A&P II Ch. 20.4 Adaptive immunity

T cell receptor (TCR)

A receptor on a T cell, that bind to a specific antigen

be coupled with a peptide to function fully as an antigen

Antigens consist of carbohydrates, lipids, and metals but must what?

Immunogens (antigens)

Antigens that can generate a response from the immune ssytem

the antigens bound to Class I MHC molecules are not recognized as foreign, but allohafts and enogafts do contain antigens that lead to reaction.

Autografts and isografts result in no response from Tc cell because

Helper T cells (Th cells, CD4 Cells) and the cytotoxic T cells (Tc or CD8 Cells)

Cell mediated immunity involves the different classes of T cells, including ?

endogenous, exogenous antigens

Class I MHC molecules present _____ antigens and class II present ?

Cross presentation

Dendritic cells can undergo ______ in which they are able to display some of the ingest viral and bacterial antigens on Class I MHC molecules, in this way they can interacted with and activate Naive Tc cells.

Clone

Each population of T cells that can respond to a specific antigen is known as a ______

Class II MHC molecules

Found on the surface of antigen presenting cells, including dendritic cells, macrophages, and B cells

Major Histocompatibility Complex (MHC)

Glycoproteins found on the surface of cells that bind and display antigen fragments

phagocytic or cytotoxic abilities

Helper T cells have no ____ or ____

Human Leukocyte Antigen (HLA)

Molecules found on all nucleated cells in the body that help the immune system to recognize whether or not a cell is foreign to the body. These antigens are inherited from one's parents. Human leukocyte antigens are used to determine the compatibility of kidneys and pancreases for transplantation from one individual to another. The major groups of HLA antigens are HLA-A, HLA-B, and HLA-DR.

Class I and Class II MHC molecules

Naive cytotoxic T cells generally interact only with ______ where Naive helper T cells interact with?

kill other cells, specifically those with foreign antigens bound to class I MHC molecules

Primary function of Cytotoxic T cells (Tc) ?

others are not

Some T cell clones are capable of recognizing and responding to pathogens, where?

The cell synthesizes either a self antigen or a foreign antigen (things such as intracellular bacteria are not synthesized by the cell)

Step 1 by which Class I MHC molecules process and display an endogenous antigen

The cell ingest a pahtogen by phagocytosis

Step 1 by which Class II MHC molecules process and display an exogenous antigen

The antigen are broken down by enzymes in the cytosol

Step 2 by which Class I MHC molecules process and display an endogenous antigen

the phagocytic vesicle fuses with a lysosome; the pahtogen is degraded and its antigens are fragmented

Step 2 by which Class II MHC molecules process and display an exogenous antigen

An antigen fragment containing the antigenic determinant is transported into the rough endoplasmic reticulum (RER) and is coupled with a class I MHC molecule in the RER membrane

Step 3 by which Class I MHC molecules process and display an endogenous antigen

the lysosome fuses with a vesicle from the RER that contains Class II MHC molecules, and an antigen fragment binds to the MHC molecule

Step 3 by which Class II MHC molecules process and display an exogenous antigen

The MHC antigen complex leaves the RER by a vesicle and is inserted into the cells plasma membrane

Step 4 by which Class I MHC molecules process and display an endogenous antigen

The MHC antigen complex is inserted into the cell's plasma membrane

Step 4 by which Class II MHC molecules process and display an exogenous antigen

bone marrow, thymus

T cell are formed in the ____ but mature in the ______

interact only with pieces of antigen bound to glycoproteins

T cells cannot directly interact with an antigen, they instead?

Naive T cells

T cells that do survive the screening and are released into circulation are known as ______ because they have yet encountered their specific antigen and they must bind to specific antigens before they become activated

detect abnormalities in any cell type with a nucleus, critical for detection of cancer cells, foreign cells, and cells infected with intracellular pathogens such as viruses and bacteria

Tc cells ability to interact with Class I MHC molecules means they can ? which is critical for?

sameway, require IL-2 from Th cells to activate fully (preventing abnormal Tc activation)

Tc cells are activated in the _____ way as Th cells, with the addition that they require?

cytokines that then activate and enhance various components of the immune system

Th Cells primarily exert their effects through the secretion of ________ that the_____

cell mediated

The first ae of adaptive immune system is ______ immunity

clonal selection

The phenomenon whereby cells of adaptive immunity respond more quickly and efficiently to subsequent exposures to an antigen

Immunological memory

The phenomenon whereby cells of adaptive immunity respond more quickly and efficiently to subsequent exposures to an antigen)

the type of MHC molecule involved

The process of naive T cell activation is very similar for Th and Tc cells, the main difference being ?

screens, recognize antigens

The thymus _____ these cells and mediates the destruction of those clones that cannot _______

CLass I and class II MHC molecules

Two types of MHC molecules

Memory T cells

____ cells respond more efficiently to exposure upon antigen. One reason for this is because ______ have no need of a Co stimulator

self-reactive T cells, Self tolerance

________ recognize self antigens as foreign and would attack your cells if released into circulation, however, these are also destroyed ensuring ______

endogenous antigen

a foreign antigen present on a pathogen that lives inside you cell such as an intracellular bacterium OR a foreign or self antigen encoded by your DNA (things such a cancer due to mutated DNA or a viral antigen)

immunocompetent

ability o mount a normal response to foreign antigens

exogenous or endogenous

antigens can be classified as ______ or _______

no

are MHC molecules found on erythrocytes?

Class I MHC molecules

found on the surface of the plasma membrane of nearly all nucleated cells

autografts, isografts, allografts, xenografts

four basic types of organ transplants

Innate immunity: stimulation of macrophages (Th Cells secrete interleukin-3 which stimulates macrophages and also causes macrophages to produce interleukin 12 which stimulates Th cells to generate more Interleukin 3 cells creating a positive feedback loop)

function 1 of Th Cells

adaptive cell mediated immunity: Activation of Tc cells (Th secrete interleukin 12 which activate Tc cells

function 2 of Th Cells

adaptive antibody mediated immunity:stimulation of B cells (Th Cells directly bind to B cells and stimulate their proliferate and differentiation. Th cells get their name derived from this because they help initiate B cell response)

function 3 of Th Cells

isografts

involve organs and tissue transplant between two genetically identical individuals

autografts

involves tissue transplanted from one site to another in the SAME individual. Such as skin grafts

allografts

most common, involve organs and tissue transplanted between two non identical individuals of the same species

exogenous antigen

one that originates outside the cell and must be taken into the cell by phagocytosis

Xenografts

rare and involve organs and tissues transplanted between two individuals of different species

haptens (urushiol) , a protein carrier

self antigens (antigens on your own cells) are not immunogens but very small antigens called ______ are immunogenic only if they are attached to ?

Dendritic cells display the antigen fragments on their MHC molecules, and the MHC antigen complex binds to the receptor of a specific naive Th or Tc cell clone (multiple changes occur inside the T cell when its receptor recognizes and binds this complex, and then activation beings this is known as clonal selection because the antigen selects a particular T cell clone)

step 1 of T cell activation, clonal selection, and differentiation

the actiavted T cell binds to its target cell

step 1 of function of TC cells

Cells of the lymphoid line divide in the bone marrow

step 1 of tell cell maturation

The Th or Tc cell binds a co stimulator and becomes activated ( Full T cell activation requires the interaction of the naive T cell with other molecules on the cells called Co stimualtors, this is because T cells have a low affinity for the MHC antigen complex to prevent unnecessary naive T cell activation)

step 2 of T cell activation, clonal selection, and differentiation

the Tc cells releases perforin, which from pres in the target cells plasma membrane

step 2 of function of TC cells

immaute T cells exit the beone marrow and migrate to the thymus

step 2 of tell cell maturation

The activated Th or Tc cell clone proliferates and differentiates into effector cells (cells that causes immediate effect) and memory T cells (Th or Tc increased in number when activated)

step 3 of T cell activation, clonal selection, and differentiation

The Tc cell then releases enzymes that can now enter the target cell and fragment its DNA

step 3 of function of TC cells

the thymus stimulates T cell maturation and destruction of self reactive T cells

step 3 of tell cell maturation

when the target cell begins to degrade, the Tc cell detaches and searches for a new target cell

step 4 of function of TC cells

Mature naive T cells migrated to lymphoid organs

step 4 of tell cell maturation

antigen determinant

the unique portion of the antigen to which the receptor binds to is known as its ________

necrosis

tissue death

Finding a good HLA match and suppressing the immune system

two ways of preventing graft rejection.

cells infected with intracellular pathogens (viruses and bacteria), cancer cells, and foreign cells such as a transplanted organ

what do cell mediated cells respond to

cluster of differentiation which referred to specific molecules within the plasma membrane that differentiate one cell type from another

what does CD stand for