Lecture 42 - Host response Flashcards
what are the 4 barriers (in order) do viruses have to overcome to infect a host
- anatomical/physical
- intrinsic host defenses
- innate immune system
- adaptive immune system
what is the primary role of physical barriers
prevent viral acquisition
T/F: apoptosis is regulated and no inflammation is present
TRUE
T/F: necrosis is the uncontrolled rupturing of cells and no inflammation is present
FALSE - there is localized inflammation present
what is a virus’s counter-response to apoptosis?
inhibition or delay apoptosis until the virus is replicated
summarize the characteristics of the innate immune system
- rapid, first response
- cytokines and sentinel cells
- non-specific
- no immune memory
- can initiate the adaptive immune response
how does the innate immune system recognize viruses but not self?
PRRs and PAMPs
what are interferons?
produced by viral-infected cells and uninfected sentinel cells in response to recognition of viral components
IFN-a and IFN-b are produced by:
all cells
IFN-gamma is produced by
T cells and NK cells
IFN-lambda is produced by
epithelial cells
T/F: the antiviral response makes the cell protected from viral infection
TRUE
How have viruses evolved to inhibit interferon response?
- avoid PRRs
- inhibit cell factors that induce IFNs
- inhibit antiviral genes induced by IFNs
what are sentinel cells
NK cells, macrophages, dendritic cells
what is the role of NK cells
directly kill infected cells
what is the role of macrophages
secrete cytokines to aid in the immune response
what is the role of dendritic cells
deliver viral antigen to the lymph node to start an adaptive immune response
summarize the characteristics of the adaptive immune response
- tailored to virus
- slow response
- T and B cells, antibodies
- long-term immune memory
what delivers viral antigens to T cells
dendritic cells
once T cells are activated what happens
they proliferate and differentiate to form memory T cells and cytotoxic T lymphocytes
T/F: cytotoxic T lymphocytes directly kill infected cells
TRUE
describe memory T cells
- in both lymphoid and non-lymphoid tissues
- contribute to memory
- quickly expand and produce effector function upon reinfection
describe memory B cells
- in spleen and lymph nodes
- contribute to memory
- do not produce antibodies
what kind of b cells produce antibodies
plasma cells
neutralization
antibody binds directly
antibody-mediated killing of infected cells
antibody binds viral antigen on infected cell and links it to NK cells
