ryan- cells and organs of adaptive immune system

what are 2 factors that make the adaptive/acquired immune response different than the innate?

memory and specificity

what cells are involved in the adaptive immune response?

antigen presenting cells (dendritic cells, monocytes), lymphocytes (t and b cells/lymphocytes)

what is the main job of b lymphocytes/b cells?

once activated, mosy act as a plasma cell where they make antibodies

what is the main job of t lymphocytes/t cells?

once activated they become either cytotoxic t cells to kill the infected cell or helper t cells to help other cells do their job

are NK cells innate or adaptive?

made in the bone marrow with lymphocytes but act in the innate system

what is a mature lymphocyte?

fully developed lymphocyte that is capable of being activated and respond to a specific stimulus

what is a naive lymphocyte? can a mature lymphocyte also be naive?

lymphocyte that has NOT encountered its specific antigen yet, lymphocytes can be both mature AND naive

what is the importance of lymphoid organs?

location that lymphocytes are generated in, mature in, become activated in, and perform effector functions in

what are the 2 primary lymphoid organs we discussed?

bone marrow and thymus

what is the primary lymphoid organ in birds?

bursa of fabricius

what happens inside of primary lymphoid organs?

lymphocytes form and mature, both B and T cells aquire their specific antigen receptor, B and T cells are screened to prevent attack of “self antigens”

what are examples of secondary lymphoid organs?

spleen, lymphatics/lymph nodes, mucosa-associated lymphatic tissues (MALT)

what happens inside of secondary lymphoid organs?

mature lymphocytes are maintained (after going through primary organ), adaptive immune responses are initiated, lymphocytes perform their effector functions

what kind of stem cells are found in the bone marrow that give rise to all blood cells?

hematopoietic stem cells (pluripotent stem cells)

what is the difference between red and yellow marrow?

yellow is mostly fat, red is where hematopoiesis occurs and lymphocytes are generated

name and describe the receptors found on b lymphocytes

b cell receptors (BCRs); bind to specific antigen, antien does NOT need to be processed intracellularly

name and describe the receptors found on t lymphocytes

t cell receptors (TCRs); bind to specific antigen AFTER the protein has been processed intracellularly, is displayed by MHC surface proteins

where do b cells develop and where do they perform their actions?

bone marrow, secondary lymphoid organs

steps of b cell activation

during maturation the b cell develops a functional BCR, move to secondary lymphoid organs (mature but naive), become activated when specific antigen is encountered

where are BCRs located?

cell surface receptor connected to other receptors as part of a co-receptor complex

what form of antigen can b cells recognize?

native conformation (original, unprocessed)

once b cells bind to their specific antigen, what occurs?

clonal expansion and development of antibody producing cells

describe clonal expansion

b cells bind antigen and multiply, daughter cells have same BCR as parent cell and now many cells can recognize the antigen

what does a differentiated (mature and activated) B cell become?

plasma cells that produce antibody (in various secondary lymphoid organs)

simple t cell life cycle

born in bone marrow, travels to thymus to differentiate into thymocytes, exit thymus as mature/naive t cells, secondary lymphoid ograns to participate in immune responses and become effector t cells

describe the flow of lymphocytes inside the thymus

enter from bone marrow, interact with epithelial cells in cortex, mature as they move towards medulla, interact with medullary epithelial cells/macrophages/dendritic cells, exit thymus as mature, naive t cells

where are TCRs located?

surface receptors

what form of antigen do t cells recognize?

linear peptides (protein broken down into linear component), must be processed intracellularly and presented by APCs

how is the processed antigen presented to the t cell?

MHC molecule

which lymphocytes are responsible for cell mediated immunity?

t-lymphocytes

two possible types of t cells and their function

CD8+ cytotoxic t cells— directly kills cell, CD4+ helper t cells— produces cytokines to activate humoral immunity and innate immune cells

what are cytokines? which lymphocyte(s) do they activate?

chemical communicators that can have functions that impact other cells in the body (can activate t and b cells)

which lymphocytes are “humoral”?

b lymphocytes

what type of receptor are antibodies?

BCRs that are bound to the cell surface and cannot be released

what are lymph nodes designed for?

maximal exposure of T and B cells to antigen

what is carried in lymphatic fluid?

antigen, pathogens, debris, toxins, etc

where are t cells located in the spleen?

paracortical region

where are primary follicles located in the spleen?

cortical region

where are secondary follicles located in the spleen?

germinal centers

where are plasma cells located in the spleen?

medullary sinus

what does the spleen do?

mounts immune responsess to the blood borne pathogens, resident macrophages help to recycle senscent RBCs

NALT

nasopharyngeal associated lymphoid tissue

SALT

skin associated lymphatic tissue

primary lymphoid organ function

generates mature lymphocytes

secondary lymphoid organ fucntion

concentrates cells of the adaptive immune system