The effect of IgA from human immunodeficiency virus type 1 (HIV-1)-infected patients on infection... more The effect of IgA from human immunodeficiency virus type 1 (HIV-1)-infected patients on infection of primary human blood monocytes with the monocyte-tropic strain HIV-1Bal was evaluated in vitro. Preincubation of HIV-1Bal with purified serum IgA from 6 of 14 patients but from none of 5 seronegative subjects caused a > 50% increase in reverse transcriptase activity. This increase was inhibited by preincubation of monocytes with nonimmune IgA, suggesting a role for Fc alpha receptors. Results were independent of CD4 T cell number and clinical stage. The IgA-mediated enhancement extended to more biologically relevant human mononuclear cells isolated from the intestinal lamina propria. The ability of serum IgA to enhance HIV-1 infection may be relevant to infection of both circulating monocytes and mucosal macrophages. These studies suggest the need to characterize the complex contribution of IgA and the mucosal immune system in promoting and preventing primary HIV-1 infection.
Transforming growth factor beta (TGF-beta), a cytokine identified in acute and chronic inflammato... more Transforming growth factor beta (TGF-beta), a cytokine identified in acute and chronic inflammatory sites, mediates leukocyte recruitment and activation essential to the development of such lesions. Released by platelets upon aggregation and by leukocytes stimulated with bacterial products or inflammatory mediators, TGF-beta has potent chemotactic activity for blood neutrophils, monocytes, and lymphocytes. By augmenting integrin expression, TGF-beta facilitates leukocyte adhesion to the vessel wall and extracellular matrix at the site of inflammation. Once within the inflammatory site, mononuclear cells are stimulated by TGF-beta to release cytokines important in the network of molecules regulating the host response to microorganisms and immunologic challenge. Thus, bacteria and their products, in addition to directly recruiting and activating leukocytes at sites of infection, indirectly influence these events through the induction of cytokines such as TGF-beta. By antagonizing the activity of TGF-beta with neutralizing antibodies, a causal relationship between this cytokine, inflammation, and pathogenesis has been demonstrated. Administration of anti-TGF-beta to sites of chronic destructive inflammation not only blocked leukocyte recruitment and activation, but also inhibited the subsequent destruction of bone and cartilage characteristics of such lesions.
Group A streptococcal cell wall fragments (SCW) induce erosive polyarthritis, characterized by sy... more Group A streptococcal cell wall fragments (SCW) induce erosive polyarthritis, characterized by synovial cell hyperplasia and intense mononuclear cell infiltration, in susceptible rats. Because of the known antiproliferative and immunomodulatory effects of interferon (IFN), we evaluated the effect of systemically administered alpha, beta and gamma IFN on the evolution of these destructive lesions. Treatment with gamma IFN not only reduced the acute response, but had an even greater suppressive effect on the chronic mononuclear cell-mediated destructive phase of the disease (articular index 10.2 +/- 1.2 for SCW only versus 3.8 +/- 0.7 for SCW + gamma IFN; p less than 0.01). Treatment with gamma IFN was more effective in the suppression of the arthritis than alpha, beta IFN. Histopathologic evaluation of the joints demonstrated that gamma IFN-treated animals had significantly fewer inflammatory cells, and less synovial hyperplasia and erosions than the SCW controls. gamma IFN suppression of mononuclear cell prostaglandin synthesis and synovial fibroblast proliferation was consistent with its anti-arthritic effects. These data indicate that the pathophysiology of SCW-induced erosive polyarthritis is subject to regulatory control by gamma IFN and that the mechanisms of suppression may be relevant in the treatment of rheumatoid arthritis.
In intestinal fluid samples from 39 human immunodeficiency virus type 1 (HIV-1)-infected patients... more In intestinal fluid samples from 39 human immunodeficiency virus type 1 (HIV-1)-infected patients, IgA and IgG levels were equivalent, whereas in 10 controls, IgA levels were significantly higher than those of IgG (P < .05). Intestinal IgA in patients contained predominantly monomeric IgA1, whereas IgA1 and IgA2 subclass levels in controls were nearly equivalent and primarily polymeric. The predominance of IgG and monomeric IgA1 in mucosal fluid samples from HIV-1-infected patients suggests exudation of serum immunoglobulins into the intestine. The decreased proportion of mucosal plasma cells producing IgA and IgA2 in the HIV-1-infected patients (P < .01) may also contribute to the abnormal intestinal immunoglobulin levels. Intestinal IgG reacted with most HIV-1 antigens, whereas specific IgA was present in only 10 of 17 patients and reacted with only envelope (gp120 and gp160) and, less often, core (p17 and p24) antigens. Aberrant mucosal antibody responses and decreased integrity of the mucosal barrier may contribute to the intestinal dysfunction and infections that characterize HIV-1 infection.
Host Defense Dysfunction in Trauma, Shock and Sepsis, 1993
Intraperitoneal injection of peptidoglycan-polysaccharide cell wall fragments from group A strept... more Intraperitoneal injection of peptidoglycan-polysaccharide cell wall fragments from group A streptococci (SCW) results in the dissemination of the fragments primarily to the spleen, liver, bone marrow, and peripheral joints [1]. Early localization of SCW within Kupffer cells (KC) of the hepatic sinusoids is followed by acute hepatic edema and leukocyte infiltration. Although the acute inflammation resolves over the next 3–5 days, many KC remain laden with SCW antigens and granulomas develop over the next 2–3 weeks. The granulomas are composed primarily of macrophages, T lymphocytes, and less numerous neutrophils and mast cells [2]. Infiltrating fibroblasts encapsulate the granulomas and synthesize large amounts of collagen types I and III and other matrix proteins. In the final stage (12–24 weeks post injection) the chronic inflammatory reaction diminishes and the granulomas exhibit scar tissue. The role of KC in orchestrating the evolution of SCW-induced inflammation, granuloma formation, and fibrosis are not well elucidated.
SummarySecretory leukocyte protease inhibitor (SLPI) is a cationic serine protease inhibitor with... more SummarySecretory leukocyte protease inhibitor (SLPI) is a cationic serine protease inhibitor with anti-microbial and anti-inflammatory properties found in large quantities in mucosal fluids, including saliva. SLPI is expressed during cutaneous wound healing, however, its role in oral wound repair is unknown. We have used a novel approach involving a murine buccal mucosal acute wound model to investigate the role of SLPI in oral healing. In parallel to the observed cutaneous healing phenotype, an absence of SLPI results in markedly impaired oral wound healing associated with increased inflammation and raised elastase activity. Moreover, matrix deposition was decreased, while MMP activity was enhanced in the oral SLPI null wounds suggesting deregulated proteolysis. Intriguingly, regardless of genotype, reduced collagen deposition was observed in oral compared to dermal wounds, associated with reduced TGF-β expression and decreased fibroblast collagen expression in vitro. We propose that SLPI is a pivotal endogenous factor necessary for optimal tissue repair including intra-oral wound healing. In addition, our model provides a unique opportunity to delineate the cellular and molecular mechanisms underlying the differences between dermal scarring and oral scar-free healing.
HIV infection occurs primarily through mucosal surfaces, indicating that protection at mucosal si... more HIV infection occurs primarily through mucosal surfaces, indicating that protection at mucosal sites may be crucial in prevention and treatment. The host innate and adaptive immune elements provide a level of protection, which differs between mucosal compartments, and appears to be most successful in the oral environment, where transmission is rare. In addition to the distinct oral mucosal architecture and cellular constituents, oral fluids, unlike other mucosal secretions, are rarely a vehicle for HIV infection. Multiple soluble factors may contribute to this antiviral activity, including neutralizing antibodies, secretory leukocyte protease inhibitor (SLPI), antiviral peptides such as defensins and cystatins, glycoproteins including thrombospondin and lactoferrin, and complement components. Understanding the antiviral activities of these and other potential resistance factors is becoming increasingly important in attempts to design treatments in the era of HAART resistance. In this regard, the mechanism of anti-HIV action of SLPI has recently been further elucidated by the discovery of its binding protein/receptor, which plays a key role in the infection of macrophages and may consequently be a novel therapeutic target. Continued elucidation of the unique features of mucosal HIV immunology is essential for understanding HIV pathogenesis and for developing effective vaccines and therapeutics.
Annals of the New York Academy of Sciences, Dec 1, 1990
bNational Cancer Institute Bethesda, Maryland 20892 ‘Civilized Software, Inc. Bethesda, Maryland ... more bNational Cancer Institute Bethesda, Maryland 20892 ‘Civilized Software, Inc. Bethesda, Maryland 20814 dNational Cancer Institute Frederick Cancer Research Facility and Program Resources, Inc. Frederick, Maryland Veterans Affairs Medical Center Department of Pediatrics and Emory University School of Medicine Atlanta, Georgia 30033 fLaboratory of Immunology National Institute of Dental Research Bethesda, Maryland 20892
The generation of animals lacking SMAD proteins, which transduce signals from transforming growth... more The generation of animals lacking SMAD proteins, which transduce signals from transforming growth factor-beta (TGF-beta), has made it possible to explore the contribution of the SMAD proteins to TGF-beta activity in vivo. Here we report that, in contrast to predictions made on the basis of the ability of exogenous TGF-beta to improve wound healing, Smad3-null (Smad3ex8/ex8) mice paradoxically show accelerated cutaneous wound healing compared with wild-type mice, characterized by an increased rate of re-epithelialization and significantly reduced local infiltration of monocytes. Smad3ex8/ex8 keratinocytes show altered patterns of growth and migration, and Smad3ex8/ex8 monocytes exhibit a selectively blunted chemotactic response to TGF-beta. These data are, to our knowledge, the first to implicate Smad3 in specific pathways of tissue repair and in the modulation of keratinocyte and monocyte function in vivo.
A study was made of a lymphokine produced by human T lymphocytes that mediates activation of huma... more A study was made of a lymphokine produced by human T lymphocytes that mediates activation of human monocytes and monocyte-like cell lines, measured by increased production of H2O2. The lymphokine was produced either by stimulation of human nonadherent peripheral blood mononuclear cells with concanavalin A (Con A) or by stimulation of a human T cell line, HSB2, with Con A and phorbol myristic acetate (PMA). When incubated with freshly isolated peripheral blood monocytes for 48 to 72 hr, the H2O2-potentiating factor (HPPF) stimulated increased production of H2O2, measured in a PMA-triggered assay for H2O2 secretion. Because variations occurred in the response of normal blood donors to the HPPF, human monocyte-like cell lines were used as homogeneous and consistently responsive targets for the lymphokine to facilitate biochemical characterization studies of the factor. Two cell lines were studied: HL60, a human promyelocytic cell line, and U937, a human histiocytic cell line. When target cells of either type were incubated in the presence of the HPPF for 48 to 72 hr, they produced increased amounts of H2O2 in a dose-dependent fashion. H2O2 levels were assessed by means of a microassay that measures peroxide-mediated oxidation of phenol red after an oxidative burst triggered with PMA. By using this assay, HPPF was found to have an apparent m.w. of 54,000 and an isoelectric point of 5.5. The bouyant density was determined to be 1.307, indicating that HPPF is a protein. The utilization of cell lines for both the production and assay of HPPF should facilitate the purification of this lymphokine and the subsequent evaluation of its relationship to other lymphokines known to affect macrophage microbicidal and tumoricidal function.
The effect of IgA from human immunodeficiency virus type 1 (HIV-1)-infected patients on infection... more The effect of IgA from human immunodeficiency virus type 1 (HIV-1)-infected patients on infection of primary human blood monocytes with the monocyte-tropic strain HIV-1Bal was evaluated in vitro. Preincubation of HIV-1Bal with purified serum IgA from 6 of 14 patients but from none of 5 seronegative subjects caused a > 50% increase in reverse transcriptase activity. This increase was inhibited by preincubation of monocytes with nonimmune IgA, suggesting a role for Fc alpha receptors. Results were independent of CD4 T cell number and clinical stage. The IgA-mediated enhancement extended to more biologically relevant human mononuclear cells isolated from the intestinal lamina propria. The ability of serum IgA to enhance HIV-1 infection may be relevant to infection of both circulating monocytes and mucosal macrophages. These studies suggest the need to characterize the complex contribution of IgA and the mucosal immune system in promoting and preventing primary HIV-1 infection.
Transforming growth factor beta (TGF-beta), a cytokine identified in acute and chronic inflammato... more Transforming growth factor beta (TGF-beta), a cytokine identified in acute and chronic inflammatory sites, mediates leukocyte recruitment and activation essential to the development of such lesions. Released by platelets upon aggregation and by leukocytes stimulated with bacterial products or inflammatory mediators, TGF-beta has potent chemotactic activity for blood neutrophils, monocytes, and lymphocytes. By augmenting integrin expression, TGF-beta facilitates leukocyte adhesion to the vessel wall and extracellular matrix at the site of inflammation. Once within the inflammatory site, mononuclear cells are stimulated by TGF-beta to release cytokines important in the network of molecules regulating the host response to microorganisms and immunologic challenge. Thus, bacteria and their products, in addition to directly recruiting and activating leukocytes at sites of infection, indirectly influence these events through the induction of cytokines such as TGF-beta. By antagonizing the activity of TGF-beta with neutralizing antibodies, a causal relationship between this cytokine, inflammation, and pathogenesis has been demonstrated. Administration of anti-TGF-beta to sites of chronic destructive inflammation not only blocked leukocyte recruitment and activation, but also inhibited the subsequent destruction of bone and cartilage characteristics of such lesions.
Group A streptococcal cell wall fragments (SCW) induce erosive polyarthritis, characterized by sy... more Group A streptococcal cell wall fragments (SCW) induce erosive polyarthritis, characterized by synovial cell hyperplasia and intense mononuclear cell infiltration, in susceptible rats. Because of the known antiproliferative and immunomodulatory effects of interferon (IFN), we evaluated the effect of systemically administered alpha, beta and gamma IFN on the evolution of these destructive lesions. Treatment with gamma IFN not only reduced the acute response, but had an even greater suppressive effect on the chronic mononuclear cell-mediated destructive phase of the disease (articular index 10.2 +/- 1.2 for SCW only versus 3.8 +/- 0.7 for SCW + gamma IFN; p less than 0.01). Treatment with gamma IFN was more effective in the suppression of the arthritis than alpha, beta IFN. Histopathologic evaluation of the joints demonstrated that gamma IFN-treated animals had significantly fewer inflammatory cells, and less synovial hyperplasia and erosions than the SCW controls. gamma IFN suppression of mononuclear cell prostaglandin synthesis and synovial fibroblast proliferation was consistent with its anti-arthritic effects. These data indicate that the pathophysiology of SCW-induced erosive polyarthritis is subject to regulatory control by gamma IFN and that the mechanisms of suppression may be relevant in the treatment of rheumatoid arthritis.
In intestinal fluid samples from 39 human immunodeficiency virus type 1 (HIV-1)-infected patients... more In intestinal fluid samples from 39 human immunodeficiency virus type 1 (HIV-1)-infected patients, IgA and IgG levels were equivalent, whereas in 10 controls, IgA levels were significantly higher than those of IgG (P < .05). Intestinal IgA in patients contained predominantly monomeric IgA1, whereas IgA1 and IgA2 subclass levels in controls were nearly equivalent and primarily polymeric. The predominance of IgG and monomeric IgA1 in mucosal fluid samples from HIV-1-infected patients suggests exudation of serum immunoglobulins into the intestine. The decreased proportion of mucosal plasma cells producing IgA and IgA2 in the HIV-1-infected patients (P < .01) may also contribute to the abnormal intestinal immunoglobulin levels. Intestinal IgG reacted with most HIV-1 antigens, whereas specific IgA was present in only 10 of 17 patients and reacted with only envelope (gp120 and gp160) and, less often, core (p17 and p24) antigens. Aberrant mucosal antibody responses and decreased integrity of the mucosal barrier may contribute to the intestinal dysfunction and infections that characterize HIV-1 infection.
Host Defense Dysfunction in Trauma, Shock and Sepsis, 1993
Intraperitoneal injection of peptidoglycan-polysaccharide cell wall fragments from group A strept... more Intraperitoneal injection of peptidoglycan-polysaccharide cell wall fragments from group A streptococci (SCW) results in the dissemination of the fragments primarily to the spleen, liver, bone marrow, and peripheral joints [1]. Early localization of SCW within Kupffer cells (KC) of the hepatic sinusoids is followed by acute hepatic edema and leukocyte infiltration. Although the acute inflammation resolves over the next 3–5 days, many KC remain laden with SCW antigens and granulomas develop over the next 2–3 weeks. The granulomas are composed primarily of macrophages, T lymphocytes, and less numerous neutrophils and mast cells [2]. Infiltrating fibroblasts encapsulate the granulomas and synthesize large amounts of collagen types I and III and other matrix proteins. In the final stage (12–24 weeks post injection) the chronic inflammatory reaction diminishes and the granulomas exhibit scar tissue. The role of KC in orchestrating the evolution of SCW-induced inflammation, granuloma formation, and fibrosis are not well elucidated.
SummarySecretory leukocyte protease inhibitor (SLPI) is a cationic serine protease inhibitor with... more SummarySecretory leukocyte protease inhibitor (SLPI) is a cationic serine protease inhibitor with anti-microbial and anti-inflammatory properties found in large quantities in mucosal fluids, including saliva. SLPI is expressed during cutaneous wound healing, however, its role in oral wound repair is unknown. We have used a novel approach involving a murine buccal mucosal acute wound model to investigate the role of SLPI in oral healing. In parallel to the observed cutaneous healing phenotype, an absence of SLPI results in markedly impaired oral wound healing associated with increased inflammation and raised elastase activity. Moreover, matrix deposition was decreased, while MMP activity was enhanced in the oral SLPI null wounds suggesting deregulated proteolysis. Intriguingly, regardless of genotype, reduced collagen deposition was observed in oral compared to dermal wounds, associated with reduced TGF-β expression and decreased fibroblast collagen expression in vitro. We propose that SLPI is a pivotal endogenous factor necessary for optimal tissue repair including intra-oral wound healing. In addition, our model provides a unique opportunity to delineate the cellular and molecular mechanisms underlying the differences between dermal scarring and oral scar-free healing.
HIV infection occurs primarily through mucosal surfaces, indicating that protection at mucosal si... more HIV infection occurs primarily through mucosal surfaces, indicating that protection at mucosal sites may be crucial in prevention and treatment. The host innate and adaptive immune elements provide a level of protection, which differs between mucosal compartments, and appears to be most successful in the oral environment, where transmission is rare. In addition to the distinct oral mucosal architecture and cellular constituents, oral fluids, unlike other mucosal secretions, are rarely a vehicle for HIV infection. Multiple soluble factors may contribute to this antiviral activity, including neutralizing antibodies, secretory leukocyte protease inhibitor (SLPI), antiviral peptides such as defensins and cystatins, glycoproteins including thrombospondin and lactoferrin, and complement components. Understanding the antiviral activities of these and other potential resistance factors is becoming increasingly important in attempts to design treatments in the era of HAART resistance. In this regard, the mechanism of anti-HIV action of SLPI has recently been further elucidated by the discovery of its binding protein/receptor, which plays a key role in the infection of macrophages and may consequently be a novel therapeutic target. Continued elucidation of the unique features of mucosal HIV immunology is essential for understanding HIV pathogenesis and for developing effective vaccines and therapeutics.
Annals of the New York Academy of Sciences, Dec 1, 1990
bNational Cancer Institute Bethesda, Maryland 20892 ‘Civilized Software, Inc. Bethesda, Maryland ... more bNational Cancer Institute Bethesda, Maryland 20892 ‘Civilized Software, Inc. Bethesda, Maryland 20814 dNational Cancer Institute Frederick Cancer Research Facility and Program Resources, Inc. Frederick, Maryland Veterans Affairs Medical Center Department of Pediatrics and Emory University School of Medicine Atlanta, Georgia 30033 fLaboratory of Immunology National Institute of Dental Research Bethesda, Maryland 20892
The generation of animals lacking SMAD proteins, which transduce signals from transforming growth... more The generation of animals lacking SMAD proteins, which transduce signals from transforming growth factor-beta (TGF-beta), has made it possible to explore the contribution of the SMAD proteins to TGF-beta activity in vivo. Here we report that, in contrast to predictions made on the basis of the ability of exogenous TGF-beta to improve wound healing, Smad3-null (Smad3ex8/ex8) mice paradoxically show accelerated cutaneous wound healing compared with wild-type mice, characterized by an increased rate of re-epithelialization and significantly reduced local infiltration of monocytes. Smad3ex8/ex8 keratinocytes show altered patterns of growth and migration, and Smad3ex8/ex8 monocytes exhibit a selectively blunted chemotactic response to TGF-beta. These data are, to our knowledge, the first to implicate Smad3 in specific pathways of tissue repair and in the modulation of keratinocyte and monocyte function in vivo.
A study was made of a lymphokine produced by human T lymphocytes that mediates activation of huma... more A study was made of a lymphokine produced by human T lymphocytes that mediates activation of human monocytes and monocyte-like cell lines, measured by increased production of H2O2. The lymphokine was produced either by stimulation of human nonadherent peripheral blood mononuclear cells with concanavalin A (Con A) or by stimulation of a human T cell line, HSB2, with Con A and phorbol myristic acetate (PMA). When incubated with freshly isolated peripheral blood monocytes for 48 to 72 hr, the H2O2-potentiating factor (HPPF) stimulated increased production of H2O2, measured in a PMA-triggered assay for H2O2 secretion. Because variations occurred in the response of normal blood donors to the HPPF, human monocyte-like cell lines were used as homogeneous and consistently responsive targets for the lymphokine to facilitate biochemical characterization studies of the factor. Two cell lines were studied: HL60, a human promyelocytic cell line, and U937, a human histiocytic cell line. When target cells of either type were incubated in the presence of the HPPF for 48 to 72 hr, they produced increased amounts of H2O2 in a dose-dependent fashion. H2O2 levels were assessed by means of a microassay that measures peroxide-mediated oxidation of phenol red after an oxidative burst triggered with PMA. By using this assay, HPPF was found to have an apparent m.w. of 54,000 and an isoelectric point of 5.5. The bouyant density was determined to be 1.307, indicating that HPPF is a protein. The utilization of cell lines for both the production and assay of HPPF should facilitate the purification of this lymphokine and the subsequent evaluation of its relationship to other lymphokines known to affect macrophage microbicidal and tumoricidal function.
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