Exam 10: Immunological Tolerance and Autoimmunity

The adaptive immune system has mechanisms of homeostasis that serve to terminate immune responses and return the immune system to a basal resting state.Which of the following is LEAST likely to be involved in lymphocyte homeostasis?

Failure of self-tolerance is the cause of which one of the following types of diseases?

Which of the following statements about B cell tolerance is NOT true?

Which one of the following is NOT a mechanism of T cell tolerance?

Which of the following terms best describes the mechanism by which effector T cells are deleted by repeated stimulation by persistent antigen?

Which one of the following factors generally favors tolerance to an antigen and not stimulation of an immune response?

Which of the following is NOT a property of regulatory T cells?

Which one of the following statements regarding positive and negative selection of T cells is NOT true?

Many tumors are found to overexpress bcl-2,which favors survival of the transformed cells.Which of the following best describes the function of bcl-2?

Which of the following factors generally favors stimulation of an adaptive immune response to an antigen,and not tolerance?

Transgenic mouse lines have been very useful for the study of mechanisms of self-tolerance.In one such line,transgenes were introduced encoding a T cell receptor (TCR)specific for the H-Y antigen,which is a protein expressed by many cell types only in male mice.When these transgenic mice were analyzed,researchers found that T cells expressing the H-Y-specific TCR developed normally in female mice but not in male mice.This finding illustrates which of the following mechanism of self tolerance?

Immunologic tolerance is defined as:

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)is a rare disease in which there is autoimmune destruction of several endocrine organs.This disease is caused by mutations in the autoimmune regulator gene called AIRE.AIRE is normally expressed primarily in the thymus and serves as a transcription factor in thymic epithelial cells.A failure to produce AIRE leads to a failure in tolerance to several self-proteins.Which ONE of the following statements best explains the influence of AIRE on self tolerance?

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

All of the following describe features of apoptosis EXCEPT:

Which of the following molecules does NOT promote lymphocyte apoptosis?

A genetic deficiency in the ability to produce which of the following molecules results in autoimmunity?