STAGES OF B AND T CELL DIFFERENTIATION Flashcards
IL-7
Pro-B Cells
Double Negative Stage
IL-2
Activated B Cell
Activated T Cell
IgM
Pre-B Cell
Immature B Cell
IgM and IgD
Mature B Cell
Pro-B Cells Surface Marker
CD 24, CD19 and CD45R
Immature B Cell Surface Marker
CD21 (Epstein-Barr virus) and CD 35
Activated B Cell Surface Marker
CD25
Lacks CD4 and CD8
Double Negative Stage
Contains both CD4 and CD8 markers
Double Positive Stage
Either CD4 or CD8
Mature T Cells
Activated T Cell Surface Marker
CD25
Pro-B Cells
Rearrangement of the genes that codes for
heavy chain on:
chromosome 14
Pre-B Cell
Rearrangement of the genes that codes for
light chains
on:
o Kappa = chromosome 2
o Lambda = chromosome 22
Double Negative
Rearrangement of the genes that codes for
TCR (beta chain with CD3)
Double Positive
Rearrangement of the genes that codes for
TCR (alpha chain + beta chain with CD3 = CD3-αβ receptor complex)
Mu chains
Pre-B Cell
Naïve B cell
Mature B Cell
Antigen Independent Phase
Pro-B Cells
Important Growth or Transcription factors for differentiation
Pro-B Cells
Begins at the synthesis of the heavy chain part of antibody
Pre-B Cell
Immature B Cell Distinguishing characteristic:
Presence of complete IgM molecule in the cell surface
Immature B Cell 2 Destinations:
▪ Programmed cell death
▪ Cells leave the bone marrow and seed the lymphoid organs
Antigen-dependent phase
Mature B Cell
Activated B Cell
Takes place in the spleen
o Marginal Zone B cell
Mature B Cell
Lymph nodes and Other SLO
o Follicular B Cell
Mature B Cell
Mature B Cell Distinguishing characteristic:
Presence of IgM and IgD- same specificity for a particular antigen or group of antigens
Primary Follicles of Peripheral Lymphoid tissues
Activated B Cell
Early thymocyte
Double Negative Stage
Double Negative Stage Active Proliferation
Outer cortex
Expression of CD3ab Receptor Complex
Double Postive Stage
Double positive cells with functioning TCR
Positive selection
Deletion of developing T cells
Negative Selection
Survivors of selection exhibit only one type of marker, either CD4 or CD8, and they migrate to the medulla.
Mature T Cells
✓ MHC Class II Protein
CD4+ T Cells
✓ MHC Class I Protein
CD8+ T Cells
✓ Cytotoxic T Cells
CD8+ T Cells
✓ Helper or Inducer T Cells
CD4+ T Cells
✓ TH1:
IFN-y and TNF-b
✓ TH2:
IL-4, IL-5, IL-10 and IL11
– site of differentiation
Thymus
– Lymphocyte Precursors
Thymocytes
– Chemical messenger that dictates migration of thymocyte
Chemokines
Early Surface markers of Thymocytes:
CD44 and CD25
Maturation period:
3 weeks
Characterized by polyribosome filled cytoplasm
Assisting B Cells in Antibody production
Activated T Cell
Kills tumor and other target cells
Activated T Cell
Rejects grafts
Activated T Cell
Stimulates hematopoiesis in the bone marrow
Activated T Cell
Stimulates delayed hypersensitivity reaction
Activated T Cell
Spherical or ellipsoidal
Plasma Cells
Characterized by: Abundant cytoplasmic Immunoglobulin
Plasma Cells
Nucleus: eccentric or oval (heavily clamped chromatinstains dark)
Plasma Cells
Abundant ER and well-defined golgi zone
Plasma Cells
Present in the germinal center of the peripheral lymphoid organ
Plasma Cells
Found in germinal layer
Memory Cells
Has longer life span
Memory Cells
Represents progeny of antigen stimulated B cells
Memory Cells
Similar in appearance with unstimulated B cells
Memory Cells
