6.3 and 11.1 Flashcards
Antigens
foreign substance that induces an immune response in the body, especially the production of antibodies.
Antibodies
blood protein produced by plasma B cell in response to and counteracting a specific antigen
List and describe 3 lines of defense (nonspecific vs. specific)
1 st Line of Defense- NONSPECIFIC- Skin & mucous membranes: Skin is the barrier against most pathogens; mucus can trap incoming pathogens and prevent them from reaching cells that they could infect.
• 2 nd Line of Defense- NONSPECIFIC- Macrophages- they are large leukocytes that are able to change their cellular shape to surround an invading cell through the process of phagocytosis. Phagocytes typically contain many lysosome organelles, in order to digest chemically whatever has been engulfed.
• 3 rd Line of Defense- SPECIFIC- B & T Cells
Primary vs. secondary immune response- include discussion of memory cells!
When a pathogen does enter the body, a series of events begin known as the immune response.
▪ If this is a first encounter with a particular pathogen, the response is known as a primary immune response. If it is a second (or third, etc.) encounter, the response is known as a secondary immune response.
▪ A primary immune response takes at least a week or more to be successful, and it is common to experience the symptoms associated with a disease while the immune system is working to reduce and finally eliminate the pathogen.
▪ A secondary immune response is both quicker and more intense,so symptoms are rarely experienced– the memory cells will initiate a very quick secondary immune response because they remember the specific antigen
Passive vs. Active immunity
When we build up our own immunity it is active as an example, a vaccine exposes the body to antigens and you naturally build an immunity to them
If we gain immunity from something else it is passive- when a mother feeds her child with breastmilk
Specific structure of an antibody!
Antibodies are protein molecules that are produced by the body in response to a specific type of pathogen (antigen).
• Each type of antibody is different because each type has been produced in response to a different pathogen.
• Each antibody is a protein that is Y-shaped. At the end of each of the forks of the Y is a binding site which are identical to each other and are capable of binding to the same type of antigen.
The binding site is where the antibody attaches itself to an antigen.
3 ways antibodies help the immune response
- ) One way is by binding to the pathogen and marking it for destruction by other cells (macrophages) of the immune system. 2.)Another way is for the antibodies to use their two binding sites on two antigens. This helps by binding the antigens together, often leading to clumps of pathogens because the antibodies are acting to stick them to each other. This agglutination of pathogens helps macrophages and other phagocytic cells mark the pathogens for destruction.
- )Another way that antibodies help is by recruiting other cells and proteins to fight the pathogen.
Blood types & transfusions
A person who has only the A protein is type A (dominant)
A person who has only the B protein is type B (dominant)
A person who has both the A and B protein is type AB (codominant)
A person who has neither A or B protein is type O (recessive)
If a person with a blood type of A Rh+ (A+ for short) was to donate blood to an individual that has B Rh- (B-) blood, the recipient would be receiving erythrocytes that have two types of proteins that they do not already have as a part of their genetic makeup.
The two proteins would be treated as antigens by the recipient, and antibodies would be created that are specific to the A and Rh proteins on the transfused blood cells.
Monoclonal antibodies
A primary immune response by an organism is called a polyclonal response.This is because the pathogen is typically being recognized as many antigens and not just one. Each of the protein types can cause an immune response, and thus several different kinds of plasma B cells undergo clonal selection, so several different kinds of antibodies are produced.
Once a polyclonal immune response has occurred, it is very difficult to separate the different kinds of antibodies that have been produced.*isolating one type of antibody then they can administer this antibody to those who are sick. Especially if the person is unable to produce this antibody on their own.
Role of vaccines in the immune response
Vaccines are weakened or non-pathogenic forms of pathogens that cause a primary immune response within your body. ▪ This leads to the production of the same memory lymphocytes as the actual disease. ▪ Thus, following a vaccination, if you do encounter the actual pathogen, the memory cells will initiate a very quick secondary immune response. ▪ In most instances, the secondary immune response is so quick that symptoms associated with the pathogen do not have time to develop.
The importance in the choice of the antigen
The choice of the antigen is very important because the antibodies that will be produced will bind only to this specific antigen. After the injection, the animal is given time to go through a primary immune response.
The animal then sleeps so at least some of the leukocytes cloned for the antigen that was recently injected will be a part of the cellular population within the spleen. There are two problems that need to be addressed at this point in the procedure:Keeping the B-cell types alive for an extended period of time andIdentifying the B-cell type that produces the antibody that recognizes the desired antigen. The B cells are kept alive by fusing them with cancerous (myeloma) cells. When B cells and myeloma cells are grown together in the proper environmental conditions, a few of the cells fuse together and become a hybrid cell called a hybridoma.These hybrid cells have characteristics of both cells: they produce antibodies of a particular type and they are very long-lived (as are all cancer cells).They are then kept separate and tested for the presence of the specific antigen,
➢Differentiate between B cells (humoral response) & T cells (cell mediated response)
Humoral immunity is triggered by B cells while cell mediated immunity is triggered by T cells. The main difference between humoral and cell mediated immunity is that antigen-specific antibodies are produced in humoral immunity whereas antibodies are not produced in cell mediated immunity.
B cells release the antibodies, the T cells- take out cells that are affected. Helper T cells work with both of these.
