A T Cell Line Growing in Culture Is Subjected to a Chemical

question 31

Multiple Choice

A T cell line growing in culture is subjected to a chemical mutagen, and individual mutant lines are derived from this population. The individual mutant cell lines are each screened for their ability to proliferate in response to stimulation with antibodies to the T-cell receptor plus CD28 (anti-CD3 + anti-CD28) . In addition, the cells are treated with varying doses of added IL-2, and three days later, T cell proliferation is measured by ³H-thymidine incorporation (cpm) . The data for one mutant line and the wild-type control are shown in Figure Q16) .
Figure Q16) The gene that is defective in this mutant T cell line most likely encodes:

• A) The CD3 epsilon subunit of the T-cell receptor complex
• B) The co-stimulatory molecule CD28
• C) CD25, also known as the IL-2 receptor \(\alpha\) chain
• D) The IL-2 receptor \(\beta\) chain
• E) The cytokine IL-2

---

Definitions:

Market Failure

An instance where a laissez-faire market's distribution of goods and services is inefficient, typically resulting in a reduction of collective social welfare.

Centrally Planned Economy

An economic system where the government makes all decisions on the production and consumption of goods and services.

Market Economy

An economic system where supply and demand from consumers determine the production of goods and services.

Scenario Planning

A strategic planning method that organizations use to envision and prepare for various future scenarios, helping to make flexible long-term plans.