• Invasion and intracellular survival of Bordetella bronchiseptica in mouse dendritic cells.

      Guzman, C A; Rohde, Manfred; Bock, M; Timmis, K N (1994-12)
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    • Local treatment with BPPcysMPEG reduces allergic airway inflammation in sensitized mice.

      Knothe, S; Mutschler, V; Rochlitzer, S; Winkler, C; Ebensen, T; Guzman, C A; Hohlfeld, J; Braun, A; Muller, M; Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Department of Immunology, Allergology and Immunotoxicology, Hannover, Germany. (2011-07-07)
      According to the hygiene hypothesis, triggering the immune system with microbial components during childhood balances the inherent Th2 bias. In contrast, specific immunotherapy involves exposure of the patient to the allergen in order to achieve desensitization to subsequent contact. In a human in vitro allergy model the potential of the TLR2/6 agonist BPPcysMPEG to modulate antigen presenting cells and allergen-specific immune responses was evaluated. Specific immunomodulation via co-administration of the allergen and BPPcysMPEG enhanced expression of co-stimulatory molecules on DC and increased secretion of the proinflammatory cytokine TNF-α. Acting as an adjuvant, BPPcysMPEG elevated allergen-specific immune responses in co-culture with autologous lymphocytes. Although administration of BPPcysMPEG alone enhanced expression of co-stimulatory molecules on DC, proliferation of autologous lymphocytes was not induced. Based on this finding, the potential of BPPcysMPEG to reduce allergic airway inflammation by preventive modulation of the innate immune system via TLR2/6 agonization was investigated in mice. Local administration of BPPcysMPEG altered cellular influx and cell composition in BAL fluid. Furthermore, the Th2-associated cytokines IL-4 and IL-5 were diminished. Allergen-specific restimulation of cells from mediastinal lymph nodes and splenocytes suggested an alteration of immune responses. The treatment with BPPcysMPEG induced a Th1-dominated cytokine milieu in mediastinal lymph nodes, while allergen-specific immune responses in splenocytes were diminished. The co-administration of allergen and BPPcysMPEG reduced cytokine secretion upon restimulation in mediastinal lymph nodes and splenocytes. From these data we conclude that BPPcysMPEG was able to influence the immune system with regard to subsequent allergen contact by TLR2/6 agonization.
    • The NKT cell ligand αgalactosylceramide suppresses allergic airway inflammation by induction of a Th1 response.

      Knothe, S; Mutschler, V; Rochlitzer, S; Winkler, C; Ebensen, T; Guzman, C A; Hohlfeld, J; Braun, A; Muller, M; Fraunhofer Institute for Toxicology and Experimental Medicine, Department of Immunology, Allergology and Immunotoxicology, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany. (2011-06-06)
      One experimental approach for the treatment of allergic reactions is the stimulation of immunoregulatory NKT cells with the synthetic glycolipid αgalactosylceramide. For a first evaluation of the immunomodulatory potential of αGalCerMPEG a human in vitro allergy model was exploited. Acting as an adjuvant, the glycolipid induced an enhanced Th1-biased allergen-specific immune response of autologous lymphocytes. In a mouse model of allergic airway inflammation, αGalCerMPEG-activated NKT cells promoted a cytokine environment in the spleen, leading to priming of Th1 cells. The shift towards a Th1-dominated allergen-specific immune response thus might mediate the abrogation of allergic airway inflammation and thereby might provide a valid option for therapeutic intervention.
    • Peptidoglycan-treated tumor antigen-pulsed dendritic cells impart complete resistance against tumor rechallenge.

      Patidar, A; Selvaraj, S; Chauhan, P; Guzman, C A; Ebensen, T; Sarkar, A; Chattopadhyay, D; Saha, B (2020-06-26)
    • Superior immunogenicity of HCV envelope glycoproteins when adjuvanted with cyclic-di-AMP, a STING activator or archaeosomes.

      Landi, A; Law, J; Hockman, D; Logan, M; Crawford, K; Chen, C; Kundu, J; Ebensen, T; Guzman, C A; Deschatelets, L; et al. (2017-12-15)
      Three decades after the discovery, hepatitis C virus (HCV) is still the leading cause of liver transplantation and poses a major threat to global health. In spite of recent advances in the development of direct acting antivirals, there is still a need for a prophylactic vaccine to limit the virus spread and protect at-risk populations, especially in developing countries, where the cost of the new treatments may severely limit access. The use of recombinant HCV glycoproteins E1E2 (rE1E2) in combination with the MF59, an oil-in-water emulsion-based adjuvant, has previously been shown to reduce the rate of chronicity in chimpanzees and to induce production of cross-neutralizing antibodies and cellular immune responses in human volunteers. To further improve neutralizing antibody responses in recipients along with robust T cell responses, we have explored the immunogenicity of different adjuvants when formulated with the HCV rE1E2 vaccine in mice. Our data show that cyclic di-adenosine monophosphate (c-di-AMP) and archaeosomes elicit strong neutralizing antibodies similar to those elicited using aluminum hydroxide/monophosphoryl lipid A (Alum/monophos. /MPLA) and MF59. However, both c-di-AMP and archaeosomes induced a more robust cellular immune response, which was confirmed by the detection of vaccine-specific poly-functional CD4+ T cells. We conclude that these adjuvants may substantially boost the immunogenicity of our E1E2 vaccine. In addition, our data also indicates that use of a partial or exclusive intranasal immunization regimen may also be feasible using c-di-AMP as adjuvant.