Question

Which cells interaction leads to development regulatory T cells in thymus? a. thymic epithelial cells with CD3-CD4-CD8- cells b. thymic epithelial cells with CD3+CD4-CD8- cells c. dendritic cells with CD3+CD4+CD8- cells d. thymic epithelial cells with CD3+CD4+CD25- cells e. dendritic cells with CD3+CD4-CD8+ cells

Short answer

Answer: Thymic epithelial cells with CD3+CD4+CD25- cells.

Step-by-step solution

Understand T cell development in the thymus

T cell development occurs in the thymus, an organ in the immune system. Immature T cells go through different stages of development characterized by the expression of different surface molecules. One key molecule during this process is CD3, a marker present on all T cells. T cells also express the co-receptors CD4 and CD8, which define their functional specificity as helper T cells (CD4+) or cytotoxic T cells (CD8+). Regulatory T cells (Tregs) are a subset of CD4+ T cells, with an essential role in preventing autoimmunity by controlling the activity of self-reactive T cells.

Understand the role of thymic epithelial cells and dendritic cells in T cell development

During the development in the thymus, T cells interact with different types of cells, including thymic epithelial cells and dendritic cells. Thymic epithelial cells play a crucial role in positive and negative selection, ensuring that those T cells, recognizing self-antigens, are eliminated or differentiated into regulatory T cells. Dendritic cells can also participate in T cell selection but have a more prominent role in peripheral immune responses.

Identify the surface molecules involved in regulatory T cell development

As mentioned earlier, regulatory T cells are a subset of CD4+ T cells, expressing high levels of the interleukin-2 receptor alpha chain (CD25). Therefore, the correct cell interaction for Treg development should involve CD4+CD25+ T cells.

Choose the correct cell interaction that leads to regulatory T cell development

Now that the important clues about T cell development are understood, it's possible to identify the right cell interaction from the given options: a. thymic epithelial cells with CD3-CD4-CD8- cells b. thymic epithelial cells with CD3+CD4-CD8- cells c. dendritic cells with CD3+CD4+CD8- cells d. thymic epithelial cells with CD3+CD4+CD25- cells e. dendritic cells with CD3+CD4-CD8+ cells Out of these options, the correct answer is the interaction that involves CD4+ T cells and thymic epithelial cells. Therefore, the answer is: d. thymic epithelial cells with CD3+CD4+CD25- cells