Immune III

1. T cells coordinate multiple aspects of adaptive immunity throughout life, including responses to pathogens, allergens, and tumors.

True False

2. In humans, T cells must control multiple insults simultaneously throughout the body and maintain immune homeostasis over decades.

True False

3. Human T lymphocytes originate from bone marrow progenitors that migrate to the thymus for maturation, selection, and export as naïve T cells.

True False

4. Regulatory T (Treg) cells are a T cell subset that helps keep immune responses in check and maintain self-tolerance.

True False

5. In early life, the majority of T cells are naïve T cells newly emerged from the thymus, with Treg cells also significantly represented.

True False

6. During childhood, memory T cells accumulate with antigen experience and their levels plateau and remain relatively stable throughout adulthood.

True False

7. In adulthood, the role of T cells shifts more toward maintaining homeostasis and immunoregulation rather than encountering many new antigens.

True False

8. At later stages of life, immunosenescent changes include increased inflammation and a decline in T cell functionality, leading to increased susceptibility to pathogens.

True False

9. The majority of T cells in the human body are found in peripheral blood, with only a small fraction residing in lymphoid and mucosal tissues.

True False

10. Humans are born with a full complement of T cells, unlike mice, which are born lymphopenic.

True False

11. In humans, T cell progenitors are detected in the fetal thymus by around 9 weeks of gestation, with mature T cells appearing in thymus and peripheral lymphoid organs before birth.

True False

12. Neonatal thymectomy in humans inevitably leads to severe immunodeficiency and high rates of life‑threatening infections in adulthood.

True False

13. Adults who underwent neonatal thymectomy can remain healthy, with no clear increase in infections, despite more pronounced age‑related declines in naïve T cells.

True False

14. Infants born with congenital defects in Treg cell development (e.g., Foxp3 mutation) develop IPEX syndrome with systemic autoimmunity and multi‑organ infiltrates.

True False

15. In humans, thymic function declines progressively and shows a steep reduction in thymopoiesis after about 40 years of age.

True False

16. Residual thymic activity can still be detected beyond the fifth decade of life in some individuals, suggesting potential for thymic regeneration strategies.

True False

17. In humans, most naïve T cells in adults are maintained predominantly by continued high thymic output, with very little peripheral division.

True False

18. Human naïve T cells can persist for many years and show substantial peripheral turnover, even in younger adults.

True False

19. Naïve T cells in elderly individuals still maintain a highly diverse TCR repertoire, although diversity is somewhat reduced compared with young adults.

True False

20. In early life, Treg cells can comprise 10–30% of CD4⁺ T cells in blood, lymphoid tissue, and mucosal sites, but their frequency falls to under 5% in adults.

True False

21. Compared with conventional naïve T cells, human Treg cells show higher turnover rates, which may contribute to their declining frequency with age.

True False

22. Human memory CD4⁺ and CD8⁺ T cells are classically divided into central memory (Tcm), effector memory (Tem), and stem‑cell memory (Tscm) subsets based on phenotype and function.

True False

23. Effector memory (Tem) cells typically have high proliferative capacity and home mainly to lymphoid organs, while central memory (Tcm) cells are more terminally differentiated and tissue‑resident.

True False

24. In adult humans, Tem cells are the predominant memory population in many tissues, including lung, intestine, spleen, and a substantial fraction of lymph node T cells.

True False

25. Human tissue‑resident memory T (Trm) cells commonly express CD69 and often CD103, and they are enriched in barrier and mucosal tissues where they can provide rapid local protection.

True False

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T Cell Development True/False Quiz

25 Questions – Maximum 2 Attempts