Term
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Definition
| Bone marrow from progenitor lymphoid cells |
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Term
| During development phase, the progenitor B cell acquires ? |
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Definition
| Its antigen receptor, which is membrane immunoglobulin (BCR, mIg ?) / antibodies |
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Term
| What mediates interaction b/w B-cell and the intact antigen ? |
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Definition
| Abs (membrane immunoglobulins or antigen recgonizing receptors) on their cell surface |
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Term
| Abs or membrane immunoglobulins (mIg) are expressed in relation to what ? |
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Definition
| The heterodimer CD79a/CD79b (Ig@-IgB) |
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Term
| Abs (Immunoglobulins) are composed of ? |
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Definition
| Two identical heavy chains and two identical light chains linked by disulfide bonds, and each chain is made of a variable region and a constant region |
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Term
| In naive mature B cells, the heavy chain and light chain constant regions are what? |
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Definition
| Heavy chain constant regions are mu and delta, and the light chain constant regions are kappa or lambda |
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Term
| On Abs, the light chain and heavy chain variable region are made up of which segments ? |
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Definition
Light chain variable region is made up of segments designated V and J
Heavy chain variable region is made up of segments designated V, D, and J (Variable, Deiversity, and Joining segments) |
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Term
| What is the same in all Abs ? |
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Definition
| The constant regions are same in all Abs |
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Term
| The antigen binding site (or paratope) is found where ? |
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Definition
| In the combined variable regions of the light and heavy chains / hypervariable regions or complementary regions |
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Term
| Attraction b/w the antigen binding site and an epitope ? |
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Definition
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Term
| Overall attraction, including all Fab regions is referred to as ? |
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Definition
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Term
| The random selection of V, D, and J gene segments generates B cell receptors that may be... |
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Definition
| Autoreactive, so these B cells must be deleted or inactivated |
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Term
| What is the average B cell reportoire ? |
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Definition
| In any given individual, it is possible to generate 10^9 to 10^11 different B cell clones |
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Term
| Somatic recombination is triggered by what? |
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Definition
| Triggered by recomibinases, nucleoprotein products of RAG-1 and RAG-2 genes (recombination activating genes) |
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Term
| What is combinatorial diversity ? |
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Definition
| The random selection of V, D, and J |
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Term
| What is junctional diversity ? |
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Definition
| Nucleotides may be inserted or deleted at V, D, or J segment junctions in order to maintain an open reading frame |
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Term
| What does TdT (terminal deoxynucleotidyl transferse) ? |
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Definition
| Incorporation of nucleotides at junctions is mediated by a template independent DNA polymerase |
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Term
| What is allelic exclusion ? |
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Definition
| Successful rearrangement of heavy chain variable region from one chromosome inhibits the somatic recombination of the heavy chain variable region on the other member of the chromosome pair |
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Term
| The penultimate event of B cell maturation is ? |
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Definition
| The generation of a B cell repertoire that is non-autoreactive |
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Term
| Four stages of B cell differentiation are ? |
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Definition
Pro-B cell stage (transcription)
Pre-B cell stage (Expression of Pre-BCR)
Immature B cell stage (Tolerance Induction)
Mature B cell stage (Alternative Splicing) |
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Term
| What things occur in the Pro-B cell stage? |
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Definition
Transcription of:
RAG-1 and RAG-2
CD19
Tdt
CD79 |
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Term
| What things occur in Pre-B cell stage ? |
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Definition
Expression of pre-BCR
Somatic recombination ??
CD20 (from now to rest of B-cell stages) |
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Term
| What things occur in the Immature B cell stage ? |
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Definition
Tolerance Induction
BCR expressed now
Inactivation of autoreactive Ab by apoptosis and anergy |
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Term
| What things occur in Mature B-cell stage (alternative splicing) ? |
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Definition
Alternative splicing
Co-expression of IgM and IgD
Mature naive B cells migrate to peripheral lymphoid tissue |
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Term
| Exit of mature/naive B cell from blood into peripheral lymphoid nodes is mediated by what ? |
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Definition
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Term
| Bruton's X-linked agammaglobulinemia is associated with what mutation ? |
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Definition
Mutations in Btk kinase
This block occurs at transition b/w pro-B to pre-B cell transition |
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Term
| What are "leaky B cells" ? |
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Definition
| Small numbers of B cells that are present in peripheral blood of most X-linked Agammaglobulinemia (Bruton's) patients |
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