A. VDJ rearrangement of the T-cell receptor β chain occurs first in T-cell development, as opposed to the B-cell receptor, which undergoes VDJ rearrangement after light-chain VJ rearrangement.
B. T cells do not require the formation of a pre-T-cell receptor in order to advance their development, as opposed to B cells, which require signaling through the pre-B-cell receptor in order to undergo allelic exclusion and continue development.
C. Expression of the B-cell receptor stops further light-chain rearrangement and enforces strict allelic exclusion, while expression of the T-cell receptor does not restrict further rearrangements of the alpha chain until there is signaling through peptide:MHC binding, resulting in many T cells that express two different TCRα chains.
D. TCRα chains cannot undergo successive rearrangements, as opposed to B-cell receptors, which go through the process of receptor editing.
8.13 Multiple Choice: Which of the following correctly describes T regulatory cells (Treg cells)?
A. Treg cells are a subset of CD8+ T cells that express cytotoxic activity against cells infected by intracellular pathogens.
B. The Treg T-cell receptor is characterized by its weak affinity for self MHC so that self-tolerance can be mediated.
C. Treg cells express FoxP3.
D. In many cases, autoimmunity is the product of overactive T cells.
General references.
Loffert, D., Schaal, S., Ehlich, A., Hardy, R.R., Zou, Y.R., Muller, W., and Rajewsky, K.: Early B-cell development in the mouse—insights from mutations introduced by gene targeting. Immunol. Rev. 1994, 137:135–153.
Melchers, F., ten Boekel, E., Seidl, T., Kong, X.C., Yamagami, T., Onishi, K., Shimizu, T., Rolink, A.G., and Andersson, J.: Repertoire selection by pre-B-cell receptors and B-cell receptors, and genetic control of B-cell development from immature to mature B cells. Immunol. Rev. 2000, 175:33–46.
Starr, T.K., Jameson, S.C., and Hogquist, K.A.: Positive and negative selection of T cells. Annu. Rev. Immunol. 2003, 21:139–176.
von Boehmer, H.: The developmental biology of T lymphocytes. Annu. Rev. Immunol. 1993, 6:309–326.
Weinberg, R.A.: The Biology of Cancer, 2nd ed. New York: Garland Science, 2014.
Section references.
8-1 Lymphocytes derive from hematopoietic stem cells in the bone marrow.
Busslinger, M.: Transcriptional control of early B cell development. Annu. Rev. Immunol. 2004, 22:55–79.
Chao, M.P., Seita, J., and Weissman, I.L.: Establishment of a normal hematopoietic and leukemia stem cell hierarchy. Cold Spring Harb. Symp. Quant. Biol. 2008, 73:439–449.
Funk, P.E., Kincade, P.W., and Witte, P.L.: Native associations of early hematopoietic stem-cells and stromal cells isolated in bone-marrow cell aggregates. Blood 1994, 83:361–369.