| 1. |
- Velasquez, L. N., et al.
(författare)
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Targeting Mycobacterium tuberculosis Antigens to Dendritic Cells via the DC-Specific-ICAM3-Grabbing-Nonintegrin Receptor Induces Strong T-Helper 1 Immune Responses
- 2018
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Tuberculosis remains a major global health problem and efforts to develop a more effective vaccine have been unsuccessful so far. Targeting antigens (Ags) to dendritic cells (DCs) in vivo has emerged as a new promising vaccine strategy. In this approach, Ags are delivered directly to DCs via antibodies that bind to endocytic cell-surface receptors. Here, we explored DC-specific-ICAM3-grabbing-nonintegrin (DC-SIGN) targeting as a potential vaccine against tuberculosis. For this, we made use of the hSIGN mouse model that expresses human DC-SIGN under the control of the murine CD11c promoter. We show that in vitro and in vivo delivery of anti-DC-SIGN antibodies conjugated to Ag85B and peptide 25 of Ag85B in combination with anti-CD40, the fungal cell wall component zymosan, and the cholera toxin-derived fusion protein CTA1-DD induces strong Ag-specific CD4(+) T-cell responses. Improved anti-mycobacterial immunity was accompanied by increased frequencies of Ag-specific IFN-gamma(+) IL-2(+) TNF-alpha(+) polyfunctional CD4(+) T cells in vaccinated mice compared with controls. Taken together, in this study we provide the proof of concept that the human DC-SIGN receptor can be efficiently exploited for vaccine purposes to promote immunity against mycobacterial infections.
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| 2. |
- Agrawal, K., et al.
(författare)
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Allergic sensitization impairs lung resident memory CD8 T-cell response and virus clearance
- 2022
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749. ; 150:6
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with asthma often suffer from frequent respiratory viral infections and reduced virus clearance. Lung resident memory T cells provide rapid protection against viral reinfections. Objective: Because the development of resident memory T cells relies on the lung microenvironment, we investigated the impact of allergen sensitization on the development of virus-specific lung resident memory T cells and viral clearance. Methods: Mice were sensitized with house dust mite extract followed by priming with X47 and a subsequent secondary influenza infection. Antiviral memory T-cell response and protection to viral infection was assessed before and after secondary influenza infection, respectively. Gene set variation analysis was performed on data sets from the U-BIOPRED asthma cohort using an IFN-γ–induced epithelial cell signature and a tissue resident memory T-cell signature. Results: Viral loads were higher in lungs of sensitized compared with nonsensitized mice after secondary infection, indicating reduced virus clearance. X47 priming induced fewer antiviral lung resident memory CD8 T cells and resulted in lower pulmonary IFN-γ levels in the lungs of sensitized as compared with nonsensitized mice. Using data from the U-BIOPRED cohort, we found that patients with enrichment of epithelial IFN-γ–induced genes in nasal brushings and bronchial biopsies were also enriched in resident memory T-cell–associated genes, had more epithelial CD8 T cells, and reported significantly fewer exacerbations. Conclusions: The allergen-sensitized lung microenvironment interferes with the formation of antiviral resident memory CD8 T cells in lungs and virus clearance. Defective antiviral memory response might contribute to increased susceptibility of patients with asthma to viral exacerbations.
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| 3. |
- Akhiani, Aliasghar, 1957, et al.
(författare)
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Helicobacter pylori-Specific Antibodies Impair the Development of Gastritis, Facilitate Bacterial Colonization, and Counteract Resistance against Infection
- 2004
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Ingår i: Journal of Immunology. - 1550-6606. ; 172:8, s. 5024-5033
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, Abs have been considered a correlate rather than an effector of resistance against Helicobacter pylori infection. However, it is still poorly understood to what extent Ab production correlates with gastric immunopathology. Here we report that Abs not only are dispensable for protection, but they are detrimental to elimination of the bacteria and appear to impair gastric inflammatory responses. We found that the initial colonization with H. pylori bacteria was normal in the B cell-deficient ( micro MT) mice, whereas at later times (>8 wk) most of the bacteria were cleared, concomitant with the development of severe gastritis. In contrast, wild-type (WT) mice exhibited extensive bacterial colonization and only mild gastric inflammation, even at 16 wk after inoculation. Oral immunizations with H. pylori lysate and cholera toxin adjuvant stimulated comparable levels of protection in micro MT and WT mice. The level of protection in both strains correlated well with the severity of the postimmunization gastritis. Thus, T cells were responsible for the gastritis, whereas Abs, including potentially host cell cross-reactive Abs, were not involved in causing the gastritis. The T cells in micro MT and WT mice produced high and comparable levels of IFN-gamma to recall Ag at 2 and after 8 wk, whereas IL-4 was detected after 8 wk only, indicating that Th1 activity dominated the early phase of protection, whereas later a mixed Th1 and Th2 activity was seen.
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| 4. |
- Akhiani, Aliasghar, 1957, et al.
(författare)
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IgA antibodies impair resistance against Helicobacter pylori infection: studies on immune evasion in IL-10-deficient mice.
- 2005
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - 0022-1767. ; 174:12, s. 8144-53
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Tidskriftsartikel (refereegranskat)abstract
- We recently reported that Helicobacter pylori-specific Abs impair the development of gastritis and down-regulate resistance against H. pylori infection. In this study, we asked whether IgA Abs specifically can have an impact on H. pylori colonization and gastric inflammation. To obtain a sensitive model for the study of inflammation we crossed IgA- and IL-10-deficient mice. We found that IL-10(-/-)/IgA(-/-) mice were significantly less colonized than IL-10(-/-)/IgA(+/+) mice, which in turn were less colonized than wild-type (WT) mice. The IL-10(-/-)/IgA(-/-) mice exhibited a 1.2-log reduction in bacterial counts compared with that in IL-10(-/-)/IgA(+/+) mice, suggesting that IgA Abs rather promoted than prevented infection. The reduced colonization in IL-10(-/-)/IgA(-/-) mice was associated with the most severe gastritis observed, albeit all IL-10(-/-) mice demonstrated more severe gastric inflammation than wild-type mice. The gastritis score and the infiltration of CD4(+) T cells into the gastric mucosa were significantly higher in IL-10(-/-)/IgA(-/-) mice than in IL-10(-/-)/IgA(+/+) mice, arguing that IgA Abs counteracted inflammation. Moreover, following oral immunization, IL-10(-/-)/IgA(-/-) mice were significantly better protected against colonization than IL-10(-/-)/IgA(+/+) mice. However, the stronger protection was associated with more severe postimmunization gastritis and gastric infiltration of CD4(+) T cells. There was also a clear increase in complement receptor-expressing cells in IL-10(-/-)/IgA(-/-) mice, though C3b-fragment deposition in the gastric mucosa was comparable between the two. Finally, specific T cell responses to recall Ag demonstrated higher levels of IFN-gamma production in IL-10(-/-)/IgA(-/-) as compared with IL-10(-/-)/IgA(+/+) mice. Thus, it appears that IgA and IL-10 help H. pylori bacteria evade host resistance against infection.
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| 5. |
- Akhiani, Aliasghar, 1957, et al.
(författare)
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Lack of interferon-gamma receptor does not influence the outcome of infection in murine schistosomiasis mansoni
- 1996
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Ingår i: Scand J Immunol. ; 43:3, s. 257-62
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Tidskriftsartikel (refereegranskat)abstract
- Studies of vaccine-induced immunity in experimental schistosomiasis in mice have suggested that interferon-gamma (IFN-gamma) is an important factor for the induction of protective immunity against schistosomiasis. The present study compares some parameters during primary schistosome infection in IFN-gamma receptor deficient mice and wild type mice. No significant difference in worm burden between the two groups was found. Almost the same number of eggs in the liver as well as typical granulomas with numerous macrophages and eosinophils were observed in both groups of mice. Furthermore, IFN-gamma receptor deficient mice infected with S. mansoni displayed a significant reduction in the number of IgG2a secreting cells in the spleen and a significant enhancement of IgA secreting cells in the spleen and in the lungs. These findings suggest that the lack of IFN-gamma activity may result in an enhanced dominance of Th2 cells which, however, does not influence the development of a primary schistosome infection.
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| 6. |
- Akhiani, Aliasghar, 1957, et al.
(författare)
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Protection against Helicobacter pylori infection following immunization is IL-12-dependent and mediated by Th1 cells
- 2002
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Ingår i: J Immunol. ; 169:12, s. 6977-84
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Tidskriftsartikel (refereegranskat)abstract
- The regulatory roles of Th1 and Th2 cells in immune protection against Helicobacter infection are not clearly understood. In this study, we report that a primary H. pylori infection can be established in the absence of IL-12 or IFN-gamma. However, IFN-gamma, but not IL-12, was involved in the development of gastritis because IFN-gamma(-/-) (GKO) mice exhibited significantly less inflammation as compared with IL-12(-/-) or wild-type (WT) mice. Both IL-12(-/-) and GKO mice failed to develop protection following oral immunization with H. pylori lysate and cholera toxin adjuvant. By contrast, Th2-deficient, IL-4(-/-), and WT mice were equally well protected. Mucosal immunization in the presence of coadministered rIL-12 in WT mice increased Ag-specific IFN-gamma-producing T cells by 5-fold and gave an additional 4-fold reduction in colonizing bacteria, confirming a key role of Th1 cells in protection. Importantly, only protected IL-4(-/-) and WT mice demonstrated substantial influx of CD4(+) T cells in the gastric mucosa. The extent of inflammation in challenged IL-12(-/-) and GKO mice was much reduced compared with that in WT mice, indicating that IFN-gamma/Th1 cells also play a major role in postimmunization gastritis. Of note, postimmunization gastritis in IL-4(-/-) mice was significantly milder than WT mice, despite a similar level of protection, indicating that immune protection is not directly linked to the degree of gastric inflammation. Only protected mice had T cells that produced high levels of IFN-gamma to recall Ag, whereas both protected and unprotected mice produced high levels of IL-13. We conclude that IL-12 and Th1 responses are crucial for H. pylori-specific protective immunity.
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| 7. |
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| 8. |
- Akhiani, Aliasghar, 1957, et al.
(författare)
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The nontoxic CTA1-DD adjuvant enhances protective immunity against Helicobacter pylori infection following mucosal immunization.
- 2006
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Ingår i: Scandinavian journal of immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 63:2, s. 97-105
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Tidskriftsartikel (refereegranskat)abstract
- Safe and efficacious adjuvants are much needed to facilitate the development of mucosal vaccines. Here, we have asked whether our nontoxic vaccine adjuvant, CTA1-DD, can enhance protective immunity against Helicobacter pylori infection. Intranasal immunizations with H. pylori lysate together with CTA1-DD-adjuvant induced significant protection in C57Bl/6 mice, almost as strong as similar immunizations using cholera toxin (CT)-adjuvant. Protection remained strong even at 8 weeks postchallenge and the bacterial colonization was reduced by 20-fold compared to lysate-immunized controls. Although CTA1-DD was designed to bind to B cells, microMT mice developed significant, but lower, level of protection following immunization. Intranasal immunizations with CT adjuvant in C57Bl/6 mice resulted in the development of severe postimmunization gastritis at 2 and 8 weeks postchallenge, whereas the degree of gastritis was substantially lower in the CTA1-DD-immunized mice. Protection induced by both CTA1-DD- and CT adjuvant was associated with a strong local infiltration of CD4(+) T cells in the gastric mucosa, and recall responses to specific Ag elicited substantial IFN-gamma production, indicating Th1-dominance. These findings clearly demonstrate that CTA1-DD adjuvant is a promising candidate to be further exploited in the development of a mucosal vaccine against H. pylori infection.
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| 9. |
- Akhiani, Aliasghar, 1957, et al.
(författare)
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Vaccine-induced immunity against Helicobacter pylori infection is impaired in IL-18-deficient mice.
- 2004
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Ingår i: Journal of immunology. - 0022-1767. ; 173:5, s. 3348-56
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Forskningsöversikt (refereegranskat)abstract
- Protective immunity against Helicobacter pylori infection in mice has been associated with a strong Th1 response, involving IL-12 as well as IFN-gamma, but recent studies have also demonstrated prominent eosinophilic infiltration, possibly linked to local Th2 activity in the gastric mucosa. In this study we investigated the role of IL-18, because this cytokine has been found to be a coregulator of Th1 development as well as involved in Th2-type responses with local eotaxin production that could influence gastric eosinophilia and resistance to infection. We found that IL-18(-/-) mice failed to develop protection after oral immunization with H. pylori lysate and cholera toxin adjuvant, indicating an important role of IL-18 in protection. Well-protected C57BL/6 wild-type (WT) mice demonstrated substantial influx of CD4(+) T cells and eosinophilic cells in the gastric mucosa, whereas IL-18(-/-) mice had less gastritis, few CD4(+) T cells, and significantly reduced numbers of eosinophilic cells. T cells in well-protected WT mice produced increased levels of IFN-gamma and IL-18 to recall Ag. By contrast, unprotected IL-18(-/-) mice exhibited significantly reduced gastric IFN-gamma and specific IgG2a Ab levels. Despite differences in gastric eosinophilic cell infiltration, protected WT and unprotected IL-18(-/-) mice had comparable levels of local eotaxin, suggesting that IL-18 influences protection via Th1 development and IFN-gamma production rather than through promoting local production of eotaxin and eosinophilic cell infiltration.
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| 10. |
- Albutti, A., et al.
(författare)
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Type II NKT cell agonist, sulfatide, is an effective adjuvant for oral heat-killed cholera vaccines
- 2021
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Ingår i: Vaccines. - : MDPI AG. - 2076-393X. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- Oral vaccination has the potential to offer a safer and more efficacious approach for protection against enteric pathogens than injection-based approaches, especially in developing countries. One key advantage is the potential to induce intestinal immune responses in addition to systemic immunity. In general, antigen delivery via the oral route triggers weak immune responses or immunological tolerance. The effectiveness of oral vaccination can be improved by co-administering adjuvants. However, a major challenge is the absence of potent and safe oral adjuvants for clinical application. Here, the Type II NKT cell activator sulfatide is shown for the first time to be an effective oral adjuvant for Vibrio cholerae vaccine antigens in a mouse model. Specifically, administration of sulfatide with the oral cholera vaccine Dukoral® resulted in enhancement of intestinal antigen-specific IgA in addition to Th1 and Th17 immune responses. In summary, sulfatide is a promising adjuvant for inclusion in an oral cholera vaccine and our data further support the potential of adjuvants targeting NKT cells in new vaccine strategies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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