Term
What is the immune system?
In order for an immune response to be effective, what 2 processes must occur? examples? |
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Definition
-defense system that requires cells and molecules to act together to generate an immune response to protect host from an antigen (Ag)
-2 step process...
1. Recognition of Ag (self/nonself)
2. Effector response (destroy or neutralize Ag, inhibit reproduction) ex: neutralization, phagocytosis, lysis, apoptosis |
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Term
| Define innate vs. Adaptive immunities |
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Definition
Innate: hours, Occurs due to natural biological makeup, nonspecific (will act same with every Ag), Primary (oldest), no memory
Adaptive: days, specific to 1 Ag, Secondary: highly specialized, memory for specific Ag (ex Memory Bcells) |
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Term
| Describe 4 types of defense barriers that comprise your innate immunity |
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Definition
1. ANATOMIC- Skin, Mucous
2. PHYSIOLOGICAL- Temperature, low pH, chemical mediators
3. PHAGOCYTIC/ENDOCYTIC- BACTERIUM attaches to membrane's PSEUDOPODIA and is ingested forming a PHAGOSOME. The phagosome fuses with LYSOSOME which secretes lysosomal ENZYMES to digest captured material, products then RELEASED from cell.
4. INFLAMMATION- Tissue damage-> margination of antibody to capillary wall, extravasation of antibody and compliment c reactive protein exudates through wall--> provoking inflammatory response as they fend off the bacterium |
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Term
What three cell types are found are found in human blood?
*Which of these cells are most important in an immune response? |
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Definition
1. Erythrocytes: red blood cells
*2. Leukocytes: white blood cells
3. Thrombocytes: platelets |
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Term
Certain immune cells are capable of carrying out phagocytosis(4)?
What is phagocytosis? |
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Definition
Neutrophils, macrophages, eosinophil and monocytes
Phagocytosis: cellular uptake of particular materials through engulfment |
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Term
| What types of molecules function as soluble mediators of immunity? |
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Definition
Adaptive Immunity
a)Complement system
->collection of proteins
->produced by liver
->destruction
b)Cytokines
->produced by immune cells and secreted
- ex) interferon
c)Soluble antibody
->produced by plasma cells (blood, lymphatic system, tissue, bodily secretions)
->free floating
->2 responses: cell mediated(lymphocytes, Tcells) and humoral(Bcells) |
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Term
| What is the advantage to an antigen being opsonized? |
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Definition
Opsonize: pathogen is marked for ingestion and destruction by a phagocyte
->involves binding of opsonin to a receptor on pathogen's cell membrane-- makes phagocytes attracted to pathogen-- enhance phagocytosis |
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Term
How does the immune system destroy/neutralize antigens?(4)
[review examples of effector responses discussed in lecture] |
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Definition
a) Neutralization= Antibody opsonizes Ag an inhibits it from reproducing-- forces shut down-- preps for ingestion by phagocyte
b)Phagocytosis= Ag ingested then digested and contents released out of cell
c) Lysis= target and damage plasma membrane of Ag
d) Apotosis= programmed cell death --> activate(on) intracellular pathway triggered cell death, allows elimination of cell w/o releasing harmful substances |
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Term
| Where do cells that are destined to become immune cells originate? |
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Definition
| Hematopoietic stem cell--> bone marrow primary lymphoid that helps to mature into blood cells of 2 differing lineages (myeloid progenitor and lymphoid progenitor) |
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Term
Differentiate between a cell mediated response and humoral response in terms of the cells involved;
*are these two responses independent of each other? |
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Definition
*They can both work synonymously
Humoral->
-involves interaction of Bcells w/ foreign proteins (Ag)
-the secreted antibody binds to foreign proteins/infectious agents-- help clear them from the body
Cell Mediated->
-involves Tcells-- can perform many functions-secrete soluble messengers that help direct other cells of the immune system and directly kill infected cells |
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Term
| What must a cell be able to do in order to be called an antigen-presenting cell (APC)? |
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Definition
APC: can be an infected host or immune cell (Bcell, macrophage, dendritic cell)
-function: process and present antigen to T cells |
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Term
| Differentiate between B, T_H, and T_cell with regard to how they recognize Ag and their unique surface receptors |
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Definition
B-> Membrane bound Antibody on Bcell can recognize Ag that are intact (soluble or particulate Ag)
T_H->
-guide the behavior of other immune cells--select action taken by immune response
-recognize TCR/CD4 marker/ MHC II
T_cell->
-only sees processed pueces of Ag that are bound to cell membrane proteins (MHC);molecules that form these complexes with the Ag can decorate their surfaces as being foreign
-Thymus: place where Tcelll undergo selection |
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Term
What are the various function of cell surface markers?
Are the numbers and kinds of receptors that you find on the cell surface fixed? |
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Definition
CD Functions:
-antigen recognition, cell-cell communication and receptors for soluble mediators of immunity (compliment, cytokines, chemokines, and antibodies) numbers and receptors are not fixed. |
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Term
| Organs and tissues that make up the PRIMARY lymphoid system and their function |
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Definition
Bone Marrow:
-supports self renewal and differentiation of hematopoietic stem cells into mature blood cells
-produce Bcells, monocytes, dendritic cells(come from bcells, PCR) and granulocytes(category of WBC granules in cytoplasm)
Thymus: produce T lymphocytes
-where (T cell) undergo selection
-(-) and (+) selection
-bone marrow--thymus
*lymphocytes and myeoloid cells develop to maturity |
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Term
| Organs and tissues that make up the SECONDARY lymphoid system and their function (MALT, BALT, NALT, GALT) |
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Definition
Lymph nodes: most specialized
-regulates an immune response
-trap Ag in lymphatic fluid and tissue fluid
Spleen: important for response in systematic infections
-mounts immune responses to antigens in the bloodstream
-filters blood and traps blood borne antigens
MALT: organized lymphoid tissue (mucose-associated lymphoid tissue)
-defend the mucosal membrane which is a major entry for many pathogens
BALT:lymphoid tissue associated w/ respiratory epithelium (bronchus)
NALT:Nasal
GALT: gastrointestinal tract |
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Term
| Organs and tissues that make up the TERTIARY lymphoid system and their function |
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Definition
| Tissues that are the site of an infection serve to organize immune cells; include lungs, liver and brain |
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Term
| What must lymphoid progenitor cells do in order to develop into a specific type of immune cell? |
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Definition
-Travel to thymus: become T cell
-Stay in bone marrow: become Bcell |
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Term
| If the mechanisms that regulate hematopoiesis breakdown what may be the possible outcome? |
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Definition
-defect --can't regulate anymore thus you get elevated # of progenitor cells
-"Leukemic" (could be genetic) |
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Term
| Describe the selection processes that thymocutes are undergoing in the thymus |
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Definition
POSITIVE SELECTION; thymocutes that bind self MHC peptides w/ an intermediate affinity result in their survival, maturation and migration to the thymic medulla
NEGATIVE SELECTION; Thymocytes whose T cell receptors bind self MHC-peptide complexes w/ too high affinity are triggered to die |
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Term
| Describe the selection process that immature Bcells go through in the bone marrow |
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Definition
pro bcell-> pre bcell-> immature bcell
-as it differentiates, rearrangements at the immunoglobulin (Ig, proteins that function as antibodies within serum of blood) loci results in the generation and surface expession pre B cell --- then later produces the mature BCR .( Bind to Ag)
-go through selection process any further development of self reacting cells |
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Term
| Why is it important that your immune cells continue to circulate through out your body ? |
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Definition
| - In the chance of Ag and your defense cell connecting/Coming into contact -- different ways for Ag to get into body and by cirrculating in the immune system it can catch the Ag no matter what path the Ag took to get into our bodies. |
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Term
| How can morphology be used to differentiate between dendritic cells and granulocytes. |
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Definition
- Dendritic cells : psuedopodia used to catch food and destroy : function as APC cells.
- Granulocytes: granules that are dispersed from a cell by degranulation -- granules are free floating and are cytotoxic.
- Take on different shapes means different functions |
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Term
By what process do lymphocytes move between the move between the blood and secondary lymph organs/tissues?
BE ABLE to DESCRIBE the process and discuss why certain cells only cross at specific locations |
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Definition
-extravasation-- can only take place in HEV regions (high endothelial venules)
HEV: adhesion receptors-- make surface sticky(ICAM1,MAdCAM,E-Selectin)/Lymphocytes-- adhesion homing(CLA,LFA,LPAM)-- sticky and make extravasate
1) Rolling;Homing->[ L-selectin(mucosal) E-selectin(skin)] binds to CD34 starts process of extravasation
2)Activation; Chemokine 'activate' and mobilize white blood cells (Tcell)
3)Arrest/adhesion- LFA1 binds to ICAM1 which stops 'rolling'
4)Transendothelial migration; seeps/squeezes between endothelial cells (extravasates) |
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Term
| Be able to differentiate between soluble and surface Ab |
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Definition
-Soluble Ab: free floating (plasma cells)
-Surface Ab: on surface of Bcells |
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Term
What is an Antibody?
Why are antibodies said to be bi-functional? |
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Definition
| -Antibody: (Ig) Y shaped protein produced by the Bcell that are used in the immune system to identify and neutralize foreign objects -- recognizes Ag-- tip of ends of the Y has a paratope (Ag binding site of Ab) that is specific for one particular epitope (part of Ag which Ab binds to) |
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Term
Be able to diagram in detail the monomeric form of an Antibody
*see page 2 chapter 2 study guide* |
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Definition
| *see page 2 chapter 2 study guide* |
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Term
| Know Ab classes and major characteristics |
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Definition
1) IgA: 2 subclasses external secretion dimeric form has a secretory component attached
2) IgD: Present on surface of Bcells function; unknown
3) IgE: Associated with intestinal parasite infection, bind to Fc receptor-- induces degranulation
4) IgG: Activate effector (compliment system of phago) 4 subclasses, major immunoglobulin in human serum, predominant Ab made during second immune response that can also be transplacentally transmitted
5) IgM: Predominant Ab produced during primary Immune response, soluble form = pentamer intravascular system
*All: class of Ab determined by the heavy chain, monomeric form= 2heavy and 2 light chain, light chain made of either lambda or kappa chains |
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Term
| What is an effector response/function? |
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Definition
| -Action that occurs after recognition and binding of Ag by Ab (ex. lysis by complement by protein is an effector response) |
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Term
What is an Ag?
What makes a good Ag? |
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Definition
-foreign molecules that signal presence of nonself
-bind to receptors via non-covalent bond |
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Term
| What is an Epitope/antigenic determinant? |
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Definition
| -immunologically active regions on an Ag that are recognized as nonself/foreign-- recognized and bound by an Ab or TCR/MHC(<-distinguished between cells) combo |
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Term
| Why do bcells only recognize accessible epitopes? |
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Definition
| -Surface Ab on Bcells bind to inactive/native Ag--can see it as foreign/nonself when it is in tact because it specific |
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Term
| Why is it not important where the epitopes are located when it comes to Tcell activation? |
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Definition
| -they are not Ag specific; just as long as it is processed and presented by the APC |
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Term
| How does an Ab recognize and bind to an antigen? |
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Definition
| - Ab with the use of BCR-- sees accessory epitope as foreign |
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Term
| What types of bonds are formed when an antibody binds to an Ag? |
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Definition
| -h-bonds, ionic bonds, van der waal interaction, hydrophobic interactions |
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Term
| Be able to differentiate between affinity and avidity? |
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Definition
-Avidity:describe overall strength of the collective binding interactions that occur during multivalent binding
-Affinity: strength w/ which a ligand interacts w/ a binding site (ka) |
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Term
Some antibodies are cross-reactive.
What does this mean?
When can this be an advantage/disadvantage to the host? |
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Definition
| -ability of particular antibody or Tcell receptor to react w/ 2 or more Ag that possess a common epitope |
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Term
| What are the lymphocytes of individuals with Leucocyte Adhesion Deficiency(LAD) lacking/missing? |
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Definition
- Lack Leukocytes recruitment at the site of infection
- failure to express CD18 |
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