This English summary contains an overview of topics discussed in Parham et al. 2012, Chapter 7 'The development of T cells in the thymus'.
It contains all the important concepts and definitions of Chapter 7, including illustration for clarification. Among other things: gene rearrangement, positive...
SUMMARY chapter 1-10 The Immune system; Peter Parham (4th edition)
Complete summary of Immunology (AB_1144) at VU Amsterdam
Immunology (The Immune System by Peter Parham 5th edition) summary chapter 1
All for this textbook (16)
Written for
Vrije Universiteit Amsterdam (VU)
Geneeskunde
Schade, Afweer en Herstel
All documents for this subject (15)
1
review
By: mellandry • 3 year ago
Seller
Follow
manuelavooijs
Reviews received
Content preview
THE IMMUNE SYSTEM – PARHAM 4TH EDITION
CHAPTER 7
T lymphocyte cells originate from the bone marrow but mature in the thymus.
Two lineages develop from a common T-cell precursor
α:β T cells
γ:δ T cells
The thymus is a primary lymphoid organ which gives rise to thymocytes in the thymic stroma = epithelial cells.
The thymus does not receive lymph; T-cells enter via the blood.
Embryological development thymus
1) The thymic anlage is formed from:
Ectoderm " epithelial cells of the cortex
Endoderm " epithelial cells of the medulla
2) Progenitor cells from the bone marrow colonize the thymic anlage.
3) Progenitor cells " thymocytes and dendritic cells
(DCs reside in medulla).
4) Bone marrow-derived macrophages colonize thymus.
5) T-cell progenitors differentiate and move to medulla.
The thymus degenerates after birth = thymic involution. Fat cells replace original cells as you grow older.
Thymic involution and thymectomy do not impair T-cell immunity: they are long-lived.
DiGeorge syndrome is a genetic disease where the thymus fails to develop. T-cells are absent, but B-cells present.
Patients have opportunistic infections and no adaptive immune system.
T-cell development
Lineage commitment
1) The T-cell progenitor cells express CD34 and other glycoproteins that characterize stem cells.
2) CD34 is replaced with CD2 (adhesion) and CD5 (glycoprotein) – after differentiation in the cortex.
The T-cells express neither CD4 or CD8 = double-negative T-cells or DN T-cells.
3) Race of gene rearrangement: β, γ and δ loci start at same time.
The T-cells express both CD4 and CD8 = double-positive T-cells or DP T-cells.
4) β first? α rearrangement continues, as well as γ:δ (another race!). ).
5) α:β first? T-cell commits to the α:β lineage!).
Commitment to β is favored:
Need only 1 functional rearrangement (γ:δ needs 2).
Has two Cβ loci per chromosome; if one is dysfunctional, 2nd loci can be used and (associated D and J segments).
!). Cells that fail productive rearrangement (98%) die by apoptosis and are eaten by macrophages in the cortex.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller manuelavooijs. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.23. You're not tied to anything after your purchase.
