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K W Beagley

Publications and source records attributed to K W Beagley.

At least 37 records · Page 2Linked to original sources
PubMed1997

TNF-alpha is not the sole mediator of WEHI-164 tumour cell killing in natural cytotoxicity.

Using a mAb to NC-1.1, a receptor involved in recognition of tumour targets, the authors have examined the dogma that murine natural cytotoxicity (NC) is exclusively mediated by TNF-alpha. Three different NC-1.1+ spleen cells, WEHI-3BR1 myelomonocytic cells and an uncloned mast cell line-MCL) were reacted with NC-sensitive WEHI-164 targets in vitro, and the induction of TNF-alpha mRNA, surface expression of TNF-alpha, and the appearance of apoptotic bodies in the culture were simultaneously measured. NC-1.1+ spleen cells and WEHI-3BR1 cells showed marked induction of TNF-alpha mRNA within 30 min and this was maintained for up to 18 h. Only transient TNF-alpha mRNA induction was observed in MCL cells at 30 min. Surface TNF-alpha was detected on WEHI-3BR1 cells by 4 h, but was not detected on MCL cells. All three effector cell types mediated NC against WEHI-164 targets within 18 h, but they responded differently to the addition of anti-TNF-alpha mAb: anti-TNF-alpha completely blocked WEHI-3BR1 NC, blocked NC-1.1+ spleen cell NC by approximately 70%, and did not block NC by MCL cells. This indicates that TNF-alpha is induced during NC by WEHI-3BR1 effectors and NC-1.1+ spleen cells, is the sole mediator of NC by WEHI-3BR1, and appears to play no role in NC by MCL cells.

Animals↗
PubMed1997

Development of antibody-secreting cells and antigen-specific T cells in cervical lymph nodes after intranasal immunization.

Intranasal (i.n.) immunization with bacterial protein antigens coupled to cholera toxin B subunit (CTB) effectively induces mucosal, especially salivary immunoglobulin A (IgA), and nonmucosal antibody responses in mice. To examine the regional distribution of antigen-specific B and T cells after i.n. immunization, antibody-secreting cells and antigen-responsive T cells in cervical lymph nodes (CLN) were compared with those found after intraoral or subcutaneous (in the neck) administration of the same antigen and with T cells found in mesenteric lymph nodes (MLN) and spleen after intragastric immunization. The i.n. immunization induced predominantly IgA antibody-secreting cells in salivary glands and IgA and IgG antibody-secreting cells in the superficial and central CLN; these responses were quantitatively enhanced if the antigen was coupled to CTB. Intraoral immunization also induced IgA and IgG antibody-secreting cells in the superficial and central CLN, but only if intact cholera toxin was included as an adjuvant. In contrast, subcutaneous (neck) immunization induced IgG antibody-secreting cells mainly in the draining facial lymph nodes. CLN cell populations resembled those of MLN, except that CLN lymphocytes had higher proportions of T cells and lower proportions of B cells and a slightly higher CD4+/CD8+ ratio among T cells than the MLN lymphocytes did. T cells that proliferated in response to antigen in vitro were found especially in central CLN 2 days after i.n. immunization and persisted for up to 6 months, whereas after intragastric immunization, responsive T cells were not found in the MLN for up to 14 days. After culture with antigen in vitro, T cells from the superficial CLN of i.n. immunized mice secreted both gamma interferon and interleukin-4. Therefore, after i.n. immunization, superficial and central CLN represent sites of regional lymphocyte development, and the central CLN in particular appear to be sites where memory T cells persist.

Adjuvants, Immunologic↗
PubMed1996

Hapten-induced model of murine inflammatory bowel disease: mucosa immune responses and protection by tolerance.

We report here a murine model for experimental chronic colitis where administration of trinitrobenzene sulfonic acid (TNBS) in 50% ethanol induced inflammation of large intestine in susceptible (C3H/HeJ and BALB/c) but not resistant (C57BL/6 and DBA/2) mouse strains. We queried whether mucosal trinitrophenyl (TNP)-specific B cell responses were induced in mice with TNBS-induced colitis, and if induction of tolerance to TNBS by oral administration of this hapten protected mice from development of colitis. Isotypes and subclasses of polyclonal and TNP-specific Ab-forming cells (AFC) were assessed in mucosal and peripheral lymphoid tissues of C3H/HeJ mice with TNBS-induced colitis. Increased numbers of IgA- and IgG-secreting cells were found in the inflamed colon lamina propria. Inflamed colonic tissue also contained high frequencies of IgG anti-TNP AFC (predominantly of IgG1, IgG2a, and IgG2b subclasses); however, anti-TNP responses in noninflamed mucosal tissues of mice with colitis exhibited dominant IgA and IgM with low IgG anti-TNP responses. CD4+ T cells stimulated with TNP-splenocytes produced more IFN-gamma and less IL-4, suggesting a Th1-type response. Oral administration of TNBS before induction of colitis markedly decreased mucosal anti-TNP responses and completely inhibited anti-TNP IgG2a and IgG2b responses. Control mice did not show inhibition of anti-TNP AFC responses or TNBS-induced colitis. Intracolonic sensitization of susceptible C3H/HeJ mice with TNBS induces a localized IgG anti-TNP B cell response in the inflamed tissue, whereas prior oral administration of TNBS results in unresponsiveness to this agent and protects mice from development of TNBS-induced colitis.

Administration, Oral↗
PubMed1996

Dendritic cells from different tissues induce production of different T cell cytokine profiles.

The precise role of antigen-presenting cells (APC) in regulating the balance of T-helper type 1 (Th1) and T-helper type 2 (Th2) cytokine production is unclear. Dendritic cells (DC), the most potent APC for activation of naive T cells, were found to regulate Th1 and Th2 cytokine profiles in a fashion dependent upon their tissue of origin. Spleen (systemic) DC induce mainly Th1 cytokines and Peyer's patch (mucosal) DC induce predominantly Th2 cytokines. These findings support the current concept that different tissues, each with its distinct microenvironment of cytokines, hormones, and cellular elements, are involved in the selection, promotion, and/or maintenance of different immune responses. With regard to DC, it is apparent that the tissue of DC origin determines the cytokine profiles produced by T cells and that DC from different tissues favor either cellular versus humoral immune responses by influencing T cell cytokine production.

Animals↗
PubMed1996

Regulation of mucosal IgA responses in vivo: cytokines and adjuvants.

The predominance of IgA plasma cells at mucosal sites reflects a combination of the selective localisation and vigorous proliferation after extravasation of IgA plasma cell precursors. Experiments are described here which demonstrate that post-extravasation events leading to IgA precursor cell retention, proliferation and antibody secretion are under cytokine control. This has led to investigation of therapeutic interventions to modify cytokine availability to maximise mucosal vaccination responses and correct IgA deficiencies.

Adjuvants, Immunologic↗
PubMed1996

Induction of antibody-secreting cells and T-helper and memory cells in murine nasal lymphoid tissue.

Intranasal (i.n.) immunization is an effective route for inducing mucosal immune responses especially in the upper respiratory tract and mouth. To characterize the cells involved in these responses, nasal lymphoid tissue (NALT; considered to be the equivalent of Waldeyer's ring in humans) of normal mice, and of mice immunized intranasally with a bacterial protein antigen conjugated to cholera toxin B subunit, was isolated and the lymphoid cells analysed according to surface phenotype, immunoglobulin and antibody secretion, and cytokine profile. Compared with cells obtained from Peyer's patches (PP), NALT cells contained a higher proportion of T cells, especially naive (CD45RB+hi) T-helper cells, and fewer surface (s)IgA+ cells. Both tissues contained high proportions of sIgM+ IgD+ unswitched B cells. After i.n. immunization, IgA antibody-secreting cells were increased, indicating that isotype switching and differentiation of B cells to IgA-secreting cells occurred in NALT, whereas smaller numbers of antibody-secreting cells were found in PP after intragastric (i.g.) immunization. Antigen-specific memory cells persisted in NALT for at least 8 months after initial immunization. The cytokine expression profiles of antigen-stimulated NALT and PP cells of immunized mice, revealed by reverse transcription polymerase chain reaction analysis of mRNA, were similar. Both NALT and PP cells tended to express type 2 earlier or for longer than type 1 cytokine mRNA, but NALT cells tended to express interleukin-4 (IL-4) earlier, and IL-5 for a longer period, than PP cells. Thus NALT shares with PP cell populations typical of a mucosal inductive site, including unswitched B cells and naive T-helper (Th) cells. After i.n. immunization, NALT has the capacity to provide help for B-cell maturation and differentiation, as well as to maintain immune memory.

Animals↗
PubMed1996

Kinetics of cytokine expression during healing of acute colitis in mice.

The mechanisms of wound healing in the gut are poorly understood but are mediated by cytokines in other tissues. In this study we wanted to determine which cytokines were expressed after nonspecific colonic injury, the kinetics of that expression, and how cytokine expression correlated with tissue histology. At 0, 4, 8, 12, 24, 48, and 72 h after intrarectal administration of 3% acetic acid to C3H/HeJ mice, their colons were removed for histology, organ culture, and RNA extraction. Cytokine mRNA expression for various cytokines was assessed by reverse transcriptase-polymerase chain reaction with primers specific for each cytokine. Cytokine production in organ cultures was measured with bioassays. Shortly after colonic injury and during colonic regeneration, proinflammatory cytokines such as interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein (MIP), and transforming growth factor-beta (TGF-beta) were expressed. In contrast, expression of T cell-derived cytokines was not detected at any time point. Cytokines such as IL-1 beta, IL-6, IL-10, TNF-alpha, and MIP-1 are important mediators of tissue repair and restitution after nonspecific colonic injury and may subserve a similar role in human colitis.

Acetic Acid↗
PubMed1995

Differences in intraepithelial lymphocyte T cell subsets isolated from murine small versus large intestine.

Intraepithelial lymphocytes (IELs) have been extensively studied in the murine small intestine. However, to date no studies have assessed IEL in the large intestine, despite the marked differences in function and lumenal environment. In the present study, we isolated IEL from both small and large intestine of three mouse strains (BALB/c, C3H/HeN, C57BL/6) and determined the frequency of CD2, CD4, and CD8 expression on CD3+ IEL, as well as the frequency of alpha beta and gamma delta TCR usage and V beta distribution. Higher numbers of IEL/unit length were always isolated from the small intestine (20-30 x 10(6)/5 mice) compared with large intestine (1.1-2.5 x 10(6)/5 mice). Interestingly, IEL from the large intestine of all strains were predominantly alpha beta TCR+ whereas gamma delta TCR+ IELs predominated in small intestine. Large intestinal IELs were mainly CD4+, in both BALB/c and C3H/HeN mouse strains. IELs from large intestine of C57BL/6 mice were mainly CD8+; however, the CD4+ subset was fourfold higher when compared with small intestine IEL. Potential functional differences between IEL subsets was assessed by determining the relative levels of mRNA for IL-1, 2, 4, 5, 10, IFN-gamma, TGF-beta, and TNF-gamma. Similar patterns of IL-1, IFN-gamma and TNF-alpha were seen while more IL-2, IL-4, IL-5, and IL-10 mRNA was noted in large intestinal IEL. Stimulation of C3H/HeJ IEL with anti-CD3 also resulted in higher levels of IL-3/GM-CSF, IL-4, and IL-6 by IEL from large intestine. These results show that marked differences occur among the T cell subsets present in IELs from mouse small and large intestine.

Animals↗
PubMed1995

IgA production by peritoneal cavity B cells is IL-6 independent: implications for intestinal IgA responses.

We have shown previously both in vitro and in vivo that IL-6 is an important factor for the development of IgA-producing B cells. However, despite the lack of this cytokine in mice with targeted disruption of the interleukin (IL)-6 gene (gene knockout mice), a substantial number of IgA-producing plasma cells occur in their intestinal mucosa. The experiments reported here indicate that there is a population of IgA-producing B cell precursors originating from the peritoneal cavity, distinguished from conventional Peyer's patch-derived precursors by their expression of CD5, and that IgA secretion by these cells is IL-6-independent. Further, there is an increase in CD5 expression among brightly staining IgA-producing cells obtained from the intestinal lamina propria of IL-6 gene-disrupted mice compared to normal controls. These data suggest an explanation for the persistence of IgA-producing plasma cells in the intestinal mucosa of IL-6-depleted mice and indicate the importance of IL-6 for development of conventional precursors of IgA-producing B cells, but not those derived from the peritoneal cavity pool.

Animals↗
PubMed1995

Peritoneal cavity CD5 (Bla) B cells: cytokine induced IgA secretion and homing to intestinal lamina propria in SCID mice.

The mouse peritoneal cavity contains a unique population of B cells (Bla) with a high IgM/low IgD ratio, CD5+ (Ly1), MAC-1 + phenotype. These cells arise early in ontogeny, utilize a limited repertoire of immunoglobulin V genes, produce polyreactive IgM antibodies and have been implicated as the source of many auto-reactive immunoglobulins. Recent data from chimeric mice suggest that this B cell population also contains the precursors of many IgA plasma cells found in the lamina propria of the small intestine. In the present study we have investigated the potential of this cell population to secrete IgA (and IgG) in response to various cytokines. IL-5 alone, or in combination with IL-2, greatly enhanced secretion of both IgG and IgA. Cytokine-induced IgA secretion resulted from expansion of a subset of CD5 B cells co-expressing sIgA. Adoptive transfer of CD5 B cells while peripheral lymph nodes contained only IgM+ and some IgG+ B cells. Transfer of CD5+ B cells also reconstituted serum IgM, IgG and IgA and IgG, immunoglobulins characteristic of mucosal and anamnestic responses, when cultured in vitro with the appropriate cytokines. These cells also give rise to IgA plasma cells in the intestinal lamina propria following adoptive transfer to SCID mice, further supporting the hypothesis that cells of this lineage may be important in immune responses at mucosal surfaces.

Animals↗
PubMed1994

Cytokine synthesis and apoptosis by intestinal intraepithelial lymphocytes: signaling of high density alpha beta T cell receptor+ and gamma delta T cell receptor+ T cells via T cell receptor-CD3 complex results in interferon-gamma and interleukin-5 production, while low density T cells undergo DNA fragmentation.

To study the biological consequences of cytokine production and apoptosis by intraepithelial lymphocytes (IEL), we have studied these characteristics in both the high and low density CD3+ IEL populations. Stimulation of low- or high-density CD3+ IEL via the T cell receptor (TCR)-CD3 complex using monoclonal anti-CD3, anti-alpha beta TCR or anti-gamma delta TCR antibodies resulted in opposing effects. In one case, a significant number of the high-density CD3+ T cells entered cell cycle from the resting stage (DNA replication was observed) and anti-TCR-CD3 treatment enhanced the numbers of interferon-gamma and interleukin-5 spot-forming cells in this cell fraction. In contrast, when the low-density alpha beta TCR+ or gamma delta TCR+ T cells were activated via the TCR-CD3 complex, DNA fragmentation was observed. These results demonstrated that the activation signals transduced via the TCR-CD3 complex resulted in their entry into the cell cycle and subsequent interferon-gamma and interleukin-5 production in the high-density IEL T cell subset. However, identical signals induced apoptosis in the majority of the low-density fraction of CD3+ IEL.

Animals↗