Approximately One in Every Three $\alpha$ $\beta$ T Cells Expresses Two Different Rearranged TCR

question 5

Multiple Choice

Approximately one in every three $\alpha$ : $\beta$ T cells expresses two different rearranged TCR $\alpha$ chain proteins. Yet T cells are still considered to have 'clonal specificity' for recognizing antigen. The reason for asserting that each T cell has a single functional specificity for recognizing antigen is that:

• A) Only one of the two TCR\(\alpha\) chains expressed by a T cell will pair with its TCR\(\beta\) chain.
• B) T cells expressing two different TCR\(\alpha\) chains will die by apoptosis when they are activated.
• C) Only one T-cell receptor expressed by each T cell will recognize peptide presented by self-MHC molecules.
• D) The majority of T cells in an individual will never encounter their specific peptide-MHC ligand and so will not be part of an immune response.
• E) The majority of T cells are self-reactive and therefore eliminated during their development in the thymus.

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Definitions:

Psyche

Jung’s term for personality.

Persona

The aspect of an individual's character that is presented to or perceived by others; often a social mask worn by individuals.

Ego

In psychoanalytic theory, the part of the mind that mediates between conscious and unconscious processes, often associated with a sense of self and reality testing.

Libido

The psychological and emotional energy associated with instinctual biological drives, especially related to sexuality.