Antiviral immunity l Flashcards
Why cant viruses replicate by themselves?
Viruses have simple genomes and must hijack a host biosynthetic machinery to replicate
What must viruses do to replicate?
Infect host cells and hijack their biosynthetic machinery.
How does the immune system recognise and elimate viruses?
Through mechanisms involving infected cells and specialised immune cells (dendritic cells , b cells , CD4 and CD8 cells )
How do viruses evade the immune system?
By learning to hide and disrupting the immune response.
What are cytokines?
Low molecular weight extracellular polypeptides/glycoproteins that promote and regulate the immune response.
What do infected cells and dendritic cells produce after detecting a virus?
Type 1 interferons
What is the role of IFNs in the immune system?
They induce ISG , ,MHC ll expression , Nk cell activation and t cell activation.
What are NK cells and what do they do ?
Granular lymphocytes central to the innate immune response , they eliminate infected cells and play a key role early in viral infections
How are NK cells activated?
By IFNs
What do NK cells detect to eliminate infected cells?
Changes in the expression of cell surface receptors caused by virus infection
What is the role of CD4+ and CD8+ t cells in immunity?
CD4+ cells coordinate immune responses , CD8+ cells destroy virus infected cells
How do NK cells differ from CD8+ t cells in infection control?
NK cells act early , detecting infected cells that lack MHCl molecules , CD8+ are generated later.
How do dendritic cells initiate adaptive immunity?
By detetcting viruses, activating , migrating to lymph nodes and presenting viral antigens to t cells via MHC proteins.
What drives DC activation?
Detection of PAMPS
What do B lymphocytes and plasma cells secrete to combat viruses?
Antibodies
How are B cells activated?
By detetcting antigens with their B cell receptors and receiving help from CD4+ T cells
What is the role of antibodies in viral defence?
Neutraizing viruses , opsonising viruses and activating the classical pathway of the complement system.
How do antibodies neutralize viruses ?
By binding to viral surface proteins and preventing host cell entry.
What is opsinisation?
The process where antibodies bind to viruses , facilitating phagocytosis and destruction.
