CSIM 1.13 - Introduction to Immunology 2 Flashcards
What anatomical sites may be defined as central lymphoid tissue?
Bone marrow
Thymus
Where to T-cells mature?
Thymus
What anatomical sites may be defined as peripheral lymphoid tissue?
Lymph nodes
Spleen
Mucosa associated lymphoid tissue (Payer’s patch)
Where is the thymus located?
In the thorax (anterior mediastinum)
Describe the physical changes observed in the thymus during life?
Enlarges during childhood (active)
Post-puberty it in-volutes (reduction in functioning mass)
How is the thymus defined histologically?
Distinctive outer cortex
Inner medulla
What is Di-George’s syndrome?
Hereditary condition resulting in an inability to fight infections (immunodeficiency) in association with absence of parathyroid/thymus.
Where do T-cell progenitors first start maturing within the thymus?
Cortex - (Sub-capsular region)
The Interactions between which cells play an important part in the development of maturing T-cells?
T-cell receptor and MHC peptide complexes displayed by the thymus corticle epithelial cells
The initial developing T-cell displays which receptors?
CD4
CD8
T-cell receptor
How are CD8 receptor expressing T-cells created?
T-cells with receptors able to recognise MHC-class 1 receptor are given survival and maturation signals Eventually they stop expressing CD4 receptors and only maintain CD8
How are CD4 receptor expressing T-cells created?
T-cells with receptors able to recognise MHC-class 2 receptor are given survival and maturation signals Eventually they stop expressing CD8 receptors and only maintain CD4
Describe central tolerance (negative selection)?
Thymocytes which recognise MHC-1//MHC-2 too avidly are given signals which drives them to apoptosis
Thymocytes responding to self-peptide antigens are also eliminated in the process
Where do lymphocytes begin to interact?
Lymph nodes: dendritic cells, T-cells, B-cells
Antigen presentation and Antigen recognition
Where are lymph nodes not present?
CNS
