1050 Finals Flashcards
Describe acute phase reactants
- Proteins that increase due to infection, injury and trauma
- proteins usually are:
→ c reactive protein
→ alpha-1 anti-trypsin
→ haptoglobin
→ fibrinogen
→ others, such as complement
What is an antigen?
→ foreign substance that stimulates antibody production
→ they are large complex molecules
→ molecular weight → usually more than 10,000
→ usually protein or polysacchandes in nature
What is an antibody?
immunoglobulin produced by plasma cells in response to antigen
What is avidity?
Strength of bond between antigen and antibody
What are chemokines?
→ are cytokines that attract cells to a particular site
→ important in inflammatory response
What is chemotaxis?
→ Migration of cells towards the chemokine
What are cytokines?
→ are chemical produced by activated immune cells that affect function of other cells
→ includes:
-interferons
- chemokines
-tumor necrosis factor
- transforming growth factor
- colony-stimulating factors
-interleukins
What is epitope?
- A determinant site on an antigen
What are haptens?
-Low molecular weight
-substance that bind to antibody once its formed but is incapable of stimulating antibody’s production and less bound to large carrier molecule
What is histamine?
Vasoactive amines released from mast cells and basophils during an allergic reaction
What is hypersensitivity?
During allergic reaction hypersensitivity heightened state of immune responsiveness that causes tissue damage in the host
What is immunity?
immunity is resistance to infection
What is immunogen
Any substance capable of inducing an immune response
What is immunoglobulin?
-(Ig)
An antibody
What is immunology?
Study of reactions of hosts when exposed to foreign substance
What is inflammation?
Cellular and humoral mechanisms involved in reaction to injury or infection
What are interferons?
→ Cytokines with anti-viral properties
→ active against certain tumors and inflammatory processes
What are interleukins?
Cytokines produced by leukocytes that affect inflammatory response through increase in soluble factors i cent
What are ligands?
→ A molecule that binds to another molecule of complementary configuration
→ the substance being measured in immunoassays
What is Lysozyme?
Enzyme found in tears and saliva that attacks cell walls of microorganisms
What is major histocompatibility complex?
→ System of genes that controls expression of MHC molecules found on all nucleated cells originally
→also known as human leukocytes antigens
What is monoclonal? antibody
Antibody derived from a single b-cell clone
What is opsonin?
Serum proteins that attach to foreign substance to enhance phagocytosis
What is phagocytosis?
Engulfment of cell or particular matter by neutrophils or macrophages
What are plasma cells?
- Transformed B cells that secrete antibody
-in peripheral lymphoid tissues is non-dividing and they die in a few days
What is polyclonal antibody?
Antibody produced by many B cell clones
What is postzone?
→ Reduced antigen- antibody complexes due to antigen excess
→ can cause false negatives in aerological testing
For antibody
→test can be repeated in 1-2 weeks
What is prozone
→ Is a reduced antibody. Antigen complex due to antibody excess
→ this can cause false negatives in serological tests for antibody
→ dilute the semi, and retest it
What is seroconversion?
A change of serological tests from negative to positive due to the development of detectable antibodies
What is serum sickness?
Type III hypersensitily reaction that results from a build up of antibodiesto animal serum used in some passive immunizations
What is the thymus?
→ Small flat bi-lobed organ found in the thorax
→ is site of T lymphocytes development
→ one of the primary organs of lymphoid system
What is titer?
→ Means of expressing antibody concentration
→is reciprocal of the highest dilution with a positive reaction
What is a vaccination?
→ Injection of immune genetic material to induce immunity
What is zone of equivalence?
→ When number of multivalent sites of antigen and antibody are approximately equal
→ results in optimal precipitation
What are the branches of the immune system?
-humoral
- cell-mediated
What is humoral immune response?
→ Antibody mediated
→ defends against bacteria and extracellular
→ cells involved are B cells and plasma cells
→ these cells produce antibody production
What is cell-mediated immune response?
→ cell-mediated
→. Defends against viruses-fungi, mycobacteria and other intracellular pathogens and tumor cells
→ cells involved are T lymphocytes and macrophages
→ examples: graft rejection, hypersensitivity reactions and elimination of tumor cells
What are the steps of the humoral immune response?
① first exposure to antigen
② antigens engined and displayed by dendritic cells
③intact antigen activates B cells which give rise to the plasma cells and memory B cells
④these cells eventually secrete antibodies that defend against the pathogens or toxins in the extracellular fluid
What are the steps of cell-mediated immune response?
① first exposure to antigen
② antigens engulfed and displayed by dendstic cells
③ antigens displayed by infected cells and activates the helper T cells secrete the cytokines
④this activates the cytotoxic T cells and give rise to active and memory helper T cells
⑤ cytotoxic t-cells give rise to memory cytotoxic T-cells and active cytotoxic T cells
⑥this defends against infected cells, cancer cells and and transplanted tissue
What are the types of immunity
-innate (natural) defense
-adaptive (acquired) defense
Describe the innate defense?
-present at birth
- not antigen specific
- surface barriers ( skin, mucous membrane, mucus in respiratory tracts)
-internal defenses (inflammation phagocytes, NK cells fever)
What are the two types of adaptive defenses
- humoral immunity (B cells)
- cellular immunity (T cells)
What are two types of adaptive immunity?
-naturally acquired
-artificially acquired
What are the two types of naturally acquired adaptive immunity?
① active → antigen enters body naturally
→ body induces antibodies and specialized lymphocytes
② passive → antibodies pass from mother to fetus via placenta or to infant via breast milk
What are two types of artificially acquired adaptive immunity?
① active → antigens introduced via vaccine
→ body produces antibodies and specialized lymphocytes
② passive → preformed antibodies in immune serum are introduced by injection
What are the 5 leukocytes of natural immune system?
①basophil
②eosinophil
③neutrophil
④ monocyte/macrophage
⑤ lymphocytes
What the 3 granulocytes of the natural immune system?
①basophil
②neutrophil
⑤ eosinophil
Describe neutrophil
- Functions for phagocytosis and inflammatory response
-respond to chemotaxis
-granules contain bacterial enzymes
Describe eosinophils
- Neutralize basophil or mast cell products
-responsible for destruction of some helmets (parasites)
-they have some phagocytic ability
Describe basophils
-seen in hypersensitivity reactions
-they have granules that contain histamine, heparin, eosinophil chemotactic factor A
-in allergic response, they bind to IgE and granules release contents in the presence of the antigen
Describe monocytes
-responsible for phagocytosis
-they migrate to tissues and become macrophages
-respond to chemotaxins
Describe mast cell
-A tissue cell
-responsible for hypersensitivity reaction
-seen in connective tissue cells
-resemble basophils but are larger and they contain more granules and bind to IgG
Describe macrophages
-phagocytosis
-help eliminate bacteria, intracellular parasites, tumor cells
- secretion of cell mediators
- antigen presentation
-activated by contact with microorganisms or cytokines from T lymphocytes
Describe dendritic cells
-phagocytosis in nature
-responsible for presentation of antigen to helper T cells in the blood and lymph organs
-initiate acquired immune response.
- tissue cells with long membranous extensions
Describe Natural killer cells (NK)
- First line of defense against tumor cells and cells infected with viruses
-lymph’s without T or B markers
-CD16 and CD56 positive on cell surface - bridge between acquired and innate immunity
- lack specificity
- stimulated by cytolones
-respond early infection which allows time for the T and B cells to be activated
What are the cells of the acquired immune system
-T lymphocytes
- plasma cell
- killer cells
Describe T lymphocytes
- function of cell mediated immunity
-derived from cells in bone marrow
-they develop T cells specific surface antigen in the same thymus
-60 - 80 % lymphocytes are T lymphocytes
Describe helper inducer cells
- Orchestrate cell mediated immunity,
- activate B cells, cytoxic cells and NK cells
-CD4 positive - 2/3 peripheral T cells
- normal CD4 is about 1,000 per milliliter, in AIDS → > 200 per milliliter
What is attenuation?
→ A process of producing nonpathological bacteria or rinses for use in vaccines
→ organisms have been weakened by treatment with chemicals, changed temperature or repeated passage in cell culture
What are chemotaxins?
- A protein or other substances that acts as a chemical messenger to produce chemotaxis
What is diapedesis
Process by which cells are capable of moving from the circulating blood to the tissues by squeezing through the wall of blood vessel
Describe germinal center
Interior of secondary follicle where blast transformation ot B cells take place.
Describe memory cells
- Progeny of an antigen activated B or T cells that is able to respond to antigen more quickly than the parent cell
Describe primary follicle
A cluster of B cells that have not yet been stimulated by antigen
Describe primary lymphoid organs
-the organs in which lymphocytes mature: these are bone marrow and the thymus
Describe secondary follicle
→ A cluster of cells that are proliferating in response to specific antigen.
→ has germinal center and stimulated B cells
Describe secondary lymphoid organs
- Where the main contact with forgein antigens takes place
- spleen, lymph nodes, appendix, tonsils and other mucosal-associated lymphoid tissue
Describe spleen
- Largest secondary lymphoid organ
- filters out aged cells and foreign
Describe thymocytes
-immature lymphocytes
-found in the thymus
-undergoes differentiation of T cells to become a mature cells
Describe complement
- Series of proteins (30 or more) that are normally present in serum
-overall functions are medication, osponization, chemotaxis, cell lysis or inflammation and destruction of foreign cells
-most are inactive enzyme precursor that ave converted to active enzymes in precise order
Describe defenses
- Small canonic proteins
- released by lysosomal granules
- can kill bacteria and many fungi by destroying their cell walls
Describe fibrinogen
-acute-phase reactant that changes to fibrin
-forms clot in the bloodsteam
Describe haptoglobin
- An acute-phase reactant
- binds irreversibly to free hemoglobin released by intravascular hemolysis.
Describe opsonins
- Serum proteins that attach to a foreign substance and enhance phagocytosis
Describe oxidative burst
- Increase in oxygen consumption in phagocyticceas which generate oxygen radicals used to kill/engulf microorganism
Describe Pathogen-associated molecular patterns (pamps)
-.structural patterns of carbohydrates, nucleic acids, bacterial peptides or microorganism
- recognized by the pathogen recognition receptors on the cells of the innate immune system
Describe toll-like receptors
-receptors found on human leukocytes and other cell types
-recognize microorganisms and aid in their digestion
Describe adjuvant
Substance administered with a immunogen that enhances and potentates the immune system
Describe alloantigen
- Antigen that is found in another membrane of the hosts species
- capable of eliciting an immune component host
Describe autoantigen
Antigen that belongs to the host and is not capable of eliciting an immune response under normal control circumstances
Describe hapten
- A small molecule which, when combined with a larger carrier such as a protein, can elicit the production of antibodies which bind specifically to
Describe heteroantigens
An antigen of a species different from that of the host, such as other animals,, plants, or microorganism
Describe antigen dependent stage
-final phase of B cell development in bone marrow that results in mature B cells that have not been exposed to antigen.
Describe antigen- independent phase
-If a B call is stimulated by antigens it undergoes transformation to blast stage that eventually forms memory cells and antibody secreting plasma cells
Describe heterophil antigen
Antigen that exists in unrelated plants or animals but either identical or closely related so that antibody to one Will cross- react with antibody to the other.
Describe suppressor T cells
- Inhibit helper T cells and cytotoxic cells that kill other cells
- CD8 positive
- 1/3 of peripheral T cells