Angela's Immunotherapy Flashcards
What cells are inherent to innate immunity?
NK cells, Macrophages and dendritic cells
What is the role of NK cells?
Lymphocytes that recognize and destroy stressed tissues (e.g., by viruses or cancer)
What is the role of Macrophages?
Production of soluble cytokines and chemokines that support growth and survival of inflammatory cells
Which immune cell secretes IL-1?
Macrophages; IL-1 is pro-inflammatory
What Macrophage activities promotes tumor growth?
Macrophages secrete pro angiogenesis molecules (VEGF and basic FGF) and can secrete immunosuppressant cytokines/molecules (prostaglandins E2 and arginase I, and TGF-B)
What is the role of Dendritic cells?
Professional antigen presenting cells, link between Adaptive and Innate immunity.
What are the two major cell types in the adaptive immune system?
T and B lymphocytes
What is the primary role of T-cells?
Antigen recognition, when complexed with an antigen presented by antigen presenting molecules
What is the primary role of B-cells?
Produce and Secrete antibodies that recognize soluble and cell surface molecules
What immune cells are most responsible for antibody secretion?
Plasma cells, which are the most mature form of B cell
What is a plasma cell?
The most mature B-cell, responsible for copious antibody production
What is an Fv region and where is it located?
The variable fragment of an immunoglobulin that is specific to the antigen. Located in the Fab domain of immunoglobulins.
What is an Fc region and what is its function?
The constant region of an immunoglobulin where antibody class and sub class are determined
What is the most prevalent immunoglobulin type secreted in response to non-protein antigens?
IgM. IgM is a pentameric antibody that effects complement. IgM is synthesized early in the immune response
What is complement and what is it’s function?
Blood component with enzymatic properties, Results in opsonization and is recognized by complement receptors on macrophages, monocytes, neutrophils, and dendritic cells with subsequent activation of the cells leading to phagocytosis and killing.
Additionally, complement can form a membrane attack complex, resulting in complement dependent cytotoxicity.
Complement is a system of plasma proteins that can be activated directly by pathogens or indirectly by pathogen-bound antibody, leading to a cascade of reactions that occurs on the surface of pathogens and generates active components with various effector functions.
3 main functions:
1) the activation of inflammation
2) the opsonization (labeling) of pathogens and cells for clearance/destruction
3) the direct killing of target cells/microbes by lysis
What are the most effective antigen presenting cells?
Dendritic cells
What are mechanisms of immune escape?
Down regulation of MHC, tumor antigen loss, stimulation of inhibitory receptors on T cells (CTLA-4, PD1, LAG3), tumor overproduction of indoleamine 2,3-dioxygenase, increased tumor infiltration by regulatory T cells and NKT cells that inhibit immune destruction.
Antigen presenting cells with MHC class I molecules complex with what type of immune cells?
CD8+, cytotoxic T cells (these cells kill infected or tumor cells).
Antigen presenting cells with MHC class II molecules complex with what type of immune cells?
CD4+, Helper T cells, which produce chemokines and cytokines to help recruit and orchestrate other immune system components.
What is the role of CD8+T cells?
Cytotoxic
Which lymphocytes can induce apoptosis? By what pathway is this accomplished?
CD8+ T lymphocytes; accomplished via FAS pathway
Fas cell signaling pathway has a central role in the physiological regulation of programmed cell death (also called apoptosis)
This is the EXTRINSIC apoptotic pathway
What is Fas?
Cell-surface protein responsible for initiating a cascade of proteases (caspases) culminating in apoptotic cell death. belongs to the subgroup of the tumor necrosis factor receptor (TNF-R) family that contain an intra-cellular ‘death domain’ and can trigger apoptosis
What substances are secreted by Th1 CD4+ Cells?
Interferon-gamma, which activates cytotoxic T cells and macrophages for cellular immune responses.
What substances are secreted by Th2 CD4+ Cells?
Interleukin-4, which favors antibody responses
What is the function of Interferon-gamma?
activation of cytotoxic T cells and macrophages for cellular immune responses.
What is the function of IL-2?
T cell growth factor that induces CD4+ T cell expansion. Plays a critical role in maintaining regulatory T cell pool.
Some answers from study guides indicate also stimulates CTLs(think this is w IL12
What are the functions of IL-12?
- Induces interferon gamma.
- Together with IL-2, activates cytotoxic T lymphocytes and NK cells.
- Initiates differentiation of helper T cells to the Th1 phenotype.
What is the function of IL-4 and IL-10?
Meditate development of Th2 Cell, which promote humoral immunity
What Cells are CD 34 positive?
Hematopoietic stem cells
What cells are CD3 positive?
All T cells.
What cells are CD56 positive?
NK cells
Once T cells are activated by dendritic cells they gain a variety of functions. What are their most important functions?
Dendritic cells activate T cells (CD4+ and CD8+), which then differentiate to TH1 and TH2.
CD8+ cells - cytotoxic T cells
CD4+ cells -
TH1 cells - secrete IFN-gamma, which activates cytotoxic T cells and macrophages for cellular immune responses
TH2 cells - secrete IL-4, which stimulates antibody response
What are NKT cells?
Bridge between innate and adaptive immunity
They share physical and functional characteristics of NK and T cells
Activated NKT cells produce large quantities of cytokines to help differentiation in maturation of other immune cells
Decreased function of NKT cells is associated with autoimmune diseases and tumor cell progression
What functions do T cells gain after activation by dendritic cells?
Activated T cells carry out effector functions
- helper Ts produce chemokines and cytokines to recruit and orchestrate other components of the immune system
-Cytotoxic Ts are able to kill target cells by apoptosis (one method is release of cytotoxic granules)
Notes say: Creation of cytokines and cytotoxins
