KARA - Immunology Exam 4 - Chapter 7 & 8.docx

The tcr genes are in germline configuration upon

This preview shows page 7 - 11 out of 60 pages.

The TCR genes are in germline configuration Upon interaction with thymic stromal cells, the progenitor T cells will proliferate and differentiate Approximately one week later, progenitor T cells will express the T-cell specific adhesion molecule CD2 and other surface markers such as CD5 but no TCR complex No CD4 or CD8 called “double negative” thymocytes
Image of page 7

Subscribe to view the full document.

IL-7 receptor on T-cells is essential for binding IL-7 secreted by thymic stromal cells – helps tell the T-cell what to do next in its maturation. Notch 1 – at all stages of maturation in the thymus signals are sent through this receptor to drive the T-cell in their differentiation. Slide 19 | Slide 20 | T-cell Development in the Thymus is Driven by the Receptor Notch 1 Slide 21-24 | T Cells Have Two Lineages Distinguished by the Expression of an  or a  TCR o Commitment does not occur before TCR rearrangement but is a race to obtain a productive rearrangement o Thymocytes will rearrange their , and -chain genes about the same time
Image of page 8
Different from B-cell development (recall: each type of Ig gene is rearranged in turn and in a set order) o Productive and -chain gene rearrangement made prior to a productive -chain rearrangement leads to  receptor which signals cell to stop rearrangement of chain o More frequently the chain productively rearranges before the and - chains o -Chain assembles with a surrogate chain = pt (pre-T-cell receptor) which signals the cell to halt rearrangement of , and -chain genes and begin to proliferate After expression of the pre-TCR, the recombination machinery is reactivated & targeted towards the chain loci (and the and loci) In a minority of these cells successful completion of and chain gene rearrangements occurs before the chain gene has rearranged the  lineage In a majority of these cells, productive rearrangement of the -chain gene occurs first an  T cell Recall the chain locus is located within the -chain locus…a rearrangement at an -chain locus results in the deletion of the complete chain locus from the chromosome Cells committed to one lineage can contain productive rearrangements for the TCR genes of the other lineage (except for -chain).
Image of page 9

Subscribe to view the full document.

Slide 25 | Immature T Cells that undergo Apoptosis Are Ingested by Macrophages in the Thymic Cortex Failure to make a productive rearrangement results in death by apoptosis (fate of about 98% of thymocytes) Macrophages in thymus continually remove dead cells Cells have been stained for apoptosis with a red dye Apoptotic cells are scattered throughout the cortex but are rare in the medulla Higher magnification red for apoptotic cells and blue for macrophages Apoptotic cells are visible within macrophages
Image of page 10
Slide 26-27 | Production of T-cell receptor β chain stops β-chain rearrangement
Image of page 11
You've reached the end of this preview.
  • Winter '17
  • GREGORYWEIGEL
  • T Cells, T Cell, development of T cells

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern