Immunity to Viruses Flashcards
Extracellular viral infections location and immunity
Interstital space, blood, lymph
Complement, phago, AB
Intracellular viral infection location and immunity
Cytoplasmic
NK and CD8s
Phases of infection
Established when it hits certain level
Inductive phase - innate
Effector phase - adaptive
Memory phase
Innate immunity of viruses primarily
Type 1 IFNs and NK cells
Type 1 IFNs produced by infected cells reduces ability to expand
Also activate NK cells to kill to the infected cells
Adaptive immunity of viruses primarily
CTLs and ABs
ABs will neutralized
CD8 will eradicate the infection by killing the infected cells
Viruses that enter in vesicle process
TLR3 (dsRNA), TLR7 (ssRNA), TLR8 (ssRNA), and TLR9 (CpG DNA) recognize and activate IRF 3 and 7…leads to transcription of IFN alpha and beta
DNA viruses enter cytoplasmic
Activates STING…activates IRF3 and 7…leads to IFN alpha and beta
RNA viruses enter cytoplasmic
Activate RIG1 and MDA 5…activate IRF 3 and 7…increase IFNalpha and IFNbeta
Effect of IFNalpha and beta
Induce resistance to viral replication
Increase expression of ligands for NK cell receptors
Activate NK cells to kill
Process of NK cell activation by infected cell
Interferons trigger proliferation and differentation (formation of cytotoxic) of NK cells…NK cells can then bind and induce apoptosis
Macrophage activation of NK cell
Secrete IL-12 or CXCL8…NK cell binds…NK cell proliferates and differentiate into effector NK cells nd secrete IFNgamma…IFN gamma activates the macrophages to help them kill
AB resistance to viruses
IgA will bind and prevent binding to potential host cells
CD4 activation by dendritic cell with virus
Macropinocytosis and presented on MHC class 2
CD8 activation by dendritic cell with virus
Infected and presented
Can use cross-presentation of exogenous viral antigens
Can transfer from cell to cell
Present on MHC class 1
Dendritic cell that can activate CD8 on its own
CD28 (on T cell) binds B7…also have MHC class 1 binding to TCR
CD8 makes IL-2 to drive its own proliferation
Dendritic cell than needs CD4 help to activate CD8 cell
CD4 cell uses CD28/B7 interaction to bind
CD4 produces IL-2 which activates CD8 cells
What do you need to activate T cell vs. kill
Activate - need B7/CD28, co-stim, and IL-2 (proliferation and differentiation)...this occurs in lymph nodes or spleen Kill - just need MHC class 1/TCR binding...occurs aywhere
How many cells can a CD8 cell kill?
More than 1
H1N1 synopsis
Human influenza virus and avian (in this case from a pig) influenza virus came in contact and combined genetic material…different HA and NA means different nucleus and glycoproteins on the outside
