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T or F: a lymphocyte is a type of white blood cell
What is an antigen?
any molecule that indicates a lymphocyte response
What are the 2 main types of lymphocytes?
T and B cells
This type of lymphocyte attacks foreign cells by perforating its membrane and signaling the cell to undergo cell death
This type of lymphocyte can not only destroy foreign cells, but destroy our own cells What can happen with these lymphocytes when receiving an organ transplant?
cytotoxic or killer T-cell: cells from a transplant are treated as foreign do to their altered (antigenic) proteins on their surfaces.
How do antibodies work in the immune system?
They are proteins that bind to specific antigens and mark them for destruction or "flag" cells for macrophages
This type of lymphocyte detects a lack of cell surface molecules or presence of certain sugars, which then rapidly attacks it, before the immune response is activated.
Natural Killer cells (NK Cells)
What are the 3 steps of how lymphocytes are produced? (point of origin, direction, maturing)
- 1. all lymphocytes originate in the red bone marrow from lymphoid stem cells
- 2. some leave the red bone marrow into the bloodstream to become T-cells, while others stay in the bone marrow to beome B-cells.
- 3. Once the young lymphocytes meet and bind to its specific antigen, it becomes fully activated and gains the ability to attack that antigen
This type of lymphocyte waits within the lymphoid tissue until the body to attack a previously encountered antigen, even if its decades from the previous exposure
What are the 2 lymphoid organ groups?
- Primary lymphoid organs: bone marrow and thymus
- Secondary: spleen, lymph nodes, MALT (mucosa associated lymphoid tissue)
What are the functions of cytokines? 3 parts
- 1. A protein that acts as a checks and balance by stimulating immune cells to act and then inhibit them when appropriate
- 2. APromote the synthesis of even more T cells which can lead to greater cytokine production
- 3. Can stimulate or inhibit inflammation as an immune response
What are complement proteins and how do they work? what is MAC?
- Refers to a set of blood proteins that work with antibodies to destoy foreign bodies
- They work by being activated when an antibody latches to a bacteria cell wall. A series of complement proteins activate one another until they create a Membrane Attack Complex that punctures the bacteria cell wall
What is the function of phagocytes and the 3 types?
- A type of protein-rich immune cell whose job is to engulf damaged cells, bacteria or viruses:
- 1. granulocytes
- 2. Macrophages
- 3. Dendritic cells
What are the functions of granulocytes, macrophages, and dendritic cells
- Granulocytes: deal with an infection by ingesting foreign particles until they die
- Macrophages: eat large amounts of infecting material and also calling other immune cells into action
- Dendritic Cells: remove granulocytes and macrophages once they have completed their tasks
Where are MHCII found?
antigen presenting cells
Where can MHC II be found?
antigen presenting cells which are macrophages, dendritic cells, and B-cells
How do antigen presenting cells work to destroy foreign invaders?
They engulf harmful or foreign cells, breaking it down into smaller particles, and then woks with either MHC I or II to form a complex, which can be recognized by T-cells
How is clonal selection first started? 3 parts
- 1. Body makes hundreds of thousands of lymphocytes, or B-cells with different shaped receptors
- 2. The antigen presenting cells captures a foreign body
- 3. the antigen presenting cell will then find the correct T-cell receptor and bind the EPF and MHC that will fit with it
- 4. Once a fit happens, clonal selection occurs
What 2 things are made in B-cell clonal selection and what do they do?
- 1. Plasma cells: makes antibodies that recognized that particular antigen
- 2. Memory cells: a template of the envading cell so body is ready to attack it again
What are B-cells classified as and its function?
It is a antigen specific or antibody mediated used to destroy target cells.
What are cell-mediated lymphocytes?
T-cells: are agents of destruction
What 2 things are antibodies made of?
gammaglobulins and immunoglobulins
When are IgM, IgG, and IgA antibodies released?
- IgM: released upon 1st exposure to antigen
- IgG: released upon subsequent exposures
- IgA: found in secretions (mucus for example)
What is agglutination?
It refers to when things are stuck together during a membrane attack complex, it activates complement proteins.
What is opsonization?
Makes a foreign invader more appealing to white blood cells during agglutination
What cell in the tissue releases histamine and what does it do?
Mast cells: histamine increases the caillaries permeability by enlarging the capillary pores, so plasma protein can leave the blood into the inflammed tissue
How do MAC proteins kill foreign cells?
It punches holes in the cell's membranes, causing water go to in the cell and make it lyse.
How do interferons help prevent viral production?
Once a cell becomes infected with a virus, it secretes interferon to be released onto neighboring unaffected cells. When the cells bind with the interferon, they synthesize enzymes that cana break down viral messenge RNA and inhibit protein synthesis. Required for viral replication
What is pyrogen?
a substance released by bacteria that produces fever when released in the blood
This leukocyte is naturally occuring that nonspecifically destroy virus-infected cells and cancer cells that lyse their membranes
Natural Killer cell
What does antigen specific mean?
B and T cells have unique receptors protein receptors for a specific antigen type
T or F: memory cells do not participte in the current immune attack against a new antigen,, but instead remain dormand and expand this specific clone.
What 2 things can B-cells become when introduced to a new antigen?
- Plasma cells: produces antibodies
- Memory cells: if a person is ever reexposed to the same antigen again, these memory cells are primed and ready for even more immediate actioin
How are T-cells activated? What happens once activated?
- When they are on the surface of a cell that has both the foreign antigen and the MHC molecules.
- Once exposed, the T-cell secretes cytokines, which stimulate the T-cell to proliferate
- The cloned ells are ready to activate B-cells and enhnce other immune activities.
What happens to T-cells after the foreign antigens are destroyed?
Most die off, but the few that survive become memory T-cells.
What is the role of cytotoxic, or killer, T-cells?
Destroy host cells carrying any foreign antigen, such as viruses, cacner, and transplanted cells.
How do Helper T cells work?
They are considered the immune system's "master switch." They secrete cytokines, which enhance killer T-cell activity and B-cell antibody production. They also attract macrophages in an infected area.
Which virus has been known to be devestating to helper T-cells?
What are steps a dendritic cell becomes an APC?
- 1. Dendritic cell engulfs a bacterium
- 2. Large molecules of the bacterium are broken down by lysosomes into antigenic peptides
- 3. MHC molecules are synthesized by the ER-golgi comlex.
- 4. The antigenic peptide binds to the MHC molecules
- 5. The antigen and MHC is displayed on the surface of the dendritic cell
- 6. The dendritic cell is now a antigen-presenting cell (APC)
Which class of MHC can cytotoxic cells associate with?
Which class of MHC can helper T-cells and B-cells associate with? Why is this?
MHC II: helper T-cells closely interact with macropghages, dendritic cells, and B-cells. Macrophages and dendritic cells have class II MHC cells, which present anigens to helper T-cells and B cells.
How are B-cells activated? What happens once activated?
- After an APC is made and attaches the antigen to a helper T-cell, the BCR binds to this antigen and links together with the T-cell.
- The T-cell secretes interleukins, which stimulate B-cell proliferation cloning
- Some clones become plasma cells, and others become memory cells