 mRNA, as well as the transcripts that encode MMCP-5 and MC-CPA. Although rKL-developed BMMC were safranin+ and produced substantial amounts of 35S-labeled heparin proteoglycans, they contained only minimal amounts of histamine and MC-CPA enzymatic activity relative to serosal MC. These are the first studies to characterize the transcriptional granule phenotype of a population of BMMC derived using any recombinant cytokine, to demonstrate a dissociation between histochemical staining and granule maturation, and to demonstrate antagonistic regulation of late expressed protease genes by a cytokine.

Animals↗
PubMed1992

Continuous release of secretory granule proteoglycans from a cell strain derived from the bone marrow of a patient with diffuse cutaneous mastocytosis.

A human cell strain (designated HBM-M) that was derived from the bone marrow of a child with diffuse cutaneous mastocytosis was previously found to possess features that suggested it belonged in the mast cell/monocyte lineage. HBM-M cells synthesized approximately 150-Kd Pronase-resistant proteoglycans that were recognized by an antihuman secretory granule proteoglycan peptide core antibody. These cells also contained in relatively high abundance the same sized mRNA transcript that encodes the peptide core of proteoglycans that are normally localized to secretory granules of hematopoietic cells. However, unlike most other hematopoietic cells, HBM-M cells continuously released their newly synthesized 35S-labeled proteoglycans rather than retaining them in an intracellular storage compartment. Chondroitinase ABC, nitrous acid, and heparinase degraded approximately 76%, 17%, and 7%, respectively, of the HBM-M cell-derived 35S-labeled proteoglycans. As assessed by high performance liquid chromatography, 91% of the unsaturated 35S-labeled disaccharides generated by treatment with chondroitinase ABC were delta Di-4S. The remaining chondroitin sulfate 35S-labeled disaccharides appeared to be primarily a complex mixture of disulfated disaccharides. The 35S-labeled glycosaminoglycans that were not degraded by chondroitinase ABC migrated in two-dimensional cellulose acetate electrophoresis as if they were heparan sulfate or under-sulfated heparin. Thus, although the HBM-M cell-derived proteoglycans had some of the features of proteoglycans produced by normal human mast cells, the heparin-like and chondroitin sulfate glycosaminoglycans bound to the HBM-M cell proteoglycans were considerably less sulfated. Because the only human cell types that have so far been shown to synthesize proteoglycans that have heparin-like glycosaminoglycans bound to a protease-resistant peptide core are mast cells and basophilic leukocytes from patients with myelogenous leukemia, it is possible that the HBM-M cell is a mast cell progenitor cell.

Bone Marrow↗
PubMed1991

GATA-binding transcription factors in mast cells regulate the promoter of the mast cell carboxypeptidase A gene.

The transcription factors GATA-1, GATA-2, and GATA-3 were found to be expressed in several mouse and rat mast cell lines that contain mast cell carboxypeptidase A (MC-CPA) and other proteases in their cytoplasmic granules. GATA-1 mRNA was not detected in P815 cells, an immature mouse mastocytoma-derived cell line that lacks electron-dense granules and has low levels of secretory granule proteases. Because the 5'-flanking regions of the mouse and human MC-CPA genes contained a conserved GATA-binding motif 51 base pairs upstream of their translation initiation sites, the ability of GATA-binding proteins to regulate the promoter activity of the MC-CPA gene was examined in rat basophilic leukemia cells, mouse P815 cells, and transfected mouse P815 cells that expressed GATA-1. In all three mast cell lines, the promoter activity of the MC-CPA gene depended on the GATA binding site. GATA-1, GATA-2, and GATA-3 are thus the first DNA-binding proteins identified in mast cells which regulate the promoter activity of a gene that encodes a secretory granule protease.

Animals↗
PubMed1991

Molecular cloning of the mouse mast cell protease-5 gene. A novel secretory granule protease expressed early in the differentiation of serosal mast cells.

cDNAs were isolated that encode mouse mast cell protease-5 (MMCP-5), an approximately 30,000 Mr serine protease stored in the secretory granules of serosal mast cells (SMC) and Kirsten sarcoma virus-immortalized mast cells. Based on the deduced amino acid sequences of these cDNAs, MMCP-5 is synthesized as a 247-amino acid preproenzyme composed of a novel 19-residue hydrophobic signal peptide, a Gly-Glu activation peptide not present in other mast cell chymases, and a 226-amino acid protein that represents the mature enzyme. MMCP-5 possesses a unique Asn residue in the substrate binding cleft at residue 176 and is highly basically charged. The MMCP-5 gene was isolated, sequenced, and found to belong to a distinct subset of chymase genes. Allelic variations of the MMCP-5 gene were also detected. MMCP-5 is expressed in bone marrow-derived mast cells (BMMC), Kirsten sarcoma virus-immortalized mast cells, and SMC, but not in gastrointestinal mucosal mast cells of helminth-infected mice. The abundant levels of MMCP-5 mRNA in immature BMMC indicate that this chymase is expressed relatively early during the differentiation of mast cells. MMCP-5 is the first chymase to be molecularly cloned from progenitor mast cells and is also the first chymase shown to be expressed preferentially in the SMC subclass.

Amino Acid Sequence↗
PubMed1991

Molecular cloning of gp49, a cell-surface antigen that is preferentially expressed by mouse mast cell progenitors and is a new member of the immunoglobulin superfamily.

gp49 is a Mr 49,000 glycoprotein expressed on the surface of mouse bone marrow-derived mast cells, which are progenitors for the major in vivo mast cell subclasses, typified by intestinal mucosal mast cells and serosal mast cells. The amino-terminal amino acid sequence of gp49 was determined after isolation of the solubilized membrane protein by affinity chromatography with the B23.1 anti-gp49 monoclonal antibody. Redundant oligonucleotides were used to isolate a full-length 1.3-kilobase cDNA from a mouse mast cell library. The predicted amino acid sequence contains a signal peptide of 23 residues, an extracellular domain of 215 residues with three potential sites of N-linked glycosylation, a transmembrane domain of 23 residues, and a cytoplasmic tail of 42 residues. Hybridization of the gp49 cDNA was limited to mRNA extracted from those cell types that also bound the B23.1 monoclonal antibody as assessed by cytofluorographic analyses. The predicted extracellular domain of gp49 contains two regions of 48 and 51 amino acids, each flanked by cysteine residues. Both regions meet criteria for being C2-type domains of the immunoglobulin superfamily based upon the alignment of consensus amino acids and their predicted secondary structure organization. Thus, gp49, a membrane glycoprotein preferentially expressed by the progenitor mast cell population, is a new member of the immunoglobulin superfamily.

Amino Acid Sequence↗
PubMed1991

Cytokine mRNA are preferentially increased relative to secretory granule protein mRNA in mouse bone marrow-derived mast cells that have undergone IgE-mediated activation and degranulation.

The levels of mRNA that encode a number of cytokines have been reported by several laboratories to be increased in mouse mast cells after their IgE-bearing receptors have been cross-linked with Ag. In this study, we have compared the mRNA levels for Fc epsilon RI alpha, three cytokines (IL-6, granulocyte-macrophage CSF, and TNF-alpha), actin and three secretory granule-localized proteins (carboxypeptidase A, proteoglycan peptide core, and a generic serine protease) in mouse bone marrow-derived mast cells (BMMC) before and after IgE-mediated activation and degranulation to determine the kinetics and specificity of mRNA induction. An antigen concentration of approximately 10 ng/ml was optimal for the release of histamine from IgE-sensitized BMMC and for the generation and release of a cytokine that was functionally and immunochemically identical to TNF-alpha. In kinetic experiments, the levels of TNF-alpha, IL-6, and granulocyte-macrophage CSF mRNA increased greater than 23-fold 0.5 to 1 h after activation. As assessed by in situ hybridization, virtually all BMMC contained detectable proteoglycan peptide core mRNA before and after exposure to Ag, but only approximately one-half of the Ag-treated cells in the culture contained IL-6 mRNA 1 h after activation. There was a slight transient increase at 4 h in the level of proteoglycan peptide core mRNA, but no increase in the levels of those highly expressed mRNA that encode actin, Fc epsilon RI alpha, carboxypeptidase A, and serine protease. Thus, despite the remarkable increment in the levels of the transcripts that encode cytokines in BMMC after IgE-mediated, Ag-dependent activation, the levels of those transcripts that encode a plasma membrane-localized recognition receptor and several constituents of the secretory granule remain essentially unchanged. The failure to increase substantially the level of protease and proteoglycan peptide core mRNA in mast cells after the activation/secretion response suggests that regranulation of mast cells is a slow process.

Animals↗
PubMed1990

Production and isolation of rabbit anti-idiotypic antibodies directed against the human monocyte receptor for yeast beta-glucans.

beta-Glucan receptors are present on mammalian phagocytic cells and provide an important physiologic mechanism for opsonin-independent clearance of yeasts and fungi. To prepare an immunologic probe to human monocyte beta-glucan receptors, an approach was taken that focused on the ligand specificity of the receptors as expressed by an anti-Id. The algal beta-glucan laminarin was chemically coupled to protein carriers to prepare an immunogenic beta-glucan. Three mouse IgG2a mAb were raised against laminarin, and one, mAb OEA10, exhibited specificity for the soluble unit ligand yeast heptaglucoside and the ligands present on zymosan and glucan particles that are recognized by monocyte beta-glucan receptors. These findings prompted usage of mAb OEA10 as immunogen for the preparation of an anti-Id. The resulting rabbit antiserum was subjected to sequential immunoaffinity chromatography to purify anti-idiotypic antibodies. The final product contained only IgG by SDS-PAGE and was shown to be specific by its selectively blocking binding of 125I-mAb OEA10 to laminarin. Pretreatment of adherent monocytes with 0.4 micrograms/ml of the anti-Id reduced the numbers of monocytes ingesting zymosan and glucan particles by 64 and 43%, respectively, whereas ingestion of IgG-coated SRBC was unaffected by as much as 16 micrograms/ml of the anti-Id. Incubation of adherent monocytes with increasing amounts of 125I-anti-Id in the absence and presence of 40-fold molar excess unlabeled anti-Id revealed dose-dependent specific binding, which approached plateau levels with 1 microgram/ml of labeled anti-Id. Thus, the anti-Id binds to monocytes and displays functional characteristics of soluble beta-glucan ligands, indicating that some of the anti-idiotypic antibodies recognize epitopes within monocyte beta-glucan receptors.

Animals↗
PubMed1989

Different mast cell mediators produced by different mast cell phenotypes.

The activation of mast cells results in the release of a large variety of inflammatory mediators, many of which are preformed and stored within the secretory granules. Exocytosis of the secretory granule contents releases a macromolecular complex composed of proteoglycan and the neutral proteases. The proteases include both endo- and exopeptidases, suggesting the possibility of a concerted action on unknown substrates. Different proteases are expressed by different mast cells originally defined by histochemical and ultrastructural criteria. From adoptive transfer experiments it appears that the mast cell phenotype is profoundly influenced by the microenvironment. Understanding the development and regulation of the mast cell phenotype is being approached by the development of: (1) An in vitro system of differentiation using in vitro-differentiated mast cells which upon co-culture with fibroblasts demonstrate a phenotypic shift; (2) Kirsten virus-transformed mast cells exhibiting a spectrum of phenotypes. These reagents have allowed the isolation and characterization of the cDNAs of the various preformed protein mediators including the secretory granule proteoglycan peptide core, serine proteases and carboxypeptidase. These cDNAs have provided the first probes for the molecular characterization of the mast cell-associated proteoglycan peptide core, a carboxypeptidase A and a 28,000 Mr serine protease.

Animals↗
PubMed1988

A cross-reactive idiotype on anti-collagen antibodies in collagen-induced arthritis: identification and relevance to disease.

Immunization of mice with type II collagen (CII) leads to the production of anti-CII antibodies and, in susceptible strains, to the induction of arthritis. Specifically purified anti-CII antibodies from arthritic DBA/1 mice were used to prepare a rabbit anti-idiotypic antiserum. This antiserum recognizes a cross-reactive idiotype (CRI) present on 20-25% of anti-CII antibodies from DBA/1 mice immunized with bovine CII. The CRI is not present on DBA/1 anti-trinitrophenyl, undetectable in normal Ig and not Igh allotype linked. The presence of this CRI was examined after antigen specific suppression of the anti-CII antibody response by intravenous administration of chick or bovine CII. While intravenous injection of bovine CII, prior to immunization with chick CII, greatly reduces both the incidence of arthritis and the anti-CII response, the fraction of anti-bovine CII which expresses the CRI is increased by this treatment. These findings suggest that the CRI characterizes a disease-unrelated fraction of anti-CII which recognizes bovine and chick CII, but probably not mouse CII. In addition, attempts at idiotypic regulation of arthritis incidence and antibody response by in vivo administration of anti-idiotypic serum also indicate that the CRI-bearing antibody is not important for the induction of arthritis.

Animals↗
PubMed1986

Inhibition of an IgE response by secondary B cells of a different isotype.

We found that the synthesis of IgE anti-Ars antibodies is strongly inhibited by the presence of secondary non-IgE-producing cells that are specific for the Ars hapten. Such B cells can be induced by inoculation of a protein-Ars conjugate in CFA. The effect is seen after inoculation of OVA-Ars in CFA followed by KLH-Ars in alum, or, more convincingly, after adoptive transfer of B cells induced by antigen in CFA. Dose-response data indicated that inhibition can be effected by B cells containing noninhibitory numbers of contaminating T cells. Possible synergistic effects of carrier-specific regulatory T cells were ruled out by using a different protein carrier for immunization of donor and recipient mice. The effect was shown to be specific for the hapten used for immunization of donor mice.

Animals↗
PubMed1986

Influence of helper T cells on the expression of a murine intrastrain crossreactive idiotype.

The requirement for idiotype-specific helper T (Th) cells in the generation of a major intrastrain crossreactive idiotype was investigated. This idiotype, designated CRIA, is associated with a large proportion of anti-p-azobenzenearsonate (anti-Ar) antibodies in A/J mice. Secondary in vitro responses were studied. Using carrier-primed heterogeneous Th-cell populations, it was found that CRIA expression is determined by the mouse strain that provides the responding B cells and is independent of the strain of the Th cells functioning in vitro. Thus, A/J or A.BY (Ighe) B-plus-accessory-cell populations, primed in vivo to keyhole limpet hemocyanin-Ar (KLH-Ar), generated CRIA-dominant responses in vitro in the presence of KLH-Ar regardless of whether the KLH-primed Th cells were derived from CRIA+ strains (A/J or A.BY, Ighe) or CRIA- strains (B10.A or C57BL/10, Ighb). Further, when major histocompatibility complex-restricted, KLH-specific Th-cell clones were used, the CRIA dominance of the Ar-specific responses was again determined by the strain providing B plus accessory cells. Similar levels of expression of CRIA in Ar-specific antibodies were generated in the presence of heterogeneous or cloned Th cells. The results suggest that there is no absolute requirement for idiotype-specific Th cells in generating an Ar-specific secondary antibody response in vitro.

Animals↗
PubMed1983

Abrogation of epidermal antigen-presenting cell function by ultraviolet radiation administered in vivo.

The exposure of animals to ultraviolet radiation (UVR) can result in dramatic alterations to their immunologic potential. Loss of ability to be contact-sensitized to skin-reactive chemicals applied to UVR-exposed surfaces, and an enhanced susceptibility to tumors induced by UVR represent two well-documented effects of such exposure. The skin Langerhans' cell (LC) is a cell type, having antigen presentation capabilities, which is functionally inactivated by UVR. The localized loss in the ability to induce a contact hypersensitivity (CS) response and the early events associated with the acquisition of a tumor-susceptible state have been hypothesized to involve LC inactivation by UVR. In this report we have investigated the relationship between the UVR-mediated loss of CS responsiveness and antigen-presenting cell (APC) function by LC following in vivo exposure of animals to UVR. The UVR-mediated loss of CS responsiveness was found to be both time-dependent and dosage-dependent, but the loss of epidermal APC function following the UVR exposure of dissociated epidermal cells or skin was immediate and dosage-dependent. The lack of time dependency associated with the loss of epidermal APC function may be due to the nature of the assay system being employed. Add-back experiments, using the proliferation of purified antigen-primed T-cells as a read-out system to evaluate APC function, require that the accessory cell be totally functional. Initiation of CS responses may still be possible, however, with LC that are partially UVR-inactivated. Lymph-node-associated and circulating accessory cells could be integrated into the response, providing any necessary components that the UV-inactivated LC lacks. We tested this possibility and conclude from these studies that this is indeed a viable possibility. Our results, therefore, provide a possible explanation for apparent differences in LC UVR susceptibility observed when in vitro and in vivo assays are employed.

Animals↗
PubMed1983

The effects of high-dose UV exposure on murine Langerhans cell function at exposed and unexposed sites as assessed using in vivo and in vitro assays.

Exposure of mice to a single large dose of UV radiation leads to a systemic inability of these mice to develop effective contact hypersensitivity (CS) responses to epicutaneously applied dinitrofluorobenzene (DNFB). Although this effect requires time to develop when unirradiated skin sites are used for CS sensitization, it is observed immediately at the site of UV exposure. Unirradiated skin sites on mice exposed to a single large dose of UV radiation 3 days previously were found to contain histochemically detectable ATPase+ cells with normal morphology and in normal densities, and yet CS responses were not induced to DNFB applied to these sites. Epidermal cells (EC) obtained from these skin sites were found to be capable of providing accessory cell (AC) function in in vitro T-cell proliferation assays that was qualitatively similar to EC obtained from unirradiated mice, thus indicating that exposure of mice to a single large dose of UV radiation does not induce a systemic AC dysfunction. Indeed, increased levels of AC activity were obtained in EC prepared from the UV-irradiated skin sites on the third day following UV exposure. This latter effect may be due to an influx of inflammatory cells into the irradiated site in response to the tissue damage caused by the UV radiation. We hypothesize that the inflammatory response induced by the cytodestructive effects of the UV treatment may play a central role in the generation of the systemic suppression of induction of CS responses, perhaps through the induction of acute-phase proteins.

Adenosine Triphosphatases↗