Lecture 2: Cell Mediated Immunity Flashcards
Immunity Tree
Innate vs Adaptive
Adaptive-> Natural vs Artificial
Natural-> Passive (maternal) vs Active (infection)
Artificial-> Passive (antibody transfer/infusion) vs Active (immunization)
Passive immunity is short or long?
short lived/temporary/transient
Active immunity is short or long?
long lived, memory cells are produced
A second infection by the same antigen triggers a stronger and faster immune response/defense
Antibody mediated immunity
humoral or body fluid immunity (B cells) and antibodies
Cell mediated immunity
cellular immunity dependent upon various types of T cells
Lymphocytes are
T cells and B cells
B cells attack
Invaders outside of cells (via antibodies)
T cells attack
Infected cells
B cells mature in the
Bone marrow
Differentiate in the bone marrow
Take up residence in the lymph tissues
T cells mature in the
Thymus (above the heart)
Differentiate from the bone marrow
Which lymph tissues contain B cells?
Tonsils, lymph nodes, spleen, MALT (mucosal associated lymphoid tissue), appendix, and peyers patches (in the GI tract)
T cells further differentiate in the
Thymus
And then go on to populate/patrol the lymph
What 3 types do immature T cells differentiate into?
Helper T cells
Suppressor T cells
Cytotoxic T cells
Helper T cells
“Raise the alarm” by releasing cytokines that then activate other cells to kill
They can’t kill cells on their own, but can activate other killer cells
They also finish “training” naive B cells by binding to class 2 MHC/antigen complexes from things the B cell has engulfed and releasing cytoikines that activate that B cell
How many CD molecules have we identified?
over 130
Cytotoxic T cells
Cells that recognize infected cells and kill them, directed/regulated by helper T cells/cytokines
Cytotoxic T cells recognize dying, infected or cancerous cells based on the proteins presented by their class 1 MHCs
Natural killer cells NK
Also lymphocytes
Do not have B or T cell markers
Triggers apoptosis in infected cells
Primary Lymphoid tissue
Where lymphoid cells mature
Bone marrow (B cells)
Thymus (T cells)
Secondary Lymphoid tissue
Sites of immune ACTION
maximize antigen trapping Lymph nodes spleen MALT tonsils Appendix Peyers patches
MHC proteins
Major histocompatibility complex
Also called MHC antigens
Every person’s MHCs are different (tissue donation rejection)
External cell markers for identification by your immune system
Plays into recognizing self vs non-self
MHCs are used in
Paternity testing
Transplants
Disease diagnosis
Immune response during antigen presentation
MHC class 1
On the surface of all nucleated cells (not rbc’s which have no nucleus)
What are some general things that T cells do?
Cause Inflammation
Activate Macrophages (phagocytic white blood cells)
Get other T cells fired up
Regulate much of the immune response
Macrophages and MHCs
Macrophages/phagocytes engulf invaders and display the invaders’ protein components by attaching them to the cell’s external MHC proteins to visibly display those invader protein components to other immune cells in the body
Also referred to as professional antigen presenting cells
What do class 1 MHC’s do?
Present endogenous antigens
They present short chains of amino acids (proteins) based on endogenous proteins (proteins synthesized inside that particular cell)
The normal proteins on a healthy cell’s class 1 MHCs tell wandering immune cells that the particular cell is healthy
How do cancerous cells utilize MHCs?
A cancerous cell will present portions of its abnormal proteins on its class 1 MHCs to “ask” immune cells to destroy it->flagging itself as abnormal/for death
What are 3 types of cells that have class 2 MHC proteins? (“professionals”)
Macrophages
Dendritic cells
B cells
What do class 2 MHCs do?
Bind to exogenous (from the outside) proteins/anigens that are presented by other immune cells on their class 2 MHCs
such as viral or bacterial antigens/fragments
Helper T cell specificity
Specific in a similar way that the antibodies of B cells work
A naive helper T cells can only detect one specific combination of a specific antigenic fragment bound to a class 2 MHC of the individual in question
What happens when a Helper T binds to its perfect class 2 MHC/antigen trigger?
It becomes activated, and begins rapidly dividing to produce more Effector cells including Helper T cells + Regulatory cells, as well as a few Memory T cells
What do cytokines do?
They are released by Helper T cells and can trigger other helper T cells to begin dividing to rapidly ramp up the immune response
The cytokines also trigger/activate Cytotoxic (killer) T cells
Immunodeficiency
Impairs the production or function of immune cells and antibodies, which weakens the immune system’s ability to fight off invaders or cancerous cells
Regulatory T cells (a type of effector cell)
Release inhibitory cytokines that tell immune cell to stand down once the initial threat has been dealt with
Overactive immune response
Body loses the ability to distinguish self from other, and starts attacking the body
Such as MS multiple sclerosis resulting in degeneration of myelin sheaths of nerves
Type 1 diabetes, where insulin generating pancreas cells are destroyed
