scholarly journals Dissecting the contribution of O-Antigen and proteins to the immunogenicity of Shigella sonnei generalized modules for membrane antigens (GMMA)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francesca Mancini ◽  
Gianmarco Gasperini ◽  
Omar Rossi ◽  
Maria Grazia Aruta ◽  
Maria Michelina Raso ◽  
...  
Keyword(s):  
Protective Immunity ◽  
Critical Role ◽  
Shigella Sonnei ◽  
Added Value ◽  
Protein Antigens ◽  
Outer Membranes ◽  
O Antigen ◽  
Membrane Antigens ◽  
Specific Igg

AbstractGMMA are exosomes released from engineered Gram-negative bacteria resembling the composition of outer membranes. We applied the GMMA technology for the development of an O-Antigen (OAg) based vaccine against Shigella sonnei, the most epidemiologically relevant cause of shigellosis. S. sonnei OAg has been identified as a key antigen for protective immunity, and GMMA are able to induce anti-OAg-specific IgG response in animal models and healthy adults. The contribution of protein-specific antibodies induced upon vaccination with GMMA has never been fully elucidated. Anti-protein antibodies are induced in mice upon immunization with either OAg-negative and OAg-positive GMMA. Here we demonstrated that OAg chains shield the bacteria from anti-protein antibody binding and therefore anti-OAg antibodies were the main drivers of bactericidal activity against OAg-positive bacteria. Interestingly, antibodies that are not targeting the OAg are functional against OAg-negative bacteria. The immunodominant protein antigens were identified by proteomic analysis. Our study confirms a critical role of the OAg on the immune response induced by S. sonnei GMMA. However, little is known about OAg length and density regulation during infection and, therefore, protein exposure. Hence, the presence of protein antigens on S. sonnei GMMA represents an added value for GMMA vaccines compared to other OAg-based formulations.

scholarly journals Effector CD8+ T Lymphocytes against Liver Stages of Plasmodium yoelii Do Not Require Gamma Interferon for Antiparasite Activity

2008 ◽  
Vol 76 (8) ◽  
pp. 3628-3631 ◽  
Author(s):  
Sumana Chakravarty ◽  
G. Christian Baldeviano ◽  
Michael G. Overstreet ◽  
Fidel Zavala
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protective Immunity ◽  
Critical Role ◽  
Plasmodium Yoelii ◽  
Gamma Interferon ◽  
Parasite Development ◽  
Wild Type ◽  
Ifn Γ

ABSTRACT The protective immune response against liver stages of the malaria parasite critically requires CD8+ T cells. Although the nature of the effector mechanism utilized by these cells to repress parasite development remains unclear, a critical role for gamma interferon (IFN-γ) has been widely assumed based on circumstantial evidence. However, the requirement for CD8+ T-cell-mediated IFN-γ production in protective immunity to this pathogen has not been directly tested. In this report, we use an adoptive transfer strategy with circumsporozoite (CS) protein-specific transgenic T cells to examine the role of CD8+ T-cell-derived IFN-γ production in Plasmodium yoelii-infected mice. We show that despite a marginal reduction in the expansion of naive IFN-γ-deficient CS-specific transgenic T cells, their antiparasite activity remains intact. Further, adoptively transferred IFN-γ-deficient CD8+ T cells were as efficient as their wild-type counterparts in limiting parasite growth in naive mice. Taken together, these studies demonstrate that IFN-γ secretion by CS-specific CD8+ T cells is not essential to protect mice against live sporozoite challenge.

Protective immunity to erythrocytic Plasmodium chabaudi AS infection involves IFNγ-mediated responses and a cellular infiltrate to the liver

Parasitology ◽  
2000 ◽  
Vol 121 (5) ◽  
pp. 473-482 ◽  
Author(s):  
P. BALMER ◽  
J. ALEXANDER ◽  
R. S. PHILLIPS
Keyword(s):  
Mortality Rate ◽  
Adoptive Transfer ◽  
Protective Immunity ◽  
No Reduction ◽  
Cytological Analysis ◽  
Plasmodium Chabaudi ◽  
Cellular Infiltrate ◽  
Specific Igg ◽  
Deficient Mice

IFNγ receptor (IFNγR) deficient mice and IL-4 deficient mice were infected with blood-stage Plasmodium chabaudi AS in order to analyse the role of Th1 (IFNγ) and Th2 (IL-4)-associated cytokines in the development of protective immunity to the parasite. A high mortality rate and failure to reduce the primary parasitaemia to subpatent levels was observed in the IFNγR deficient mice. IL-4 deficient mice controlled a primary P. chabaudi AS infection in a similar manner to control mice and no mortality was observed. IFNγR deficient mice had a reduction in parasite-specific IgG and a significantly increased level of total IgE compared to control mice. There was no reduction in the level of parasite-specific IgG in IL-4 deficient mice. Cytological analysis of the cells present in the spleen and liver during the primary parasitaemia revealed a reduction in the numbers of lymphocytes, monocytes and polymorphonuclear (PMN) cells in the liver at the peak of parasitaemia in both IFNγR deficient mice and IL-4 deficient mice compared to control mice. Adoptive transfer studies demonstrated that cells isolated from the liver at day 11 post-infection could confer some protective immunity to P. chabaudi AS infection.

scholarly journals Role of TNF-Alpha, IFN-Gamma, and IL-10 in the Development of Pulmonary Tuberculosis

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Yone Vila Nova Cavalcanti ◽  
Maria Carolina Accioly Brelaz ◽  
Juliana Kelle de Andrade Lemoine Neves ◽  
José Candido Ferraz ◽  
Valéria Rêgo Alves Pereira
Keyword(s):  
Immune Response ◽  
Protective Immunity ◽  
Critical Role ◽  
Tnf Alpha ◽  
Infection Site ◽  
Ifn Gamma ◽  
Major Function ◽  
Reactive Nitrogen Intermediates ◽  
Th1 And Th2 Responses

Host immune response againstMycobacterium tuberculosisis mediated by cellular immunity, in which cytokines and Th1 cells play a critical role. In the process of control of the infection by mycobacteria, TNF-alpha seems to have a primordial function. This cytokine acts in synergy with IFN-gamma, stimulating the production of reactive nitrogen intermediates (RNIs), thus mediating the tuberculostatic function of macrophages, and also stimulating the migration of immune cells to the infection site, contributing to granuloma formation, which controls the disease progression. IFN-gamma is the main cytokine involved in the immune response against mycobacteria, and its major function is the activation of macrophages, allowing them to exert its microbicidal role functions. Different from TNF-alpha and IFN-gamma, IL-10 is considered primarily an inhibitory cytokine, important to an adequate balance between inflammatory and immunopathologic responses. The increase in IL-10 levels seems to support the survival of mycobacteria in the host. Although there is not yet conclusive studies concerning a clear dichotomy between Th1 and Th2 responses, involving protective immunity and susceptibility to the disease, respectively, we can suggest that the knowledge about this responses based on the prevailing cytokine profile can help to elucidate the immune response related to the protection againstM. tuberculosis.

scholarly journals The potential roles of herpesvirus and cytomegalovirus in the exacerbation of pemphigus vulgaris

2018 ◽  
pp. 262-271 ◽  
Author(s):  
Farhad Mohammadi ◽  
Zahra Khalili ◽  
Sayed Mahdi Marashi ◽  
Amirhoushang Ehsani ◽  
Maryam Daneshpazhooh ◽  
...  
Keyword(s):  
Critical Role ◽  
Pemphigus Vulgaris ◽  
Demographic Variables ◽  
Enzyme Linked Immunosorbent Assay ◽  
Significant Difference ◽  
Autoimmune Conditions ◽  
Specific Igg ◽  
Microbial Agents ◽  
Control Study

Background: Among exogenous etiologies, the critical role of microbial agents such as herpesviruses (HSV1/2) and cytomegalovirus (CMV) in triggering and flaring autoimmune conditions such as pemphigus vulgaris (PV) has been recently discovered. Objectives: The present study aimed to investigate the plausible role of these viruses in the exacerbation of PV using serological and molecular methods. Patients/Methods: Sixty patients with PV (30 with relapse type and 30 with remission type) were recruited for the purpose of this case-control study. Skin, mucosal, and throat specimens were obtained and examined for viruses by reverse transcriptase polymerase chain reaction. To determine the immunoglobulin G (IgG) titer, enzyme-linked immunosorbent assay was used. Results: Desmoglein1-specific IgG was positive in 56.7% of patients with the relapse form and in 20.0% of those with the remission form indicating a significant difference across the 2 groups (P = 0.003), but the rate of positivity for desmoglein3-specific IgG in the relapse and remission types was 76.7% and 63.3%, respectively, with no significant difference (P = 0.260). There was no difference in the mean levels of HSV-IgG and CMV-IgG in the relapse and remission groups. HSV and CMV positivity in PV patients was independent of the site of the samples. Using the multivariable linear regression model, the level of CMV-IgG in PV patients was directly affected by female sex and advanced ages. Conclusions: Our study could not demonstrate the role of HSV1/2 and CMV as triggering factors for PV exacerbation. Further studies are needed to evaluate the potential role of these viruses in PV exacerbation especially considering demographic variables.

scholarly journals Identification of the lipopolysaccharide O‐antigen biosynthesis priming enzyme and the O‐antigen ligase in Myxococcus xanthus : critical role of LPS O‐antigen in motility and development

2019 ◽  
Vol 112 (4) ◽  
pp. 1178-1198 ◽  
Author(s):  
María Pérez‐Burgos ◽  
Inmaculada García‐Romero ◽  
Jana Jung ◽  
Miguel A. Valvano ◽  
Lotte Søgaard‐Andersen
Keyword(s):  
Myxococcus Xanthus ◽  
Critical Role ◽  
O Antigen

scholarly journals Short Communication: Some Observations on the Role of Bradykinin in Immunity toTeladorsagia circumcinctain Sheep

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Andrew R. Williams
Keyword(s):  
Smooth Muscle ◽  
Mast Cells ◽  
Muscle Contraction ◽  
Protective Immunity ◽  
Short Communication ◽  
Smooth Muscle Contraction ◽  
Teladorsagia Circumcincta ◽  
Specific Igg ◽  
Allergic Disorders

Bradykinin is a physiologically active peptide involved in vasodilation and smooth muscle contraction and is previously shown to be increased in gastrointestinal mucus during nematode challenge in sheep. Here, it is shown that bradykinin in the abomasum is positively correlated with both mast cells and globule leukocytes in the abomasum, and that all three of these parameters are negatively associated with numbers of adultTeladorsagia circumcinctaduring the challenge of immune sheep. It is suggested that bradykinin either stimulates the degranulation of mast cells, or is released during this degranulation process, or both. Multiple regression showed that almost 60% of the variation of in adultT. circumcinctacould be explained by two variables, bradykinin andT. circumcincta—specific IgG1in plasma. This provides further evidence that bradykinin may be a mechanism of protective immunity in sheep, although its involvement in asthma and other allergic disorders raises questions about its role in unwanted immunopathology.

Sign in / Sign up

Export Citation Format

Share Document