Chapter 4 - Cellular Immunity Flashcards
What is the basis of an “immune network”?
- Activation of T cells
- Essential to a strong and successful immune response
What 2 cells are needed for an immune response to occur?
- Experiment shows that antigen presenting cells + T cells needed for a response
Cellular Interactions: experiment wherein animals were irradiated to remove all immune cells, then reconstituted with B cells, T cells, or both
- which could generate a response?
- what is the MHC restriction?
- Only animals with both could make a response
- Antigen presenting cell and the T cell has to be of the same MHC haplotype for the response to occur
- Response called MHC restricted
Antigen Presenting Cells
- what are the 6 major types?
- B cells
- Macrophages
- Dendritic cells
- Fibroblasts
- Thymic epithelial cells
- Vascular endothelial cells
Professional APCs
- what does this mean?
- what are the three types of professional APCs?
- Major antigen presenting cells
- Types:
- Dendritic cells
- Macrophages
- B cells
Professional APCs: Dendritic cells
- efficiency level?
- which MHC class?
- what patterns do they recognize?
- Most efficient
- High levels of MHC class II molecules
- Recognize pathogen-associated molecular patterns (PAMP)
Professional APCs: Macrophages
- What MHC class do these interact with?
- what do they do to those molecules?
- what markers do they recognize?
- Upregulate surface MHC class II after phagocytosis
- Recognize certain carbohydrate markers on the surface of a pathogen (PAMPs)
- What are the three major types of T cells?
- What CD markers are seen on each type?
- Helper T cells (CD4+)
- Cytotoxic T cells (CD8+)
- Regulatory T cells (CD25+ and usually CD4+)
- What are the three types (2 major) Helper T cells?
- What is each type responsible for?
Two major: - Th1 -- Stimulate CD8 T cells -- Stimulate macrophage and phagocytosis - Th2 -- Stimulate antibody production Third - Th17 Involved in autoimmunity
Professional APCs
- How do B cells recognize antigen?
- Recognize antigen via surface immunoglobulin
Cytotoxic T cells
- what type of antigen do they recognize?
- what action do they take when they recognize the antigen?
- Recognize antigen associated with MHC class I and kill target cell presenting that antigen
Regulatory T cells
- what is there responsibility?
- Downregulate the immune response
Immunological Tolerance
- what are three characteristics?
- Unresponsiveness to a specific antigen
- Induced by prior exposure to the antigen
- Prevents body from attacking itself
Immunological Tolerance
- describe the process
- where does it occur?
- when and for what cell does this occur?
- what cells does it target and what does it do to those cells?
- Process in the thymus during development of T cells that removes self reactive cells
- Positive and negative selection occurs in thymus
- Not genetically programmed
Immunological Tolerance
- Describe the process of positive selection.
- Double positive thymocytes are presented with MHC Class I or II
- If they recognize self MHC survive and proliferate
- If they do not recognize self-MHC, they die within the thymus