Chapter 13: Host Defenses Adaptive Immunity- Part 1 Flashcards
Third line of defense
Includes specific host defenses that must be developed uniquely for each microbe through the action of specialized white blood cells
The two adaptive immune responses
Type I: Cell-mediated
Type II: Humoral or antibody mediated
The two types of immune responses are often ________ _______
Mutually exclusive
What type of cells are the big responder in type II immunity?
B cells
B cells are covered with…
Thousands of copies of a membrane-bound immunoglobulin, termed B cell receptor (BCR) or surface Ig (sIg)
Is the sIg specific?
Yes, specific for a particular molecule from a particular species of pathogen
What must B cells also receive to fully activate?
A chemical signal (cytokines) from Helper T cells
If a pathogen enters the body… (Type II)
B cell will bind to it using its BCR
The binding of a BCR to a pathogen will result in..
The activation and maturation of the B cell into a plasma cell
What does a plasma cell do?
Secretes soluble versions of its sIg (Ab)
Antibodies (ab) secreted by plasma cells can circulate in the blood for…
Years!
If antibodies secreted by the plasma cell bind to an antigen, what do they do?
They target it for destruction
What cells are responsible for creating antibodies?
B cells
B cell receptor is AKA…
Antibody
Plasma cells have to stay in the lymphoid tissue but…
Antibodies can go into blood and tissue
What cells are the “generals” of the immune response?
Helper T cells
What cells are the big responders of Type I immunity?
T cells
Helper T (Th) cells
Secretes cytokines that mediate local immune responses
Cytotoxic T (Tc) cells
Physically interact with cells harboring a pathogen (such as a virus) and kills the cell
What cells are the “special forces” of the immune response?
Cytotoxic T (Tc) cells
Regulatory T (Treg) cells
Suppress inflammation as the immune response wanes
In cellular (type I) immunity, what do Helper T cells do?
Stimulates Cytotoxic T cells and macrophages
The first step in adaptive immunity is usually _______ and second is usually________
Recognizing the antigen
Cytokines from Helper T cells
What are primary lymphoid organs?
Where immune cells develop from stem cells
What organs are primary lymphoid organs?
Bone marrow
Thymus
What are secondary lymphoid organs?
Where immune cells gather to coordinate their activities
What organs are secondary lymphoid organs?
Lymph nodes
Spleen
Peyer’s patches (large intestine)
Many others
T cells finish out maturation in the….
Thymus
Antigen composition
- Protein
- Lipids linked to other macromolecules
- Carbohydrates linked to other macromolecules
A microbe usually has tens to thousands of ______ ______ or _____ that can be recognized by the immune system
Antigenic determinants
Epitopes
What is the best type of antigen?
Protein because T cells can only recognize this kind (non-proteinaceous can have all the other cells responding to it but not T cells)
Antibodies are ______ (what are they made up of)
Glycoproteins (carbohydrates and tetra peptides)
The glycoprotein structure of antibodies have 2 ______ chains and 2 _____ chains
Heavy
Light
Two regions of an antibody
Fab region
Fc region
Fab region of an antibody
Antigen binding region (looks like a v)
Fc region of an antibody
Bound by Fc receptors on phagocytes, determines biological function
There are __ antibody classes based upon the __ chains
5
H
H chains dictate..
An antibody’s biological function
The 5 antibody classes
IgG IgM IgE IgA IgD
