DNase treatment to break down genomic DNA that could lead to false positive gene expression results was accomplished using DNA-free DNase (Ambion, Grand Island, NY). infected animals present a high heterogeneous cytokine response independent of clinical presentation. Heat map of differentially expressed genes from animals in different clinical groups. Clinical score was accessed and animals were classified as low (0C2), medium (3C6) or high score (7C18). Red corresponds to higher AZD1080 gene expression levels.(TIF) pone.0123009.s003.tif (530K) GUID:?31638AB6-28C9-46B5-8644-F6FF826C8897 S4 Fig: Declining trend of splenic cytokines mRNA according to spleen organization in infected dogs. Ex-vivo analyses of relative mRNA levels for indicated genes in the splenic compartments of mongrel dogs infected with are shown in animals with different degrees of white pulp organization by histopatology. Gene expression levels of each tested cytokine were normalized AZD1080 using HPRT and RP32 expression. Error bars indicate the standard error. Mann Whitney test.(TIF) pone.0123009.s004.tif (8.9M) GUID:?3A2632DE-F6BB-49F4-ACEB-935FB9777236 S1 Table: Target genes and primers. (DOCX) pone.0123009.s005.docx (15K) GUID:?EF8EE3BC-D49E-4D87-8323-60AF43530162 Data Availability StatementAll relevant data are within the AZD1080 paper and its Supporting Information files. Abstract Canine Visceral Leishmaniasis (CVL) shares many aspects with the human disease and dogs are considered the main urban reservoir of in zoonotic VL. Infected dogs develop progressive disease with a large clinical spectrum. A complex balance between the parasite and the genetic/immunological background of the host are decisive for contamination evolution and clinical outcome. This study comprised 92 Leishmania infected mongrel dogs of various ages from Mato Grosso, Brazil. Spleen samples were collected for determining parasite load, humoral response, cytokine mRNA expression and histopathology alterations. By real-time PCR for the ssrRNA Leishmania gene, two groups were defined; a low (lowP, n = 46) and a high parasite load groups (highP, n = 42). When comparing these groups, results show variable individual humoral immune response with higher specific IgG production in infected animals but with a notable difference in CVL rapid test optical densities (DPP) between highP and lowP groups. Splenic architecture disruption was characterized by disorganization of white pulp, more evident in animals with high parasitism. All cytokine transcripts in spleen were less expressed in highP than lowP groups with a large heterogeneous variation in response. Individual correlation analysis between cytokine expression and parasite load revealed a negative correlation for both pro-inflammatory cytokines: IFN, IL-12, IL-6; and anti-inflammatory cytokines: IL-10 and TGF. TNF showed the best unfavorable correlation (r2 = 0.231; p 0.001). Herein we describe impairment on mRNA cytokine expression in leishmania infected dogs with high parasite load associated with a structural modification in the splenic lymphoid micro-architecture. We also discuss the possible mechanism responsible for the uncontrolled parasite growth and clinical outcome. Introduction Canine Visceral Leishmaniasis (CVL) shares many aspects with the human disease and dogs are considered the main urban reservoir of in zoonotic VL. Canine contamination may precede the emergence of human cases  and the presence of infected dogs is usually directly associated with the risk of human contamination . The control programs of VL in endemic areas of Latin America include the detection and treatment of infected and sick humans, insecticide spraying in residential outhouses and selective removal of seropositive dogs. Screening and mass culling of seropositive dogs has not been proved to be uniformly effective in control Erg programs  and many studies have questioned its effectiveness [4C7]. Therefore, the knowledge of the immune mechanisms involved in animal pathology and protection plays a pivotal role in the endemic control . Infected dogs develop progressive disease, characterized by lymphadenopathy, hepatosplenomegaly, onychogryphosis, body weight loss, dermatitis, anemia and ultimately death. The large spectrum of clinical presentations ranges from asymptomatic to symptomatic contamination . A complex balance between the parasite and the genetic/immunological background of AZD1080 the host are decisive for the progression towards disease. However, no conclusive data are available around the immunological mechanisms responsible for resistance or disease progression in CVL. The infection is usually characterized by a marked humoral response [10,11] and the parasite load follows the clinical outcome . Several studies show a mixed cellular response related to contamination [2,13C15]. Such a mixed response is also observed under different experimental conditions . The immune response to viscerotropic parasites is usually organ-specific [17C19] and the spleen is an important target in VL . Overall, AZD1080 in spleen the production of Th1 cytokines (such as IFN-, IL-12 and TNF) of both asymptomatic and symptomatic dogs does not show any differences [13,14,20], however they are increased during contamination.