Immunology Test 2

Front 1

Unproductive light gene rearrange can be replaced

Back 1

1) using V & J gene segments not used in prev. rear.
2) Further rear can result in a fnx gene.
3) When 2nd joint made->DNA w/ 1st joint excised

Front 2

Surrogate light chain contains

Back 2

1) A 2 protiens
a) /\5 protien > constant region
b) VpreB > variable region

Front 3

Pre-B-cell receptor

Back 3

1) On cell surface > short time.

Front 4

What does the expression of the pre-B-cell receptor generate

Back 4

1) Positive signal allowing B cell =/ apoptosis > proceeds to next stage of maturation.
2) u, Iga, and IgB > synth. & retained in E.R

Front 5

What happens when the RAG genes are turned back on?

Back 5

(i) Light chain gene rearang. Proceeds

Front 6

When fnxal light chain gene is formed?

Back 6

1) Light chains are made & assemb. w/ u to form IgM.

Front 7

What happens to the IgM

Back 7

1) Iga & IgB join it > form mature B-cell receptor
2) Which moves to cell surface

Front 8

The appearance of a fnxal b cell receptor leads to ?

Back 8

1) Light chain gene rearrangement

Front 9

Cell division initiated by signal through the preBcell receptor results?

Back 9

1) In a clone of 30-70 small preB cell
2) All have same H gene
3) Potential to have diff L gene

Front 10

TdT

Back 10

1) Terminal deoxynucleotidyl transferase
a) Enzyme that adds N nucleotides at the jnx b/t rear. Gene segments
b) expressed in proB cells

Front 11

When is TdT expressed?

Back 11

1) When the H chain gene begin to rearrng

Front 12

When is TdT not expressed?

Back 12

1) In small pre-B cells when light chain gene begin to rearrange

Front 13

What is the signifigance of TdT expression

Back 13

1) N nucleotides are found in all VD and DJ joints of rearranged human H chain genes
2) But only in half the VJ joint of human L chains

Front 14

when is synthesis of Iga & IgB polypeptides is turned on

Back 14

1) pro-B cell stage & continues thru life of B cell

Front 15

What is the period “ON” for Iga and IgB consitent with

Back 15

1) With the polypeptides being necessary for the cell surface expression of immunoglobulin
2) & for the transduction of signals from pre-B cell and B-cell receptors to the interior of the cell

Front 16

when is Iga and IgB genes turned off?

Back 16

1) when An stimulated B cells diff into Ab-secreting plasma cells,
2) and their An receptors are no longer required,
a) Ig ceases to apprear on cell surface

Front 17

BtK?

Back 17

1) Brutons tyrosine kinase
a) Another signal transduction molecule
b) Encoded by a gene on the X chrom
c) Essential for B cell maturation

Front 18

Patients who lack a fnx Btk gene have?

Back 18

1) Almost no circulating Ab b/c tgheir B cells are blocked at the pre-B cell stagge
2) Results in X-linked agammaglobulinemia

Front 19

X-linked agammaglobulinemia?

Back 19

1) Leads to recurrent infections

Front 20

many B cell tumors carry?

Back 20

1) Chromos translocations > join Ig genes to genes regulating cell growth.’

Front 21

transformation of a normal cell into a tumor cell involves?

Back 21

1) Series of mutations that release the cell from the normal restraints on its growth.

Front 22

translocations?

Back 22

1) events that fuse part of a chromosome with another
a) in B cell tumorsthe Ig gene has often b/c joined to a gene involved in the control of cell growth

Front 23

Proto-oncogenes?

Back 23

1) Genes that cause cancer when their fnx or expression is perturbed.

Front 24

Oncogenes?

Back 24

1) The viral gnes responsible for transformation

Front 25

Two examples of protooncognes?

Back 25

1) Burkitt’s lymphoma
2) BCL2

Front 26

Burkitt's Lymphoma?

Back 26

1) The MYC protooncogne
a) On chromosome 8
(i) translocation to either
(a) an Ig heavy-chain gene on chrom 14
(b) a k L chain gene on chrom 2
(c) a /\ L chain gne on chrom 22

Front 27

BCL2?

Back 27

1) Translocation found in b cell tumors
2) Normally prevent premature apoptosis
3) In tumors enable B cells to live longer
a) So they accumulate additional mustations that can lead to malignant transformation

Front 28

B-1 Cells?

Back 28

1) Subset of human Bcells
2) Arise in early embryonic development
a) From stem cell
3) Expresses CD5 (a gp) on cell surface

Front 29

CD5?

Back 29

1) Gp on cell surface
2) Otherwise considered a marker for the human T cell lineage

Front 30

Specific characteristics of B-1 Cells?

Back 30

1) Little or no IgD on surface
2) Distinctive repertoire of antigen receptors
3) A.k.a CD5 B cells

Front 31

B-1 vs. B-2

When first produced?

Back 31

1) Fetus VS after birth

Front 32

B-1 vs. B-2

N-regions in VDJ junctions?

Back 32

1) Few VS extensive

Front 33

B-1 vs. B-2

V-region repertoire?

Back 33

1) Restricted VS diverse

Front 34

B-1 vs. B-2

Primary location?

Back 34

1) Peritoneal & pleural cavities VS 2nd lymph organs

Front 35

B-1 vs. B-2

mode of renewal?

Back 35

1) self renewing(IL-10) VS replaced from bone marrow

Front 36

B-1 vs. B-2

spontaneous production of Ig?

Back 36

1) High VS low

Front 37

B-1 vs. B-2

isotypes secreted?

Back 37

1) IgM>>IgG VS IgG> IgM

Front 38

B-1 vs. B-2

response to carbohydrate antigen?

Back 38

1) Yes VS Maybe

Front 39

B-1 vs. B-2

response to protein antigen?

Back 39

1) maybe VS Yes

Front 40

B-1 vs. B-2

requirement for Tcell help?

Back 40

1) No VS yes

Front 41

B-1 vs. B-2

somatic hypermutation?

Back 41

1) Low-none VS High

Front 42

B-1 vs. B-2

Memory development?

Back 42

1) Little or none VS yes

Front 43

B-1 cell Tumor?

Back 43

1) Chronic lymphocytic leukemia (CLL)
a) A bone marrow transplant from identical sibling is successful treatment

Front 44

Self-reactive immature B cells are altered, eliminated or inactivated by?

Back 44

1) Contact with self antigens

Front 45

when is a B cell 1st described as an immature B cell?

Back 45

1) when it first expresses IgM on its surface.

Front 46

Becoming a mature B cell involves?

Back 46

1) Emigration from the bone marrow
2) Use of alternative splicing of H chaim mRNA
a) To place IgD, as well a IgM on the cell surface.

Front 47

Self-Antigens?

Back 47

1) Quality control mechanisms
a) Prevent maturation of B cells whose receptors bind to normal components of the human body

Front 48

If B cells whose receptors bind to normal compoenets of the human body were allowed to mature?

Back 48

1) They could make potentially disease-causing antibodies

Front 49

kinds of self antigens?

Back 49

1) Multivalent
2) Soluble

Front 50

immature B cells that do not encounter a stimulatory self-An?

Back 50

1) leave the bone marrow and enter the peripheral circulation, expressing both IgM & IgD on their surfaces

Front 51

Multivalent self antigens?

Back 51

1) Consists of gp,proteoglycans and glycolipids
2) Go through clonal selection >apoptosis

Front 52

Soluble self anitigen?

Back 52

1) Soluble proteins & gp
2) When surface IgM of an immature B cell binds to a soluble self-antigen, > Bcell inactive > Does Not Die
3) Becomes anergic

Front 53

Anergy?

Back 53

1) The state in which the B cel matures but does not respond to subsequent exposure to antigen
2) Migrate to periphery > where they express IgD > but remain anergic.

Front 54

Receptor Editing?

Back 54

1) A process of assessing the compatibility of receptors produced from successive gene rearrang.

Front 55

Steps of receptor Editing?

Back 55

1) Ligation of IgM on self-antigen
2) Arrest of B cell development
3) New receptor specifity is now expressed
a) If new receptor is still self- reactive > apotosis
b) If new receptor is no longer self reac> imm B cell migrates to periphery and matures

Front 56

Clonal deletion?

Back 56

1) Apoptosis in receptor editing
a) Occurs within the bone marrow or shortly after cell enters peripheral circulation

Front 57

Ligation of IgM on self antigen?

Back 57

1) When dev. B cell produces antigen receptors htat are strongly X linked by multivalent self antigen
2) B cell undergoes develop arrest.

Front 58

Arrest of B development?

Back 58

1) and cont. L chain rearran.: low cell surface IgM
2) Amount of IgM on the surface is reduced
a) RAG genes are not turned off.

Front 59

new receptor specificity?

Back 59

1) cont synthesis of RAG proteins allows the cell to cont L chain gene rear.
a) Leads to a new productive rear. & expression of a new L chain
(i) Which combines w/ the previous H chain to form new receptor

Front 60

Primary lymphoid follicles?

Back 60

1) Within 2nd lymphoid tiss, B cells congregate in organized structures