Background: Matrix metalloproteinase 9 (MMP-9) is significant in the progression of osteosarcoma (OS) via increasing tumor growth, invasion and metastasis. Although previous reports indicate the prognostic value of MMP-9 in OS, there is still a great degree on inconsistency between studies. Here we report a comprehensive evaluation of the value of MMP-9 in metastasis of OS by conducting a meta-analysis of published studies. Methods: The quantity of the studies was evaluated using the Newcastle-Ottawa quality assessment scale (NOS). Sixteen studies with a total of 816 patients with OS were examined and we calculated the pooled odds ratio (OR) with corresponding 95% confidence interval (CI) (95% CI) to evaluate that the positive expression of MMP-9 predicts neoplasm metastasis and poor survival in OS. Results: The results of Meta-analysis indicated that patients with positive expression of MMP-9 were significantly associated with neoplasm metastasis (OR = 4.69, 95% CI: 3.05–7.21, P <.001) and poor survival in OS with the pooled OR of 7.19 (95% CI 4.32–11.98, P <.001) when compared to their counterparts with a negative expression of MMP-9. The results of sensitivity analysis showed that the pooled OR was stable. It doesn’t significantly change when a single study was removed. Conclusions: The results of meta-analysis indicated that MMP-9 may be a prognostic biomarker guiding the clinical therapy for OS.

Toxoplasma gondii can lead to congenital infections in human. Surface antigen protein 4 (SAG4) of Toxoplasma gondii is a potential stimulator for humoral and cellular immune responses. In the present study, a DNA vaccine encoding SAG4 from T. gondii was constructed and used to immunize BALB/c mice with peptide to evaluate the protective efficacy of the vaccine. The productions of IgG antibodies and cytokines (IFN-γ) from the vaccine (pSAG4/peptide) group were significantly higher than pSAG4 or peptide groups. After a lethal challenge by 1×104 tachyzoites from the Ⅰ strain (RH), the survival time of mice immunized by pSAG4/peptide was longer than that of pSAG4 or peptide immunized mice or control mice. Moreover, after challenging by 20 cysts of the Ⅱ strain (PRU) of Toxoplasma gondii, the number of brain cysts from pSAG4/peptide vaccinated mice was only 31% of the number in PBS injected mice. The findings suggested the SAG4 DNA vaccine with peptide led significant immune responses and improved the protection against Toxoplasma gondii challenges.

A widely prevalent disease, toxoplasmosis poses serious health threats to both humans and animals; therefore, development of an ideal DNA vaccine against Toxoplasma gondii is needed eagerly. The purpose of the present study is to assess the protective efficacy of a DNA vaccine encoding the T. gondii toxofilin gene (pEGFP-toxofilin). In addition, toxofilin DNA vaccine combined with the individual adjuvants, alum or monophosphoryl lipid A (MPLA), or a mixture of alum-MPLA adjuvant were screened for their ability to enhance antibody responses. Using bioinformatics, we analyzed the gene and amino acid sequences of the toxofilin protein, recognizing and identifying several potential linear B and T helper (Th)-1 cell epitopes. BALB/c mice were immunized three times with either toxofilin DNA vaccine alone or in combination with the adjuvants such as alum, MPLA or an alum-MPLA mixture. The systemic immune response was evaluated by cytokine, the percentage of CD4 (+) and CD8 (+) T cells and specific antibody measurement. Two weeks after the last immunization, protective efficacy was evaluated by challenging intraperitoneally with 1 × 104 tachyzoites of T. gondii or intragastrically with 20 cysts of T. gondii PRU strain. All experimentally immunized mice developed strong humoral and cellular immune responses compared with the control groups. Moreover, by comparison with the non-adjuvant toxofilin DNA vaccine group, adding alum adjuvant to toxofilin DNA vaccine resulted in an increase in humoral response and a skewed Th2 response. However, the MPLA adjuvant with toxofilin DNA vaccine induced significantly enhanced humoral and Th1-biased immune responses. Importantly, the co-administration of alum-MPLA adjuvant in combination with the toxofilin DNA vaccine shifted the Th2 immune response to a Th1 response compared with the alum-toxofilin group, and elicited the strongest humoral and Th1 responses among all the groups. At the same time, a longer survival time and less cyst amounts against T. gondii infection were also observed in the alum-MPLA-toxofilin group in comparison with single or no adjuvant groups. Toxoplasma gondii toxofilin is a promising vaccine candidate that warrants further development. Co-administration of the alum-MPLA adjuvant mixture with DNA vaccine could effectively enhance immunogenicity and strongly skew the cellular immune response towards a Th1 phenotype.

Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite with a broad host range including most warm-blooded animals, including humans. T. gondii surface antigen 1 (SAG1) is a well-characterized T. gondii antigen. T. gondii expresses five nonmitochondrial rhomboid intramembrane proteases, TgROM1-5. TgROM4 is uniformly distributed on the surface of T. gondii and involved in regulating MIC2, MIC3, MIC6, and AMA1 during T. gondii invasion of host cells. Bioinformatics have predicted ROM4 B-cell and T-cell epitopes. Immunization strategy is also a key factor in determining the effectiveness of the immune response and has gained increasing attention in T. gondii vaccine research. In this study, we used a DNA prime-peptide boost vaccination regimen to assess the protective efficacy of various vaccination strategies using TgROM4. We identified a polypeptide (YALLGALIPYCVEYWKSIPR) using a bioinformatics approach, and immunized mice using a DNA-prime and polypeptide-boost regimen. BALB/c mice were randomly divided into six groups, including three experimental groups (peptide, pROM4 and pROM4/peptide) and three control groups (PBS, pEGFP-C1 and pSAG1). Mice were then immunized intramuscularly four times. After immunization, IgG and cytokine productions were determined using enzyme-linked immunosorbent assays. The survival time of mice was evaluated after challenge with tachyzoites of T. gondii RH strain. Additionally, the number of cysts in the brain was determined after intragastric challenge with cysts of T. gondii PRU strain. Mice vaccinated with different immunization regimens (peptide, pROM4 and pROM4/peptide) elicited specific humoral and cellular responses, with high levels of IgG, IgG2a, and interferon (IFN)-γ. Moreover, IgG, IgG2a and IFN-γ levels were highest in the pROM4/peptide group. Immunized mice, especially those in the pROM4/peptide group, had prolonged survival times after challenge with tachyzoites and reduced numbers of brain cysts after infection compared with negative controls. A DNA prime-peptide boost regimen based on ROM4 elicited the highest level of humoral and cellular immune responses among immunization regimens, and may be a promising approach to increase the efficacy of DNA immunization.

We used bioinformatics approaches to identify B-cell and T-cell epitopes on the ROP19 protein of Toxoplasma gondii. Then, we constructed plasmids with ROP19 (pEGFP-C1-ROP19) and injected them into BALB/c mice to test the immunoprotection induced by this vaccine candidate. The results showed that immunization with pEGFP-C1-ROP19 induced effective cellular and humoral immune responses in mice; specifically, high serum levels of T. gondii-specific IgG and increased interferon-gamma production by splenocytes. Furthermore, the mice vaccinated with pROP19 had significantly fewer brain cysts (583 ± 160) than the mice injected with phosphate-buffered saline (1350 ± 243) or with the control plasmid, pEGFP-C1 (1300 ± 167). Compared with PBS-treated mice, those immunized with pROP19 had only 43% of the number of brain cysts. These results suggest that the DNA vaccine encoding ROP19 induced a significant immune response and provided protection against a challenge with T. gondii strain PRU cysts. Nous avons utilisé des approches bio-informatiques pour identifier des épitopes de lymphocytes B et de lymphocytes T sur la protéine ROP19 de Toxoplasma gondii. Ensuite, nous avons construit des plasmides avec ROP19 (pEGFP-C1-ROP19) et les avons injectés à des souris BALB/c pour tester l’immunoprotection induite par ce candidat vaccin. Les résultats ont montré que l’immunisation avec pEGFP-C1-ROP19 a induit des réponses immunitaires cellulaires et humorales efficaces chez la souris, en particulier des taux sériques élevés d’IgG spécifiques à T. gondii et une production accrue d’interféron gamma par les splénocytes. En outre, les souris vaccinées avec pROP19 avaient significativement moins de kystes cérébraux (583 ± 160) que les souris injectées avec du tampon phosphate salin (1350 ± 243) ou avec le plasmide témoin pEGFP-C1 (1300 ± 167). En comparaison avec les souris traitées au PBS, celles qui sont immunisées avec pROP19 avaient seulement 43 % du nombre de kystes dans le cerveau. Ces résultats suggèrent que le vaccin à ADN codant pour la ROP19 induit une réponse immunitaire significative et fournit une protection contre une provocation avec des kystes de la souche PRU de T. gondii.