NOS2 and infection: Based on previously published results of in vivo and in vitro assays for the phenotypic characterization of several T. gondii isolates [22], a total of six strains belonging to different genotypes, geographical locations and origins of tissue sample and recently isolated from sheep, were selected with the intention of evaluating, through in vitro assays with OvMØs, the effect of such features by studying the cell infection rate (cIR) using immunostaining and the immune response through transcript expression of cytokines and iNOS after infection.