Search results for "Virology"
showing 10 items of 2354 documents
Molecular basis of early epithelial response to streptococcal exotoxin: role of STIM1 and Orai1 proteins
2011
Streptolysin O (SLO) is a cholesterol-dependent cytolysin (CDC) from Streptococcus pyogenes. SLO induces diverse types of Ca(2+) signalling in host cells which play a key role in membrane repair and cell fate determination. The mechanisms behind SLO-induced Ca(2+) signalling remain poorly understood. Here, we show that in NCI-H441 cells, wild-type SLO as well as non-pore-forming mutant induces long-lasting intracellular Ca(2+) oscillations via IP(3) -mediated depletion of intracellular stores and activation of store-operated Ca(2+) (SOC) entry. SLO-induced activation of SOC entry was confirmed by Ca(2+) add-back experiments, pharmacologically and by overexpression as well as silencing of ST…
Clinical significance of the polymerase chain reaction (PCR) assay in chronic HBV carriers
1992
PCR was evaluated as a clinical tool for use in accurate identification of the specific etiologic agent in chronic HBV carriers. The method was found to be valuable in diagnosis and for monitoring therapy, as well as for elucidation of genotypic variants of HBV in chronic HBV cases. By this means an HBV defective variant with alterations in the preSl/preS2 sequence was detected and is consequently described here.
TLR7 controls VSV replication in CD169(+) SCS macrophages and associated viral neuroinvasion
2019
Vesicular stomatitis virus (VSV) is an insect-transmitted rhabdovirus that is neurovirulent in mice. Upon peripheral VSV infection, CD169+ subcapsular sinus (SCS) macrophages capture VSV in the lymph, support viral replication, and prevent CNS neuroinvasion. To date, the precise mechanisms controlling VSV infection in SCS macrophages remain incompletely understood. Here, we show that Toll-like receptor-7 (TLR7), the main sensing receptor for VSV, is central in controlling lymph-borne VSV infection. Following VSV skin infection, TLR7−/− mice display significantly less VSV titers in the draining lymph nodes (dLN) and viral replication is attenuated in SCS macrophages. In contrast to effects o…
Neutrophils: Between host defence, immune modulation, and tissue injury.
2015
Neutrophils, the most abundant human immune cells, are rapidly recruited to sites of infection, where they fulfill their life-saving antimicrobial functions. While traditionally regarded as short-lived phagocytes, recent findings on long-term survival, neutrophil extracellular trap (NET) formation, heterogeneity and plasticity, suppressive functions, and tissue injury have expanded our understanding of their diverse role in infection and inflammation. This review summarises our current understanding of neutrophils in host-pathogen interactions and disease involvement, illustrating the versatility and plasticity of the neutrophil, moving between host defence, immune modulation, and tissue da…
How the knowledge of interactions between meningococcus and the human immune system has been used to prepare effective Neisseria meningitidis vaccines
2015
In the last decades, tremendous advancement in dissecting the mechanisms of pathogenicity ofNeisseria meningitidisat a molecular level has been achieved, exploiting converging approaches of different disciplines, ranging from pathology to microbiology, immunology, and omics sciences (such as genomics and proteomics). Here, we review the molecular biology of the infectious agent and, in particular, its interactions with the immune system, focusing on both the innate and the adaptive responses. Meningococci exploit different mechanisms and complex machineries in order to subvert the immune system and to avoid being killed. Capsular polysaccharide and lipooligosaccharide glycan composition, in…
Control of Murine Cytomegalovirus Infection by γδ T Cells
2015
Infections with cytomegalovirus (CMV) can cause severe disease in immunosuppressed patients and infected newborns. Innate as well as cellular and humoral adaptive immune effector functions contribute to the control of CMV in immunocompetent individuals. None of the innate or adaptive immune functions are essential for virus control, however. Expansion of γδ T cells has been observed during human CMV (HCMV) infection in the fetus and in transplant patients with HCMV reactivation but the protective function of γδ T cells under these conditions remains unclear. Here we show for murine CMV (MCMV) infections that mice that lack CD8 and CD4 αβ-T cells as well as B lymphocytes can control a MCMV i…
Antigen-specific T cells and cytokines detection as useful tool for understanding immunity against zoonotic infections.
2012
Zoonoses include a broad range of diseases, that are becoming of great interest, due to the climate changing, that cause the adaptation of vectors to new niches and environments. Host immune responses play a crucial role in determining the outcome of infections, as documented by expansion of antigen-specific T cells during several zoonotic infections. Thus, understanding of the contribution of antigen-specific T-cell subsets in the host immune response is a powerful tool to evaluate the different immunological mechanisms involved in zoonotic infections and for the development of effective vaccines. In this paper we discuss the role of T cells in some eukaryotic and prokaryotic infectious mo…
γδ T Cells Cross-Link Innate and Adaptive Immunity in Mycobacterium tuberculosis Infection
2011
Protective immunity against mycobacterial infections such asMycobacterium tuberculosisis mediated by interactions between specific T cells and activated antigen presenting cells. To date, many aspects of mycobacterial immunity have shown that innate cells could be the key elements that substantially may influence the subsequent adaptive host response. During the early phases of infection, innate lymphocyte subsets play a pivotal role in this context. Here we summarize the findings of recent investigations onγδT lymphocytes and their role in tuberculosis immunity.
Functional Signatures of Human CD4 and CD8 T Cell Responses to Mycobacterium tuberculosis
2014
With 1.4 million deaths and 8.7 million new cases in 2011, tuberculosis (TB) remains a global health care problem and together with HIV and Malaria represents one of the three infectious diseases world-wide. Control of the global TB epidemic has been impaired by the lack of an effective vaccine, by the emergence of drug-resistant forms of Mycobacterium tuberculosis (Mtb) and by the lack of sensitive and rapid diagnostics. It is estimated, by epidemiological reports, that one third of the world's population is latently infected with Mtb, but the majority of infected individuals develop long-lived protective immunity, which controls and contains Mtb in a T cell-dependent manner. Development o…
Chlamydia trachomatis Infection and Anti-Hsp60 Immunity: The Two Sides of the Coin
2009
Chlamydia trachomatis (CT) infection is one of the most common causes of reproductive tract diseases and infertility. CT-Hsp60 is synthesized during infection and is released in the bloodstream. As a consequence, immune cells will produce anti-CT-Hsp60 antibodies. Hsp60, a ubiquitous and evolutionarily conserved chaperonin, is normally sequestered inside the cell, particularly into mitochondria. However, upon cell stress, as well as during carcinogenesis, the chaperonin becomes exposed on the cell surface (sf-Hsp60) and/or is secreted from cells into the extracellular space and circulation. Reports in the literature on circulating Hsp and anti-Hsp antibodies are in many cases short on detai…