0502 - Lymphocyte Development II - EG Flashcards Preview

B1 Foundation Block > 0502 - Lymphocyte Development II - EG > Flashcards

Flashcards in 0502 - Lymphocyte Development II - EG Deck (18):
1

What do T cells recognise?

antigenic peptides displayed on the surface of the body's own cells.

2

What cells are antigen presenting cells?

dendritic cells, B cells, and macrophages.

3

What does HLA stand for? What are they?

Human leukocyte antigens. Products of MHC genes, both class I MHC and class II MHC.

4

What does MHC stand for?

Major histocompatibility complex, region of genes encoded on chromosome 6.

5

What do the HLA regions A, B, and C (ie HLA-A, HLA-B, and HLA-c) code for?

MHC class I

6

What do the HLA regions: HLA-DP, HLA-DQ, and HLA-DR, code for?

MHC class II

7

Where are MHC class I expressed? To what type of T cells do they present antigens?

On the surface of all nucleated cells. Present antigens to CD8+ T cells.

8

Where are MHC class II expressed? To what type of T cells do they present antigens?

On the surface of specialised antigen presenting cells, dentritic cells, macrophages, B cells. Present antigens to CD4+ T cells.

9

Where do T cells originally arise from?

Firstly derived from progenitors of the pluripotent haemopoietic stem cells of the bone marrow, then travel as undifferentiated lymphocytes to the thymus where they differentiate into T cells (various types).

10

List some of the phases/stages of T cell development

DN1 - immature thymocytes; DN2 - pro-T cell, expression of RAG-1 and RAG-2 for TCR beta chain D-J rearrangement; DN3 - pre-T cell, further beta chain V to DJ rearrangement; DN4 - proliferation by IL-2 signal; surrogate alpha chain (V-J) expressed and CD3. DP - CD4 and CD8 expression.Positive and negative selection stage. SP - expression of either CD4 or CD8.Mature T cell leaves thymus

11

What type of MHC does a CD4 T cell recognise?

MHC class II (dendritic cells, macrophages, B cells)

12

What type of MHC does a CD8 T cell recognise?

MHC class I (all nucleated cells)

13

What is positive selection?

Thymocyte development stage where T cells that are able to bind to a self-MHC will survive, and those that do not recognise a self-MHC die by apoptosis.

14

What is negative selection?

Thymocyte development stage where T cells that bind strongly to a self-peptide-self-MHC will die by apoptosis to prevent auto-reactivity.

15

What cells facilitate the negative selection stage of T cell development?

Thymic medullary epithelial cells, which express a nuclear protein autoimmune regulator (AIRE) to induce the expression of tissue specific genes in the thymus to make a range of tissue specific peptides available for presentation to developing T cells.

16

Which type of T cell is involved in both the innate and adaptive immune response?

NK cells

17

What is expressed in the thymus to attract immature lymphocytes into the thymus for commitment to T cell development?

Notch 1

18

At what stage is the TCR expressed in T cell development?

Pre-T cell.

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