Topic 10 Immune System: Acquired/Adaptive Immunity Flashcards
1
Q
- Adaptive immunity is the specific third line of defense that develops after the body has been attacked. Here, the immune response targets specific antigens, rather than doing a broad sweep like in the complement system or inflammatory response. Let’s highlight the components of this specific response:
A
Note
2
Q
- The mechanism by which the immune system is able to differentiate between self and non-self. A foreign MHC triggers a T cell attack.
- MHC is a collection of glycoprotein that exists on membranes of all body cells. The proteins of a single individual cell are unique (20 genes, each with 50+ alleles, and we are unlikely to have the same cells with the same MHC set as someone else)
- MHC also assists with antigen presentation, and is involved in organ transplant or graft rejection.
A
- Major Histocompatibility Complex
3
Q
- Primary agents of the immune response. Are leukocytes that originate in bone marrow and concentrate in lymphatic tissue such as the lymph nodes, thymus gland, and spleen
A
- Lymphocyte
4
Q
- Originate and mature in the bone marrow, and are activated in response to antigens. The plasma membrane of B cells contain antigen-receptor antibodies, the soluble form of these receptors are antibodies (or immunoglobulins).
A
- B cells (produce antibodies)
5
Q
a. Antibodies
b. Proliferation
A
Types of B cells
6
Q
- Proteins that are specific to each antigen, and have 5 classes: IgA, IgD, IgE, IgG, and IgM. These are Y-shaped proteins with constant and variable regions, and disulfide bonds connect heavy chains to each other, and to light chains.
A
a. Antibodies
7
Q
- when an antigen binds to a B cell, proliferation (or expansion of the B cell population) occurs, thus forming daughter B cells.
A
b. Proliferation
8
Q
- B cells that circulate in blood and release specific free antibodies that dispose of antigens by:
a. Preventing virus from blocking to host cell
b. Marking the antigen for phagocytosis via macrophage, neutrophil, or natural killer cell (opsonization)
c. Lysis by complement proteins (pore formation)
d. Agglutination of antigenic substance
e. Chemical inactivation (if a toxin)
f. Free antibodies may also attach their base to mast cells, and if it encounters an antigen, it releases histamine
A
Plasma Cells
9
Q
- Long-lived B cells that do not release antibodies in response to immediate antigen invasion. Instead, they circulate the body, proliferate, and respond quickly (via antibody synthesis) to eliminate subsequent invasion by the same antigen.
a. The secondary response takes less time (~5 days) thanks to the memory cells which are able to quickly spring into action and release antibodies
A
Memory Cells
10
Q
- Originate in the bone marrow but mature in the thymus, and have antigen receptors yet do not make antibodies. Instead, T cells check molecules displayed by non-self cells, and if a T cell binds to a self antigen in the thymus, it is destroyed (negative selection). If not, it is released to circulate in lymphoid tissue, blood or lymph
A
- T Cells
11
Q
- MHC markers on plasma membrane of cells
- When body cell is invaded by a non- self pathogen, it displays a combination of self and non-self markers, and the T cell interprets this as a non-self cell
- Cancer cells or tissue transplant cells are often recognized as non-self cells by T cells due to the combination of self and non-self markers
A
Discrimination of self and non-self are as follow:
12
Q
- Remember antigens are ANTibody GENerators, and are therefore the foreign object in the body. Antibodies are produced in response to antigens
- Note that in the table, the protection of the fetus by the mother’s IgG antibodies is considered passive immunity, because the antibodies in the recipient (fetus) are produced by another individual. Also note that in fetuses, B cells mature in the liver and not the bone marrow.
A
Note
13
Q
a. Cytotoxic T Cell
b. Helper T Cell
c. Suppressor T Cell
d. Memory T Cell
A
When a T cell encounters a non-self cell, it divides and produces 4 kinds of cells:
14
Q
- Killer T cells that recognize and destroy by releasing perforin protein that punctures cells (lysis). These can attack many cells because they do not phagocytize their victims.
A
a. Cytotoxic T Cell
15
Q
- Stimulate activation of B cells, cytotoxic T cells, and suppressor T cells. Are also the target for the virus that causes AIDs (HIV)
A
b. Helper T Cell
