# Iron and vitamin D intake on a diet are able to modify the in vitro immune response to Mycobacterium leprae

## TL;DR

This study shows that dietary iron and vitamin D affect immune responses to Mycobacterium leprae in mice, suggesting nutrition could influence leprosy progression.

## Contribution

The study demonstrates how dietary iron and vitamin D modulate immune responses to M. leprae in vitro, offering new insights into nutritional impacts on leprosy.

## Key findings

- Vitamin D supplementation and iron restriction reduced IL-6 and TNF production in peritoneal cells.
- Iron supplementation reduced IFN-γ, TNF, IL-6, and IL-10 in splenocytes.
- Nutrient status influences host-M. leprae interactions, potentially affecting leprosy progression.

## Abstract

The impact of nutrient availability on the survival of Mycobacterium leprae and the development of leprosy remains largely unknown. Iron is essential for the survival and replication of pathogens, while vitamin D has been involved with pathogen elimination and immunoregulation.

We evaluated the influence of dietary iron and vitamin D supplementation and restriction on the inflammatory response of mouse immune cells in vitro.

After 30 days of standard or modified diets, peritoneal cells and splenocytes were stimulated with the alive microorganisms and sonicated antigens of M. leprae, respectively. The production of inflammatory cytokines, reactive oxygen species, and cell proliferation were evaluated.

In peritoneal cells, vitamin D supplementation and iron restriction reduced the production of IL-6 and TNF in response to M. leprae, while splenocytes presented a reduction in TNF production under the same conditions. Lower levels of IFN-γ and TNF were observed in both iron-supplemented and iron-deficient splenocytes. Besides, iron supplementation also reduced the production of IL-6 and IL-10. No changes in the production of reactive oxygen species or in cell proliferation were observed related to different diets.

Taken together, these data point to an interference of the status of these nutrients on the interaction between the host and M. leprae, with the potential to interfere with the progression of leprosy. Our results highlight the impact of nutritional aspects on this neglected disease, which is significantly associated with unfavourable social conditions.