RESUMO
Toxoplasma gondii is an obligate intracellular parasite that can infect a variety of mammals including humans and causes toxoplasmosis. Unfortunately, a protective and safe vaccine against toxoplasmosis hasn't been developed yet. In this study, we developed a DNA vaccine encoding the SRS13 protein and immunized BALB/c mice thrice with pVAX1-SRS13 through the intramuscular route (IM) or intradermally using an electroporation device (ID + EP). The immunogenicity of pVAX1-SRS13 was analyzed by ELISA, Western blot, cytokine ELISA, and flow cytometry. The protective efficacy of the pVAX1-SRS13 was investigated by challenging mice orally with T. gondii PRU strain tissue cysts. The results revealed that pVAX1-SRS13 administered through IM or ID + EP routes induced high level of anti-SRS13 IgG antibody responses (P = 0.0037 and P < 0.0001). The IFN-γ level elicited by the pVAX1-SRS13 (ID + EP) was significantly higher compared to the control group (P = 0.00159). In mice administered with pVAX1-SRS13 (ID + EP), CD8+ cells secreting IFN-γ was significantly higher compared to pVAX1-SRS13 (IM) (P = 0.0035) and the control group (P = 0.0068). Mice vaccinated with the SRS13 DNA vaccine did not induce significant IL-4 level. Moreover, a significant reduction in the number of tissue cysts and the load of T. gondii DNA was detected in brains of mice administered with pVAX1-SRS13 through ID + EP and IM routes compared to controls. In conclusion, the SRS13 DNA vaccine was found to be highly immunogenic and confers strong protection against chronic toxoplasmosis.
RESUMO
Pneumocystis jirovecii is an opportunistic respiratory pathogen causing Pneumocystis pneumonia (PcP) in immunocompromised patients. The aim of this study was to investigate the genetic diversity of P. jirovecii isolates (n: 84) obtained from PcP patients using multilocus sequencing method based on mt26S, SOD, and CYB loci. Among the 84 clinical samples that were positive for P. jirovecii DNA, 31 (36.90%) of them were genotyped using at least one locus. Of the 31 clinical samples, 26 of them were successfully genotyped using all loci whereas three samples were genotyped using either mt26S/CYB loci or mt26S/SOD loci. Additionally, there were two more clinical samples that were genotyped using CYB or SOD locus. Using mt26S locus, genotypes 2, 3, 7, and 8 were detected. Frequencies of genotype 7 and 8 were higher and both of them were found in 11 (n: 29; 37.93%) clinical samples. Using SOD locus, SOD 1, 2, and 4 genotypes were detected. SOD 1 was the predominant genotype (20/28; 71.42%). During the analyses of CYB locus, CYB 1, 2, 5, 6, and 7 as well as a new CYB genotype were detected. CYB 1 (16/29; 55.17%) and 2 (10/29; 34.48%) were the predominant genotypes. Overall, according to the multilocus sequencing results E, F, M, N, P, and V multilocus genotypes were detected among the PcP patients. In addition, SOD 1 was the predominant genotype and CYB had a more polymorphic locus.
