Molecular Characterization of the Gene Encoding SJCHGC 03921 Protein of the Lung Stage of Schistosoma Mansoni (7-Days Schistosomula)

Abstract

The parasitic helminth Schistosoma mansoni (S. mansoni) is a major public health concern in many developing countries. Over 200 million people have, and another 600 million are at risk of contracting schistosomiasis which is one of the major neglected tropical diseases. For this dangerous disease the development of longlasting immunity through vaccination may be the real solution to control the spread of the disease. The molecules on the surface or associated with the tegument of S. mansoni are a major focus as potential vaccine candidates. In the present study, all surface and internal proteins of the lung stage of the parasite were screened to increase the chances for the discovery of a unique protein of the parasite to be targeted by the immune system of the host. Pooled sera were collected from S. mansoni chronically infected patients, then, purified over a column made of soluble extract of the lung stage (7-days schistosomula) of S. mansoni. The eluted antibodies were used to immunoscreen λgt11 cDNA library of 7-days schistosomula. A number of cDNA clones were identified after three rounds of immunoscreening and plaques purification. The phage DNAs of the isolated clones were amplified by polymerase chain reaction (PCR) using λgt11 forward and reverse primers, then, cloned in PCR TM II plasmid vector. The isolated clone 4-65 was fully sequenced and was found encoding the gene of SJCHGC 03921 protein of 7-days schistosomula of S. mansoni. Also, the 0.9 kb cDNA clone was found to have a single open reading frame (ORF) encoding 269 amino acids, which exhibited 94% homology with the gene of SJCHGC 03921 protein of Schistosoma japonicum.