Which of the following statements about induction or maintenance of T cell tolerance is NOT true?

Question

A. Central tolerance is induced when immature developing T cells in bone marrow or thymus encounter self antigens.
B. Peripheral T cell tolerance results when mature naive T cells recognize antigens without adequate B7-1- or B7-2-mediated costimulation.
C. Peripheral T cell tolerance results when T cells recognize antigen in the setting of an innate immune response to the antigen.
D. Peripheral T cell tolerance to some antigens is induced when mature T cells recognize antigen and bind B7-1 or B7-2 via the inhibitory CTLA-4 receptor.
E. Peripheral T cell tolerance to an antigen may be induced by persistent and repeated stimulation of lymphocytes by that antigen in tissues.

Answer 1

ANS: C. Innate immune responses are usually required for induction of adaptive immune responses and may actually contribute to breaking tolerance to self antigens. Central tolerance occurs because of the susceptibility of immature lymphocytes to death in response to antigen receptor signals. Autoreactive lymphocytes that are not deleted during development must be regulated by a mechanism of peripheral tolerance, which is induced in T cells by antigen receptor stimulation without costimulation, with CTLA-4-mediated negative signaling, by repeated and persistent stimulation by antigen, and by suppression by regulatory T cells.