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Toxocara canis (T. canis) is a common parasitic nematode in dogs and cats. Parasitic worms can cause chronic and long-term infections in their host, due to their ability to neutralize the host's defense mechanisms. They can stimulate immune response-mediated regulatory T (T-reg) cells. The aim of this study is to evaluate the effect of recombinant T. canis C-type lectin protein (TCTL-1) on cell infiltration in the brains of BALB /c mice as well as the number of regulatory T cells. Six-week-old female BALB/c mice received the recombinant C-type lectin protein of T. canis six times intravenously and intraperitoneally. Twenty-eight days after the first injection, the spleen and brain of mice were removed under sterile conditions. The brains of mice were examined by histopathological staining methods. The FOXP3+ regulatory T cell population was determined by flow cytometry. The cell populations of regulatory T cells in spleen mononuclear cell culture of 3 female BALB/c mice injected with recombinant TCTL-1 (group I) were 2.59%, 1.64%, and 1.78 and in spleen mononuclear cell culture of three female BALB/c mice injected with sterile PBS (group II) as a control group were 1.14%, 1.13%, and 1.15%. Also, no cell infiltration was seen around the cerebral arteries of mice receiving this protein. This recombinant protein would increase the population of FOXP3+ regulatory T cells. These results suggest that recombinant C-type lectin protein of T. canis can modulate immune responses, reduce severe inflammatory responses, and induce FOXP3+ regulatory T cells.

Background: This study aimed to identify Rickettsia spp. and their circulation in ticks collected from sheep in the Khuzestan province, Southwest Iran. Methods: Four hundred and forty adult hard ticks were collected from the parasite-infected sheep from nine cities of Khuzestan province. DNA samples were extracted and subjected to the single-round polymerase chain reaction amplification of citrate synthase gene (gltA). Results: The tick species were identified as Hyalomma marginatum, Hyalomma anatolicum, Hyalomma dromedarii, Hyalomma schulzei, Rhipicephalus bursa, and Rhipicephalus turanicus. The presence of Rickettsia spp. was observed in half of the collected ticks (50%). For a definitive identification of Rickettsia spp., the amplicons (n: 10) were directly sequenced. Sequencing and phylogenetic analyses revealed the definitive presence of Rickettsia aeschlimannii (60%), Rickettsia massiliae (30%), and Rickettsia conorii (10%) in the infected ticks. Conclusions: The results indicated a significant incidence of tick-borne Rickettsia spp. and their unequivocal circulation in Southwest Iran. Hence, the prevalence of spotted fever group Rickettsia should be detected in suspected humans and domestic animals in wider areas of Iran.