ATI RN
Lymphatic System Questions and Answers PDF Questions
Question 1 of 5
How do T cells with high affinity for self-antigens get eliminated?
Correct Answer: C
Rationale: High self-affinity T cells are removed by negative selection ; anergy is peripheral, activation and positive selection retain cells.
Question 2 of 5
When complement proteins are covalently deposited onto the surface of a bacterium, this can sometimes lead to direct lysis of the bacterium. However, more commonly, the deposition of complement proteins onto the bacterial surface does not directly harm the bacterium. Instead, these complement proteins aid in bacterial elimination by:
Correct Answer: D
Rationale: Complement (e.g., C3b) enhances phagocytosis via complement receptors ; Fc receptors are antibody-related, not replication or B-cell stimulation .
Question 3 of 5
Innate lymphoid cells (ILCs) are effector cells that generally reside in barrier tissues, such as the skin, the gut, and the lung. These cells closely resemble subsets of T lymphocytes, but lack a T cell antigen-receptor. Instead, these cells produce their effector molecules following stimulation by:
Correct Answer: D
Rationale: ILCs respond to cytokines from innate cells ; PAMPs are indirect, TNF-α or acute phase proteins are less specific triggers.
Question 4 of 5
Scaffold proteins are often phosphorylated at multiple sites, allowing the recruitment of several different signaling proteins. In antigen receptor signaling pathways, this mechanism is used to bring enzymes in close proximity to their substrates. Termination of this signaling mechanism would be most efficiently accomplished by:
Correct Answer: D
Rationale: Dephosphorylation disrupts scaffold signaling; ubiquitination is slower, GAP or depletion are less direct.
Question 5 of 5
Natural killer cells
Correct Answer: B
Rationale: Natural killer (NK) cells release chemicals (e.g., perforin) to induce apoptosis in virus-infected cells, not phagocytosis or antibody tagging.