Innate Immunity Flashcards
What is Innate Immunity?
(Non-Specific) immunity includes the external physical nd chemical barriers provided by the skin & mucous membranes.
Besides the Skin and Mucous membranes, What else is apart of the “Innate Immunity”?
This also includes various internal defences such as Antimicrobial Substances, Natural killer cells, Phagocytes, inflammation and Fever.
What is involved in the Second line of Defence for the body?
Antimicrobial Substances, Natural Killer cells and Phagocytes, Inflammation, BV’s and Fever.
What is Adaptive Immunity?
This is the ability of the body to defend itself against specific invading agents, Such as bacteria, toxins, viruses and Foreign Tish.
What are the 2 properties that distinguish Adaptive immunity from Innate immunity?
1: Selectivity for particular foreign molecules (AGS)
2: Memory for the most previous (AGS) so that a second encounter prompts an even more rapid and vigorous response.
What is involved in the maturation of B & T cells?
Adaptive immunity involves Lymphocytes called B-cells and T-cells.
B-cells complete their development in the RBM, a process that continues through life.
What are the types of Adaptive immunity?
There are 2 types of immunity, (Cell mediated & Antibody mediated).
What is Cell Mediated Immunity?
In this type Cytotoxic T-cells directly attack invading AGS.
Works inside the cells.
What is Antibody Mediated Immunity?
In this type B-cells transform into plasma cells, that synthesis and secrete specific proteins called “Antibodies” (ABS).
Works against Extracellular pathogens.
What do given antibodies bind to?
They can bind to specific Antigens and Deactivate them.
What is Cell Mediated Immunity particularly effective against?
1: Intracellular Pathogens.
2: Some cancer cells.
3: Foreign Tish transplants.
Antigens have 2 important characteristics, what are they?
Immunogenicity & Reactivity.
What is the characteristic “Immunogenicity” of an Antigen?
This is the ability to provoke an immune response by stimulating the production of specific AB’s and the proliferation of specific T-cells or both.
What is the characteristic “Reactivity” of an Antigen?
This is the ability of an AG to react specifically with AB’s or cells it provoked.
What happens when the immune response fails to determine if the target is a friend or foe?
This results in an Autoimmune disorder in which self-molecules or cells are attacked as though they were Foreign.
What is the function of (MHC) Antigens?
The are used for helping T-cells recognize that an AG s foreign and not self.
What must B / T cells do for an Immune response to occur?
They must recognize that a foreign substance is present.
Where can B-cells bind to AG’s in the body?
They can do this is in the Lymph, IF or Blood plasma.
What occurs in AG processing?
Antigenic proteins are broken down into peptide fragments that then associate with MHC molecules.
Next Antigen-MHC complex is inserted into the plasma membrane of a cell body, Called “Antigen Presentation”.
If a peptide is from a forearm protein, T-cells recognize the antigen-MHC complex as an intruder.
What is the process of Exogenous AG’s?
Foreign AG’s that are found inn fluids outside the body cells are termed “Exogenous Antigens”.
What are examples of Exogenous Antigens?
This includes:
Bacteria and Bacterial toxins, parasitic worms, inhaled pollen and Dust, and viruses that have not yet infected a body cell.
What are Antigen Presenting cells?
These are a special class of cells that process and present "Exogenous Antigens". They are strategically located in places where AG's are likely to penetrate the "Innate Defences".
How does the processing of “Endogenous AG’s” work?
Foreign AG’s that are present inside the body cells are termed “Endogenous AG’s”.
What are “Cytokines”?
These are small protein hormones that stimulate or inhibit many normal cell functions, such as cell growth.
Once a T-cell is activated what occurs?
It will undergo “Clonal Selection”.
What happens at the start of Cell mediated immune response for clone selection to occur?
Cell mediated immune response starts with activation of a small number of T-cells.
Once a T-cell has been activated it undergoes “Clone Selection”.
What are the results of clone selection?
The formation of a clone of cells that can recognize the same AG as the original lymphocyte.
What happens to some of the cells of a T-cell clone?
Some become effector cells while the others become memory cells.
Effector cells carry out immunity responses that ultimately eliminate the intruder.
What is involved in the activation of T-cells?
Specific Antigen receptors on the surface of T-cells (TCR’s) bind to specific foreign Antigen-MHC complex.
A T-cell only becomes active if it binds to the Foreign AG and at the same time receives a second signal called “Costimulation”.
Why is “Costimulation” needed for?
It is needed to help prevent immune responses from occurring accidentally.
Once a T-cell has Antigen recognition and Co-stimulation it is activated.
Within the Cell mediated immune response, what are the things that do the Elimination of Invaders?
Cytotoxic T-cells.
How do Cytotoxic T-cells help in the Elimination process of the Cell mediated immune response?
The Cytotoxic T-cells kill infected target body cells much like Natural killer cells.
The major difference is that Cytotoxic T-cells have receptors specific for for a particular microbe and only kills targets infected with this type of microbe.
What are the 2 Mechinhisoms for killing infected target cells that a Cytotoxic T-cell has?
1: They recognize and bind to the infected target cells that have microbial antigens on the surface.
2: They bind to the infected body cells and release 2 proteins, Perforin & Granuysin.
What are Perforin and Granulysin?
These are Proteins released by a Cytoxoic T-cell to kill infected body cells.
During an immune response Cytotoxic T-cells leave the Lymph Tish to destroy foreign antigens, what happens to B-cells?
They stay put, ..
What are Antibodies in depth?
It can combine specifically with the Epitope on the Antigen that triggered its production.
Ab’s structure matches its AG much as a lock accepts a certain key.
What causes Immunological Memory?
It is due to the presence of long lasting AB’s and very long-lived Lymphocytes that arise during Clonal Selection of B & T-cells.
What is the Primary immune response?
This occurs when an AG comes in contact to the immune system for the first time.
The immune system has to learn to recognize the AG.
What is the Secondary Response?
This is when the Immune system comes in contact with an AG and there are AB’s present to have a stronger reaction than the first time the body encountered the AG.
What are other secretions produced by other organs of the body to help protect the Epithelial surfaces?
The main portions of the First line of Defence includes the (Skin / Mucus membranes).
Other secretions produced by various organs to help protect Epithelial Surfaces:
Saliva, Urine, Vomiting, Perspiration, Deification.
