TNF-a

Question 1

What are the local and systemic roles of TNF-a?

Answer 1

Local- triggers local containment of infection
systemic- induces shock when released systemically

Question 2

What does it act on?

Answer 2

blood vessels, especially venules, to increase blood flow and vascular permeability to fluid, proteins, and cells, and to increase endothelial adhesiveness for leukocytes and platelets

Question 3

What does TNF-a do in terms of local release?

Answer 3

allow influx of fluid, cells, and proteins into the infected tissue, where they participate in host defense

blood clots form in the small vessels, preventing spread of infection via the blood + accumulated fluid and cells drain to regional lymph nodes, where an adaptive immune response is initiated

Question 4

TNF-ais released into blood by macrophages in liver and spleen and acts on all small blood vessels in the body ausing shock, disseminated intravascular coagulation with depletion of clotting factors, and consequent bleeding, multiple organ failure, and frequently death

Answer 4

systemic release

Question 5

cytokines Induced by macrophages and dendritic cells.Proteins that go out to tissue when there is a pathogen. The main organ to produce more of those proteins is the liver.

Answer 5

acute-phase response (APR)

Question 6

APR induced by proinflammatory cytokines s (IL-1, TNF-α, and IL-6) actiavats what 2 things?-

Answer 6

hepatocytes to synthesize acute-phase proteins (MBL, CRP, Complement components, etc) and activate bone marrow endothelium to release neutrophils

Question 7

What are endogenous pyrogens?

Answer 7

Things that can cause fever. IL-1, TNF-α, and IL-6

Question 8

What are the mechanisms by which type-I interferons promote antiviral immunity?

Answer 8

The interferons IFN-a and IFN- b(type-I interferons) promote antiviral immunity through multiple mechanisms

Mechanism 1- Induce resistance to viral replication in uninfected cells by activating genes that cause the destruction of mRNA and inhibit the translation of viral proteins and some host proteins.

Mechanism 2- ● Induce MHC class I expression in most cell types → enhance their resistance to NK cells

Mechanism 3- May also induce increased synthesis of MHC class I molecules in cells that are newly infected by virus → make them more susceptible to being killed by CD8 cytotoxic T cells

Mechanism 4- Activate NK cells, which then selectively kill virus-infected cells

Question 9

What molecules can activate NK cells?

Answer 9

type-I IFNs and macrophagederived cytokines

Question 10

What are the innate lymphoid subgroups?

Answer 10

NK cells, ILC1, ILC2, ILC3 (LTI cells)