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Immunology
Chapter 6
25
Other
Undergraduate 2
10/08/2009

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Term
Stromal Cells
Definition

In bone marrow

 

Make specific contacts with developing B Cells

 

Produce growth factors

Term
Movement of B Cells as they mature
Definition

1. Subendosteum to central axis of marrow cavity.

 

2. Secondary Lymphoid Organ.

 

 

Term
First Stage: Early Pro B Cell
Definition

E2A and EBF cause genes to turn on (RAGs, surrogate L chain, and Pax-5).

 

H chain gene rearrangement of DJ.

 

Go onto second stage even if they fail here

Term

Second Stage: Late Pro B Cell

 

Checkpoint 1

Definition

Rearrangement of V with DJ.

 

Testing of Surrogate L Chain:

Surrogate Light Chain (VpreB and Lambda-5) tested on membrane of E.R.

 

Together with the heavy chain and IgAlpha and IgBeta it makes the Pre-B Cell Receptor

 

Has TWO chances

Term
Third Stage: Large Pre B Cell
Definition

Heavy Chain Rearranged

 

Allelic Exclusion

 

Rounds of cell division

 

Term

Fourth Stage: Small Pre-B Cell

 

Checkpoint 2

Definition

L Chain Rearrangement begins

 

85% success rate

 

Recombination will occur until there is a functional chain or it runs out of choices

Term
Fifth Stage: Immature B Cells
Definition

Receptors on cell surface

 

Express IgM

 

Need to be self tolerant

 

Make IgM AND IgD (more IgD on cell surface)

 

 

Term
Pax-5
Definition
Determines B Cell Path rather than T Cell path
Term
Kit Receptor
Definition

Binds to SCF

 

Causes B Cell Proliferation of Large Pre B Cells

Term
Proto-oncogenes
Definition
Genes that cause cancer when perturbed
Term
Burkitts Lymphoma
Definition

Translocation of MYC gene on chromosome 8 with a chain gene

 

requires more than just this mutation to be expressed

 

Term
B1 Cells
Definition

Express CD5

 

make up 5% of B cells in humans

 

few have N nucleotides in H chain (All B2 cells have them)

 

Polyspecific

 

Self Renewing

Term
Receptor Editing
Definition

Successive rearrangements of L Chains in B Cells to find one that is not self reactive

 

Occurs with Multivalent self antigens

 

 

Term
Clonal Deletion
Definition
B Cells that fail to make a functional receptor or are self reactive are signaled to die
Term
Anergy
Definition

State of developmental arrest

 

Self reactive with monovalent self antigens

 

IgM is retained inside the cell

 

Allowed to enter periphery if not already there

Term
Lupus Erythematosis
Definition
DNA is attacked by B Cells because escaped tolerance
Term
Mature B Cells
Definition

Need access to lymphoid follicles to mature:

 

1. Enter organ via High Endothelial Venules (HEV). Attracted by CCL21 (binds to CCR7) & CCL19.

2. Follicular Dendritic Cells secrete CXCL13 to attract B Cell into follicle.

Term
Lymphotoxin (LT)
Definition

Protein on B Cells that helps maintain FDC integrity when they interact.

 

 

Term
B Cell Activating Factor (BAFF)
Definition
promotes B Cell survival
Term
Secondary Lymphoid Follicle
Definition

Activated mature B Cells congregate here and form a germinal center.

 

B Cells become large dividing Centroblasts ---> Centrocytes which have undergone somatic hypermutation and class switching

 

Some become memory cells

Term
Myelomas
Definition
Plasma Cell Tumors
Term
Hodgkins Disease
Definition

B Cell with lost receptor

 

Known as Reed-Sternberg cells

Term
HEV
Definition
Immature B Cells enter the secondary lymphoid organ
Term
CXCL13
Definition
FDC attract immature B Cells into follicles
Term
CCL21 and CCL19
Definition
Chemokines that attract Immature B Cells into lymphoid organ via HEV
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