Regulatory parameters of the lung immune response during the early phase of experimental trichinellosis

FALDUTO G.H.; VILA C.C.; SARACINO M.P.; GENTILINI M.V.; VENTURIELLO S.M.

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016

0304-4017

Parasitic infection caused by Trichinella spiralis provokes an early stimulation of the mucosal immune system whichcauses an allergic inflammatory response in the lungs. The present work was intended to characterize the kinetics of emergenceof regulatory parameters in Wistar rat lungs during this early inflammatory response, between days 0 and 13 p.i.The presence of regulatory cells such as regulatory T cells (Tregs) and alternatively activated macrophages (AAM) wasanalyzed in lung cell suspensions. Moreover, a regulatory cytokine (TGF-β) was studied in lung tissue extracts. Consideringthat newborn larvae (NBL) travel along the pulmonary microvasculature, the ability of this parasite stage to modulatethe activation of lung macrophages was evaluated. For this purpose, lung macrophages from non-infected or infected rats(day 6 p.i.) were cultured with live or dead NBL. Arginase activity (characteristic of AAM) and nitric oxide (NO producedby iNOS, characteristic of classical activated macrophages) were measured after 48 h. Our results revealed a significantincrease in the percentage of Tregs on days 6 and 13 p.i., arginase activity on day 13 p.i. and TGF-β levels on days6 and 13 p.i. Lung macrophages from non-infected rats cultured with live NBL showed a significant increase in arginaseactivity and NO levels. Live and dead NBL induced a significant increase in arginase activity in lung macrophages frominfected rats. Only live NBL significantly increased NO levels in these macrophages. The present work demonstrates forthe first time, the emergence of regulatory parameters in the early lung immune response during T. spiralis infection. Theimmumodulatory properties exerted by NBL during its passage through this organ could be the cause of such regulation.Moreover, we have shown the ability of NBL to activate macrophages from the lung parenchyma by the classical andalternative pathways