Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 13 1 2018 03 14 49 57 Fazeleh ETEBAR Dept. of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Seyed Hossein HOSSEINI Dept. of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Fatemeh JALOUSIAN Dept. of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Mohammad Mehdi RANJBAR Dept. of Immunology, Razi Vaccine and Serum Research Institute, Karaj, Iran 2018 03 14 2018 03 14 Background: C type lectin (CTL) family is a type of calcium-dependent proteins found in vertebrates and invertebrates. The objective of this study was to perform a comparative analysis and phylogenetic inferring for understanding the similarities and differences of carbohydrate recognition domain (CRD) domain of Toxocara canis CTL and other nematodes, and similar C type lectin involved in the immune system of mouse and human as their host. Methods: The female T. canis was retrieved from the 2-6 months puppies (Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, 2015). To collect T. canis eggs, the worms were cultured for 5 d until they were embryonated. The hatching process was accelerated for collecting the stage 2 larvae, and the larvae were cultured for a week. A cDNA library was made from the total mRNA of T. canis infective larvae. The PCR amplification for C type lectin gene was performed and the amino acids were analyzed using the alignment method and the construction of phylogenetic tree. Results: The suspension sample maintained at 30 ºC for four weeks could embryonate 90%-100% of eggs. T. canis CTL gene was 657 bp in length and encoded a protein with 219 amino acids. The CTL of species of Strongylida order were closely placed in the tree, whereas the members of Ascaridida orders were located in a separate branch. High levels of similarity (36%-44%) and conservation of C type lectin from T. canis with mouse and human C type lectins. Its C type lectin showed a higher similarity with asialoglycoprotein receptor (ASGPR), macrophage lectin, dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN), MINCLE receptor of mouse and human. Conclusion: Analysis of CRD domain of C type lectin protein could make a better understanding of their role in the interaction of nematode parasite with their hosts. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/2044 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/2044/806