Iranian Journal of Parasitology (Mar 2018)
Phylogenetic Analysis of C Type Lectin from Toxocara canis Infective Larvae and Comparison with the C Type Lectin Family in the Immune System of Mouse and Human
Abstract
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.
