Tetanus neurotoxin HCC protein commits T cells to IFN-γ producing cells

A protective response against tetanus toxin and toxoid demands efficient specific T cell and B cell responses. Tetanus neurotoxin (TeNT), a 150 kDa polypeptide, is the main cause of tetanus disease. TeNT consists of two structurally distinct chains, a 50 kDa N-terminal light (L) and a 100 kDa C-terminal heavy (H) chain. C-terminal heavy (H) chain (fragment C) has two sub-domains named as proximal HCN and carboxy sub-domain or HCC. Beside neural binding property, HCC has been recently found as an immunodominant module of TeNT. In the present study, we investigated the effects of recombinant HCC (rHCC) on the expression of lineage specific transcription factors and secretion of a panel of functional cytokines including IFN-γ, IL-4, and IL-17 from purified human T cells. Our results revealed that T-bet transcript level, as TH1 specific transcription factor, was significantly increased in the cells treated with 10 and 20 µg/ml of rHCC following 48 h treatment(p<0.05). Treated purified human T cells with rHCC showed significant increase in IFN-γ mRNA level and cytokine secretion, but not IL-4 and IL-17, following 48 h treatment. In conclusion, our results showed that treatment of T cells with r HCC resulted in development of Th1 lineage phenotype, which might lead to a specific and protective antibody mediated response against tetanus toxin.

Genotypic characterization of Echinococcus granulosus isolates based on the mitochondrial cytochrome c oxidase 1 (cox1) gene in Northwest Iran

Hydatidosis is one of the most important zoonotic parasitic diseases caused by the larval stage of Echinococcus granulosus which causes great health and economic losses. The aim of this study was to use the sequencing method to evaluate genotypes of E. granulosus isolated from humans and bovines using mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. The samples were taken in the East Azerbaijan Province, Northwest Iran. Overall, 26 hydatid cyst samples (10 human and 16 cattle isolates) were collected. DNA extraction was taken from the protoscoleces of human and germinal layer of bovine samples. PCR was performed using the mitochondrial cytochrome c oxidase subunit 1(cox1) gene, and then it was sequenced. Sequences were analyzed for identification of their genotypes. All 16 bovine isolates were recognized as G1 genotypes (sheep strain) and G1B subtypes. Out of ten human host samples, seven isolates were G1B subtypes, and three samples were identified as G3 genotypes. The results of this study showed that G1 and especially G1B are the predominant genotype and subtype in humans and cattle in Northwest Iran.

Assessment of the efficacy of 8 weeks of primaquine for the prevention of relapse in vivax malaria patients using SSCP-PCR and sequencing in South and South-East Iran, 2008-2011

BACKGROUND

Treatment of vivax malaria with primaquine prevents the risk of relapse. This study was designed to assess the efficacy of 8 weeks of primaquine treatment in prevention of relapse in patients with vivax malaria in south and south-east Iran by SSCP-PCR and sequencing.

METHODS

A total of 163 symptomatic vivax malaria cases were followed up in Hormozgan and Sistan, Baluchestan provinces in south and south-east Iran between December 2008 and December 2011. DNA was extracted from primary and secondary positive samples. A variation region of PvMSP-1 gene was selected and amplified by PCR. The obtained fragments were processed in polyacrylamide gel for single-strand conformational polymorphism (SSCP) and then sequenced.

RESULTS

Among 145 patients treated with chloroquine plus primaquine who completed the study period, two patients (1.4%) experienced a secondary infection after the initial episode of Plasmodium vivax. The comparison between primary and secondary isolates by SSCP indicated different banding patterns and electrophoretic mobility. Alignment of nucleotide sequences between pair primary and secondary isolates revealed dissimilar homology. Secondary isolates of both patients were considered as reinfection. Five of the 18 cases (28%) treated with chloroquine only revealed secondary infection. Analysis of nucleotide sequences and SSCP patterns indicated the relapse in all of them.

CONCLUSION

This survey indicates that intake of primaquine, 0.75 mg/kg, weekly for 8 consecutive weeks, is effective for the prevention of relapse in vivax cases in Iran.

Genetic Variation of MSP-1 Gene in Plasmodium vivax Isolated from Patients in Hormozgan Province, Iran using SSCP-PCR

BACKGROUND

The main goal of present study was to detect polymorphism in MSP-1 gene which is a major blood stage candidate for vaccine in Plasmodium vivax by Single Strand Conformational Polymorphism-Polymerase Chain Reaction (SSCP-PCR).

METHODS

During 2008 to 2010 fifty samples were collected from Iranian patients with P. vivax in Hormozgan Province, southern Iran. All of the samples were detected by microscopical examination. Amplification of MSP-1 gene was done by PCR after DNA extraction. Single strand DNAs due to using in SSCP, was electrophoresed on polyacrylamid- Bisacrylamid gel then banding patterns were revealed by silver-staining method. Sequencing as a typing method was performed for some isolates.

RESULTS

All of the 50 isolates were positive microscopically. Totally 12 (24%) isolates showed 440 bp and 38 (76%) showed 500 bp in PCR assay. SSCP analysis revealed four banding patterns. Pattern I (10/50), Pattern II (12/50), Pattern III (27/50), and Pattern IV (1/50). The results sequencing analysis of the MSP-1 gene in 19 isolates revealed diversity in nucleotides and amino acid in Iranian P. vivax isolates.

CONCLUSION

Our study confirms that the SSCP-PCR is a rapid method for detecting polymorphism in MSP-1 gene in P. vivax. The presence of different haplotypes in MSP-1 gene shows that several P. vivax strains exist in malaria endemic areas of Iran.