Supplementary Materials Supplemental material supp_85_10_e00069-17__index. around 25% of the global human population (1). Although infection is principally asymptomatic, it can cause severe neurological complications in immunocompromised individuals, disseminated congenital infections in the developing fetus, and ocular manifestations in otherwise healthy individuals (1). In the early phase of infection, inflammatory monocytic cells are recruited to the site of infection. Interleukin-12 (IL-12) and interferon gamma (IFN-) production ensures the establishment of the specific cell-mediated immune response leading to protection against recurrent infections via T cells and natural killer (NK) cells and later by B cell-mediated antibody production (2). Eribulin Mesylate While different cell types, e.g., epithelial cells or cells of the central nervous system (CNS), may provide a refuge for an intracellular pathogen, leukocytes also mediate immune surveillance and are essential for pathogen clearance. Paradoxically, the inherent migratory functions of leukocytes also make them a suitable target for pathogens so that the pathogens may use them as a Trojan horse to mediate their dispersion in the organism (3, 4). A major effector mechanism of immune cells is their ability to kill pathogens in infected cells, thereby limiting the spread of an infectious agent. The driving of Th1 responses by NK cells and CD8+ T cells enhances the intracellular killing of (5). Furthermore, killing of infected cells through perforin-mediated pathways could also protect hosts from contamination (6). However, recent observations on T cells, NK cells, and dendritic cells (DCs) vis vis their contamination by have highlighted potential mechanisms by which this obligate intracellular parasite might evade cellular immunity and also might manipulate cell-mediated cytotoxicity to its own advantage (7, 8). Death receptor ligation in were also observed using 2-photon microscopy (9). Similarly, perforin-dependent NK Eribulin Mesylate cell-mediated cytotoxicity of DCs induced parasite egress, which led to contamination of NK cells both and (8). More recently, it has been shown that contamination of NK cells may induce hypermotility in NK cells (10). Since NK cells have important roles in immune responses to (11, 12), in the present study, we examined the effect of contamination on NK cell effector function. We also identify potential molecular pathways targeted by the parasite that could affect NK cell functions. RESULTS NK cells infected by exhibit reduced cytotoxicity is efficiently transmitted from infected DCs to effector NK cells and T cells during the cytotoxicity of infected cells (7, 8), we investigated the functional consequences of these infections on NK cells. Since, in Eribulin Mesylate our previous study, IL-2-stimulated NK cells could become infected upon conversation with infected dendritic cells (8), we first infected IL-2-stimulated NK cells and tested for their cytotoxicity against YAC1 tumor cells were compared with control unchallenged NK cells for their ability to kill YAC1 cells in a 51Cr release assay, there was a significant decrease in the killing of YAC1 cells by the inhibits NK cell-mediated killing. (A) YAC1 cell killing by uninfected IL-2-stimulated NK cells or by NK cells infected with the RH-LDM strain in the LIMK1 51Cr release assay. The data represent means SEMs. *, 0.05, paired test (= 3 separate experiments). (B) Degranulation by IL-2-stimulated NK cells. (Left) Results of one representative experiment of degranulation by NK cells in the presence of YAC1 cells (10:1); (right) bar graph representing the percentage of CD107a+ cells by gating around the infected (GFP+) or uninfected (GFP?) NK cells separately. *, 0.01, ANOVA with the Bonferroni correction.