Cholera Toxin B Subunit as a Carrier Molecule Promotes Antigen Presentation and Increases CD40 and CD86 Expression on Antigen-Presenting Cells (original) (raw)
Related papers
International Immunology, 1996
Little is known about the mechanism of the immunomodulatory activity of CTB. In this study, both CT and CTB were found to dramatically enhance IL-4 production from a T cell clone stimulated with antigen and the B cell hybridoma LB as antigen-presenting cell (APC). Enhancement of cytokine production was seen following pretreatment of the APC with CT or CTB, while pretreatment of the T cells had no effect. Furthermore, stimulatory activity on the APC was stable to fixation with paraformaldehyde, demonstrating that the activity was mediated by a surface molecule on the APC. CTpretreated APC also enhanced IL-4 production from anti-CD3 mAb-stimulated T cells, indicating that CT was providing a co-stimulatory signal. CT treatment of LB cells did not alter the expression of class II MHC molecules, CTLA-4 counter-receptors, LFA-1 or ICAM-1. When mAb were raised against the CT-pretreated APC, the only antibodies that were found to inhibit IL-4 production were those specific for CTB itself. The antibodies blocked even when the CT or CTB were already bound to the APC, arguing that co-stimulation was provided by a direct interaction with CTB. Blocking experiments suggested that APC-associated CTB molecules are interacting with non-GM1 receptors on the T cells. This novel finding of CTB-mediated T-B interaction provides one of the first potential mechanisms for the adjuvant activity of CTB.
Infection and Immunity, 2003
CT was shown to be a strong adjuvant when it was coadministered to DC with OVA and was even stronger when it was coadministered with OVA-CTB and primed for a mixed Th1-Th2 response. The antibody and T-cell responses were further enhanced if OVA was coupled to CT, implying that CT can utilize a combined carrier and adjuvant function vis-a-vis linked antigens for DC vaccination. The immunopotentiating capacity of CT-and CTB-linked antigen was associated with both upregulated secretion of interleukin-1 by the pulsed DC and increased expression of CD80 and CD86 on the DC surface. These results imply that CT and CTB can be used to both markedly increase and partially direct the DC vaccineinduced immune response with respect to Th1 and Th2 responses, which has obvious implications for DCbased vaccine development.
International Immunology, 2011
Priming of naive CD8 T cells by dendritic cells (DCs) entails both effective antigen presentation on MHC class I products and co-stimulatory signaling. Their optimal coupling is a major goal in the development of CTL-inducing vaccines. We recently reported that a membranal derivative of the invariant MHC-I light chain, b 2-microglobulin (b 2 m), markedly stabilizes MHC-I molecules and can serve as a universal platform for exceptional presentation of genetically linked peptides. To test whether it is possible to equip the resulting MHC-I complexes with an inherent ability to activate antigen-presenting cells, we engrafted the intracellular Toll/IL-1 receptor domain of mouse Toll-like receptor (TLR) 4 or TLR2 onto the peptide-b 2 m scaffold. We evaluated the level of peptide presentation and status of cell activation conferred by such constructs in stably transfected mouse RAW264.7 macrophages and mRNA-transfected mouse DC2.4 DCs. We show that the encoded peptide-b 2 m-TLR polypeptides are expressed at the cell surface, pair with endogenous heavy chains, stabilize MHC-I products, prompt efficient peptide-specific T-cell recognition and confer a constitutively activated phenotype on the transfected cells, as judged by the up-regulation of proinflammatory genes and surface co-stimulatory molecules. Our results provide evidence that the product of a single recombinant gene can couple MHC peptide presentation to TLR-mediated signaling and offer a safe, economical and highly versatile modality for a novel category of genetic CTL-inducing vaccines.
The Journal of Immunology, 2003
Topical application of cholera toxin (CT) onto mouse skin can induce a humoral immune response to CT as well as to coadministered Ags. In this study, we examined the nontoxic cell-binding B subunit of CT (CTB) as a potential adjuvant for cutaneous immune responses when coadministered with the prototype protein Ag, OVA. CTB applied onto skin induced serum Ab responses to itself with magnitudes comparable to those evoked by CT but was poorly efficient at promoting systemic Ab responses to coadministered OVA. However, transcutaneous immunization (TCI) with either CT or CTB and OVA led to vigorous OVAspecific T cell proliferative responses. Furthermore, CTB potentiated Th1-driven responses (IFN-␥ production) whereas CT induced both Th1 and Th2 cytokine production. Coadministration of the toxic subunit CTA, together with CTB and OVA Ag, led to enhanced Th1 and Th2 responses. Moreover, whereas TCI with CT enhanced serum IgE responses to coadministered OVA, CTB suppressed these responses. TCI with either CT or CTB led to an increased accumulation of dendritic cells in the exposed epidermis and the underlying dermis. Thus, in contrast to CT, CTB appears to behave very differently when given by the transcutaneous as opposed to a mucosal route and the results suggest that the adjuvanticity of CT on Th1-and Th2-dependent responses induced by TCI involves two distinct moieties, the B and the A subunits, respectively.
Scandinavian Journal of Immunology, 2007
Sublingual (s.l.) immunotherapy has in the last decade emerged as an effective approach to desensitize patients with pollen, food and insect sting allergies. This treatment has recently also attracted interest as a potential modality to control self-reactive T-cell responses associated with autoimmune disorders. Here, we show that s.l. administration of ovalbumin (OVA) conjugated to cholera toxin B subunit (CTB) (OVA ⁄ CTB) can efficiently suppress peripheral effector T (Teff) cell responses to OVA in mice that had adoptively received OVA-specific T-cell receptor (TCR) transgenic CD4 + T cells, and that the suppression was associated with the development of OVA-specific Foxp3 + CD25 + CD4 + regulatory T (Treg) cells as well as with apoptosis (Annexin V + ) and depletion of OVA-specific Teff cells in peripheral lymph nodes. The induction of Teff cell apoptosis by s.l. OVA ⁄ CTB administration was found to be critically dependent on CD25 + Treg cells but independent of IL-10 production. Our results suggest that s.l administration of a CTB-conjugated antigen can efficiently induce peripheral Teff cell tolerance through the induction of antigen-specific Treg cells that both inhibit Teff cell proliferation and cytokine production and induce Teff cell apoptosis and depletion.
Vaccine, 2001
We recently developed a novel immunomodulating gene fusion protein, CTA1-DD, that combines the ADP-ribosylating ability of cholera toxin (CT) with a dimer of an Ig-binding fragment, D, of Staphylococcus aureus protein A. The CTA1-DD adjuvant was found to be non-toxic and greatly augmented T cell dependent and independent responses. Following injection it binds to both naïve and memory B cells and up-regulates co-stimulatory molecules as well as prevents apoptosis of activated B cells. Here we show that CTA1-DD is a potent mucosal adjuvant administered intranasally. A dose-response analysis revealed that the adjuvant effect of CTA1-DD given intranasally was equally strong to that observed after systemic immunizations. The adjuvant effect was independent of any possible contamination with endotoxin as indicated by the similar enhancing effects of CTA1-DD in C3H/HeN and the LPS-insensitive C3H/HeJ mice. Contrary to many other adjuvants CTA1-DD induces an immune response to itself. Howe...
European Journal of Immunology, 2004
We previously demonstrated that cholera toxin (CT) is highly efficient as a combined carrier and adjuvant for dendritic cell (DC) vaccination, inducing strong Th1-dominated B cell and CD4 + T cell responses. In this study we show that vaccination with DC pre-pulsed ex vivo with CT-conjugated OVA (OVA-CT) gives rise to OVA-specific CD8 + T cells that produce IFN-+ and are cytotoxic for OVA-expressing E.G7 tumor cells both in vitro and in vivo. The induction of specific CD8 + CTL by OVA-CT-treated DC was associated with enhanced presentation of OVA peptide (SIINFEKL) on MHC class I in combination with an overall activation of the pulsed DC. Vaccination of mice with OVA-CT-pulsed DC resulted in rejection of already established MHC class I-positive, MHC class II-negative, OVA-expressing E.G7 tumors in an antigen-specific, CD8 + T cell-dependent fashion and was associated with high numbers of tumor-infiltrating CD8 + T cells. Conjugation of antigen to CT facilitated DC uptake of the linked antigen through the GM1 receptor-binding B subunit and induced strong activationmaturation signals through the biologically active A subunit. These results have interesting implications for DC vaccination aimed at inducing CTL immune responses. Abbreviations: CT: Cholera toxin CTB: Cholera toxin B subunit OVA-CT: CT-conjugated OVA OVA-CTB: CTBconjugated OVA PGE2: Prostaglandin E2 1272 K. Eriksson et al.
Cholera toxin B subunit modulation of mucosal vaccines for infectious and autoimmune diseases
Current opinion in investigational drugs (London, England : 2000), 2010
Parenteral vaccination is generally considered to be the most effective form of therapy for protection against infectious diseases. In recent years, vaccination at mucosal surfaces and combinatorial vaccination strategies that link immunostimulatory molecules to antigens have been developed to enhance vaccine efficacy. Prominent among immunological enhancement strategies are the bacterial A and B toxins, which include the cholera toxin (CT)A and CTB subunits. In contrast to the toxic CTA subunit, the non-toxic CTB subunit displays both carrier and immunostimulatory properties. When linked to pathogen antigens, CTB can impart immunostimulatory properties that are characteristic of the linked antigen. Vaccination strategies have also been broadened to include 'self' proteins applied for the immunological suppression of autoimmunity. When CTB is linked to an autoantigen, the outcome might be considered paradoxical. In type 1 diabetes, self proteins become strongly immunosuppres...