Biomedical subjects

D N Sauder

Publications and source records attributed to D N Sauder.

At least 127 records · Page 7Linked to original sources

PubMed1989

Inductive effects of immunological cytokines in the skin.

There is little doubt that cytokines play a major role in cell-mediated immunity and in inflammation. Cytokines within the skin can provide stimuli that can mobilize, attract, and activate a variety of circulating cells that participate in local inflammation. Perhaps most importantly, epidermal cytokines can amplify the effect of interactions between lymphocytes and specific antigens to generate immunologic reactivity. On the basis of in vitro studies, the number of activities is extremely large. It is clear that skin and particularly epidermis can play an active role in local and inflammatory immune events.

Acute-Phase Proteins↗

PubMed1989

Effect of age on epidermal immune function.

Like other systems in the body, the immune system deteriorates with age. Age-related changes in epidermal immune function include morphologic and functional changes in Langerhans cells, decreased production and response to epidermal thymocyte-activating factor (ETAF), and altered allergic contact dermatitis. These may be primary age-related changes in epidermal immune function or may be secondary to aging of the organism. In either case, the age-related changes in epidermal immunity may contribute to the increased susceptibility to cutaneous infections and neoplasms with advancing age.

Aging↗

PubMed1989

Differential effects of interleukin-1 and formylmethionylleucylphenylalanine on chemotaxis and human endothelium adhesivity for A549 tumor cells.

We investigated the effects of formylmethionylleucylphenylalanine (FMLP), interleukin-1 alpha (IL1 alpha) and interleukin-1 beta (IL1 beta) on tumor cell chemotaxis and tumor cell/endothelial cell adhesion. Chemotaxis of A549 human lung carcinoma cells was measured as the number of tumor cells which migrated across a nitrocellulose filter in a Boyden chamber. Tumor cell/endothelial cell adhesion was measured as the number of 125IUdR tumor cells adherent to monolayers of endothelial cells. Confluent monolayers of human umbilical endothelial cells were incubated from 10 to 240 minutes with FMLP, monocyte-derived interleukin-1, or recombinant IL1 alpha or IL1 beta. The endothelial cells were washed and then incubated with 125IUdR-tumor cells. Thirty minutes later the number of adherent tumor cells was assessed isotopically. Our results demonstrate that (a) interleukin-1 but not FMLP, has chemotactic activity for tumor cells, and (b) both FMLP and interleukin-1 enhance tumor cell adhesion to the endothelium independent of any chemotactic activity. Furthermore, we demonstrate that IL1 alpha and IL1 beta have different effects on tumor cell/endothelial cell adhesion, and raise the possibility that IL1 alpha but not IL1 beta is continuously synthesized and stored within the endothelium. We postulate that IL1 alpha and IL1 beta influence tumor cell/endothelial cell adhesion independent of chemotaxis through the expression of adhesive receptors on the endothelial cell surface.

Cell Adhesion↗

PubMed1988

Chemotactic activity of endothelial cell-derived interleukin 1 for human tumor cells.

Endothelium and the vascular basement membrane form important barriers between the circulation and extravascular compartment. Cancer cell motility contributes to the passage of metastatic cells across this barrier, an essential step in tumor dissemination. In this study we found that the conditioned media of human endothelial monolayers contained a chemoattractant for neoplastic cells and that the chemoattractant activity was greater in the media of cultures which had been stimulated 4 h previously with 10 micrograms/ml bacterial lipopolysaccharide or the peptide formyl-L-methionyl-L-leucyl-L-phenylalanine at a concentration of 10(-6) M. The generation of this activity correlated with the expression of intracellular mRNA for interleukin 1 (IL-1) and with the presence of IL-1 biological activity in the conditioned media. The chemotactic activity in these media was lost after they had been incubated with anti-IL-1. Finally, recombinant human IL-1 alpha and IL-1 beta stimulated dose-dependent, random, and directed migration of human tumor cell populations in the Boyden chamber assay. Thus, this paper describes a mechanism by which the production of IL-1 by endothelial cells could modulate the behavior of tumor cells within the circulation.

Cell Movement↗

PubMed1988

Autocrine growth stimulation of human keratinocytes by epidermal cell-derived thymocyte-activating factor: implications for skin aging.

The monocyte-derived cytokine interleukin-1 (IL-1) has growth-promoting activity for a variety of cell types, including lymphocytes and fibroblasts. We have previously shown that the epidermal cell-derived thymocyte-activating factor (ETAF) strongly resembles IL-1 in terms of biological, biochemical, and molecular biological properties. Because some lymphokines are known ot alter epidermal cell growth and differentiation and because cultured epidermal keratinocytes are capable of autocrine growth stimulation in vitro through "conditioning" of their culture medium, we sought to evaluate the effect of ETAF on keratinocyte growth. While there was marked donor variability in the responsiveness of keratinocytes to ETAF, partially purified preparations of ETAF showed substantial ability to stimulate the growth of keratinocytes, particularly those of newborn donors. In addition, in conditioned media there appeared to be activities distinct from ETAF that also promoted keratinocyte growth. Keratinocytes in serum-free medium secreted large amounts of ETAF, as reported previously, and keratinocyte cultures derived from newborn donors secreted significantly more than did those derived from adult donors. These results are consistent with an autocrine growth regulatory role of ETAF in human epidermis and with an age-associated loss of this phenomenon.

Adult↗

PubMed1988

Isolated late cutaneous skin test response to ampicillin: a distinct entity.

A case presentation describes a young woman with a history of two reactions to ampicillin therapy and a reproducible skin test reaction of intermediate timing that disappeared within 48 hours. The skin test response was to ampicillin only and not to other penicillin-related skin test reagents. Tests for serum IgE and IgG antibody to ampicillin were negative. The histology was that of a mononuclear and neutrophilic cellular infiltrate with neutrophil margination in the vessels. There was no immunoglobulin, complement, or fibrin deposition. The skin test reaction began and ended earlier than would be expected for a classic delayed hypersensitivity reaction. It is considered to be an isolated late cutaneous response but cannot yet be designated a late cutaneous allergic response. Reactants characteristic of an Arthus reaction were not present, and no alternative immunologic basis was confirmed.

Adult↗

PubMed1988

In situ detection of interleukin-1 mRNA in human monocytes.

The interleukin-1 (IL-1) family of soluble pleiotropic immunoregulatory and proinflammatory peptides has at least two distinct members, alpha IL-1 and beta IL-1. Since beta IL-1 is the predominant species in human monocytes, this study was undertaken to identify its mRNA in monocytes using in situ hybridization with a 35S-dCTP labelled beta IL-1 cDNA probe. Grain count analysis demonstrated that adherent lipopolysaccharide-stimulated monocytes were positive, while unstimulated monocytes, lymphocytes and neutrophils, and cells probed with vector only (35S-labelled pBR322) were all negative. We have also shown that in situ hybridization is approx. 13-fold more sensitive than conventional hybridization and in addition this technique allows visualization of mRNA coding for IL-1 in individual cells with morphology preserved. We conclude that in situ hybridization is a specific and sensitive technique for the detection of beta IL-1 mRNA in individual human peripheral blood monocytes.

Autoradiography↗

PubMed1988

Epidermal interleukin-1 is increased in cutaneous T-cell lymphoma.

Interleukin-1 (IL-1) is a monocyte-derived polypeptide with immunoregulatory and proinflammatory functions. Although monocytes are the principle source of IL-1, other cells, such as keratinocytes, endothelial cells, renal mesangial cells, and neutrophils, produce a factor with IL-1 activity. The IL-1-like polypeptide produced by keratinocytes, epidermal-derived thymocyte-activating factor (ETAF), is similar on biological, biochemical, and molecular levels to monocyte-derived IL-1. Studies of IL-1 or ETAF have for the most part been undertaken using cell culture supernatants or cell lysates, and in situ localization of ETAF has not been demonstrated. Previous studies have suggested that ETAF is involved in the pathogenesis of cutaneous T-cell lymphoma (CTCL). To gain insights into the role of these cytokines in disease states, we investigated whether IL-1 could be localized in tissue sections using a direct immunofluorescence technique with a monoclonal antibody directed against IL-1. This monoclonal antibody partially inhibited ETAF activity and totally inhibited IL-1 activity in the co-stimulator assay and so could be used to detect IL-1 or ETAF. We studied skin biopsies from 10 healthy individuals, 10 patients with CTCL, and 11 patients with various inflammatory dermatoses. Intense epidermal fluorescence was demonstrated in all cases of CTCL, whereas minimal reactivity was visible in normal biopsies and the inflammatory dermatoses. Most patients with CTCL showed an intercellular pattern, while none of the normal controls or those with inflammatory dermatoses showed this pattern. An irrelevant IgM monoclonal antibody, used as a negative control, did not demonstrate epidermal staining. To further demonstrate specificity, we incubated the anti-IL-1 antibody with recombinant beta IL-1:Epidermal reactivity was completely blocked. In a separate experiment, COLO 16 cells, a squamous cell carcinoma cell line that constitutively produces ETAF, stained positively for the IL-1 antibody. We conclude that epidermal IL-1 is elevated in CTCL.

Adult↗

PubMed1988

Tumorigenicity and metastatic behavior in nude mice of two human squamous cell carcinoma lines that differ in production of the cytokine ETAF/IL-1.

The purpose of these studies was to determine whether the production of the cytokine epidermal cell thymocyte-activating factor (ETAF) by human squamous cell carcinoma (SCC) cells correlated with their tumorigenicity and metastatic potential in athymic nude mice. Cells of the human SCC line A431 produced rapidly growing subcutaneous tumors, few experimental lung metastases, and low levels of ETAF activity in vitro. In contrast, cells of the SCC Colo-16 line produced slower growing subcutaneous tumors, high numbers of experimental lung metastases, and a high level of ETAF activity in culture supernatants. The apparent relationship between production of ETAF and experimental metastasis formation was not consistent. Clonal populations of the SCC A431 and Colo-16 were isolated in vitro. The clones of Colo-16 varied in their ability to produce experimental metastases and in production of ETAF in vitro. However, the levels of ETAF production did not correlate with the propensity of the SCC cells to produce experimental metastases. We conclude that while the growth and metastasis of human SCC in nude mice may benefit from production of the cytokine ETAF, the ETAF production per se is not invariably linked with the capability of the SCC cells to metastasize.

Animals↗

PubMed1988

Biology and molecular biology of epidermal cell-derived thymocyte activating factor.

ETAF/IL-1 has a multiplicity of divergent biological effects: enhancement of thymocyte proliferation, stimulation of cells in the hypothalamus to mediate fever, leukocyte chemotaxis, stimulation of hepatic synthesis of acute-phase proteins, augmentation of IL-2 production and keratinocyte proliferation. Until recently, it has not been possible to determine whether these divergent activities are mediated by closely related cytokines or separate cytokines. Now with the identification of IL-1 alpha, IL-1 beta and IL-1k from keratinocytes, these studies will become possible. In either case, it is likely that ETAF/IL-1 plays an important role in local cutaneous and systemic inflammatory and immunological events.

Animals↗

PubMed1988

Whole body hyperthermia (41-42 degrees C) induces interleukin-1 in vivo.

The role of endogenous mediated fever and exogenous hyperthermia as modulators of immunological processes against infection and neoplasms remains poorly understood. Hyperthermia appears to modulate the activity of a number of immunological cytokines including Interleukin-1 (IL-1). Using a recently developed Radiant Heat technology for safely producing 41-42 degrees C Whole Body Hyperthermia in mice, we have investigated the effect of 1 hour of 41 +/- 0.5 degrees C WBH on the production of cutaneous IL-1. After a transient fall in IL-1 production 4 hours post WBH, significant elevations (up to twice control levels) were noted with a peak at 16-20 hours post WBH. IL-1 levels remained elevated for 5-6 days post-WBH. The potential clinical significance of this finding is discussed with particular reference to human malignant melanoma.

Animals↗

PubMed1987

Role of epidermal cell thymocyte-activating factor in the proliferation and differentiation of murine B cells.

The role of antigen nonspecific cytokines in T- and B-lymphocyte responses is now well established. Interleukin-1 (IL-1) has been shown to augment B-cell maturation and proliferation. While the major source of IL-1 is from monocytes or macrophages, other cell types have been shown to produce IL-1-like cytokines. Epidermal cells produce a cytokine termed "epidermal cell-derived thymocyte-activating factor" (ETAF) which is similar if not identical with monocyte-derived IL-1. In this report we show that ETAF induces polyclonal stimulation of murine B cells. We show that ETAF augments B cell proliferation and differentiation in the absence of any added antigens or mitogens. This activity can be partially inhibited by anti-IL-1 antibodies. ETAF appears to activate B cells directly, although its activity is increased in the presence of T cells. Thus, ETAF may be involved in local polyclonal antibody responses occurring in the skin.

Animals↗

PubMed1987

Epidermal Langerhans cell density and contact sensitivity in young and aged BALB/c mice.

The loss of tissue and organ function with age may depend on the inability of old cells to carry out specialized functions. Like other systems in the body, the immune system deteriorates with age. Over the past 10 years it has become clear that the skin can play an active role in immunological processes. In this report we evaluated changes in murine cutaneous immunity with age. Studies in humans had shown a decreased Langerhans cell density with age, but it is difficult to control for the effect of ultraviolet light in human studies. Since ultraviolet light has a significant effect on Langerhans cells, we chose to evaluate the effect of age on Langerhans cell density using inbred mice not exposed to ultraviolet light. Cutaneous immunity was examined phenotypically by studying Langerhans cell density and functionally by studying allergic contact sensitivity. Langerhans cell density was assessed in epidermal sheets prepared from ear skin of mice and examined by ATPase histochemistry and fluoresceinated anti-Ia staining. With both methods, aged (18 months old) mice had approximately two-thirds the number of Langerhans cells that young (10-12 weeks old) animals did. Allergic contact sensitivity response to trinitrochlorobenzene (TNCB) was compared between aged and young animals. Although the aged animals demonstrated increased variability in their responsiveness, there was no overall difference in this example of cutaneous immunoreactivity between the two age groups.

Aging↗

PubMed1987

Formation of epidermal cell thymocyte-activating factor (ETAF) from cultured human keratinocytes from normal and uninvolved psoriatic skin.

Cultures of keratinocytes from uninvolved psoriatic skin have been shown to exhibit increased DNA synthesis. Since epidermal cell-derived thymocyte-activating factor (ETAF) can stimulate the proliferation of human keratinocytes in vitro, we have compared the formation of ETAF in cultured keratinocytes from normal and uninvolved psoriatic skin. Trypsinized epidermal cells were plated at nonconfluent concentrations in dishes coated with a collagen type I gel. Normal keratinocyte cultures spontaneously released ETAF into the supernatant from day 1, reaching a maximum level (mean 124 +/- 4 units/micrograms DNA) on day 7, just before the cultures became completely confluent (days 9-12). The ETAF release then gradually decreased until a plateau (mean 16 +/- 7 units/micrograms DNA) was reached on day 18. In normal keratinocyte cultures the incorporation of [3H]thymidine into DNA changed in parallel with the ETAF release. Psoriatic keratinocytes had normal rates of ETAF release and of DNA synthesis until the time of culture confluency. However, when complete confluency was obtained, psoriatic keratinocytes continued to synthesize DNA at high levels (increased by 146% on day 15) while their ETAF release declined. Analysis of intracellular ETAF showed a significant correlation with the extracellular ETAF in cultures from both normal (r = 0.77, n = 10, p less than 0.02) and uninvolved psoriatic skin (r = 0.76, n = 12, p less than 0.01). These results indicate a relation between ETAF formation and DNA synthesis of normal keratinocyte cultures. However, factors other than ETAF appear to be responsible for the elevated DNA synthesis of confluent keratinocyte cultures from uninvolved psoriatic skin.

Adult↗

PubMed1987

Expression of mRNA homologous to interleukin 1 in human epidermal cells.

Epidermal cells produce an interleukin 1 (IL-1)-related molecule known as epidermal cell-derived thymocyte activating factor (ETAF). Given their similar physical and biologic properties, it was presumed that ETAF would share homology to known IL-1 sequences. A murine IL-1 alpha complimentary DNA (cDNA) probe hybridized with a 2.1 kb RNA from the murine keratinocyte cell line PAMM 212. Further, a 24-base synthetic IL-1 beta probe complementary to a region 700 bases from the putative 5'-end of human IL-1 beta hybridized with 2.7- and 1.6-kb RNAs in human keratinocytes, monocytes, and promyelocytic leukemia cells. Reverse transcripts primed with the IL-1 beta oligonucleotide revealed major first-strand cDNAs from human keratinocyte COLO-16 cell mRNA and human monocyte mRNA of about 700 bases, consistent with the expected cDNA from IL-1 beta. A partial library constructed from this cDNA contained clones that hybridized with the IL-1 beta oligonucleotide. The 750 bp-IL-1 beta-like cDNA clones were not identical to IL-1 beta as judged by restriction mapping and Northern analysis. These cDNA clones hybridized with the 1.6-kb keratinocyte mRNA but not to the 1.6-kb monocyte nor to the 2.7-kb mRNA. The 1.6-kb keratinocyte mRNA may encode a new IL-1-like species.

Cloning, Molecular↗

PubMed1987

Purified interleukin-1 (IL-1) from human monocytes stimulates acute-phase protein synthesis by rodent hepatocytes in vitro.

A universal component of inflammation is the increased synthesis of a series of plasma proteins (acute-phase proteins) by the liver. The postulated messenger of acute-phase protein induction is released by leucocytes at the site of inflammation and has been shown to co-purify with endogenous pyrogen or lymphocyte-activating factor. Interleukin-1, molecular weight 17,000, pI 6 X 8-7 X 2, was purified to homogeneity from adherent human blood monocytes by a combination of affinity chromatography, gel filtration and isoelectric focusing. We examined the direct effect of pure IL-1 on the induction of acute-phase protein synthesis in vitro using rat and mouse hepatocytes. IL-1 caused significant increased synthesis of alpha 1-acid glycoprotein and smaller increases in the synthesis of other acute-phase proteins, and significant decreased synthesis of albumin. The pattern of induction of acute-phase proteins differs from that seen with a separate 30,000 molecular weight hepatocyte-stimulating factor from human monocytes described previously. We conclude that human IL-1 is one of the mediators responsible for the acute-phase protein response of the liver in inflammation and can directly cause stimulation of specific gene expression in normal hepatocytes.

Acute-Phase Proteins↗

PubMed1987

Whole-body exposure to ultraviolet radiation results in increased serum interleukin-1 activity in humans.

Human volunteers given one minimal erythemal dose of ultraviolet radiation (UVR) from fluorescent sunlamps developed increased serum interleukin-1 (IL-1) activity as assessed by the thymocyte co-stimulator assay. This activity peaked 1 to 4 hours after exposure and returned to baseline by 8 hours after exposure. Six to 12 months later, some of the same subjects had blood samples taken over the same time course but without exposure to UVR; no elevation in serum IL-1 was observed. In addition to lymphocyte activating activity, IL-1 has been reported to have endogenous pyrogen activity, chemotactic activity for neutrophils and mononuclear cells, and inflammatory activity when injected subcutaneously in vivo. Elevations in serum IL-1 activity after exposure to ultraviolet radiation may account for some of the manifestations of the sunburn response.

Adult↗

PubMed1986

The role of Langerhans cells and keratinocytes in epidermal immunity.

The immunology of the epidermis has received considerable study over recent years. After the antigen-presenting capacity of epidermal Langerhans cells was confirmed, subsequent studies suggested that keratinocytes could modulate certain immunologic events through production of a cytokine, epidermal cell-derived thymocyte-activating factor (ETAF). Most recently, a murine epidermal cell population, the dendritic Thy-1-positive cell, has been shown to possess natural killer-cell-like activity. In this review, the biology of these cell types are discussed. A discussion of allergic contact hypersensitivity and its alteration by ultraviolet light is used to illustrate some of the complex control mechanisms that continue to be the subject of ongoing study.

Animals↗