Experimental Mouse Models Have Been Developed to Study the Mechanisms $\beta$

question 11

Multiple Choice

Experimental mouse models have been developed to study the mechanisms leading to the breakdown of self-tolerance and the onset of autoimmunity. One strategy is to express a foreign antigen, such as a viral protein, in a single defined cell type in a peripheral organ. For instance, the lymphocytic choriomeningitis virus (LCMV) glycoprotein has been expressed in β-islet cells of the pancreas by making a line of mice that is transgenic for a construct linking the LCMV-glycoprotein gene to the insulin promoter. In these transgenic mice, the LCMV protein is expressed only in pancreatic $\beta$ -islet cells. Thymocytes with T-cell receptors specific for a peptide of LCMV-glycoprotein bound to MHC class I develop normally in the thymus, and do not undergo negative selection. The fate of these T cells once they emigrate from the thymus would likely be:

• A) They would be activated in the periphery and attach and kill the pancreatic \(\beta\)-islet cells.
• B) They would either be deleted in the periphery or would become unresponsive.
• C) They would induce an inflammatory response in the pancreas that would up-regulate co-stimulatory molecules on antigen-presenting cells.
• D) They would secrete cytokines that promote T cell proliferation.
• E) They would differentiate into virus-specific memory T cells that would protect mice upon infection with LCMV.

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Definitions:

Defense Mechanisms

Psychological strategies unconsciously employed to protect oneself from anxiety and the unacceptable aspects of reality.

Differentiation

The process of identifying and defining one's own thoughts, feelings, and actions as distinct from those of others, often used in the context of family systems theory.

Mature Dependency

A healthy form of dependency in relationships, characterized by mutual respect and support without undue reliance on the other.

Consciousness

The state of being aware of and able to think about one's own existence, sensations, and thoughts.