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W Strober

Publications and source records attributed to W Strober.

At least 91 records · Page 5Linked to original sources
PubMed1996

Experimental granulomatous colitis in mice is abrogated by induction of TGF-beta-mediated oral tolerance.

In previous studies we showed that a chronic colitis associated with a Th1 T cell response can be induced by the rectal administration of the haptenizing reagent 2,4,6-trinitrobenzene sulfonic acid (TNBS). We report here that oral administration of haptenized colonic proteins (HCP) before rectal administration of TNBS effectively suppresses the ability of the latter to induce colitis. This suppression (oral tolerance) appears to be due to the generation of mucosal T cells producing TGF-beta and Th2-type cytokines after oral HCP administration. Peyer's patch and lamina propria CD4+ T cells from HCP-fed animals stimulated with anti-CD3/anti-CD28 had a 5-10-fold increase in their production of TGF-beta and secreted increased amounts of IL-4 and IL-10 but lower levels of IFN-gamma in comparison to T cells from ovalbumin-fed control animals. In addition, the colons of HCP-fed mice showed strikingly increased TGF-beta but decreased IL-12 expression by immunohistochemical studies and isolated mononuclear cells from HCP-fed animals secreted less IL-12 heterodimer. Finally, and most importantly, the suppressive effect of orally administered HCP was abrogated by the concomitant systemic administration of anti-TGF-beta or rIL-12 suggesting a reciprocal relationship between IL-12 and TGF-beta on tolerance induction in TNBS-induced colitis. In parallel studies we demonstrated that TNBS-induced colitis can be transferred to naive recipient animals with purified CD4+ T cells from the colon of TNBS-treated animals and that such animals develop lethal pancolitis when exposed to very low doses of TNBS. Feeding of HCP suppressed this sensitivity to TNBS, indicating that oral feeding can suppress the response of pre-committed T cells in vivo. These studies suggest for the first time that TGF-beta production can abrogate experimental granulomatous colitis even after such colitis is established, and thus, that regulation of TGF-beta levels may have relevance to the treatment of human inflammatory bowel disease.

Animals↗
PubMed1996

The T cell-B cell interaction via OX40-OX40L is necessary for the T cell-dependent humoral immune response.

Recent in vitro studies have established that activated B cells express OX40 ligand (L), a member of the tumor necrosis factor/nerve growth factor family of cytokines, and become stimulated to proliferate and secrete immunoglobulin (Ig) after cross-linking of OX40L by its counterreceptor OX40, which is expressed on activated T cells. In the present study we investigated the in vivo role of this receptor-ligand pair for the interaction of T and B cells in the course of the T-dependent B cell response against 2,4,6 trinitro-phenyl-keyhole limpet hemocyanin. First, we showed that OX40 is maximally expressed by T cells in the periarteriolar lymphoid sheath (PALS) 3 d after primary immunization. These OX40+ cells are located in close proximity to antigen-specific, activated B cells. Second, we demonstrated that blocking of OX40-OX40L interaction with polyclonal anti-OX40 antibody or with antibodies against certain peptide sequences within its extracellular domain resulted in a profound decrease of the anti-hapten IgG response, whereas the antihapten IgM response was grossly unchanged. Third, we showed that this antibody treatment leads to an inhibition of the development of PALS-associated B cell foci, whereas the formation of germinal centers remained intact. Finally, our data suggest that, whereas B cell memory development was not impaired by anti-OX40 administration, OX40-OX40L interaction seems to be crucial in the secondary immune response. We conclude from these data that the OX40-OX40L interaction in vivo is necessary for the differentiation of activated B cells into highly Ig-producing cells, but is not involved in other pathways of antigen-driven B cell differentiation such as memory cell development in the germinal centers.

Animals↗
PubMed1996

Blocking the CD40L-CD40 interaction in vivo specifically prevents the priming of T helper 1 cells through the inhibition of interleukin 12 secretion.

The recent finding that CD40L on activated T cells induces interleukin (IL) 12 secretion in human peripheral blood monocytes in vitro suggests that the CD40L-CD40 interaction may be of importance in the priming of T helper (Th) 1-type T cells. We therefore investigated the in vivo relevance of this interaction in an experimental model for a Th1-mediated disease, the hapten reagent (2,4,6-trinitrobenzene sulfonic acid [TNBS])-induced colitis. The administration of anti-gp39 (CD40L) antibodies during the induction phase of the Th1 response prevented interferon gamma production by lamina propria CD4+ T cells and also clinical and histological evidence of disease. In contrast, the secretion of IL-4, a Th2-type cytokine, was increased after anti-gp39 treatment. In further studies we showed that the prevention of disease activity was caused by an inhibition of IL-12 secretion, as demonstrated by immunohistochemistry. In addition, the injection of recombinant IL-12 p70 heterodimer into TNBS + anti-gp39-treated mice reversed the effect of anti-gp39 and resulted in severe disease activity. When anti-gp39 was given after the disease was established, no effect on the disease activity was observed. In conclusion, we demonstrated that the CD40L-CD40 interaction is crucial for the in vivo priming of Th1 T cells via the stimulation of IL-12 secretion by antigen-presenting cells (APC).

Animals↗
PubMed1996

Distinct populations of dendritic cells are present in the subepithelial dome and T cell regions of the murine Peyer's patch.

Despite the fact that the Peyer's patch (PP) is the primary site for antigen uptake in the intestine, the cellular basis of antigen handling after transport into the PP is poorly understood. We performed immunohistology of murine PPs using the dendritic cell (DC)-reactive monoclonal antibodies N418, NLDC-145, M342, and 2A1, as well as antibodies to other T cell, B cell, and macrophage markers. N418+, 2A1+, NLDC-145-, M342- cells form a dense layer of cells in the subepithelial dome (SED), just beneath the follicle epithelium, and are scattered throughout the follicle, sparing the germinal center. In contrast, N418+, 2A1+, NLDC-145+, and M342+ DCs are present in the interfollicular T cell regions (IFR). CD3+ and CD4+, but no CD8+ T cells were present in the SED and the follicle, including the germinal center, while CD3+, CD4+, and CD8+ T cells were present in the IFR. B cells and macrophages were poorly represented in the SED as no B220+ cells, only few Mac-1lo cells, and no F4/80+ cells were present at this site. In contrast, Mac-1hi cells were found in the IFR and lamina propria of intestinal villi, while F4/80+ cells were found only in the latter. In further phenotypic studies, we analyzed surface molecules of PP and spleen DCs by flow cytometry and found that these cells had similar fluorescence profiles when stained with N418, NLDC-145, and 33D1 DC-reactive antibodies, and antibodies to the costimulatory molecules B7-1 (1G10) and B7-2 (GL1). In contrast, PP DCs expressed 5-10-fold higher levels of major histocompatibility complex class II antigens (IEk) than spleen DCs. Finally, in functional studies, we demonstrated that both PP and spleen DCs process soluble protein antigens during overnight culture and induce similar levels of proliferation in CD3+ T cells, and CD4+/Mel 14hi T cells from T cell receptor transgenic mice. The in vivo relevance of such presentation was shown by the fact that PP DCs isolated from Balb/c mice after being fed ovalbumin stimulated proliferation in ovalbumin T cell receptor T cells. Taken together, our data suggest that DCs in the SED of the PP are uniquely positioned for the processing of antigens passed into the PP from the overlying M cell, and that PP DCs are effective at processing and presenting oral antigens to naive T cells.

Animals↗
PubMed1996

Differential activation requirements of isotype-switched B cells.

In the present studies, we compared the activation requirements of sIgM+/sIgD+ B cells with those of isotype-switched sIgM-/sIgA+ B cells. We found that whereas sIgM+ B cells respond to T cell-independent (TI) and T cell-dependent (TD) Ag with no significant bias toward one stimulus, sIgA+ B cells were deficient in their ability to respond to antigen receptor cross-linking but responded remarkably well to TD stimuli. Thus, dextran-conjugated anti-IgA antibody (anti-IgA-dextran), anti-kappa-dextran, or various immobilized anti-IgA antibodies (Ab) induced only low-level IgA B cell proliferation and no IgA secretion in the presence of various lymphokines; in marked contrast, sIgA+ B cells responded to cognate and noncognate T cell stimulation as well as to stimulation by CD40 ligand-bearing fibroblasts by secreting large amounts of IgA (up to 240 000 ng/ml per 10(5) cells). This pattern of sIgA+ B cell responsiveness was noted with both germinal center peanut agglutininhi (PNAhi) and non-germinal center PNAlo B cells. In confirmation of these results, whole Peyer's patch or lamina propria cell populations containing less than 15% sIgA+ B cells stimulated with a noncognate T cell stimulus or T cell membranes secreted mainly IgA (68%-94% of the total Ig secreted) and relatively little IgM. The strict T cell dependence of IgA B cell activation and differentiation provides important insights into immune responses of mucosal tissues and must be considered in the development of vaccines, particularly those designed to stimulate mucosal tissues containing large numbers of isotype-switched B cells.

Animals↗
PubMed1996

Local administration of antisense phosphorothioate oligonucleotides to the p65 subunit of NF-kappa B abrogates established experimental colitis in mice.

Chronic intestinal inflammation induced by 2,4,6,-trinitrobenzene sulfonic acid (TNBS) is characterized by a transmural granulomatous colitis that mimics some characteristics of human Crohn's disease. Here, we show that the transcription factor NF-kappa B p65 was strongly activated in TNBS-induced colitis and in colitis of interleukin-10-deficient mice. Local administration of p65 antisense phosphorothioate oligonucleotides abrogated clinical and histological signs of colitis and was more effective in treating TNBS-induced colitis than single or daily administration of glucocorticoids. The data provide direct evidence for the central importance of p65 in chronic intestinal inflammation and suggest a potential therapeutic utility of p65 antisense oligonucleotides as a novel molecular approach for the treatment of patients with Crohn's disease.

Adrenal Cortex Hormones↗
PubMed1996

Differential usage of T-cell receptor V beta gene families by CD4+ and CD8+ T cells in patients with CD8hi common variable immunodeficiency: evidence of a post-thymic effect.

In this study, we report that differences between T-cell receptor (TCR) V beta gene family usage in CD4+ and CD8+ T cells are significantly greater in a subgroup of patients with common variable immunodeficiency (CVI) and high levels of activated CD8+ T cells (CD8hi CVI) than in controls (P < 0.001). In CD8hi CVI patients, such differences were also significantly greater for V beta 12 than for other V beta families. As the causes of the differential usage of V beta gene families by CD4+ and CD8+ T cells are under investigation, it was interesting that the combined differences between V beta gene family usage in the CD4+ and CD8+ T-cell subpopulations as a whole were significantly lower than the combined differences between individual V beta gene family usage in either CD4+ or CD8+ T-cell subpopulations (P < 0.001 in both control and CD8hi CVI patients). Further, the pattern of V beta gene family usage in CD4+ T cells was remarkably similar to that in CD8+ T cells in both groups. These data strongly suggest that differences in V beta gene family usage arising from coselection by major histocompatibility complex (MHC) class I versus MHC class II restriction elements do not fundamentally distort 'basic' V beta gene family usage patterns. They also support the concept that differences in CD4+ and CD8+ T-cell V beta gene family usage, which were increased in CD8hi CVI, can arise from high-affinity interactions between disease-associated antigens or superantigens and T cells in the post-thymic T-cell compartment.

Base Sequence↗
PubMed1996

Hypoproliferative human lamina propria T cells retain the capacity to secrete lymphokines when stimulated via CD2/CD28 pathways.

Human lamina propria (LP) T cells exhibit a reduced proliferative capacity in response to antigen-specific stimulation. To investigate the functional state of such hypoproliferative T cells, we determined the capacity of LP T cells to produce lymphokines when stimulated by monoclonal antibodies that crosslink either the TCR/CD3 complex or accessory pathway molecules (CD2,CD28). We found that TCR/CD3-mediated proliferative responses of LP T cells were greatly diminished when compared to peripheral blood (PB) T cells, but were largely restored when cells were preincubated in IL-2. Despite their proliferative hyporesponsiveness, LP T cells (as compared to PB T cells) secreted equal amounts of IL-2 and increased amounts of IFN-gamma, IL-4 and IL-5; these increased cytokine responses were most evident when cells were stimulated via the accessory pathways. In further studies, purified CD4+ LP T cells were compared with purified CD4+/CD45RO+ PB T cells (i.e., the PB T cell subset they most resemble). LP T cells produced significantly more IFN-gamma and IL-5 but less IL-4 than their CD45RO+ PB counterparts. Overall, LP T cells are unresponsive T cells following stimulation via the TCR/CD3 pathway but nevertheless retain the capacity to produce increased levels of TH1 and TH2-type lymphokines following stimulation via the CD2/CD28 accessory pathway; thus, they are best classified as modified "anergic" T cells.

CD2 Antigens↗
PubMed1996

Whipple's disease.

Whipple's disease (WD) is a rare systemic disease caused by infection with the recently identified actinomycetes, Tropheryma whippelii. The disorder affects mostly middle-aged men, and the major clinical features are weight loss, arthropathy, and diarrhea; other symptoms, caused by systemic infection, are not infrequent. The diagnosis is usually established by duodenal biopsy, which shows the pathognomonic periodic acid Schiff-positive infiltrates in the lamina propria. In addition, RT-polymerase chain reaction of tissue specimens can be used to verify the presence of T whippelii. In most cases, patients can be successfully treated by prolonged administration of antimicrobials, such as trimethoprim-sulfamethoxazole. The unusual chronic-relapsing course of the disease, the predisposition of middle-aged, HLA-B27-positive men for WD, and other characteristics of the disease imply that host factors are involved in the etiopathogenesis of WD. Indeed, it has been shown that patients with WD have suppressed delayed-type hypersensitivity responses in vivo and decreased in vitro T-cell responses, eg, to phytohemagglutinin and concanavalin A. In addition, serum-suppressor factors and shifts in T-cell subpopulations have been found. Perhaps most importantly, WD macrophages have a decreased ability to degrade intracellular microorganisms and patients have reduced numbers of circulating cells expressing CD11b, a cell adhesion and complement receptor molecule on macrophages involved in the activation of intracellular killing of pathogens. Most of those immunologic alterations also occur in patients with longstanding clinical remission, suggesting that this subtle host-defense defect plays an important role in disease pathogenesis.

Anti-Bacterial Agents↗
PubMed1995

Antibodies to interleukin 12 abrogate established experimental colitis in mice.

In this study, we describe a novel murine model of chronic intestinal inflammation induced by the hapten reagent 2,4,6-trinitrobenzene sulfonic acid (TNBS). Rectal application of low doses of TNBS in BALB/c and SJL/J mice resulted in a chronic transmural colitis with severe diarrhea, weight loss, and rectal prolapse, an illness that mimics some characteristics of Crohn's disease in humans. The colon of TNBS-treated mice on day 7 was marked by infiltration of CD4+ T cells; furthermore, in situ polymerase chain reaction studies revealed high levels of interferon (IFN)-gamma mRNA in diseased colons. Isolated lamina propria (LP) CD4+ T cells from TNBS-treated mice stimulated with anti-CD3 and anti-CD28 antibodies exhibited a Th1 pattern of cytokine secretion: a 20-50-fold increase in IL-2 and IFN-gamma levels and a 5-fold decrease in IL-4 levels as compared with those of stimulated LP CD4+ T cells from control BALB/c mice. Administration of monoclonal anti-IL-12 antibodies to the TNBS-treated mice both early (at 5 d) and late (at 20 d) after induction of colitis led to a striking improvement in both the clinical and histopathological aspects of the disease and frequently abrogated the established colitis completely. Furthermore, LP CD4+ T cells isolated from anti-IL-12-treated mice failed to secrete IFN-gamma upon in vitro stimulation. In summary, the data demonstrate the pivotal role of IL-12 and IFN-gamma in a TNBS-induced murine model of chronic intestinal inflammation. Furthermore, they suggest the potential utility of anti-IL-12 antibodies in patients with Crohn's disease.

Animals↗
PubMed1995

Dominant interfering Fas gene mutations impair apoptosis in a human autoimmune lymphoproliferative syndrome.

Five unrelated children are described with a rare autoimmune lymphoproliferative syndrome (ALPS) characterized by massive nonmalignant lymphadenopathy, autoimmune phenomena, and expanded populations of TCR-CD3+CD4-CD8- lymphocytes. These findings, suggesting a genetic defect in the ability of T lymphocytes to respond to normal immunoregulatory mechanisms, prompted an evaluation of lymphocyte apoptosis. Each child had defective Fas-mediated T lymphocyte apoptosis associated with a unique, deleterious Fas gene mutation. One mutation appeared to cause a simple loss of function; however, four others had a dominant negative phenotype when coexpressed with normal Fas. Family studies demonstrated the inheritance of the mutant Fas alleles. The occurrence of Fas mutations together with abnormal T cell apoptosis in ALPS patients suggests an involvement of Fas in this recently recognized disorder of lymphocyte homeostasis and peripheral self-tolerance.

Antigens, Surface↗
PubMed1995

Pax5 (BSAP) regulates the murine immunoglobulin 3' alpha enhancer by suppressing binding of NF-alpha P, a protein that controls heavy chain transcription.

The Pax5 transcription factor BSAP (B-cell-specific activator protein) is known to bind to and repress the activity of the immunoglobulin heavy chain 3' alpha enhancer. We have detected an element--designated alpha P--that lies approximately 50 bp downstream of the BSAP binding site 1 and is required for maximal enhancer activity. In vitro binding experiments suggest that the 40-kDa protein that binds to this element (NF-alpha P) is a member of the Ets family present in both B-cell and plasma-cell nuclei. However, in vivo footprint analysis suggests that the alpha P site is occupied only in plasma cells, whereas the BSAP site is occupied in B cells but not in plasma cells. When Pax5 binding to the enhancer in B cells was blocked in vivo by transfection with a triple-helix-forming oligonucleotide an alpha P footprint appeared and endogenous immunoglobulin heavy chain transcripts increased. The triple-helix-forming oligonucleotide also increased enhancer activity of a transfected construct in B cells, but only when the alpha P site was intact. Pax5 thus regulates the 3' alpha enhancer and immunoglobulin gene transcription by blocking activation by NF-alpha P.

Animals↗
PubMed1995

The role of BSAP in immunoglobulin isotype switching and B-cell proliferation.

A role for the transcription factor B cell-specific activator protein (BSAP) in switch recombination has been proposed because binding sites for this protein have been found near switch regions of several isotypes. We have attempted to assess BSAP's role by altering the expression of this protein in B cells switching in culture to IgG1. We found that a phosphorothioate oligonucleotide antisense to the BSAP translation initiation site was able, when incubated with B cells, to decrease BSAP activity in nuclear extracts, and that IgG1 expression was reduced in such cells compared to cells incubated with control oligonucleotides. However, it is not clear whether this apparent reduction in switch recombination was mediated by the known BSAP binding sites in the immunoglobulin heavy chain locus because the antisense experiments revealed an additional activity of this protein: it is a rate-limiting regulator of cell proliferation. Down-regulation of BSAP was associated with decreased proliferation, while increasing BSAP (by transfection with a BSAP expression plasmid) increased proliferation. Thus because switch recombination apparently requires cell division, the effect of BSAP down-regulation on switching might have resulted from decreased proliferation. The role of BSAP in B cell proliferation suggests that dysregulation of this protein could contribute to neoplastic transformation of B cells. Because of BSAP's many activities, experiments to elucidate the mechanisms of its effects on switching and proliferation will be challenging.

Animals↗
PubMed1995

BSAP: a key regulator of B-cell development and differentiation.

B-cell-specific activator protein (BSAP) is a recently identified member of the Pax-gene family of transcription factors; in the lymphoid system, BSAP is produced only in B cells. Here, Markus Neurath, Eckhard Stüber and Warren Strober describe the molecular structure of BSAP and focus on the ability of this protein to regulate the expression of B-cell-specific genes. They propose that BSAP is a key protein of B cells and that it not only influence B-cell development but also influences the balance between B-cell proliferation and immunoglobulin secretion at later stages of B-cell differentiation.

Animals↗
PubMed1995

Cross-linking of OX40 ligand, a member of the TNF/NGF cytokine family, induces proliferation and differentiation in murine splenic B cells.

OX40 is a member of the TNF/NGF-receptor family expressed on activated T cells, whose ligand is found on activated T and B cells. In the present study, we show that cross-linking of OX40L on CD40L-stimulated B cells, alpha IgD dextran-stimulated B cells, or both results in a significantly enhanced proliferative response with no change in the cell survival rate. Furthermore, OX40 stimulation increases immunoglobulin heavy chain mRNA levels and immunoglobulin secretion, which could not be blocked by anti-cytokine antibodies. In additional molecular studies, we show that OX40L cross-linking results in the down-regulation of the transcription factor BSAP. This, in turn, leads to a change in the in vivo binding pattern of the immunoglobulin heavy chain gene 3' alpha enhancer, suggesting its activation. This effect may thus be one mechanism for OX40-induced increase in immunoglobulin secretion. In conclusion, our data suggest that the OX40-OX40L interaction is a novel pathway in T cell-dependent B cell proliferation and differentiation.

Animals↗