ATI RN
Pediatric Immunization Test Questions Questions
Question 1 of 5
Presence of the TCR co-receptor molecules (CD4 or CD8) has been estimated to reduce the number of MHC-peptide complexes required to trigger a T-cell response by about:
Correct Answer: D
Rationale: CD4/CD8 co-receptors enhance TCR sensitivity, reducing MHC-peptide complexes needed by ~100-fold.
Question 2 of 5
The thymus is the primary site of T-cell development. Which of the following is the correct order arranged from the area with the earliest progenitor cells to the area with the most mature T lymphocytes?
Correct Answer: D
Rationale: T cell maturation progresses from subcapsular zone (progenitors) to cortex to medulla (mature T cells).
Question 3 of 5
Intraepithelial lymphocytes (IEL) act to protect the host against viral and bacterial pathogens encountered in the gut and secrete cytokines. Their predominant phenotype is:
Correct Answer: B
Rationale: IELs are predominantly γδ T cells in the gut.
Question 4 of 5
During B cell development, when is there rearrangement in the light (L) chain of the immunoblobulin gene started?
Correct Answer: C
Rationale: Light chain rearrangement starts in the late pre-B cell stage.
Question 5 of 5
A young child undergoes implantation of a cardiac pacemaker. During surgery, the physician must remove the thymus. If this child encounters an antigen requiring B-cell-Tcell collaboration, they will to mount an immune response. These antigens are thus called
Correct Answer: C
Rationale: Thymectomy prevents T cell development, impairing responses to thymus-dependent antigens.