Immunology Exam 2- Adaptive Immunity

Characteristics of Adaptive Immunity

slow, very specific and complex with specificity

All B& T cells in the body don't recognize the same epitote, very few have the same \____

recognition

Antibodies target the \________ structure

extracellular structure

3rd line of defense

physical barriers (where pathogen gets past) and innate immunity

If the 3rd line of defense breaks its physical barriers it gets past innate system; it goes to the \____ \____ \_____

adaptive immune system

When the B cell immunoglobulins -means more potential \_____

targets

2 types of effector cells

B & T cells

Innate immunity

genes inherited; fixed repertoire of receptors

Adaptive immunity

evolve; one type of receptor; infinite variety

Millions of different T or B cell \_____ with unique binding capabilities

receptors

Small \____ possess each receptor - 1 out of every 10,000

subset

\________ specific - divide and differentiate--recognize specific epitotpes

Pathogen

Adaptive immunity has versatility to recognize any \___

target

Process of dendritic cell taking infection to secondary lymphoid

1. pathogens adhere to the epithelium
2. skin wound allows pathogens to penetrate epithelium
3. local infection, innate immunity
4. dendritic cells take infection to lymph node and stimulate adaptive immunity
5. Effector cells and molecules of adaptive immunity travel to infected tissue

TCR

peptide (8-10 amino acids)

Ig

peptide, proteins,polysaccharide **more variability

The 2 resident cells and what they do

Macrophage: induce inflammation response and make it more robust innate response

Dendritic cell: pick up and take to the nearest secondsary lymphoid tissue to activate the immune response (t-b cell)

Clonal selection-teacher defintion

The T & B cells are specific for the pathogen; B & T cells find the antigen--then proliferate and grow to make more B/T cells

\*antigen specific

Clonal selection picture definition

1. during development,progenitor cells give rise to large numbers of circulating lymphocytes, each having a different form of cell-surface receptor


2. the receptors of only a few circulating lymphocytes interact with any given pathogen
3. pathogen-reactive lymphocytes are triggered to divide and proliferate
4. pathogen-activated lymphocytes differentiate into effector cells that eliminate the pathogen

Clonal selection is a \_____ \_____ of lymphocytes

Small proportion

Clonal selection proliferates the population of \_____ using mitosis

clones

what does it mean when clonal selection is identical to the surface Ig(immunoglobulin) or TCR (t cell receptor)?

when the correct b or t cell is found through clonal selection they will go through mitosis to produce identical of the same receptor needed for that pathogen which is either a Ig to TCR

what does it mean when the clonal expansion differentiate into effector cells?

when clonal expansion is happening it is mitosis of the b or t cell that has the receptor they need so once there is a whole bunch of cells are made the pathogen will bind they differentiate from a b cell to a plasma cell and a t cell to either a CTL or a helper t cell depending on the MHC1 or MHC2

\*depends on innate immune system

B cell-\_____

B cell(gp120)-plasma(differential effector cell)

T cell-\_____

T cell(peptide of gp120)- effector T cells(CTL,Th1,Th2)

Clonal selection and clonal expansion are part of the \_____ adaptive immune response

primary

Differentiation is very important and \____ on innate immune response

dependent

ANTIGEN RECEPTORS B cell

B cells receptor-Immunoglobulins

* Surface associated
* bind to pathogens
* Antibodies - soluble immunoglobulins
* B cells have a wide variety of chemical structures

B cell is selected when it meets the pathogen:gp120-B cell finds the antigen & goes through mitosis-which makes a lot of B cells since they are \____ \_____ and then differentiate into effector cell (aka plasma cell)

antigen specific

ANTIGEN RECEPTORS T Cell

T cell receptor-T cell receptor

* Only surface associated
* Limited range of antigens

T cells go through clonal selection and recognize the peptide gp120- then clonally expand (mitosis) and differentiate into \____ T cells (CTL,Th1,Th2,etc)

effector

Ig (Immunoglobulin)

Have 2 different polypeptides

\-heavy & light chain \n -2 of each \n -both have variable and constant regions

Ig have variable regions which \_____ \____

binds antigen, can be any biomolecule

Alpha chain is a \____ \_____

heavy chain

Beta chain is \____ \____

light chain

Ig-Transmembrane region

\-end of heavy chain-releases antibody post transcription modification (splicing)

\-binds to the cell \n -lacks antibodies

TCR-T cell receptor

α chain and β chain

• Both anchored to the cell \n • No soluble counterpart \n • Variable and constant regions - Variable = antigen binding \n • Complimentary determining regions (CDRs)

TCR have variable and constant regions the variable regions are involved in \_____ \_____

widing

The \____ binds between the light and heavy chain

epitope

T cell receptor picture

B cells have \___ antigen binding sites and t cells have 1.

2

Antigen processing process

1. the dendritic cell takes up the pathogen for degradation
2. pathogen is taken apart inside of the dendritic cell
3. pathogen proteins are unfolded and cut into small pieces
4. peptides bind to MHC molecules and the complexes go to the cell surface
5. T cell receptors bind to peptide:MHC complexes on dendritic cell surface

2 co receptors of the T cell are _____ and CD4+

CD8+

CD8+

cytotoxic t lymphocytes-recognize the MHC1--destined to die natural killer cells and tumor bearing cells

CD4+

T helper cell-secretes cytokines to activate other cells recognize MHC 2(b cells,neutro,mac) \n they want to be helped; they need peptide on MHC2

What are the 3 professional Antigen presenting cells (APC)

dendritic cell-80% activation MAC-8% \n B cell-can act on T cell and 2%

ANTIGEN PROCESSING TCR

• TCR does not recognize surface macromolecules

* Do not interact directly with the pathogen
• TCRs recognize short peptide fragments - 8-25 aa
* Degraded pathogen protein
• A variety of peptides can be generated by one
protein
• Peptides are produced by DCs - Proteases

In MHC activation all mature \___ cells express either CD4 or CD8

T

MHC ACTIVATION CTL-CD8-_____

MHC1-for intracellular infections which is almost all cells of the body

MHC ACTIVATION Th-CD4-______

MHC2-for extracellular infections \n -involves DC,B cells and macrophages(antigen presenting cells)

MHC ACTIVATION CD stands for ______

cluster of differentiation \n - Cell types, lineages, stages of development/differentiation

CTL stands for ___ ___ ___

cytotoxic t lymphocytes

What does CTL do?

1\.Virus infects cell
2\. viral proteins are synthesized in the cytoplasm
3\.peptide fragment of viral proteins bound by MHC1 in ER
4\. bound peptides are transported by MHC1 to the cell surface
5\.Cytotoxic T cell recognizes complex of viral peptide with MHC1 and kills the infected cell

MHC2 process with macrophage

1. macrophage engulfs and degrades bacteria, making peptides
2. bacteria peptides are bound by MHC2
3. the peptides are transported by MHC2 and presented on cell surface
4. Helper t cells recognize the peptide antigen with MHC2 and activate macrophage

B cell has 2 antigen binding site; t cells has \___ binding site

1

MHC2 process with B cell

1. the cell surface immunoglobulin of B cell binds bacteria; the cell engulfs and degrades them, producing peptides
2. bacteria peptides are bonded to MHC 2 endocytosis
3. peptides are transported to MHC2 and presented on cell surface
4. helper t cell recognizes complex of peptide antigen with MHC2 and activates the B cell

B cells sole purpose is to make \_____

antibodies

B cells start as \____

phagocytes

B cell & macrophage are MHC2's primary \____

target

T cells and B cells are part of the \_____ immune response

adaptive

\___ cells only recognize peptide antigens

T

the immunoglobulins is the antigen receptor in the \_____ cell

B

Alpha and beta chains are found on \___ cell receptors

T

The tips of the "arms" of the immunoglobulin, where the antigen binds, are composed of the \_____ regions

variable

When a T or B cell encounters its antigen it is termed \___ \____

clonal selection

The macrophages, dendritic cells, and B cells are termed professional \____ \____ \____ because of their ability to activate T cells

antigen presenting cells

This adaptive immune cell acts like a natural killer cell, but has much greater specificity: \_____ \___ \____

Cytotoxic T Lymphocyte

One of the cells that T helper cells can "help" is the MAC/\__ \___-

B cell

Antigens are presented in the peptide binding grooves of the \____ molecule

MHC

B cells involve proliferation &differentiate to \_____ \_____

plasma cell and after it becomes that it loses the transmembrane region

Th: \_____:MHC2

CD4+

Ctl:\____:MHC1

CD8+

In B cells antibodies(small; but numerous) are released into mucosa or blood and bind to pathogens for neutralization, opsonization, and \____ \____

complement activation

Neutralization prevents the pathogen from \_____ \____ \____ \____

binding to the cell (target) but it activates the classical complement pathway

The best protective immunity response is the \____ \____

antibody response; it helps you survive

where the antigen is attached at tips

Fab

Fc stands for __ ____

fragment crystalization

FCR

found on all phagocytes or innate cells(mac, dc)--enhanced phagocytosis-antibody attaches with pathogen

Fab, Fc, and FCR enhance the \___ \____

B cell

C3b helps with enhanced \____

recognition

Neutralization prevent the microbe from binding to the target and activate the \___ \____ \____

classical complement pathway

ANTIBODY STRUCTURE AND DIVERSITY

\-have to have different antibodies to fight different infections

\-diversity in binding region site(in antigen binding site) (change one means it no longer binds)

ANTIBODY STRUCTURE AND DIVERSITY: Ig vs Antibody

\-B cells are more specific:1 epitope-1 pathogen
\-B cells can self activate but now use T cell

PAPCs-Peripheral blood antigen-presenting cells

- a lot of rough ER in plasma cell\=antibodies "protein production" and folding?????

Ig structure

• Variable & constant regions

• Heavy & light chains \n • Hinge \n • Fab & Fc regions

Heavy chains - isotypes

\*B cells can have different constant regions

FCR is blocked so operon can't happen \n Pentomer-5 \n Dimer-2 \n \*They all start with either U(self assembley as antibody/good at healing;best at complement activation) or S(its the 1st and produced in high quantities)

IgM

heave U as heavy chains

IgD

important in respiratory bacteria

IgG

Y heavy chain; small, good at neutrophil & complement in deep tissue infections and blood

\*most versatile antibody we have

IgA

alpha; mostly secreted as a dimer--pass mucosal system

\*mucosal=75% antibodies \n \*most prominent

IgE

IgE Y-allergies and parasites

Light chains - kappa or lambda

no functional difference and no antibody

Variable regions are genetic \________ and can change

rearrangements

\____ \_____ make up the antigen binding cells

variable regions

Complement determining -hypervariability (a region of a GENOME that is made up of a variable number of repeated sequences and is diagnostic for an individual.)

CDR1,CDR2,CDR3

Antigen binding

wide variety based on specificity

\___ regions are where variability exsists

CD

What does CD region stand for?

Complementary Determining- which is segments of DNA used to recombine different forms of immunoglobulin isotopes

Rearrangement - diversity

segments of DNA & introduces variation into the rearranged immunoglobulin variable region that is subject to negative and positive selection to yield improved antigen binding

Somatic recombination

change DNA (on DNA) and can't go back

\-develops diversity