SET 6 - Aarti Raja PDF

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Aarti Raja...

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SET 6 third and final What line of defense is specific immunity?

Specific immunity immunity acquired only after an immunizing even such as an infection or vaccination

immunocompetence the ability of the body to react to foreign substances

immunocompetence development of B and T lymphocytes

immunocompetence lymphocytes become specialized for reacting to only one specific antigen or immunogen

specificity and memory two characterizing features of the third line of defense

-lymphocyte development and differentiation - the presentation of antigens - the challenge of B and T lymphocytes by antigens - B lymphocytes and the production and activities of antibodies - T lymphocyte response the five main stages of immunologic development and interaction

the first stage of immunologic development and interaction lymphocyte development and differentiation

the second stage of immunologic development and interaction the presentation of antigens

the third stage of immunologic development and interaction the challenge of B and T lymphocytes by antigens

the fourth stage of immunologic development and interation B lymphocytes and the production and activities of antibodies

the fifth stage of immunologic development and interaction T lymphocyte response

-B cell and T cells work together - high level of communication between the two cell types -When antigens are present, both B and T cells are activated development of dual lymphocyte system

-foreign cells cross the first line of defense and enter the tissue -phagocytes migrate to the site entrance and presentation of antigens and clonal section

antigen-presenting cells (APC) -macrophages ingest the pathogens and induce and inflammatory response if appropriate - Dendritic cells ingest the antigen and migrate to the nearest lymphoid organ -process and present antigen to T lymphocytes

APC process and present antigens to what lymphocytes? T lymphocytes

________ ingest the pathogen and induce an inflammatory response if appropriate macrophages

_________ cells ingest the antigen and migrate tot he nearest lymphoid organ dendritic

pieces of antigen drain into lymph nodes and activate what B cells

-when challenged by antigen, B and T cells proliferate and differentiate -this creates a clone -some become memory cells Activation of lymphocytes and clonal expansion

what do B and T cells do when challenge by an antigen proliferate and differentiate

what happens when B and T cells proliferate and differentiate creates a clone

some clones of B and T cells become what memory cells

progeny of dividing b cell clone are called plasma cells

what are plasma cells programmed to do synthesize and secrete antibodies into tissue fluid and blood

when antibodies attach to antigen, the antigen is marked for destruction and neutralization

what type of immunity is it when an antibody attaches to antigen and mark it for destruction or neutralization humoral immunity

T cells respond to antigen in what kind of immunity Cell-mediated immunity (CMI)

what three types of progeny do T cells give rise to when activated by antigen Th1 cells, Th2 cells, Tc Cells

activate macrophages to help activate Tc Cells Th1

assist B-cell processes Th2 Cells

lead to the destruction of infected host cells and other "foreign" cells Tc Cells

All __________ arise from the same basic stem cell type lymphocytes

Final maturation of B cells occurs in specialized ____ ______ sites bone marrow

Maturation of T cells occurs in the ____________

Thymus

both cell types after maturation migrate to separate areas in the _____ _____ lymphoid organs

What are the major functions of immune system markers -attachment to nonself or foreign antigens -binding to cell surface receptors that indicate self such as MHC molecules -receiving and transmitting chemical messages to coordinate the response -aiding in cellular development

______ proteins are found on host cells MHC

if MHC cells are absent what happens to the cell the cell will be destroyed by the immune system

what are MHC self markers used for present antigens

Bcells have receptors that bind _____________ antigens

T cells have receptors that bind processed ____________ plus _________ molecules on the cells that present antigens to them antigens, MHC

antigens are _______ meaning they have millions of possibilities diverse

it is generally accepted that a unique ________ _______ must exist for each antigen lymphocyte receptor

harbor stromal cells Bone marrow sites

nurture the lymphocyte stem cells and provide chemical signals that initiate B-cell development stromal cells

B cells circulate through the blood "homing" to specific sites in ..... lymph nodes, spleen, and GALT

this cell adheres to specific binding molecules where they come into contact with antigens B cells

T cell maturation is directed by the ____________ _________ and its hormones thymus gland

Mature T lymphocytes express either _________ or _________co-receptors CD4, CD8

binds to MHC class II expressed on T helper cells CD4

Binds to MCH class I found on cytotoxic T cells CD8

T ceels constantly circulate between the ______ and ______ __ _______ _________ migrating to specific T cell areas of the lymph nodes and spleen lymphatic, general circulatory system

how many gene segments can be rearranged to produce diverse receptor types? 500

Millions of different B and T cells are produced leading to _____ specificity

by the time B and T cells reach the lymphoid tissue they are equipped to respond to a single _____ ______ unique antigen

each line of lymphocyte is termed a ____ clone

early undifferentiated lymphocytes undergo a continuous series of divisions and ______ ______ genetic changes

the diversity and specificity of the immune response generates hundreds of millions of different types of _____ and _____ cells B and T

lymphocytes start in ____ ____ bone marrow

T cells develop in the thymus

b cells develop in bone marrow

immature b and t cells are called naive

what is the second stage of lymphocyte development clonal selection and expansion

clonal selection and expansion requires stimulation by an antigen

antigen contact with a lymphocyte stimulates the clone to undergo mitotic division

any clones that react to self are destroyed during the development through clonal deletion

________________ disease are thought to be caused by the loss of immune tolerance to self autoimmune

the receptor genes that undergo recombination are those governing ____________ synthesis immunoglobulin (Ig)

large glycoprotein molecules that serve as the antigen receptors of b cells and as antibodies when secreted Igs

have a Y shaped arrangement

Igs

ends of forks in Igs contain pockets called antigen binding sites

can be highly vaiable in shape to fit a wide range of antigens antigen binding sites

what two types of regions do antigen binding sites have variable regions (v) and constant regions (c)

t cell receptors contain variable region, constant region, antigen binding site, never secreted

substance that provokes and immune response antigens

antigenic molecules are..... -proteins and polypeptides - lipoproteins - glycoproteins - neucleoproteins - polysarrarides - lipopolysaccharides

molecules of complex compositions are more ____________ than simple polymers immunogenic

small molecules do not "catch"....

attention

large but repetitive molecules are less _____ antigenic

substances must be _____________ enough to initiate an immune response from the surveillance cells large

very complex with numerous component parts, each of which elicit a separate lymphocyte response mosaic antigens

small foreign molecules that consist of only a determinant group haptens

too small to elicit an immune response on their own haptens

if linked to a larger carrier molecule then the combination develops immunogenicity haptens

encounter between Leukocyte and antigen makes a basic immune response

after the encounter of leukocyte and antigen the antigen normally undergoes ________ further processing

cells that act upon and formally present antigens to lymphocytes are

antigen presenting cells (APCs)

what are the three types of APCs macrophages, b cells, and dendritic cells

APCs engulf the antigen and modify it so it is more _________ and ___________ immunogenic and recognizable

after processing, the antigen is bound to the ______ receptor and moved the the surface of the APC so it is accessible to the _____ lymphocytes MHC, T

APCs activate ______ t helper cells in the lymph nodes CD4

CD4 binds to MHC class II

CD8 binds to MHC Class I

Onc identification has occurred, a molecule on the APC activates the T helper cell

Th produces Interleukin -2 (IL-2)

once Th produduces IL-2 the T helper cells can now help activate B cells

Clonal expansion and antibody production occures with the activation of B lymphocytes

what occurs with the activation of B lymphocytes -clonal selection and binding of antigen - antigen processing and presentation -Bcell/Tcell recognition and cooperation - B cell activation - clonal expansion - antibody production and secretion - plasma cells and memory cells

4 polypeptide chains connected by disulfide bonds basic Ig structure

-F Ab- antigen binding - F c - crystallized fragment two arms of b lymphocytes

site where epitope binds, contains hypervariable region F Ab

contains an effector portion that can bind to receptors on the membranes of cells to assist immune cells Fc

the effect of the binding of F Ab and F c depends upon the cell's role

the different classes of Igs are due primarily to difference in ____ fragments Fc

-main antibody - about 80% - found in serum - Cross placenta -activates complement Immunoglobulin G

-Monomer and Dimer Form - secreted antibodies - 13% - no fixing of complement - important in mucosal defenses - colostrum Immunoglobulin A

- pentamer - found in serum - 6% - Fixes complement - Great for agglutination - first made during infection Immunoglobulin M

- not found in serum - 1%

- surface of B Cells - act as a receptor Immunoglobulin D

- Sticks to mast cells - Allergies - Parasitic worm defenses Immunoglobulin E

in the primary response the first exposure has two periods which are latent period and synthesis of antibodies

Lack of antibodies synthesis in the first exposure Latent period

-Level of synthesis (titer) - IgM first - Followed by IgG, and some IgA and IgM Synthesis of antibodies

Re-exposure to the same immunogen Secondary response

Antibody synthesis, titer, and length of antibody persistence is rapid and amplified in the secondary response

why is the secondary response faster primarily due to memory cells

- require the direct movement of T lymphocytes throughout the course of the reaction - T cells require some type of MHC recognition before they can be activated - T cells stimulate other T cells, B cells and phagocytes - Cytokine production Cell Mediated Immunity (CMI)

______________ _____________ ____________ in lymphoid organs are primed to react with antigens Mature T cells

T cells recognize an antigen only when it is presented in association with an .... MCH carrier

______ receptors recognize endocytosis peptides on MHC-II CD4

____________ receptors recognize peptides on MHC - I CD8

T cell is sensitized when an _____________/_________ complex is bound to its receptors antigen/MHC

after a t cell is sensitized and activated it transforms in preparation for mitotic divisions and differentiates into one of the ____________ subsets

what are the subsets of T cells - T helper cell 1 (Th1) - T helper cell 2 (Th2)

- T helper cell 17 (Th17) - T regulatory cell (Tr) - T cytotoxic cell (Tc)

play a central role in regulating immune reactions to antigens Th cells

inovlved in activating macrophages by receptor contact, and indirectly releasing cytokins like interferon gamma Th Cells

secrete interleukin-2 Th cells

stimulates the primary growth and activation of many types of t cells Interleukin-2

some secrete interleukins - 4, 5, and 6 Th Cells

stimulates various activities of B cells Interleukins 4, 5, and 6

when sitmulated by antigen/MHC complex, Th cells differentiate into either Th1 or Th2

- Maintain "happy medium" - carry CD 4 markers - Control inflammation

- Prevent autoimmunity - prevent immune response against normal flora Tr cells

the capacity of certain T cells to kill a specific target cell Cytotoxicity

______ __________ ________________ becomes activated when it recognizes a foreign peptide complex with self MHC-I presented to it CD8 Killer T Cell

after activation the ____ cell severely injures the target cell Tc

activation of the Tc cell involves the secretion of ____ and ___ perforins, granzymes

-viraly infected cells - cancer cells- cells from other animals and humans target cells that Tc cells destroy

-related to T cells - Lack Specificity for antigens - circulate through the spleen, blood, and lungs - probably the first killer cells to attach cancer cells and virus infected cells Natural Killer cells

four specific descriptors of the immune state

-active - passive - natural - artificial

- Natural or artificial - antigen activates B and T cells - Memory cells - Long-term protection Active immune state

natural immunity has two immune states which are active and passive

- direct exposure due to infection - develop a specific response - may suffer undesired consequenses Active natural immunity

-Mother's IgG crosses the placenta in utero - IgA present in the colostrum Passive natural immunity

artifical immunity has two immune states active and passive

- vaccination - exposure to antigen - stimulates memory response

Active artificial immunty

-injecting immune serum from virus patient - attempt to neutralize the threat - immunotherapy - no immunological memory Passive Artificial immunity

- antibodies that neutralize toxins - kill bacteria with antibiotics - then eliminate circulating toxins antitoxins

examples of antitoxins Tetanus and botulism

-antigen selection - effectiveness - ease of administration - safety - cost Principles of vaccine preparation

-live attenuated cells or viruses - killed cells or inactivated viruses whole cell or virus...