Richard L Deem

Cedars-Sinai Medical Center · Inflammatory Bowel & Immunobiology Research Institute

Background & aims: Variants in the tumor necrosis factor superfamily member 15 gene (TNFSF15, also called TL1A) have been associated with risk for inflammatory bowel diseases (IBD). TL1A affects expression of multiple cytokines to promote mucosal inflammation. Little is known about the TL1A-response pathways that regulate cytokine expression. We i...

Background: Mucosal expression of interferon (IFN)-γ plays a pivotal role in the pathogenesis of inflammatory bowel disease (IBD) and IBD risk regions flank IFNG. The conserved IFNG rs1861494 T/C introduces a new CpG methylation site, is associated with disease severity and lack of therapeutic response in other infectious and immune-mediated disor...

TL1A/TNFSF15 has been associated with IBD (inflammatory bowel disease) in GWAS (genome-wide association study) and plays a role mediating mucosal inflammation in IBD. Higher TL1A expression is associated with disease severity in both patients and mouse models. Although TL1A has been studied extensively for IBD-associated SNPs, the cis/trans-regulat...

High antibody reactivity toward microbial antigens in Crohn's disease (CD) patients is predictive of a more aggressive disease course. However, few ulcerative colitis (UC) patients exhibit serologic reactivity toward microbial antigens. Mucosal expression of IFN-γ plays a pivotal role in inflammatory bowel disease (IBD) pathogenesis. Recent genome-...

Mucosal expression of proinflammatory cytokines plays a pivotal role in inflammatory bowel disease (IBD) pathogenesis. Epigenetic remodeling of chromatin via DNA methylation regulates gene expression. In this study, IFNG DNA methylation was analyzed within the mucosal compartment in both normal and IBD populations and compared to its peripheral cou...

This study examines mucosa-specific regulatory pathways involved in modulation of interferon-gamma (IFN-gamma) in lamina propria T cells. Previous studies identified mucosa-specific CD2 cis-elements within the -204 to -108 bp IFNG promoter. Within this region, a single-site nucleotide polymorphism, -179G/T, imparts tumor necrosis factor-alpha stimu...

IFN-gamma is an important immunoregulatory protein with tightly controlled expression in activated T and NK cells. Three potential STAT binding regions have been recognized within the IFN-gamma promoter: 1) an IL-12-mediated STAT4 binding site at -236 bp; 2) a newly identified IL-2-induced STAT5 binding element at -3.6 kb; and 3) CD2-mediated STAT1...

The pathways leading to activation of mucosal lamina propria (LP) T cells differ from those of peripheral T cells. LP T cells exhibit enhanced IFN-gamma secretion when activated through the CD2 pathway. This study demonstrates CD2 signaling is followed by activation of STAT proteins in both peripheral blood mononuclear cells (PBMC) and lamina propr...

Thymus-expressed chemokine (TECK) or CCL25) is selectively expressed in the small bowel (SB), where lamina propria lymphocytes (LPL) and intraepithelial leukocyte expressing the cognate chemokine receptor CCR9 predominate. We characterize the role of TECK and CCR9-expresing lymphocytes in small intestinal Crohn's disease. CCR9 expression on lymphoc...

Activation of lamina propria (LP) T cells via the CD2 pathway enhances IFN-gamma (IFN-gamma) secretion with further enhancement after CD28 coligation. The molecular mechanisms regulating IFN-gamma expression in LP T cells remain unknown. Previous studies in PBL and T cell lines identified cis- and trans-regulatory elements in TCR-mediated expressio...

The pathways leading to activation in lamina propria (LP) T cells are different from peripheral T cells. LP T cells exhibit enhanced IL-2 secretion when activated through the CD2 pathway. Coligation of CD28 leads to synergistic enhancement of IL-2 secretion. Previous studies have characterized the CD28 augmentation of TCR-mediated signaling in peri...

The aim of this study was to identify molecular mechanisms involved in transcriptional regulation of IL-2 expression following CD2 and CD3 activation in lamina propria (LP) T cells. Studies used T cells from normal, ulcerative colitis, and Crohn's disease mucosa and freshly isolated PBMC, PBMC stimulated with IL-2 alone, and PBMC stimulated with IL...

Recent clinical studies of Crohn's disease patients demonstrated dramatic clinical responses following one i.v. infusion of a chimeric mAb to TNF-alpha (cA2). To assess the role of TNF-alpha in mucosal cytokine regulation, the effects of TNF-alpha on lamina propria mononuclear cell (LPMC) Th1 production were determined. Increased IFN-gamma producti...

The human TALL-104 cell line possesses major histocompatibility complex non-restricted cytotoxic activity against a large variety of tumor targets. Adequate therapies for prostate cancer that has spread outside its capsule are lacking. In order to identify effective therapies for this problem, we investigated the antiproliferative effects of TALL-1...

A previous study reported the increased expression of the cytokine TNF in the adipose tissue of genetically obese rodents. To examine this paradigm in humans, we studied TNF expression in lean, obese, and reduced-obese human subjects. TNF mRNA was demonstrated in human adipocytes and adipose tissue by Northern blotting and PCR. TNF protein was quan...

This study was designed to compare cytokine release in lamina propria lymphocytes (LPLs) and PBLs activated by Abs against CD3, CD2, and CD28. LPL T cells were significantly more responsive to CD2 ligation than PBL, as determined by release of IFN-gamma, IL-2, IL-4, and TNF-alpha. Moreover, CD28 co-ligation in LPLs exaggerated CD2 > CD3 dominance i...

We have developed a method to quantitate TNF alpha-mRNA in small numbers of cells by reverse transcription followed by competitive polymerase chain reaction (RT-PCR). RT-PCR allowed the accurate quantitation of TNF alpha-mRNA over a 1000-fold range of concentration. The recovery of RNA isolated from 1000 to 10,000 cells was optimized by reducing sa...

T cell activation can lead to local tissue injury in organ culture studies of human fetal jejunum, either directly through cytotoxicity or indirectly by the release of cytotoxic cytokines. The goal of this study was to establish in vitro whether cytotoxic cytokines can be released by isolated colonic T cells and what cytokine interactions are requi...

An expanded T cell subpopulation (CD8+ Leu-7+) has previously been reported in the peripheral blood of patients with Crohn's disease. This subpopulation of T cells was associated with a 'covert suppressor' function, particularly in patients with mild/early Crohn's disease, suppressing immunoglobulin production in vitro when cultured in the presence...

Thirty years of research on the role of immune-mediated cytotoxic activity in the tissue injury of inflammatory bowel disease (IBD) has yielded only inconclusive data on the relevance of cytotoxic mechanisms. Two hypotheses have been advanced. One is that the destruction of target cells is mediated by direct recognition of target antigens by cytoto...

Monoclonal antibodies to the CD3 component of the T-cell antigen receptor can trigger antigen-specific cytotoxic T cells to elicit nonantigen-specific cytotoxicity, possibly by mimicking or bypassing the requirement for antigen triggering. We have used this technique to investigate the possible presence ofin vivo primed cytotoxic T cells, of unknow...

Monoclonal antibodies to the CD3 component of the T-cell antigen receptor can trigger antigen-specific cytotoxic T cells to elicit nonantigen-specific cytotoxicity, possibly by mimicking or bypassing the requirement for antigen triggering. We have used this technique to investigate the possible presence of in vivo primed cytotoxic T cells, of unkno...

NK-depleted human peripheral blood lymphocytes can be modulated with anti-CD3 to kill certain targets during 3-hr cytotoxicity assays. When triggered by anti-CD3 antibody, these effector T cells killed only NK-sensitive targets, such as K562 and HEL 92.1.7, and NK-resistant targets, such as Daudi, whose killing is inhibited by anti-CD45 (T-200) mon...

Non-major histocompatibility complex-restricted cytotoxicity triggered by antibodies to the CD3 component of the human T-cell receptor complex is thought to be an indirect measure of in vivo primed cytotoxic T-cell activity. We have used this technique to examine the lytic activity of freshly isolated T cells from noninflamed human colonic mucosa....

Phospholipase A2 (PA-2) is known to be involved in many calcium-dependent cellular processes and inhibitors of PA-2 have been shown to inhibit natural killer cell-mediated cytotoxicity (NK CMC). Since the trigger stage is calcium dependent, it was postulated that this effector cell-associated enzyme may play a role in early calcium-dependent proces...

Natural killer cell cytotoxic factor (NKCF) has been biologically defined as a soluble cytotoxic factor produced by natural killer (NK) cells that can lyse NK-sensitive targets. This factor was initially described by Wright and Bonavida (1) and has been implicated as the lytic factor responsible for NK cell-mediated cytotoxicity (1–9). Although NKC...

Inhibitors of energy metabolism, 2-deoxyglucose and cyanide were shown to inhibit NKCF-mediated lysis of L929 target cells at the same molar concentrations that effectively inhibited cellular ATP levels and the toxic effects of pseudomonas toxin A. In addition, inhibitors of receptor-mediated endocytosis, cytochalasin B, a microtubule disrupter, an...

Previous studies have shown that NK cytotoxicity can be resolved into several stages: NK-target cell binding, triggering, programming, and killer cell independent lysis (KCIL)(1, 2). NK cells produce soluble cytolytic factors (NKCF), which can lyse NK-sensitive targets and have been used as another measure of the NK lethal hit (3, 4). Since KCIL an...

The substages of natural killer cell-derived cytolytic factor (NKCF)-mediated cytolysis have been examined by using the bifunctional protein cross-linking reagent glutaraldehyde. Glutaraldehyde (2 X 10(-4%)) enhanced both the level and rate of lysis mediated by NKCF when the factor was prebound to the L929 target cell. However, glutaraldehyde enhan...

The role of membrane movement during the stages of human NK cytolysis has been examined by using the bifunctional protein cross-linking reagent, glutaraldehyde. The binding stage was inhibited when K562 target cells or NK cells were pretreated with glutaraldehyde. When added post-binding, after initiation of calcium pulse, glutaraldehyde did not di...

Macrophage-depleted populations of splenic lymphocytes obtained from immunized and nonimmunized BALB/c mice were tested to determine their ability to kill Nocardia asteroides GUH-2 in vitro. Nocardia-primed lymphocytes, but not normal lymphocytes, killed N. asteroides. The ability of these lymphocytes to kill N. asteroides could be further enhanced...

Macrophage-depleted populations of splenic lymphocytes obtained from immunized and nonimmunized BALB/c mice were tested to determine their ability to kill Nocardia asteroides GUH-2 in vitro. Nocardia-primed lymphocytes, but not normal lymphocytes, killed N. asteroides. The ability of these lymphocytes to kill N. asteroides could be further enhanced...

A unique form of superoxide dismutase was isolated and characterized from Nocardia asteroides GUH-2. This enzyme contains 1 to 2 g atoms each of Fe, Mn, and Zn per mol and exhibits spectral properties suggestive of Fe- or Mn-containing superoxide dismutases. Its Mr = 100,000, and it is composed of four subunits of equal size which are not covalentl...

Nude mice on a BALB/c background were adoptively transferred with unprimed spleen cells, Nocardia-primed spleen cells, or Nocardia-primed splenic T lymphocytes from syngeneic, heterozygous (nu/+) littermates. Two days later, these recipient mice and unmanipulated (control) nude mice were infected intravenously with a 50% lethal dose of Nocardia ast...

Immunized and nonimmunized B-lymphocyte-deficient CBD2/F1 (CBA/N x DBA/2) mice were infected with Nocardia asteroides GUH-2 by different routes of inoculation. The 50% lethal dose, organ clearance, footpad response, and antibody titers were measured. It was observed that B-cell-deficient male mice were not significantly more susceptible to infectio...