Question

How does IL-15 cause tissue damage in CD?

Answer 1

IL-15 contributes to tissue damage in Celiac Disease by activating cytotoxic T cells and macrophages, leading to inflammation and damage to the intestinal lining as part of a misdirected immune response.

Step-by-step explanation:

IL-15 (Interleukin-15) is a pro-inflammatory cytokine that can contribute to tissue damage in Celiac Disease (CD). In CD, the presence of gluten prompts an immune response where CD4+ helper T cells are activated and release cytokines, one of them being IL-15. This cytokine can activate cytotoxic T cells (CTLs) and macrophages, which in turn cause damage to the intestinal lining. Additionally, IL-15 has been implicated in promoting the activation and differentiation of CTLs that target cells presenting the same antigen, leading to tissue damage.

Furthermore, IL-15 can enhance the effects of Type IV hypersensitivity reactions where T-cell-mediated reactions cause tissue damage. These reactions can be mediated by activated macrophages and cytotoxic T cells as a defensive response against perceived threats, such as pathogen-infected cells or cancerous cells. However, in the context of CD, these immune responses mistakenly target the body's own cells, leading to inflammation and damage.

Answer 2

IL-15 contributes to tissue damage in celiac disease by stimulating the activation and proliferation of immune cells, including cytotoxic T cells and natural killer cells, causing inflammation and damage to the intestinal lining.

Step-by-step explanation:

Interleukin-15 (IL-15) is one of many cytokines that play a pivotal role in immune responses and inflammation. In celiac disease (CD), an autoimmune condition, the ingestion of gluten leads to an inappropriate immune response, where IL-15 contributes to tissue damage in the intestine. This occurs because IL-15 can stimulate the activation and proliferation of immune cells, including cytotoxic T cells and natural killer (NK) cells, which can lead to an increase in inflammation and damage to the intestinal lining.

Furthermore, IL-15 promotes the differentiation of CD8 cytotoxic T lymphocytes (CTLs). These cells can cause direct damage to intestinal cells displaying antigenic peptides bound to MHC class I molecules. Such cytolytic activities contribute to the villous atrophy observed in CD. Additionally, IL-15 can lead to activated macrophages in the gut, which release further pro-inflammatory cytokines and exacerbate tissue damage.