Unit 2 - Specific Defences Flashcards
What are antigens
Substances that provoked a specific response
What Do the specific defenses of the immune system do
Recognizes foreign substances is not belonging to the body develops a specific immune response against them
What are anti-bodies
Proteins produced by the body in response to an antigen
What is acquired immunity
Protection and animal develops again certain types of microbes or foreign substances. Developed during an individual’s life time. Can be acquired actively or passively
What is active immunity
Immune system response following exposition to microorganisms or foreign substances
What is passive immunity
Antibodies are preformed by some other animal. Lasts only as long as the antibodies are present which is weeks to months
What is humoral immunity. Antibody mediated
Production of antibodies against foreign organisms and substances.
Where are anti-bodies found
In extracellular fluid’s such as blood plasma, lymphatic fluid, mucus secretions
Which cells are responsible for production of antibodies
The B lymphocytes
What does a Humoral immunity protect against
Bacteria, bacterial toxins and viruses
What is cell mediated immunity
Involve specialized T cells that acts against foreign organisms or tissues. Regulate the activation and proliferation of other immune system cells like macrophages
What is cell mediated immunity the most effective against
Bacteria and viruses within phagocytic or infected host cells, fungi, protozoa, Helminthes.
What is cell mediated immunity important for
Primary responder to transplanted tissue an important defense against cancer
What are antigens
Substance that the body recognizes as being foreign against which enemy in response will be mounted. Most are proteins are large polysaccharides. Lipids nucleic acid’s are usually only anti-genic if combined with proteins are polysaccharides.
What are non-microbial agents that have antigens
Pollen, egg white, blood cell surface molecules, serum proteins from other individuals
What are antigenic determinant’s or epitopes
Specific region on the surface of an antigen against which anti-bodies are formed. An antigen usually has several antigenic determinant sites that cause the production of different anti-bodies
What is a Hapten
Substance of low molecule wait that does not cause the formation of antibodies by itself but does when combined with the carrier molecule
What are antibodies
Highly specific proteins that are made in response to an antigen. Recognize unbind antigens. Hope to neutralize or destroy antigens
Describe the structure of an anti-body
Each anybody has at least two identical binding sites that bind antigenic determinant.
What is a valance
Number of antigen binding sites. Most anti-bodies are bivalent and are monomers
Describe the shape of an antibody monomer
It is a Y shape with 2 antigen binding sites
What does the variable region of the antibody monomer do
Has 2 binding sites that are antigen specific.
What are the constant regions for
For the 5 classes of immunoglobulins
What is the FC region of the antibody monomer
Fragment that crystallized in cold storage. If exposed after both arms Jim binding sites attached to an antigen the FC regions of adjacent antibodies combined complement and destroy the pathogen. Can bind to a cell and leave the antigen binding sites of adjacent antibodies free to react with antigens.
Describe the immunoglobulin classes
Five classes, determined by the constant regions. Each class please a different role in the immune response.
Describe immunoglobulin G
Bivalent monomer. Accounts for 80% of all antibodies in zero. Readily crosses walls of blood vessels and enters tissue fluids. Protect against circulating bacteria and viruses, neutralize bacterial toxins, trigger complement system, enhances phagocytosis when bound to an antigen. Maternal IgG can cross the placenta and confirm passive immunity to a fetus also present in the colostrum. 
Describe immunoglobulin M
It is a pentamer. 5 to 10% of antibodies in serum. It’s large-size prevents RGM from moving freely and it generally remains in blood vessels. First antibodies to appear in response to initial exposure to an antigen in and relatively short-lived, a second exposure results mostly in increased IgG production. Valuable in the diagnosis of the disease since it is first to appear in primary infection and is very short-lived. Effective in aggregating antigens and then reactions were involving complement. Can enhance ingestion of target cells by phagocytic cells
Describe immunoglobulin a
10 to 15% of antibodies in serum, but common in most mucous membranes and body secretions. Most abundant immunoglobulin in the body. Has two Forms
What are the two forms of immunoglobulin a
Serum IGA, secretory IGA
Describe the serum IGA
Circulates mostly as a monomer
Describe the secretory IGA
Diameter, produced by plasma cells and mucous membranes, enters and passes through a mucosal so word acquires a secretary component that protect against enzymatic Tegra Dacian. Prevents attachment of pathogens to mucosal surfaces. Present in colostrum
What is immunoglobulin D
0.2% of serum antibodies.
Bivalent monomer. Found in blood and lymph and on surfaces of B cells. No known function in serum. Act as antigens receptors on B cells.
What is immunoglobulin E
0.002% of total serum antibodies. They’re specialized cells that participate in allergic reactions. Once binded to an antigen, it triggers release of histamine which causes an allergic reaction.
Describe the B cell cycle
B cells exposed to antigens.
Activate B cells
Divide and differentiate into plasma cells
Antibody production
Where are B cells created
From stem cells in red bone marrow in adults and liver in fetuses
Where do mature B cells migrate to
Lymphoid organs such as lymph nodes or spleen
How do B cells recognize antigens
By means of antigen receptors on their cell surfaces. Once stimulated they immediately make antibodies associated with the assistance of T cells and cell mediated immune system.
How many antigens can b cells recognize
An infinite number of antigens
Each B cell can produce antibodies against how many antigens
Only one specific antigen
What does a B cell coming in contact with an antigen trigger
Proliferation of a cell that is specific for that antigen into a clone of cells with the same specificity.
What are the two series of self tolerance for B cells
Self and nonself. B and T cells that interact with self antigens are destroyed during fetal development. The body discriminates between dangerous and non dangerous cells
DeScribe the antigen-antibody complex
When an antibody encounters an antigen for which it is specific. Tags foreign cells and molecules for distraction by phagocytes and complements.
What components are part of the antigen-antibody complex
Agglutination, opsonization, neutralization, ab-dependent cell mediated cytotoxicity an action of complement
What is an antibody titer
Amounts of antibody and serum. Reflects the intensity of your humoral response.
What is the primary immune system response
Initial contact with the antigen, slow rise in antibody tighter. First IGM then IgG. Gradual decline in antibody tighter and takes a few days.
What is the secondary immune system response or memory response
Immune response after second exposure to an antigen. Memory cells rapidly differentiate into an anti-body producing plasma cells. Mostly IgG antibodies.
What cells are involved in cell mediated immunity
Involve specialized lymphocytes. T cells. Response to intracellular pathogens and non-transferred to the fetus via placenta
What is a cytokine
Chemical messengers within the immune system.
What is a interleukin
Messenger between leukocytes
What is a chemokine
induce the migration of leukocytes into infected areas
What are interferons
Help protect against viral infection of cells
What is the tumor necrosis factor
Very important and inflammatory reactions
What is the colony stimulating factor
Stimulate formation of various blood cells
Where do T cells develop
In stem cells of bone marrow
Where do the T cells migrate to
Migrate from bone marrow and mature in thymus then migrate to lymphoid organs
What are the types of T cells
Helper T cells, cytotoxic T cells, delayed hypersensitivity T cells, suppressor T cells, CD4 cells, CD8 cells
What must happen for a T cell to interact with an antigen
Antigen must be displayed on the cell surface called and antigen presenting cell.
What are the primary antigen presenting cells
Macrophages and dendritic cells.
What do antigen presenting cells do
Ingest and process the antigen, then displays fragments of antigen on the cell surface
What is necessary for a T-cell to recognize the antigenic fragment on the antigen presenting cell
Must be a close association with cell surface self molecules which are components of major histocompatibility complexes.
How is IL -1 created
Binding of helper T cells to antigen MHC complex on antigen presenting cell stimulates the secretion of IL-1
What does IL-1 do
Activates helper T cell which secretes IL-2
What does IL-2 do to the helper T cell
Stimulates receptor on that helper T cell which will proliferate and differentiate into mature helper T cells.
Which T cells are affected by IL-2
It is non specific but only Helper T cells that were stimulated by an antigen have IL-2 receptors
What do cytotoxic T cells do
Destroy target cells on contact.
How does a cytotoxic T cell lyse a cell
Cytotoxic T cell binds with MHC antigen complex on the cell surface of a viral infected cell. Releases a protein called perforin which Lyses the infected cell by forming pores in the cell membrane.
How long do cytotoxic T cells work for
Continue their activity as long as Antigen persists then undergo apoptosis
Describe delayed hypersensitivity T cells
Probably not separate population but mostly helper T cells and cytotoxic T cells. Associated with certain allergic reactions and rejection of organ transplant
What are suppressor T cells
Regulate the immune system by turning it off with an antigen is no longer present. May be helper T cells and cytotoxic T cells.
What activates the macrophages
Increased phagocytic capacities, larger and ruffled. Stimulation is primarily by ingestion of antigenic Material. Cytokines released by helper T cells. Ability to attack and destroy cancer cells. Antigen presenting cells.
Describe natural killer cells
Attack and destroy virus infected cells and tumor cells. Can undergo large parasites. doesnt need to be stimulated by an antigen. not phagocytic. participates in antibody dependant cell mediated cytotoxicity.
describe the production of antibodies
T independent antigens directly stimulate B cells to produce antibodies
describe antibody dependent cell mediated cytotoxicity
The parasite becomes coated with antibodies leaving their FC region extended. Immune system cells attached to the parasite and secrete lytic enzymes and other factors that destroy the parasite.
