Flashcards in Microbiology Chapter 15 Deck (21):
Any molecule that stimulates an immune response
B Cell receptor is what kind of a molecule?
B cells receptors are secreted as what?
Antibodies (Ab = Ig)
What is never secreted?
T-Cell receptor (TCR)
List the Antigen Presenting Cells (APC)
Macrophages, B-Cells, and Dendritic Cells (Macrophage-like cell in tissue)
What are the functions of APC?
Process and present antigen in association with MHC II (cell surface protein on host cells). T-Cell receptor recognize antigen/MHC complex.
Thought to secrete interleukin; a cytokine which suppresses helper T-Cells
Secreted protein that regulates other cells
IgG, IgA, IgM, IgD, IgE
Based on the Fc (constant region) fragment
Most prevalent in tissue fluid and blood. Only one to cross Placenta.
Monomer or dimer (secretory IgA). Dimer - two Ig held together by a J chain. Secretory IgA is there for local immunity (salivary glands, intestine, nasal membrane, breast, lung, genitourinary tract. Provides protection for newborns.
Pentomer (five monomers). First to be synthesized during primary immune response. Associated with complement activation. Circulates in the blood
Monomer. Small amounts in the serum (rarely secreted). Receptor for antigen on B-cells is its only function.
Activates during allergies and parasite infections.Constant region binds to mast cells and basophils which release chemical mediators that aid inflammation.
Direct Involvement of T-Cells. Produce and react to cytokines. Activated simultaneously with B cell activation. Subset of T cells have unique CD receptors (CD4, CD8)
Types of T-cells
Helper T-cells (TH) CD4+
Cytotoxic T cells (TC) CD8+
What helps T-cell bind to Ag on MHCII
Binds and lyses infected cells and cancer cells
T-helped cell binds to Ag plus MHC II on antigen presenting cell.
TH cell Activation