Antigen Presentation

adaptive

the immune system must adapt itself to previously unseen molecules

immunity

following recovery, individuals will never again develop infection with that same organism but can be infected with other microorganisms

-he/she is protected against one microorganism

humoral immunity

cell-mediated immunity

two forms of adaptive immunity:

B cell

-released antibodies that can get to a lot of places in large quantities

-responsible for eliminating pathogens otuside the cell

what cell works in humoral immunity?

T cell

-not good for long distances and requires direct contact between cells to kill them

-responsible for eliminating pathogens inside cell

what cell works in cell-mediated immunity?

they must first be selected before responding

T and B cells can inflict harm to the body's OWN tissues therefore...

-resists infection

-not pathogen specific

-present from birth

-no obvious enhancement but subsequent exposure

-no specific memory

-poorly effective w/o adaptive immunity

features of innate immunity:

-adapts to infection

-confers pathogen-specific immunity

-matures after birth and influenced by environment

-enhanced by subsequent exposure

-develops long-term, specific memory

-poorly effective w/o innate immunity

features of adaptive immunity:

white blood cells/leukocytes

what does both adaptive and innate immunity depend on?

PMNs and monocyte derived cells

-job is to circulate in blood

what is innate immunity mediated by?

lymphocytes and monocyte derived cells

-macrophages and dendritic cells

what is adaptive immunity mediated by?

protective immunity

requires both innate and adaptive immunity

dendritic cells select lymphocytes to activate and proliferate

adaptive immune response have a certain lag time, adn that is due to:

antigen

any molecular entity capable of triggering adapaptive immune responses

proteins (secreted toxins or on viruses) but can also be carbs, nucleic acids, or phospholipids

examples of antigens often include:

immune responses depend on context of how the antigen is presented

-inflammation (innate response)

the Danger Model suggests...

immunological specificity

cells of the immune system responding to the molecular structure of an antigen is known as...

immunological versaitility

the immune system can differentiate among the thousands of antigens your body comes into contact with, producing specific and appropriate responses to each of them and this ability it known as...

epitopes

a sub-structure of an antigen to which lymphocytes respond and remember

-triggers an immune response

true

-can attack things at many different points

TRUE OR FALSE: an antigen can have many epitopes

immunological memory

the immune system remembers all antigens that it encounters, therefore the response after a second exposure to the SAME antigen is faster and stronger than the response to the initial exposure, this concept is known as...

immunological tolerance

the ability of the immune system to respond to foreign cells and compounds but to generally ignore normal tissues and cells

-continuously maintained

-central and peripheral tolerance

the lymphatic system

-lymph nodes, spleen, bone marrow (this is primary lymphoid organ), lymphatic vessels, and tissues

where is the immune system?

true

TRUE OR FALSE: unlike RBCs, leukocytes have nuclei and make up a very small part of the blood's volume

when the body is under attack by bacteria and virsuses

when do the number of leukocytes increase?

phagocytic (internalize and digest)

diapedesis (escape extravasation)

migration (movable)

chemotactic (smell/ detect chemical signals)

what are the 4 important characteristics of leukocytes?

polymorphs or RMNs (polymorphonuclear Granulocytes)

Mononuclear Agranulocytes

what are the 2 classes of leukocytes?

polymorphs or RMNs (polymorphonuclear Granulocytes)

this class of WBC has segmented nuclei and cell-specific cytoplasmic granules

neutrophils: (bacteria) # increases during infection

eosinophils: (parasite) allergic rxn ex. asthma

basophils: (parasite) allergic rxn ex. histamine, heparin

what are the WBC that are classified as polymorphs or RMNs (polymorphonuclear Granulocytes)?

Mononuclear Agranulocytes

this class of WBC has nonsegmented nuclei and no specific cytoplasmic granules

-monocytes: dendritic cells and macrophages (antigen presentation)

-lymphocytes: responds to antigen

what are the WBC that are classified as Mononuclear Agranulocytes?

lymph vessels and nodes

a body-wide network that extends to skin and mucosal tissues

lymph

-a clear fluid that bathes the body's tissues, draining lymph nodes

what are immune cells and foreign particles conveyed through?

bone marrow

where does B cell maturation occur?

thymus

where does T cell maturation occur?

the thymus

what organ of the immune system prevents autoimmunity by inducing apoptosis of auto-reactive T cells

the ones that do NOT react strongly with the body's own antigens

T cells must pass through thymus before going to lymph nodes, what are the only t cells that will survive this?

B cells

produce antigen (epitope)-specific antibodies when activated

T cells

regulate, help, and kill in antigen (epitope)-specific manner

epitope-specific receptor

every T cell and B cell are defined by their BLANK

a unique receptor that defines the cell's antigen specificity

what does each T and B cell "clone" express?

macrophages or dendritic cells

monocytes leave the blood steam and become...

macrophages

dendritic cells

what are the professional APCs (antigen presenting cells)?

in tissues then they migrate to lymph nodes to present the antigens to lymphocytes

where do APCs reside?

sampling particles in that environment

what are APCs constantly doing?

T lymphocyte

B lymphocyte

Natural Killer cells

what are the 3 types of lymphocytes?

Cytotoxic T cells (CTL)

Helper T cells (Th)

Regulatory T cells (Tregs)

what are 3 examples of T lymphocytes?

dendritic cells

macrophages

B-lymphocytes

what are the3 examples of APCs?

FALSE

TRUE OR FALSE: plasma cells can revert back to B cells

using Signal 1 and signal 2

How do APCs select relevant T cell clones and tailor the response?

signal 1: MHC-TCR (antigen recognition)

defines specificity of the immune response

signal 2: costimulation (inflammation)

dictates intensity of the immune resposne

MHC Class I

MHC Class II

what are the 2 ways that antigens are displayed to T cells?

MHC Class I

engages cytotoxic T cells and is expressed in ALL nucleated cells

-ex.) HLA-A, HLA-B, HLA-C (many subtypes like HLA-A2)

MHC Class II

engages helper T cells and expressed mostly by APCs

-ex.) HLA-D (many subtypes like HLA-DQ1, HLA-DR4)

endogenous proteins

-8-11 amino acids

where are MHC Class I derived from?

exogenous proteins

-13-25 amino acids

where are MHC Class II derived from?

FALSE

-highly polymorphic

-genetic variations in populations; several hundred

TRUE OR FALSE: MHC genes are not really polymorphic

up to 12 different ones

how many HLA alleles can be expressed in a person?

FALSE

-extremely low

TRUE OR FALSE: the probability of 2 individuals expressing the same set of MHC molecules is extremely high

true

TRUE OR FALSE: Both MHC I and II bind peptides

mostly proteins synthesized within cells

peptides presented by MHC I are derived from...

mostly proteins synthesized through phagocytosis

peptides presented by MHC II are derived from...