The immune System Flashcards
list the cells and molecules involved in the immune response (8)
- antigen-recognition lymphoid cells
- Granulocytes
- Macrophages
- Dendritic cells
- Natural Killer Cells ( B & T Lymphocytes)
- Cytokines
- Accessory molecules
- other molecules
what are the antibody-mediated immunity (humoral) components
- Complement: lysis of bacteria and some viruses, opsonin, increase in vascular permeability, recruitment and activation of phagocytic cells
- Coagulation system: increase vascular permeability, recruitment of phagocytic cells, B-lysin from platelets which is a cationic detergent
- Lactoferrin & transferrin: compete w/bacteria for iron
- Lysozyme: breaks down bacterial cell walls
- Cytokines: various effects
what is Hematopoiesis
the process to produce immunce cells
define stem cells
an unspecialized cell that can divide w/o limit and under specific conditions differentiate into specialized cells
name the 2 main pathways from which Leukocytes are derived from?
stems cells in the bone marrow can be from ;
- Lymphoid lineage
- Myeloid lineage
define Antibody (Ab) and how does it work
blood protein that is produced in response to and countering a specific antigen. they chemically bind to a substance that the body recognizes as foreign
define Specificity
provide an example
a specific defense that is activated by 1 specific antigen
- T and B Lymphocytes has receptors that bind only 1 specific antigen
define Antigen(Ag)
molecule or molecular structure that may be present on the outside of a pathogen and can be bound by an antigen-specific antibody
- Ag= antibody generator
define Tolerance (property of immune system)
the immune system tolerates “normal” (self) antigens and only attacks foreign (nonself) antigen
failure of immune system to maintain tolerance levels leads to autoimmune diseases
what is the 2nd line of defense
- nonspecific, innate
- cell derived like phagocytosis, complement proteins, interferons, inflammation, fever
what are the cellular components of the Cell-Mediated Immunity
- Neutrophil: phagocytosis and intracellular killing which leads to inflammation and tissue damage
-
Macrophages: phagocytosis and intracellular killing,
- extracellular killing of infected or altered self targets, tissue repair, antigen presentation for specific immune resposne
- NK & LAK cells: kill virus infected and self targets
- Eosinophils: kill certain parasites
what do hematopoietic stems cells give rise to?
red blood cells (erythorcytes)
where do the cells of the immune system derive from?
pluripotent stem cells in the bone marrow
define Versatility
the immune system ability to attack any antigen at any time
due to large lymphocytes diversity in the body each which have large populations and respond to a different antigen
what are the 4 properties of immunity?
- specificity
- versatility
- memory
- tolerance
what is the 1st line of defense?
- nonspecific, innate
- physical barriers like the skin, mucous membrane and chemicals
define Memory (property of immune system)
lymphocytes remember antigens that they have encountered
- During initial response to an antigen the lymphocytes undergo repeated cell divisions which produce 2 types of cells;
- activated lymphocytes: attack antigen invader
- memory cells: remain inactive until exposed to the same antigen
what are the 2 types of immune responses
- cell-mediated immunity (CMI): response produced by T cells
- Antibody-Mediated (Humoral) Response: response produced by B cells
define Immunology
the study of our protection from foreign macromolecules or invading organisms and our response to them
in a diagram show totipotent stems cells all the way to the specific type of cells they can produce
what are precursor cells
unspecialized cells that can differentiate into various types of specialized cells in the body
what is a progenitor cell
cells that are descendants of stem cells and can differentiate to form one or more types of cells
what is the name of the process in which lymphocytes are produced? where are they stored
lymphopoiesis,
stored in the lymphoid tissues, organs and areas or red bone marrow
List the 2 types of T Cells and their function
- CD4+ T Helper Cells (TH)
- Function: stimulate function of T & B cells. B cells must be activated by T cells before they can produce antibodies
- CD8+ cytotoxic T Cells (TC)
- function: attack foreign cells or cells infected by viruses. primary cells involved in CMI
- TS: T suppressor cells are a regulatory subset of CD8+ T Cells. inhibit function of T & B cells
- function: attack foreign cells or cells infected by viruses. primary cells involved in CMI
what are the organs that are associated with the immune system called? And how are they further separated
lymphoid organs
- primary lymphoid organs or
- secondary lymphoid organs
what are the primary lymphoid organs?
site where lymphopoiesis, site where lymphoid cells proliferate, differentiate and mature to immune-competent cells in the absence of antigenic stimulation
large at birth and they atrophy w/age progression
- Thymus: where the T cells mature
- Bone marrow: B cell maturation in humans
- Bursa of fabricius: site of B cell maturation in birds
what are the secondary lymphoid organs
lymphocytes made functional in secondary lymphoid organs. organs are small and poorly developed at birth and grow progressively w/age
- Lymph nodes
- spleen
- Mucosal associated lymphoid tissues (MALT)
List the agents in the 1st line of defense
- skin
- mucous membrane
- hair in the nose
- cilia in the upper respiratory tract
- saliva
- gastric juice in the stomach
- perspiration (sweating)
- urine
- sebum
what are cytokines
small secreted proteins or chemicals released by cells to trigger/regulate the innate and adaptive immune response.
what does the immunological surveillance include?
- Natural Killer (NK) Cells: directly kill tumor cells w/help of interferon , IL-2
- cytotoxic T Cells: also directly kill tumor cells
- Cell-mediated T Cells (effector T Cells) that produce and release lymphokines
- macrophage activation factor that activates marcophage
- Gamma interferon & interleukin-2 that activate NK
- Tumor necrosis factor (cachectine)
list the different types of cytokines (4). How are they named?
cytokines are the general name
- lymphokines: cytokines made by lymphocytes
- monokine: cytokines made by monocytes
- chemokine: cytokines with chemotactic activities
- interleukin: cytokines made by one leukocyte that act on other leukocytes
explain the events in phagocytic defense
- chemotaxis of the phagocyte to microbe
- adherence
- ingestion
- fusion of vesicles (lysosomes)
- killing of microbes by enzymes and other chemicals
- elimination (exocytosis)
what are opsonins and what are their function
molecules that bind to bacteria and phagocytes
they increase phagocytosis by 1000x through process called opsonization
explain how opsonins attach to bacteria cells
- Opsonization begins when complement molecules C3b, iC3b or C4b attach to the surface of the bacteria
- those molecules have a strong affinity for macrophagic CR3 & CR4.
- when the complement molecules bind to the receptors it allows the phagocytic cell to engulf the bacteria
Can complements be considered part of the innate immunity or adaptive immunity? Explain?
Complement can be considered part of the innate immunity because its role in inflammation, phagocytosis, and bacterial killing.
It can also be considered part of the adaptive immunity because it can be activated by bacterial invasion as well as reactions between antibody and antigen
how does the complement system work
- attracts phagocytes to site of injury/infection (chemotaxis)
- enhances phagocytosis of antigen:antibody complex
- destroys target plasma membrane
- stimulates inflammation by enhancing histamine release by mast cells and basophils. this increase local inflammation and accelerated blood flow
- enzymatic system of serum proteins that are made of 9 components (C1-C9) which sequentially activated by classical pathway or alternative pathway
- membrane-attack complex which is made up of terminal complement components which assemble to form membrane spanning hydrophilic pore which damage the membrane
what are Toll-like receptors? How do they function?
TLR are transmembrane receptors that are associated with the innate immune response
Function: they are pattern recognition receptors (PRR) that detect potential harmful pathogens and turn on a response to appropriately deal with pathogens. the response is usually the expression of cytokines
how many TLR do humans have?
- they each specialize in a different response to a pathogen
what are interferons (INF)
a set of proteins that are released by viral infected cells, in vivo, which then react with uninfected cells so those cells can be resistant to infection from virus
list the different types of interferons (IFN) in humans
- alpha interferon
- beta interferon
- gamma interferon
what is inflammation?
a protective mechanism that is intended to get rid of the organism that cause the cell injury as well as to prevent the consequence of the injury such as necrotic cell and tissues
