Study On The Polymorphism Of Plasmodium Vivax Circumsporozoite Protein Gene

Objective This topic mainly through research PvCSP gene polymorphism characteristics to analysis the local and the imported of plasmodium vivax genotype in our province, combined with the comparison test results of CSP gene type at the same time,explore the distribution of PvCSP genotypes alleles in Henan province.Method Blood samples were collected during2008-2013, patients diagnosed with vivax malaria in Henan province, the patients were confirmed by both microscope and PCR, drying at room temperature, then for DNA extraction.The sequencing results were splicing by ChromasPro. Some sequences were select as domestic representative strains. The nucleotides and amino acid sequences were aligned, and the phylogenetic tree was drawn by means of mega4.0.Results1. In52field isolates, DNA fragment of600-750bp were produced by the nested PCR amplification, the isolates with falciparum malaria and healthy persons had not amplify any bands.2. CSP sequences obtained from51Henan P. vivax isolates were found to belong to the VK210type, only one isolate from Tengchong was of a VK247type.The sequences from local isolates were all VK210type.3. The number of repeat units from local isolates between20-22. In the post repeat regions, all variants of local PvCSP carried the same post-repeat sequence, GGNAANKKAEDA, after that insertion sequence, most of the local strains had the repeat units of two times, GGNA. Six different sub-types of VK210were observed in the20imported samples, and the number of repeat units betweenl7-19, some isolates displayed the insertion sequence of the12peptide,the number of subunits appeared diversity:1,2,3,5,6,7.4. In total,8distinct VK210types were recorded and two of the more frequent variants, VK210A (33.33%) and VK210G (42.42%) were found in local isolates. Compared with the VK210basic repeat units, more than75%repeat units of local PvCSP sequence have base transition non silence at least one time.7changes were observed in the central repeat units, the change mainly occurred in3,4,6,7,9,14,21,22nucleotides, among which,3,21often silent while4,7,9,14,22often non silent, and the sixth nucleotide can occur base transform both silent and non silent base transform.5. The sequences clustered into two distinct divisions for the VK210and VK247type isolates, the VK210type is consist of several sub-divisions.The sequences from local isolates were all VK210type, but most of isolates from different part of world were found to be located in different from the Henan isolates.The local isolates can be divided into2genotypes, A and B, then genotype A can be further divided into3subtypes of A1-A3. Nucleotide sequences were compared with the following published sequences, VK210, VK247, as well as with other PvCSP sequences found in the GenBank database.Conclusions Summarily, the Pv CSP genotype found in Henan province belongs to VK210type. The population structure of P.vivax from Henan province with high diversity has significant characters, eight different sequences were observed in all sequences. From the genetic distance, isolates from Henan are further with those from Africa, Southeast Asia. There were many similarity among Henan isolates and Guizhou isolates, North Korea isolates, but still can be distinguished.