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Biomedical subjects

H Kiyono

Publications and source records attributed to H Kiyono.

At least 145 records · Page 8Linked to original sources
PubMed1995

Mucosal adjuvant effect of cholera toxin in mice results from induction of T helper 2 (Th2) cells and IL-4.

Despite pathophysiologic effects including diarrhea, cholera toxin (CT) is a potent mucosal immunogen and adjuvant. We investigated the influence of CT on T helper (Th)-type 1 (Th1) and Th2 cell-regulated Ag-specific B cell isotype and IgG subclass Ab responses elicited when the toxin was co-administered orally with different protein Ags. When mice were orally immunized with tetanus toxoid (TT) and CT as adjuvant, this regimen induced TT-specific secretory IgA responses in the gastrointestinal tract as well as serum IgG, including IgG1 and IgG2b subclasses, and IgA responses. This oral regimen also induced TT- and CT-B-specific IgE responses. In addition, CT also elicited adjuvant effects for Ag-specific IgG1, IgE, and IgA responses when two other protein Ags, OVA and hen egg white lysozyme, were given by the oral route. Quantitative reverse transcriptase-PCR was performed to assess levels of mRNA for Th1 (IFN-gamma) and Th2 (IL-4) cytokine expression in TT-stimulated CD4+ T cell cultures. Both Peyer's patches and splenic CD4+ T cells expressed markedly increased levels of IL-4-specific message, but did not result in changes in IFN-gamma mRNA expression. To determine whether the route of immunization influenced IgE responses, mice were immunized s.c. with TT and CT as adjuvant. Significant increases in total and TT-specific IgE Abs were induced when CT was co-administered. Taken together, these results show that CT acts as a mucosal adjuvant to enhance Th2-type responses and in particular, the IL-4 produced results in a characteristic Ab isotype pattern associated with this cytokine.

Adjuvants, Immunologic↗
PubMed1995

Mucosal T cells induce systemic anergy for oral tolerance.

Heat-labile enterotoxin (LT) from enterotoxigenic Escherichia coli is known to possess strong immunoregulatory potential in terms of inhibition of the induction of oral tolerance and adjuvanticity in oral immunization. We found that oral administration of an immunogenic peptide of LT [LT-B(26-45); spanning the residues 26-45 of LT-B] induced systemic unresponsiveness in BALB/c mice resulting in diminished serum IgG responses. It was also shown that the spleen (SP) CD4+ T cells of tolerized mice failed to proliferate, whereas the Peyer's patches (PP) CD4+ T cells responded to the peptide. RT-PCR revealed that the SP CD4+ T cells did not generate IL-2 mRNA, while the PP CD4+ T cells expressed significant levels of IFN-gamma, IL-2, IL-4, and TGF-beta mRNA. Adoptive transfer of LT-B-specific intraepithelial lymphocytes to the tolerant mice abrogated the tolerance. In the reversed mice, LT-B(26-45)-stimulated SP CD4+ T cells expressed significant levels of IFN-gamma, IL-2, IL-4, and IL-6 mRNA. These results indicate that PP CD4+ T cells induce oral tolerance due to systemic T cell anergy.

Amino Acid Sequence↗
PubMed1995

Polarized Th2 cytokine expression by both mucosal gamma delta and alpha beta T cells.

Currently only limited information is available as to why dominant IgA isotype responses are supported by mucosal T cells in effector tissues. To address this issue directly, gamma delta and alpha beta T cells were isolated from the submandibular gland (SMG) of mice as an example of mucosal effector tissues. Freshly isolated CD3+ T cells from this tissue contained relatively high numbers of activated cells [approximately 10% interleukin-2 receptor (IL-2R)+ cells and 15% of cells in cycle stages S and G2 + M], of which 25% and 75% were gamma delta and alpha beta T cells, respectively. The cytokine-specific quantitative reverse transcriptase-polymerase chain reaction and enzyme-linked immunospot analyses revealed that, although both gamma delta and alpha beta T cells were capable of producing an array of Th1 or Th2 cytokines following stimulation via the T cell receptor-CD3 complex, these mucosal T cells were mainly committed to IL-5 and IL-6 expression in vivo (Th2 type). Both freshly isolated gamma delta and alpha beta T cells expressed mRNA and contained IL-5 and IL-6 spot-forming cells (SFC); however, only the latter exhibited high mRNA levels and SFC for a Th1 cytokine (interferon-gamma). Taken together, the results show that freshly isolated CD3+ T cells from SMG contain activated gamma delta and alpha beta T cells which are programmed to produce IL-5 and IL-6. Thus, SMG, an example of an IgA effector tissue, can be characterized as a Th2-dominant site. However, although both gamma delta and alpha beta T cells express cytokine profiles consistent with a Th2 phenotype, only the latter subset with a CD4+ CD8- phenotype provided effective help for mucosal B cell responses in vitro.

Animals↗
PubMed1995

Neutralization of HIV-1 by secretory IgA induced by oral immunization with a new macromolecular multicomponent peptide vaccine candidate.

Control of pandemic infection of human immunodeficiency virus type 1 (HIV-1) requires some means of developing mucosal immunity against HIV-1 because sexual transmission of the virus occurs mainly through the mucosal tissues. However, there is no evidence as yet that the secretory immunoglobulin A (IgA) antibody induced by immunization with antigens in experimental animals can neutralize HIV-1. We demonstrate here that oral immunization with a new macromolecular peptide antigen and cholera toxin (CT) induces a high titre (1:2") of gut-associated and secretory IgA antibody to HIV-1. Using three different neutralizing assays, we clearly demonstrate that this secretory IgA antibody is able to neutralize HIV-1IIIB, HIV-1SF2 and HIV-1MN. Our new approach may prove to be important in the development of a mucosal vaccine that will provide protection of mucosal surfaces against HIV-1.

AIDS Vaccines↗
PubMed1995

Intratracheal gene delivery with adenoviral vector induces elevated systemic IgG and mucosal IgA antibodies to adenovirus and beta-galactosidase.

One major concern about using adenoviral vectors for repetitive gene delivery to lung epithelial cells is the induction of an immune response to the vector, thus, impeding effective gene transduction. To assess the immune response to the adenoviral vector, repetitive intratracheal (i.t.) gene dosing was performed in CD-1 mice using the replication-deficient adenovirus 5 (Ade5) vector carrying the lacZ gene, and compared to the antibody responses induced by conventional intranasal (i.n.) and intraperitoneal (i.p.) routes of immunization. Kinetics of serum IgG, IgA, and IgM antibody responses to the adenoviral vector and to beta-galactosidase (beta-Gal) were evaluated. Two or three adenoviral vector doses given by i.t., i.n., or i.p. routes resulted in serum IgG titers in excess of 1:200,000, whereas serum IgM and IgA were moderately induced. Analysis of the predominant murine IgG subclass was determined to be IgG2b and IgG2a. To determine the localization of this antibody response, the ELISPOT assay was employed. Lymphocytes were isolated from the lung, the lower respiratory lymph nodes (LRLN), the nasal passages (NP), and the spleen. For i.t- and i.n.-administered mice, the highest IgA spot-forming cell (SFC) response to Ade5 and beta-Gal was located in the NP and in the lung. Both the lung and the LRLN showed elevated numbers of IgG SFCs (4- to 12-fold greater than splenic IgG SFC response) for Ade5 and beta-Gal. This evidence suggests that the lung and associated lymphoid tissues were the source for serum antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoviridae↗
PubMed1995

Characterization of cytokine producing T cells, TCR expression, and IgA plasma cells in salivary gland-associated tissues.

In this study, SMG, PGLN, and CLN from murine SGAT were employed in order to understand immunological characteristics of mononuclear cells that reside in these tissues for IgA responses. Based on our results, SMG harbor characteristics of IgA effector tissues. Further, PGLN has immunological features of both IgA effector tissue and systemic LN. On the other hand, CLN possesses classical characteristics of an organized systemic LN. Several important and unique features of T cells in SMG were demonstrated by this study. For example, approximately 40-50% of MC in SMG were CD3+ T cells which consisted of an equal distribution of CD4+, CD8- and CD4-, CD8+ T cell subsets. This can be considered as a unique feature of SMG since the other effector tissues usually have 2 to 3 times higher frequencies of CD4+ T cells over CD8+ T cells. Most interestingly, CD4-, CD8+ T cell subset contains both alpha beta TCR+ and gamma delta TCR+ T cells. Other than SMG, IELs possess significant number of gamma delta TCR bearing CD4-, CD8+ T cells. In terms of cytokine producing T cells, SMG contain significant numbers of CD4+ T cells which are capable of producing IL-5 and IFN-gamma. In addition, higher numbers of IL-5 producing Th 2-type cells was always seen in SMG when compared with IFN-gamma secreting Th1-type cells. Therefore, the occurrence of predominant IgA producing cells is associated with the appearance of a higher frequency of IL-5 secreting Th 2-type cells.

Animals↗
PubMed1995

Ig-secreting and interferon-gamma-producing cells in mice mucosally immunized with influenza virus.

1. Oral immunization of mice with influenza virus type A/Udorn, induced antigen-specific IgA antibodies in external secretions (e.g., saliva and fecal extract). 2. Increased numbers of antigen-specific IgA spot-forming cells (SFC) were seen in mononuclear cells isolated from IgA-effector tissues (e.g., SG) of mice orally-immunized with influenza virus. 3. Following oral or systemic immunization of mice, IFN gamma-secreting cells (Th1 type) displayed a characteristic pattern of distribution which was related to the route of immunization.

Administration, Oral↗
PubMed1994

Oral vaccine models: multiple delivery systems employing tetanus toxoid.

We have not yet directly examined the Th cell responses induced by using Salmonella/BRD 847 as a vector nor have we performed these experiments following immunization with microspheres. However, production of high serum levels of antigen-specific IgG1 may be indicative of a Th2-type response, whereas high serum levels of IgG2a may reflect a Th1-type response. An important issue in using various oral delivery systems is whether the system(s) employed affects the Th cell response to the same antigen. We therefore analyzed the serum antigen-specific IgG subclasses induced in each of the model systems we studied. Table 2 presents these results. Clearly, oral administration of soluble TT with CT as an adjuvant induced an IgG1 subclass, and encapsulation of TT within microspheres had no effect on this Th2-type response. On the other hand, oral immunization with live Salmonella expressing fragment C of tetanus toxin induced a strong IgG2a subclass response indicative of a Th1-type response. It should be noted that protection against a lethal TT challenge was afforded by elevated levels of both anti-TT IgG1 and IgG2a subclasses. We intend to examine the cytokine profiles in spleen CD4+ T cells from mice immunized with microspheres or Salmonella following in vitro antigen stimulation to confirm the T helper type responses suggested by the IgG subclass data. It will also be important to examine the cytokine patterns induced in Peyer's patch CD4+ T cells following immunization of C57BL/6 with Salmonella/BRD 847. Whereas analysis of the serum IgG subclass profile indicated a strong IgG2a response and thus a systemic Th1-type pattern, this vector also induced a good mucosal IgA response. If our current hypothesis concerning S-IgA production is correct, we would expect a predominant Th2-type profile in CD4+ T cells from Peyer's patch in these mice. Such a result would emphasize the bifurcation of T-cell responses in the systemic versus the mucosal immune environments. The data obtained to data suggest that adjuvants and various vehicle delivery systems may influence the induction of distinct T helper cell subsets to a specific antigen. The unique cytokine arrays produced by these T-cell subsets influence the immune responses in terms of systemic Ig subclasses produced, cell-mediated immune responses, and the production of mucosal S-IgA antibodies. Although additional studies are necessary, the manipulation of T-cell subsets employing adjuvants, antigen packaging, or perhaps even the addition of individual cytokines to various formulations holds significant promise for optimizing immune responses to orally administered vaccines.

Adjuvants, Immunologic↗
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↗
PubMed1994

Characterization of cytokine-producing cells in mucosal effector sites: CD3+ T cells of Th1 and Th2 type in salivary gland-associated tissues.

The major purpose of this study was to elucidate Th1 [interferon (IFN)-gamma and interleukin (IL)-2] and Th2 (IL-4, IL-5 and IL-6) cytokine-producing CD3+ T cells in salivary glands, which are the major mucosal effector tissues in the oral region. Thus, CD3+ T cells were isolated from salivary gland-associated tissues (SGAT) which consist of the submandibular gland (SMG: approximately 46%), the periglandular lymph node (PGLN: approximately 72%), and the cervical lymph node (CLN: approximately 90%). When SMG CD3+ T cells were examined by Th1 and Th2 cytokine-specific ELISPOT and reverse transcriptase-polymerase chain reaction assay, high levels of both cytokine-specific spot-forming cells (SFC) and mRNA for IFN-gamma, and for IL-5 and IL-6 were noted as representative Th1 or Th2 cytokines, respectively. Following stimulation with concanavalin A (Con A), SMG CD3+ T cells expressed mRNA and produced lymphokines for an array of Th1 (IFN-gamma and IL-2) and Th2 (IL-4, IL-5 and IL-6) cytokines. In comparison to the SMG CD3+ T cells, PGLN and CLN contain lower numbers of IFN-gamma-, IL-5 and IL-6-producing T cells. When these two tissues were compared, PGLN CD3+ T cells contained higher numbers of cytokine-secreting cells than CLN. Further, IL-2 and IL-4 SFC and mRNA were also noted in addition to IFN-gamma, IL-5 and IL-6 after Con A activation. These findings showed that CD3+ T cells in SGAT, especially the SMG, are programmed to produce IFN-gamma, and IL-5 and IL-6 as Th1 and Th2 cytokines, respectively in vivo, although these cells are capable of producing other Th1 and Th2 cytokines after receiving appropriate T cell activation signals.

Animals↗
PubMed1994

The enteric nervous and immune systems: interactions for mucosal immunity and inflammation.

A number of anatomical studies have demonstrated the presence of peptidergic nerve fibers infiltrating mucosal lymphoid tissues. The exact mechanisms of how neuropeptides are released to affect these lymphoid sites are unclear, but radiolabeled binding studies have shown that mucosal leukocytes bear a number of neuropeptide receptors on their cell surfaces capable of responding to neural signals. The presence of neuropeptide-containing fibers and the ability to receive neural signals suggest that mucosal lymphocytes can be influenced by neurogenic mediators. The objectives set forth in this review are to provide what is currently known about the ability of substance P and vasoactive intestinal peptide to promote mucosal IgA responses in the gastrointestinal tract via Th2 mechanisms and to discuss how these neuropeptides contribute to the exacerbation of the inflammatory diseases of the gastrointestinal tract. We describe how immune responses develop in the gastrointestinal immune system and emphasize how neuropeptides may influence the differentiation of lymphocytes in mucosal inductive tissues and their subsequent expression in mucosal effector sites. Finally, we discuss new techniques developed by the Mucosal Immunization Research Group that have enabled the study of mucosal immune responses.

Animals↗
PubMed1994

Helper Th1 and Th2 cell responses following mucosal or systemic immunization with cholera toxin.

We have used the potent mucosal immunogen cholera toxin (CT) to assess antigen-specific CD4+ T-cell responses, including Th1- and Th2-type cells in mucosa-associated tissues, e.g. Peyer's patches (PP), and systemic tissue, e.g. spleen (SP), for their regulatory role in the induction of CT-specific B-cell antibody responses in the gastrointestinal (GI) tract as well as in systemic sites. The CT was given by either oral or intravenous (i.v.) routes and the mice orally immunized with CT exhibited brisk IgA anti-CT antibody responses in faecal extracts and elevated IgG anti-CT antibody responses in serum. Further, significant IgA anti-CT spot-forming cells (SFCs) were seen in lamina propria lymphocytes (LPLs) from mice orally immunized with CT. In contrast, i.v. immunization with CT induced IgM and IgG anti-CT SFC responses in SP, and serum anti-CT antibodies of these two isotypes; no anti-CT responses were induced in the GI tract after immunization by this route. The CD4+ T cells isolated from PP and SP of mice orally immunized with CT were stimulated in vitro with CT-B-coated latex microspheres for 1-6 days, and the induction of IL-2 and interferon gamma (IFN-gamma) (Th1-type) or IL-4 and IL-5 (Th2-type) producing SFCs were analysed by a cytokine-specific ELISPOT and cytokine-specific mRNA was detected by reverse transcriptase (RT)-PCR assays.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1994

Mucosal immunity to infection with implications for vaccine development.

The induction of effective mucosal immunity that also provides systemic immunity is a considerable challenge. Over the past two years, efforts to develop novel mucosal vaccine delivery systems to induce mucosal immunity against bacterial and viral diseases, including HIV, have dramatically increased. Here we cite novel vaccines and delivery systems being used to establish effective mucosal immunity.

Animals↗
PubMed1994

The common mucosal immune system: from basic principles to enteric vaccines with relevance for the female reproductive tract.

The realization that induction of immune responses at mucosal surfaces may prevent colonization, invasion or dissemination of pathogenic microorganisms has spurred intensive efforts to develop vaccines which elicit effective mucosal immunity. In this paper, recent results are discussed for mice given cholera toxin as both an immunogen and as an adjuvant for inducing both humoral and gastrointestinal mucosal immune responses. Oral administration of cholera toxin alone or with a co-administered protein vaccine tetanus toxoid induces a strong T helper type 2 (TH2) cell response in both Peyer's patches and spleen. Both serum IgG and secretory IgA antibodies specific for cholera toxin or for the co-administered protein tetanus toxoid were induced. When administered parentally, however, no mucosal antibody responses were evident and a mixed TH1- and TH2-type CD4+ T cell response was noted in the spleen. Various vectors are being employed in an effort not only to induce mucosal immune responses but also to direct the response to a TH1-type response, thought to promote strong cell-mediated immune responses, or to a TH2-type response for maximum B cell antibody responses. The ability to manipulate the TH cell responses may provide a more rational approach for the design of vaccines. Although lymphoid tissues of the female reproductive tract differ from that of the gut, many of the strategies and evolving principles may be directly applicable to the development of vaccines designed to prevent sexually transmitted diseases.

Administration, Oral↗