How does the host respond to viral infections?
Virally infected cells produce and release small proteins called interferons, which play a role in immune protection against viruses. Interferons prevent replication of viruses, by directly interfering with their ability to replicate within an infected cell.
What is the host response to the viral infection and what is the disease pathogenesis?
Virus-induced immune pathology: the host immune response to the virus may lead to direct killing of the infected cells, or bystander killing of uninfected cells, resulting in tissue destruction, which can lead to the development of disease.
What is the host immune response?
Host immune responses are considered to be critical in controlling the infection both during primary infection and in the carrier state. Most individuals have been infected with EBV by adulthood, and have established humoral and cellular immune responses to EBV antigens.
What is responsible for activation of host immune response during viral infection?
Dendritic cells, the specialized antigen-presenting cells, bridge up the innate and adaptive immune responses during the IAV infection. Adaptive immune response begins when naïve and memory T lymphocytes recognize viral antigens presented by DCs.
What is host inflammatory response?
Several experimental approaches have illustrated the principle that the host immune or inflammatory response contributes to disease caused by gastrointestinal infections (Table 1). For example, impeding the host response can attenuate acute disease caused by infection.
What is the pathogenesis of Covid 19?
The pathological result of SARS and COVID-19 is diffuse alveolar damage with fibrin rich hyaline membranes and a few multinucleated giant cells [17, 18]. The aberrant wound healing may lead to more severe scarring and fibrosis than other forms of ARDS.
When is adaptive immunity activated?
Adaptive immunity is an immunity that occurs after exposure to an antigen either from a pathogen or a vaccination. This part of the immune system is activated when the innate immune response is insufficient to control an infection.
Why Do viruses rely on host cells?
Viruses depend on the host cells that they infect to reproduce. When found outside of host cells, viruses exist as a protein coat or capsid, sometimes enclosed within a membrane. The capsid encloses either DNA or RNA which codes for the virus elements.
What is the purpose of the host cell?
A host cell is a cell that harbors foreign molecules, viruses, or microorganisms. It may also be a cell that has been introduced with DNA (or RNA), such as a bacterial cell acting as a host cell for the DNA isolated from a bacteriophage.
What are the steps in viral pathogenesis?
Viral pathogenesis comprises of several stages, including (1) transmission and entry of the virus into the host, (2) spread in the host, (3) tropism, (4) virulence, (5) patterns of viral infection and disease, (6) host factors, (7) and host defense.
What is the repair response to viral respiratory tract infections (ruts)?
Once virus and virus-infected cells are cleared and associated pulmonary inflammation is controlled, the repair response to viral respiratory tract infection (the restoration phase) ensues.
What is the resolution and restoration phase of viral infection?
†The resolution phase encompasses the clearance of infectious virions through the actions of mainly, but not exclusively, effector T and B cells. ‡The restoration phase includes the repair/regeneration of respiratory epithelial cells and a return to homeostatic pulmonary function.
What is the role of T cells in the pathophysiology of influenza?
Sun J., Madan R., Karp C.L., Braciale T.J. Effector T cells control lung inflammation during acute influenza virus infection by producing IL-10. Nat Med. 2009;15:277–284.
How does virus infection induce proteolytic processing of IL-18?
Pirhonen J., Sareneva T., Julkunen I., Matikainen S. Virus infection induces proteolytic processing of IL-18 in human macrophages via caspase-1 and caspase-3 activation. Eur J Immunol. 2001;31:726–733.