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INTRACELLULAR
CYTOKINES
ELISPOT
TcR SPECTRATYPING
IFN-PE-A
NUMBER
PROLIFERATION
FITC-A CFSE FITC-A
CFSE-FITCA
Vol. 1  Issue 3  Spring 2008
Contact Information
ASSESSMENT OF T CELL RECOMBINANT EXCISION CIRCLES (TRECS)
Allan D. Hess, Ph.D. - Director
(410) 955-8975
E-mail: [email protected].
Reconstitution of the immune system after high dose chemotherapy can be
complex process involving both homeostatic expansion of residual mature T cells
as well as the emergence of new naive T cells from the thymus. Methodology is
available in the Human Immunology Core to identify recent thymic emigrants or
Ferdynand Kos, Ph.D.
naïve T cells. Thymocytes rearrange their T cell receptor (TCR) genes during
(410) 502-3195
E-mail: [email protected].
development. Upon completion of TCR gene rearrangement, a non-replicating
excision circle is formed that can be easily assessed to identify these cells as
Christopher Thoburn
recent thymic emigrants or naïve T cells. The results in Figure A track the
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recovery of lymphocytes after high dose chemotherapy and the relative expression
(410) 955-8568
of TRECS. Here, reconstitution clearly involves newly emigrated T cells from the
E-mail: [email protected].
thymus. It is commonly thought that many CD3+CD4+Foxp3+ regulatory T cells
emerge directly from the thymus rather than developing in the periphery. Analysis of the lymphocytes on day
30 reveals a significant number of CD3+CD4+Foxp3+ Tregs present in the peripheral blood (Figure B).
Interestingly, very few of these cells had T cell recombinant excision circles (Figure C) suggesting that they
may have been driven by antigen or expanded by homeostatic cytokines. On the other hand, a large number
of TRECs were detected in the non-regulatory T cell compartment indicating that these cells are largely
composed of recent thymic emigrants. TREC analysis can be a very powerful technique to explore important
questions regarding the reconstitution of the immune system.
TREC analysis is routinely performed in the Human Immunology Core Laboratory. For more info contact us at
our web site or give us a call. http://humanimmunology.onc.jhmi.edu.
In our next issue
Multiplex Analysis of Cytokines
T h e T C e l l C h r o n i c l e  SPRING 2 0 0 8
For Consultation Services, please contact Allan D. Hess, Ph.D.
at (410) 955-8975