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How would you describe adaptive immunity?
Specific, memory (primary and secondary immune responses), and uses lymphocytes
What are the major extracellular defense?
Antibodies
What’s recognized by antigens on the cell surfaces?
Internal pathogens and abnormal cells
What are abnormal and infected cells destroyed by?
Cell mediated immune response
What are antigens?
Antibody-generators, as well as any substance that reacts with an anti-body or T-cell receptor - they may produce an immune response
What are some examples of antigens?
Proteins, carbohydrates, the flu, E. coli
Where can antigens be found?
Free in blood/tissue, on pathogen surfaces, and on the surfaces of infected cells
How do you check an antigen?
Cells have a surface protein that shows antigens that are inside the cell
Human cells present what?
Their own antigens
What does MHC stand for?
Major histocompatibility complex
Describe MHC-I
Identifies “self,” and presents intracellular antigens on cell surface
Describe MHC-II
Antigen-presenting cells, include dendritic cells, macrophages, and B-cells - also show off phagocytosed antigens
What is the humoral immune response?
Defends against extracellular antigens, includes B-lymphocytes, plasma cells, and memory cells
What is the Fc region?
Constant region, determines type (class) of antibody
What is the Fab region?
Variable region, determines antigen specificity
What is the IgG antibody class?
Most common, can cross the placenta
What is the IgM antibody class?
First responder, pentamer
What is the IgE antibody class?
Allergic reactions, binds to mast cells, basophils
What is the IgA antibody class?
Secreted antibody, mucus, tears, saliva, breast milk
How do antibodies work?
Neutralized, aggluinate and precipitate, remote phagocytosis, activate the complement, and mark cells for destruction
What is B-cell diversity?
Each B-cell makes its own unique antibody, involved with gene splicing/rearrangement - only B-cells with the proper antibody respond to an infection
What are the humoral immune response steps?
Digestion of an APC
Free antigen binds to the B-cell
APC activates the T-cell
T-cell activates the B-cells
B-cell → antibodies and memory cells
What is class switching?
Promoted by helper T-cells
IgG → plasma and tissue
IgA → Mucus
What is a primary immune response?
First time the antigen is encountered, 1-2 weeks, low Ab levels
What is the secondary immune response?
Involved memory cells, rapid and bigger response, antigen-specific
Vaccination - what is active immunity?
Injection of killed, attenuated, or part of pathogen - generates antibody and memory
Vaccination - what is passive immunity?
Injection of antibody only, provides temporary protections
What are helper T- cells (CD-4 cells)
Interact with antigen presenting cells and release cytokines, activate B, T, NK, and macrophage cells and direct the immune response
What are cytotoxic T-cells (CD-8 cells)
Interact with any cell that has MHC-I
APC → Tc is activated by it
Tissue cell → Tc attacks it
What is cell-mediated immunity?
Defense against infected cells
How to cytotoxic T cells defend against infected cells?
Using t-lymphocytes, a CD8 receptor for MHC-I, recognition of infected cells
What to cytotoxic T cells release?
Performs and granzymes, can destruct the infected cell
What is the cell-mediated immune response?
Antigen is engulfed and processed (APC is activated by TLR)
Antigen is presented to T - cell (involves CD8 and MHC-1 + cytokines)
T cell is activated
Activated cell binds to abnormal host cells
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