While studying how the immune system operates, scientists from the University of Pennsylvania School of Veterinary Medicine discovered a previously unidentified cell population that may be the body's double-edged sword, fighting off parasitic infections but also causing the harmful immune responses that can lead to allergies and asthma.

This cell population, termed multipotent progenitor cells, or MPP, appears to be activated in the context of allergies or infection with parasitic worms and may be one of the earliest cellular events in the developing immune response.

The research by David Artis, assistant professor in the Department of Pathobiology at Penn Vet, and colleagues may identify an important process in the immune response to helminth parasites and allergies.

A better understanding of what regulates the development of this cell population and what promotes its activation and function may aid in the development of drugs.

The research team demonstrated that a molecule called IL25, a member of the IL17 cytokine family, promotes the accumulation of a lineage-negative multipotent progenitor cell population in the intestine that promotes T cell responses associated with asthma and helminth infection. The resulting cell population gives rise to cells of macrophage and granulocyte lineages.

The ability of IL25 to induce the emergence of an MPP cell population identifies a link between the IL17 cytokine family and extramedullary haematopoiesis and suggests a previously unrecognized innate immune pathway that promotes TH2 cytokine responses at mucosal sites.

The study has been published in the current issue of Nature.(ANI)