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W Strober

Publications and source records attributed to W Strober.

At least 19 recordsLinked to original sources
PubMed1999

Administration of mAb against alpha E beta 7 prevents and ameliorates immunization-induced colitis in IL-2-/- mice.

We previously demonstrated that 2,4,6-trinitrophenol (TNP)-OVA immunization leads to a transmural colitis in the IL-2-/- mouse that is caused by IL-12-driven CD4+ Th1 T cells and resembles human Crohn's disease. The integrin alpha E beta 7 is highly expressed on colonic intraepithelial lymphocytes and has been suggested to function as a homing or retention molecule for intraepithelial lymphocytes. To evaluate the role of alpha E beta 7 in colitis, we administered a mAb against alpha E beta 7 to IL-2-/- mice that were immunized at the same time with TNP-OVA in CFA. To our surprise, this treatment resulted in a significantly reduced colitis severity score, 0-2 vs 3-4, that was associated with a significant reduction in CD4+ lamina propria lymphocyte subpopulation (p < 0.01). In contrast, the total number of splenic CD4+ T cells of treated animals was significantly elevated compared with that of untreated animals (3.2 +/- 0.6 x 107 vs 1.2 +/- 0.2 x 107; p < 0.05). Similarly, functional studies revealed that IFN-gamma production by lamina propria lymphocytes isolated from IL-2-/- TNP-OVA-immunized mice treated with anti-alpha E beta 7 was significantly lower than in untreated IL-2-/- TNP-OVA-immunized mice. In contrast, IFN-gamma production by splenic cells isolated from treated IL-2-/- TNP-OVA-immunized mice was significantly higher than in untreated mice. Finally, TNP-OVA-immunized IL-2-/- mice that were treated after the colitis had been established also showed a significant decrease in mucosal inflammation after alpha E beta 7 mAb administration. Thus, the above findings demonstrate that the onset and maintenance of inflammatory bowel disease depends on the colonic localization of lamina propria CD4+ lymphocytes expressing alpha E beta 7.

Animals↗
PubMed1999

Mucosal vaccination overcomes the barrier to recombinant vaccinia immunization caused by preexisting poxvirus immunity.

Overcoming preexisting immunity to vaccinia virus in the adult population is a key requirement for development of otherwise potent recombinant vaccinia vaccines. Based on our observation that s.c. immunization with vaccinia induces cellular and antibody immunity to vaccinia only in systemic lymphoid tissue and not in mucosal sites, we hypothesized that the mucosal immune system remains naive to vaccinia and therefore amenable to immunization with recombinant vaccinia vectors despite earlier vaccinia exposure. We show that mucosal immunization of vaccinia-immune BALB/c mice with recombinant vaccinia expressing HIV gp160 induced specific serum antibody and strong HIV-specific cytotoxic T lymphocyte responses. These responses occurred not only in mucosal but also in systemic lymphoid tissue, whereas systemic immunization was ineffective under these circumstances. In this context, intrarectal immunization was more effective than intranasal immunization. Boosting with a second dose of recombinant vaccinia was also more effective via the mucosal route. The systemic HIV-specific cytotoxic T lymphocyte response was enhanced by coadministration of IL-12 at the mucosal site. These results also demonstrate the independent compartmentalization of the mucosal versus systemic immune systems and the asymmetric trafficking of lymphocytes between them. This approach to circumvent previous vaccinia immunity may be useful for induction of protective immunity against infectious diseases and cancer in the sizable populations with preexisting immunity to vaccinia from smallpox vaccination.

AIDS Vaccines↗
PubMed1999

An inherited disorder of lymphocyte apoptosis: the autoimmune lymphoproliferative syndrome.

The autoimmune lymphoproliferative syndrome (ALPS) affords novel insights into the mechanisms that regulate lymphocyte homeostasis and underlie the development of autoimmunity. This syndrome arises early in childhood in persons who inherit mutations in genes that mediate apoptosis, or programmed cell death. The timely deletion of lymphocytes is a way to prevent their accumulation and the persistence of cells that can react against the body's own antigens. In ALPS, defective lymphocyte apoptosis permits chronic, nonmalignant adenopathy and splenomegaly; the survival of normally uncommon "double-negative" CD3+ CD4- CD8- T cells; and the development of autoimmune disease. Most cases of ALPS involve heterozygous mutations in the lymphocyte surface protein Fas that impair a major apoptotic pathway. Detailed immunologic investigations of the cellular and cytokine profiles in ALPS show a prominent skewing toward a T-helper 2 phenotype; this provides a rational explanation for the humoral autoimmunity typical of patients with ALPS. Prospective evaluations of 26 patients and their families show an ever-expanding spectrum of ALPS and its major complications: hypersplenism, autoimmune hemolytic anemia, thrombocytopenia, and neutropenia. Defective apoptosis may also contribute to a heightened risk for lymphoma.

Apoptosis↗
PubMed1999

Lamina propria T cells in Crohn's disease and other gastrointestinal inflammation show defective CD2 pathway-induced apoptosis.

BACKGROUND & AIMS: Normal human lamina propria lymphocytes manifest increased unstimulated apoptosis compared with peripheral lymphocytes, which are enhanced after stimulation via the CD2 activation pathway. This activation-induced apoptosis down-regulates cell expansion and cytokine production. In previous studies, it was shown that lamina propria T cells from patients with Crohn's disease and ulcerative colitis manifest abnormal proliferation and cytokine production. It was therefore of interest to determine if such cells also showed abnormal patterns of apoptosis. METHODS: Apoptosis was evaluated by propidium iodide staining of cells followed by flow cytometric analysis. Fas expression and Bcl-2 levels in cells were evaluated by immunofluorescence. RESULTS: Lamina propria lymphocytes from patients with Crohn's disease and ulcerative colitis as well as from 2 patients with diverticulitis showed defective CD2 pathway-induced apoptosis. Studies of the mechanisms of this defect focusing on cells from patients with Crohn's disease showed that Crohn's disease lamina propria lymphocytes from inflamed tissues express the same amount of cell surface Fas but are less sensitive to Fas-mediated apoptosis than control cells. In addition, lamina propria lymphocytes from inflamed Crohn's disease tissues manifest increased expression of Bcl-2 after CD2 pathway stimulation and elevated Bcl-2 levels in cultures of unstimulated T cells. CONCLUSIONS: T cells isolated from areas of inflammation in Crohn's disease, ulcerative colitis, and other inflammatory states manifest decreased CD2 pathway-induced apoptosis. Studies of cells from inflamed Crohn's disease tissue indicate that this defect is accompanied by elevated Bcl-2 levels. These changes are probably caused by the chronic inflammation and may aggravate the underlying disease processes that are present.

Antigens, CD↗
PubMed1999

[Mechanisms and applications of oral tolerance].

The term oral tolerance (OT) describes the antigen-specific suppression of immune responses following the feeding of the antigen. While some common features with other forms of induction of systemic tolerance have been disclosed, OT can be distinguished by certain immunologic characteristics. Thus, work in experimental animal models revealed the importance of intestinal antigen processing, especially antigen processing in the Peyer's patches, in inducing OT. It has become clear that suppressive T cell cytokines derived from mucosal sites play a major role in mediating OT. The variation of the dose of fed antigen and the modulation of the cytokine milieu both have influences on the underlying immunologic mechanisms active suppression, clonal anergy and clonal deletion following oral antigen uptake. In several animal models of autoimmunity the disease activity can be suppressed by feeding oral autoantigen. Based on these results, recent clinical studies have begun to explore OT as a means to treat autoimmune disorders such as multiple sclerosis, rheumatoid arthritis and diabetes.

Administration, Oral↗
PubMed1998

The importance of local mucosal HIV-specific CD8(+) cytotoxic T lymphocytes for resistance to mucosal viral transmission in mice and enhancement of resistance by local administration of IL-12.

Although crucial to mucosal vaccine development, the mechanisms of defense against mucosal viral infection are still poorly understood. Protection, cytotoxic T lymphocytes (CTL), and neutralizing antibodies have all been observed, but cause and effect have been difficult to determine. The ability of CTL in the mucosa to mediate protection against mucosal viral transmission has never been proven. Here, we use an HIV peptide immunogen and an HIV-1 gp160-expressing recombinant vaccinia viral intrarectal murine challenge system, in which neutralizing antibodies do not play a role, to demonstrate for the first time that long-lasting immune resistance to mucosal viral transmission can be accomplished by CD8(+) CTL that must be present in the mucosal site of exposure. The resistance is ablated by depleting CD8(+) cells in vivo and requires CTL in the mucosa, whereas systemic (splenic) CTL are shown to be unable to protect against mucosal challenge. Furthermore, the resistance as well as the CTL response can be increased by local mucosal delivery of IL-12 with the vaccine. These results imply that induction of local mucosal CTL may be critical for success of a vaccine against viruses transmitted through a mucosal route, such as HIV.

Animals↗
PubMed1998

Interactions between epithelial cells and immune cells in the intestine.

Not merely a passive barrier as previously assumed, epithelial cells act as sensitive indicators of infection that initiate defense responses. Noninvasive as well as invasive organisms have been demonstrated to elicit production of chemoattractants. That noninvasive organisms have this capacity suggests that receptor-mediated signaling pathways may be involved. Epithelial cells have been found to release both chemokines and cytokines in a precise mixture that varies according to the origin or maturity of the cell. Different microorganisms also elicit different response patterns. The information presented provides a basis for a new view of epithelial cell function in relation to host defense.

Animals↗
PubMed1998

Cytokine gene transcription by NF-kappa B family members in patients with inflammatory bowel disease.

We examined the expression of the transcription factor NF-kappa B, a nuclear trans-acting factor known to play a key role in cytokine gene regulation, in patients with inflammatory bowel disease (IBD). It was found that LP macrophages in Crohn's disease (CD) and ulcerative colitis (UC) display high levels of NF-kappa B DNA-binding activity accompanied by an increased production of interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF) alpha. Western blot studies showed an increased expression of the p50 and c-rel subunits of NF-kappa B; however, the most striking finding was an increased expression level of NF-kappa B p65 in patients with CD and UC. Selective downregulation of p65 in IBD macrophages by a specific antisense phosphorothioate oligonucleotide was sufficient to considerably reduce production of proinflammatory cytokines. These results demonstrate a characteristic increase of NF-kappa B binding levels in patients with IBD. The data suggest that antisense DNA targeting NF-kappa B p65 can be used as a novel molecular approach for the treatment of patients with IBD.

Adolescent↗
PubMed1998

Murine model of oral tolerance. Induction of Fas-mediated apoptosis by blockade of interleukin-12.

We explored the immunological mechanisms underlying the development of oral tolerance with the use of ovalbumin (OVA) T-cell receptor (TCR)-transgenic mice. Feeding high doses of OVA induced tolerance in the peripheral lymphoid tissues, and the degree of peripheral tolerance was enhanced when antigen feeding was combined with systemic administration of antibodies to interleukin-12 (anti-IL-12). Using the TUNEL technique by which apoptotic cells can be specifically identified, we found evidence that peripheral clonal deletion occurs in OVA-TCR transgenic mice in vivo after oral antigen delivery and treatment with anti-IL-12, but only to a minor degree after antigen feeding alone. The mechanism that accounts for the dramatic loss of peripheral cells is Fas-mediated, since > 90% of antigen-specific Fas+ T cells were lost. In addition, antagonizing Fas but not TNF reversed the phenomenon when cells were stimulated in vitro. These findings suggest that IL-12 negatively regulates apoptosis, a major mechanism of peripheral tolerance. A combination of oral antigen feeding and administration of anti-IL-12 may thus be useful in the treatment of autoimmune diseases and may be a potent means to modulate peripheral tolerance.

Animals↗
PubMed1998

Oxazolone colitis: A murine model of T helper cell type 2 colitis treatable with antibodies to interleukin 4.

In this study we describe oxazolone colitis, a new form of experimental colitis. This model is induced in SJL/J mice by the rectal instillation of the haptenating agent, oxazolone, and is characterized by a rapidly developing colitis confined to the distal half of the colon; it consists of a mixed neutrophil/lymphocyte infiltration limited to the superficial layer of the mucosa which is associated with ulceration. Oxazolone colitis is a T helper cell type 2 (Th2)-mediated process since stimulated T cells from lesional tissue produce markedly increased amounts of interleukin (IL)-4 and IL-5; in addition, anti-IL-4 administration leads to a striking amelioration of disease, whereas anti-IL-12 administration either has no effect or exacerbates disease. Finally, this proinflammatory Th2 cytokine response is counterbalanced by a massive transforming growth factor-beta (TGF-beta) response which limits both the extent and duration of disease: lesional (distal) T cells manifest a 20-30-fold increase in TGF-beta production, whereas nonlesional (proximal) T cells manifest an even greater 40-50-fold increase. In addition, anti-TGF-beta administration leads to more severe inflammation which now involves the entire colon. The histologic features and distribution of oxazolone colitis have characteristics that resemble ulcerative colitis (UC) and thus sharply distinguish this model from most other models, which usually resemble Crohn's disease. This feature of oxazolone colitis as well as its cytokine profile have important implications to the pathogenesis and treatment of UC.

Administration, Rectal↗
PubMed1998

Factors involved in the differentiation of TGF-beta-producing cells from naive CD4+ T cells: IL-4 and IFN-gamma have opposing effects, while TGF-beta positively regulates its own production.

TGF-beta has been shown to play a central role in regulating inflammatory responses; thus, understanding the factors involved in the generation of TGF-beta-producing cells could lead to interventions that are useful in effecting disease progression. In initial studies, the capacity of naive CD4+ T cells from TCR transgenic (Tg) mice to produce TGF-beta following primary and secondary stimulation was assessed. TGF-beta, IL-4, or IFN-gamma production could not be detected from highly purified naive CD4+/lymphocyte endothelial cell adhesion molecule (LECAM)-1high cells following primary stimulation for 36 h with plate-bound anti-CD3, anti-CD28, and IL-2. This population was subsequently used to study the differentiation of TGF-beta-producing CD4+ T cells. In further studies, naive CD4+/LECAM-1high cells from TCR transgenic mice of both the BALB/c and B10.A backgrounds were stimulated with T-depleted spleen cells (TDS) and specific peptide in the presence of various cytokines and/or cytokine antagonists for 5 days, restimulated, and TGF-beta, IL-4, and IFN-gamma production were measured. Priming conditions favoring high IL-4 production and/or low IFN-gamma production greatly enhanced TGF-beta production in secondary cultures. Furthermore, the presence of IL-10 in cultures was associated with an increase in TGF-beta production following restimulation. The importance of IL-4 and IFN-gamma in regulating TGF-beta production was confirmed in studies showing that cells from IFN-gamma(-/-) mice produced more TGF-beta, while cells from IL-4(-/-) mice produced less TGF-beta compared with wild-type controls. Finally, the addition of exogenous TGF-beta to priming cultures significantly enhanced the production of TGF-beta upon restimulation, demonstrating that TGF-beta has a role in self-regulating its own production.

Animals↗
PubMed1998

The pathogenesis of mucosal inflammation in murine models of inflammatory bowel disease and Crohn disease.

In recent years, it has become apparent that overproduction of the Th1 cytokines interleukin-12 and interferon-gamma is the probable driving force behind murine models of intestinal inflammation resembling Crohn disease and intestinal inflammation in humans with Crohn disease. In addition, studies of murine models strongly suggest that this overproduction is associated with inadequate secretion of the counter-regulatory and anti-inflammatory cytokine transforming growth factor-beta. Thus, mucosal inflammation in models (and possibly in humans) may result from an imbalance between normally occurring positive (immunogenic or inflammatory) responses and negative (tolerogenic or anti-inflammatory) mucosal immune responses. These new findings and the hypotheses that arise from them are being used to construct new approaches to the treatment of Crohn disease that are based on the administration of anti-inflammatory cytokines and anti-cytokine antibodies.

Animals↗
PubMed1998

Active Wegener's granulomatosis is associated with HLA-DR+ CD4+ T cells exhibiting an unbalanced Th1-type T cell cytokine pattern: reversal with IL-10.

Wegener's granulomatosis (WG) is a granulomatous vasculitis that affects the upper respiratory tract, lung, and kidney. Since T cells make up a significant proportion of cells infiltrating granulomatous lesions in WG, we investigated the proliferative response and cytokine profile of T cells from these patients. PBMCs were isolated from 12 patients with active WG, 7 patients with inactive disease, and 12 healthy normal donors. PBMCs from clinically active WG patients exhibited increased proliferation following stimulation with either PMA/ionomycin or anti-CD2 and anti-CD28, when compared with normal donors. In addition, these PBMCs exhibited increased secretion of IFN-gamma, but not of IL-4, IL-5, or IL-10. Furthermore, TNF-alpha production from PBMCs and CD4+ T cells isolated from patients with WG was elevated, when compared with healthy donors. In further studies, we investigated the ability of WG patients' monocytes to produce IL-12 and showed that both inactive and active patients produced increased amounts of IL-12. Finally, the in vitro IFN-gamma production by WG PBMC is inhibited in a dose-dependent manner by exogenous IL-10. These data suggest that T cells from WG patients overproduce IFN-gamma and TNF-alpha, probably due to dysregulated IL-12 secretion, and that IL-10 may therefore have therapeutic implications for this disease.

Adult↗
PubMed1998

Mucosal immunization with HIV-1 peptide vaccine induces mucosal and systemic cytotoxic T lymphocytes and protective immunity in mice against intrarectal recombinant HIV-vaccinia challenge.

Mucosal tissues are major sites of HIV entry and initial infection. Thus, the induction of a mucosal cytotoxic T lymphocyte (CTL) response is an important feature for an effective HIV vaccine. However, little is known about approaches to induce such a protective CTL response in the mucosa. Here for the first time we show that intrarectal immunization with a synthetic, multideterminant HIV peptide plus cholera toxin adjuvant induced long-lasting, antigen-specific CTL memory in both the inductive (Peyer's patch) and effector (lamina propria) mucosal sites, as well as in systemic sites (spleen), whereas systemic immunization induced specific CTL only in the spleen. Cholera toxin adjuvant, while enhancing the response, was not essential. The CTL recognized target cells either pulsed with HIV peptide or expressing endogenous whole envelope glycoprotein of Mr 160,000 (gp160). Exploring the requirements for CTL induction, we show that mucosal CTL responses are both interleukin 12 and interferon-gamma dependent by using antibody-treated and knock-out mice. Finally, to determine whether a mucosal response is actually protective against local mucosal challenge with virus, we show that intrarectal immunization with the synthetic HIV peptide vaccine protected mice against infection via mucosal challenge with a recombinant vaccinia virus expressing HIV-1IIIB gp160. These studies provide an approach to development of an HIV vaccine that induces CTL immunity in the mucosal and systemic immune systems and protects against mucosal infection with a virus expressing HIV-1 gp160.

AIDS Vaccines↗
PubMed1998

Local and systemic cytokine responses during experimental human influenza A virus infection. Relation to symptom formation and host defense.

To further understand the role of cytokine responses in symptom formation and host defenses in influenza infection, we determined the levels of IL-1beta, IL-2, IL-6, IL-8, IFN-alpha, TGF-beta, and TNF-alpha in nasal lavage fluid, plasma, and serum obtained serially from 19 volunteers experimentally infected with influenza A/Texas/36/91 (H1N1) and correlated these levels with various measures of infection and illness severity. We found that IL-6 and IFN-alpha levels in nasal lavage fluids peaked early (day 2) and correlated directly with viral titers, temperature, mucus production, and symptom scores. IL-6 elevations were also found in the circulation at this time point. In contrast, TNF-alpha responses peaked later (day 3 in plasma, day 4 in nasal fluids), when viral shedding and symptoms were subsiding. Similarly, IL-8 peaked late in the illness course (days 4-6) and correlated only with lower respiratory symptoms, which also occurred late. None of IL-1beta, IL-2, or TGF-beta levels increased significantly. These data implicate IL-6 and IFN-alpha as key factors both in symptom formation and host defense in influenza.

Cytokines↗
PubMed1998

Intestinal lymphangiectasia, a disease characterized by selective loss of naive CD45RA+ lymphocytes into the gastrointestinal tract.

Intestinal lymphangiectasia (InL) is a disease characterized by hypoproteinemia and lymphocytopenia resulting from blocked intestinal lymphatics and loss of lymph fluid into the gastrointestinal tract. This leads to immunologic abnormalities including hypogammaglobulinemia, skin anergy and impaired allograft rejection. In the present study, we evaluated whether the above immunologic abnormalities are secondary to a quantitative or qualitative disorder of T cells. In initial studies we demonstrated that adult InL patients' peripheral blood contain strikingly (and significantly) reduced numbers of CD4+/CD45RA+ T cells, whereas the numbers of CD4+/CD45RO+ T cells were only moderately (and not significantly) reduced. In addition, the CD4+/CD45RO+ T cell population contained an increased percentage of highly differentiated and previously sensitized cells, as demonstrated by decreased CD27 and CD31 expression and increased HLA-DR and CD69 expression. In subsequent functional studies, we showed that the InL CD4+/CD45RO+ T cells, when stimulated in vitro, proliferate fivefold less than control CD4+/CD45RO+ T cells and produce fourfold more IL-4 and threefold less IFN-gamma and IL-2. Thus, this cytokine production profile also reflects the highly differentiated nature of the residual cell population. Overall, these studies provide new information on the trafficking of naive/mature and Th1/Th2 T cell populations in this disease model.

Adult↗
PubMed1998

Pathological findings in human autoimmune lymphoproliferative syndrome.

The defects in lymphocyte apoptosis that underlie the autoimmune lymphoproliferative syndrome (ALPS) are usually attributable to inherited mutations of the CD95 (Fas) gene. In this report, we present the histopathological and immunophenotypic features seen in the lymph nodes (n = 16), peripheral blood (n = 10), bone marrow (n = 2), spleen (n = 3), and liver (n = 2) from 10 patients with ALPS. Lymph nodes showed marked paracortical hyperplasia. Interfollicular areas were expanded and populated by T cell receptor-alphabeta CD3+ CD4-CD8- (double-negative, DN) T cells that were negative for CD45RO. CD45RA+ T cells were increased in all cases studied. The paracortical infiltrate was a result of both reduced apoptosis and increased proliferation, as measured by in situ detection of DNA fragmentation and staining with MIB-1, respectively. The paracortical proliferation may be extensive enough to suggest a diagnosis of malignant lymphoma. Many of the paracortical lymphocytes expressed markers associated with cytotoxicity, such as perforin, TIA-1, and CD57. CD25 was negative. In addition, most lymph nodes exhibited florid follicular hyperplasia, often with focal progressive transformation of germinal centers; in some cases, follicular involution was seen. A polyclonal plasmacytosis also was present. The spleens were markedly enlarged, more than 10 times normal size. There was expansion of both white pulp and red pulp, with increased DN T cells. DN T cells also were observed in liver biopsies exhibiting portal triaditis. In the peripheral blood, the T cells showed increased expression of HLA-DR and CD57 but not CD25. CD45RA+ T cells were increased in the four cases studied. Polyclonal B cell lymphocytosis with expansion of CD5+ B cells was a characteristic finding. Taken together, the histopathological and immunophenotypic findings, particularly in lymph nodes and peripheral blood, are sufficiently distinctive to suggest a diagnosis of ALPS. Of note, two affected family members of one proband developed lymphoma (T-cell-rich B-cell lymphoma and nodular lymphocyte predominance Hodgkin's disease, respectively).

Apoptosis↗