Flashcards in Defenses and Deficiencies Part 5 Deck (17):
What is an antigen?
Anything that can bind to the antigen receptor.
What can an immature dendritic cell do?
It phagocytoses pathogens
What can a mature dendritic cell do?
They can process, package and present the antigen on the cell surface.
What makes a dendritic cell move out of the epithelium and into a lymph vessel?
Changes in chemokines and chemokine receptors.
What cell does the dendritic cell present to?
Helper T cell
What type of antigen does T cell receptors recognize? Can the receptor be secreted?
Small peptides only; No receptor secretion. Do not confuse PRR's with TCRs
What type of antigen does B cell receptors recognize? Can the receptor be secreted?
Proteins, carbohydrates, lipids, and nucleic acids; Can be 'self' or foriegn. Secretion of receptor can occur (Antibody not MHC)
All TCRs on a single host T cell are identical and bind to a specific antigen peptide with a specific host MHC molecule.
TCRs on CD8 T cells bind to which MHC? CD4?
MHC class 1; MHC class 2
What kind of MHC molecule is expressed by antigen presenting cell?
Both MHC 1 and 2.
How common is the MHC class 1 molecule?
All NUCLEATED cells in the body.
How common is the MHC class 2 molecule?
ONlY professional APCs; Dendritic cells, macrophages, and B cells; Also express MHC class 1.
Are all the antibodies on a B cell identical?
Describe the adaptive immune response to a extracellular pathogen.
The pathogen is phagocytosed, presented to CD4, which in turn activated macrophages and B cells.
Describe the interaction between a macrophage and a CD4.
1. Macrophage eats extracellular antigen
2. Presents with MHC class 2 to CD4.
3. CD4 secretes cytokines
4. Activates macrophage and destroys phagocytosed antigen.
Describe the interaction between a B cell and a CD4.
1. BCR binds extracellular antigen
2. ENDOCYTOSED presented in MHC class 2 to CD4
3. CD4 secrets cytokines
4. Activates B cells to make antibodies (IgG)