immune system Flashcards
what is the primary immune structure and its role
white blood cells are developed, stored, and carried out for immune functions
-has sites that use stem cells to give rise to mature B cells and and both immature/mature pre T cells
-sites are found in bone marrow and the thymus (these change with age/season)
what is the secondary immune structure and its role
white blood cells are developed, stored, and carried out for immune functions
-has sites that carry out most immune responses
-sites are found in nodes, spleen, tonsils, appendix, and peyer’s patches
what is a pathogen
a disease causing microorganism that focuses on the innate immune system
ex: parasites, fungi, virus
what is a antigen
something that causes an adaptive immune response and reacts to the antibodies and cells it provoked
ex: cancer cell, bacteria, virus
what is a allergen
an immune response that is perceived as a threat that causes tissue damage but is well tolerated by others
what is innate immunity and its structure and function
innate has immediate responses, is non specific, and has no memory
-has surface and internal barriers that stop/destroy microorganisms and respond to inflammation and fevers
what is adaptive immunity and its structure and function
-its job is to provide protection against specific pathogens and microbes
-it is antigen specific, has lag time, has memory, and systemic responses (can find sickness anywhere in the body)
-it uses cell mediated and humoral immunity
what structures are part of the first line defense in innate immunity and what are their functions
skin and mucous membranes that use protective chemicals to stop or destroy microorganisms
-skin uses acidity, sebum, defensive proteins, dermecidin
-membranes use acidity, hairs, cilia, mucous, defensive proteins, enzymes
what structures are part of the second line defense in innate immunity and what are their functions
granulocytes, macrophages, antimicrobial proteins, and natural killer cells help fight inflammation and fever
what is the roll of toll like receptors in the activation of innate immune cells
innate cells use TLR’s to identify and bind to structures/patterns on pathogens to trigger immune responses during second line defense
what cells can perform phagocytosis and how does this help with antigen presentation
macrophages, neutrophils, and dendrites can perform phagocytosis
-This can help by inserting digested pieces of pathogens into specific membrane proteins to present the antigen
what is the role of antigen presenting cells in activating immune defenses
antigen presenting cells have MHC proteins that will allow T cells to respond once they’re processed
what is the role of interferon alpha in innate immune function
it produces an anti viral protein to block viral reproduction of infected, degrade viral rna, and activate natural killer cells
(interferons are secreted by infected cells to warn healthy neighbor cells)
what is the role of interferon beta in innate immune function
it produces an anti viral protein to block viral reproduction of infected cells, degrade viral rna, and activate natural killer cells
(interferons are secreted by infected cells to warn healthy neighbor cells)
what is the role of interferon gamma in innate immune function
T cells, natural killer cells, and macrophages secrete gamma to produce immune mobilizing effects
gamma activates the cells it is secreted from
what is the role of complement in the formation of membrane attack complexes, inflammation, and opsonization
complement proteins have 3 pathways that are used to destroy bacteria and enhance inflammation
-classical is activated by antibodies binding to bacteria
-lectin is activated when lectins bind to bacterial carbohydrates
-alternative is activated when complements directly bind to bacteria
all of these pathways merge and bind to c3, c3 will then split into c3b and c3a, c3 will also activate c5b and c5a
-c3a and c5a enhance inflammation through the release of histamine, higher blood permeability, and the attraction of phagocytes
-c3b does opsonization, coating pathogens and enhancing phagocytosis
c5b will form membrane attack complexes by inserting themselves into the target cell membrane that will then create pores allowing water to come in and cell contents to leave
how does inflammation occur and what is the benefits in regards to immune response
inflammation is a response to tissue damage usually noticed by redness, heat, swelling, or pain
-immune cells release chemicals
-phagocytes will then mobilize to the site of damage
-macrophages will clean up and consume debris
benefits include: prevention of the spread of damaging agents, gets rid of debris and pathogens, alerts adaptive immune system, and starts the repair process
leukocytosis, margination, diapedesis, chemotaxis
what is cell mediated immunity
it involves t cells and cytotoxic cells that provide immunity to intracellular bacteria, fungi, viruses, cancer, and protozoa
what is humoral immunity
it involves b cells and plasma cells that provide immunity to extracellular bacteria, viruses, and toxins
what cells have major histocompatibility complexes (MHC) 1 and 2
all body cells have MHC 1 (except red blood cells)
Only macrophages, dendritic, and b cells have MHC 2 (antigen presenting cells)
how does MHC 1 activate immune cells
they alert the immune system of infected cells by presenting pieces of the antigen so that they can be identified by t cells as foreign or self and be killed
how does MHC 2 activate immune cells
it captures the foreign antigen and notifies other immune cells to help provide a defense against it
what is the process of positive selection and what is its role in T cell maturation
-it helps with maturation as it does self recognition
-it will select cells that are capable to recognize self MHC proteins
what is the process of negative selection and what is its role in T cell maturation
-It helps with maturation as it does self tolerance
-It will select and get rid of cells that bind to self antigens that are shown by self MHC
how are endogenous antigens presented and what MHC’s are involved in the process
self cells that are infected with pathogens will secrete MHC 1 so that they can be identified and killed
-these antigens include bacteria, parasites, and viruses INSIDE cells
how are exogenous antigens presented and what MHC’s are involved in the process
-B cells are activated by antigen presenting cells and bind to the antigens in the lymph, blood, and tissue fluid
-T cells will also be activated only after the antigens are processed and presented by the APCs
-This is using MHC 2
-these antigens include bacteria, toxins, parasites, pollen, and viruses NOT YET inside the cell
what are cytokines and what are their basic functions
they are cells that directly attack and kill virus infected cells, inside cell bacteria, inside cell parasites, cancer, and foreign cells
they deliver lethal hits using perforins (make pores for granzymes to enter) and granzymes (stimulates cell death)
how are helper T cells activated and what is the end result of the activation
the t cell will bind to MHC 2 on the antigen presenting cell, it will then recognize the MHC and the foreign antigen, CD4 protein maintains coupling during the recognitions, t cell co simulatory molecules will then bind to the same molecules on the APC
end result: CD4t cells profilterate (clonal selection) and become more helper and memory cells
how are cytotoxic T cells activated and what is the role of helper T cell in this activation, what is the end result of the activation
- t helper cells are needed for the co stimulations
the t cell will bind to MHC 1 on the antigen presenting cell, it will then recognize the antigen and the MHC, CD8 protein will maintain coupling during the recognition, T helper cells will then stimulate dendritic cells to start the co stimulatory molecules, CD8 t cell co stimulatory molecules will then bind to those molecules on the APC
-End result: CD8 t cells can do clonal selection and become cytotoxic and memory cells
how are B cells activated and what is the role of helper T cells in this activation, what is the end result of the activation
there are 2 ways they can be activated
1. b cell will encounter a target antigen, the antigen will bind to b cell receptors activating the b cell
End result: clonal selection only
2. b cell encounters target antigen, antigen binds to b cell receptor and activates, receptor mediated endocytosis occurs, the processed antigen connected to MHC 2 will be shown to a t helper cell that will then bind to the antigen, cause cd4 proteins and MHC 2 to interact, inducing recognition and co stimulation of the b cell
End result: intense responses and formation of memory cells
what is the function of helper T cells and what CD proteins are associated with them
CD4 protein is associated with helper cells
functions: activate both arms of the adaptive system (humoral and cell mediated immunity)
what is the function of cytotoxic T cells and what CD proteins are associated with them
CD8 protein is associated with cytotoxic cells
functions: directly attack and kill other cells
what is the function of regulatory T cells and what CD proteins are associated with them
CD4 is associated with t reg cells
Function: supress the the immune system and and prevent over activity of immune responses
what is the general function of antibodies in the body
they are secreted by plasma cells and prepare antigens for destruction by binding to the antigen in a lock and key fashion
variable regions (arms) will do the binding sites
constant regions (stems) will determine the antibody class and function
what is the difference between a primary and secondary immune response
primary response will undergo proliferation and differentation after being exposed to antigen for first time (lags), while secondary will have a faster, stronger, and longer response when exposed to the same antigen because of its memory
what are the 4 ways to acquire adaptive immunity
- active natural: exposed to antigen by chance
- active artificial: deliberate exposure to antigen (vaccines)
- passive natural: antibodies passed from mom to kid
- passive artificial: an igG serum is received from another person/animal (bug bites)
what effect does immunodeficiencies have on the body
the body is less capable to fight off infections and produce immune functions since the immune system is no longer healthy
what effect does hyper immune reactivities have on the body
there is both immediate and delayed reactions
immediate: initial contact has no effect until the next encounter with a fast and large distribution of histamine causing inflammation
delayed: takes about 1-3 days for symptoms to occur, once occurring certain cells will cause damage to tissues
what is the location and function of IGM class antibody
location: secreted by plasma cells during primary response
function: activates complement
what is the location and function of IGA class antibody
location: saliva, sweat, intestinal juice, milk
function: stops pathogens from attaching to epithelial cell surfaces
what is the location and function of IGD class antibody
location: on b cell surfaces
function: is a b cell antigen receptor
what is the location and function of IGG class antibody
location: in plasma (most abundant)
function: activates complement in both primary and secondary response
what is the location and function of IGE class antibody
location: is on the stem end of basophils and mast cells
function: releases histamine and other chemicals for inflammation other allergic reactions
what are cytokines and what are the basic functions
they are the chemical messengers of the immune system
they mediate cell development, differentiation, and responses throughout the immune system
