Antigen Capture and Presentation Flashcards
- type of interleukin produced by APCs
- promotes the development of Th1 responses and is a powerful inducer of IFNγ production by T and NK cells
IL-12
- type of interferon/cytokine
- important activator of macrophages and inducer of Class II major histocompatibility complex (MHC) molecule expression
IFNγ
- a type of cytokine involved in the acute phase reaction
- produced chiefly by macrophages, but can be produced by many other cells
- able to induce fever, apoptotic cell death, cachexia, inflammation and to inhibit tumorigenesis, viral replication, and respond to sepsis via IL-1 and IL-6-producing cells
TNF-α
- an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine
- mediator of fever and is an acute phase protein
- can be secreted by macrophages in response to PAMPs
- stimulates acute phase protein synthesis, and production of neutrophils in bone marrow
IL-6
How does the innate immune reponse initiate adaptive immune response? (2 signals)
- APCs process and present antigen to T lymphocytes
- Generation of surface molecules that function as co-stimulatory signals with antigen to activate T and B lymphocytes
What are antigens in the periphery filtered by?
lymph and lymphoid tissues
What are antigens in the blood filtered by?
spleen
How are antigens processed? (2 steps)
- phagocytosed or pinocytosed by APCs
- APCs convert proteins to peptides for display
What are the 3 main types of APCs?
- dendritic cells
- macrophages
- B lymphocytes
(other cells than express MHC II can act as APCs in certain cases, i.e. thymic epithelial cells)
- type of APC, level of MHC class II: very high
- level of constitutive co-stimulatory molecule expression: high
- capable of cross presentation: +++
- activates naive T cells: yes
- activates effect and memory T cells: yes
dendritic cells
- type of APC, level of MHC class II: high
- level of constitutive co-stimulatory molecule expression: moderate
- capable of cross presentation: ++
- activates naive T cells: no
- activates effect and memory T cells: yes
macrophages
- type of APC, level of MHC class II: high
- level of constitutive co-stimulatory molecule expression: low
- capable of cross presentation: +/-
- activates naive T cells: no
- activates effect and memory T cells: yes
B cells
__ ____ can only recognize antigens in the form of being presented by APCs
T cells
________ and __ ____ can recognize free peptide antigens
macrophages, B cells
_______ ____ are the only cells that can activate naive T cells
dendritic cells
- type of antigen presenting cell
- high constitutive expression of MHC/HLA II expression and co-stimulatory molecules
- activate mature, naive T cells (present to them in peripheral lymphoid tissue)
- present in all tissue
- major cytokines produced: TNF, IL-6, IL-12, and IL23
dendritic cells
- type of antigen presenting cell
- present in blood and tissues
- promote innate anti-viral state
- release type I interferons
plasmacytoid dendritic cells
What happens when dendritic cells are activated by an antigen?
- lose adhesive markers, up-regulate CCR7 (lymphatic endothelium), increase expression of MHC and CD80 (B7)
- travel to regional lymphoid tissue (mature as they migrate, process Ag to T cells)