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

FALDUTO G; VILA C; SARACINO MP; GENTILINI MV; VENTURIELLO SM

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016

0304-4017

Parasitic infection caused by Trichinella spiralis provokes an early stimulation of the mucosalimmune system which causes an allergic inflammatory response in the lungs. The present work wasintended to characterize the kinetics of emergence of regulatory parameters in Wistar rat lungs duringthis early inflammatory response, between days 0 and 13 p.i. The presence of regulatory cells such asregulatory T cells (Tregs) and alternatively activated macrophages (AAM) was analyzed in lung cellsuspensions. 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 parasitestage to modulate the activation of lung macrophages was evaluated. For this purpose, lungmacrophages 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 produced by iNOS, characteristic ofclassical activated macrophages) were measured after 48 hours. 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-βlevels on days 6 and 13 p.i. Lung macrophages from non-infected rats cultured with live NBL showed asignificant increase in arginase activity and NO levels. Live and dead NBL induced a significantincrease in arginase activity in lung macrophages from infected rats. Only live NBL significantlyincreased NO levels in these macrophages. The present work demonstrates for the first time, theemergence 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 causeof such regulation. Moreover, we have shown the ability of NBL to activate macrophages from the lungparenchyma by the classical and alternative pathways.