Plasmodium immunotherapy combined with gemcitabine has a synergistic inhibitory effect on tumor growth and metastasis in murine Lewis lung cancer models.

Objective: Our previous studies have demonstrated that Plasmodium immunotherapy (infection) has antitumor effects in mice. However, as a new form of immunotherapy, this therapy has a weakness: its specific killing effect on tumor cells is relatively weak. Therefore, we tested whether Plasmodium immunotherapy combined with gemcitabine (Gem), a representative chemotherapy drug, has synergistic antitumor effects. Methods: We designed subcutaneously and intravenously implanted murine Lewis lung cancer (LLC) models to test the antitumor effect of Plasmodium chabaudi ASS (Pc) infection in combination with Gem treatment and explored its underlying mechanisms. Results: We found that both Pc infection alone and Gem treatment alone significantly inhibited tumor growth in the subcutaneous model, and combination therapy was more effective than either monotherapy. Monotherapy only tended to prolong the survival of tumor-bearing mice, while the combination therapy significantly extended the survival of mice, indicating a significant synergistic effect of the combination. In the mechanistic experiments, we found that the combination therapy significantly upregulated E-cadherin and downregulated Snail protein expression levels, thus inhibiting epithelial-mesenchymal transition (EMT) of tumor cells, which may be due to the blockade of CXCR2/TGF-ß-mediated PI3K/Akt/GSK-3ß signaling pathway. Conclusion: The combination of Pc and Gem plays a synergistic role in inhibiting tumor growth and metastasis, and prolonging mice survival in murine lung cancer models. These effects are partially attributed to the inhibition of EMT of tumor cells, which is potentially due to the blockade of CXCR2/TGF-ß-mediated PI3K/Akt/GSK-3ß/Snail signaling pathway. The clinical transformation of Plasmodium immunotherapy combined with Gem for lung cancer is worthy of expectation.

Plasmodium infection prevents recurrence and metastasis of hepatocellular carcinoma possibly via inhibition of the epithelial­mesenchymal transition.

Postoperative recurrence causes a high mortality rate among patients with hepatocellular carcinoma (HCC). The current study aimed to determine the effects of Plasmodium infection on HCC metastasis and recurrence. The antitumor effects of Plasmodium infection were determined using two murine orthotopic HCC models: The non­resection model and the resection model. Tumour tissues derived from tumour­bearing mice treated with or without Plasmodium infection were harvested 15 days post­tumour inoculation. The expression levels of biomarkers related to epithelial­mesenchymal transition (EMT) and molecules associated with CC­chemokine receptor 10 (CCR10)­mediated PI3K/Akt/GSK­3ß/Snail signalling were identified using reverse transcription­quantitative PCR and western blotting. The results demonstrated that Plasmodium infection significantly suppressed the progression, recurrence and metastasis of HCC in the two mouse models. The expression levels of E­cadherin were significantly higher in the Plasmodium­treated group compared with that in the control group, whereas the expression levels of Vimentin and Snail were significantly lower in the Plasmodium­treated group. Furthermore, Plasmodium infection inhibited the activation of Akt and GSK­3ß in the tumour tissues by downregulating the expression levels of CCR10 and subsequently suppressing the accumulation of Snail, which may contribute to the suppression of EMT and the prevention of tumour recurrence and metastasis. In conclusion, the results of the present study demonstrated that Plasmodium infection inhibited the recurrence and metastasis and improved the prognosis of HCC by suppressing CCR10­mediated PI3K/Akt/GSK­3ß/Snail signalling and preventing the EMT. These results may be important for the development of novel therapies for HCC recurrence and metastasis, especially for patients in the perioperative period.

Design and evaluation of a hypoallergenic peptide-based vaccine for Salsola kali allergy.

BACKGROUND: The Salsola kali (S. kali) pollen is one of the most important causes of allergic rhinitis in the deserts and semi-desert areas. Immunotherapy with allergen extracts remains the only available treatment addressing the underlying mechanism of allergy. However, given the low efficacy of this method, it is necessary to find more effective and alternative therapeutic interventions using molecular biology and bioinformatics tools. In this study, a hypoallergenic vaccine was designed on the basis of B-cell epitope approach for S. kali immunotherapy. METHODS: Using the Immune Epitope Database (IEDB), a 35-mer peptide was selected and chemically conjugated to a keyhole limpet hemocyanin (KLH) molecule. Specific IgG and IgE from immunized BALB/c mice sera against the vaccine (Sal k 1-KLH), S. kali extract and the recombinant protein, rSal k 1, were measured using ELISA. Also, inhibition of IgE by mouse IgG was evaluated using an inhibitory ELISA. Finally, the IgE reactivity and T-cell reactivity of the designed vaccine were evaluated by dot blot assay and MTT assay. RESULTS: Vaccination with the vaccine produced high levels of protective IgG in mice, which inhibited the binding of patients IgE to recombinant proteins. The result showed that the designed vaccine, unlike the recombinant protein and extract, did not induce T-cell lymphocytes response and also exhibited decreased IgE reactivity. CONCLUSION: The designed vaccine can be considered as a promising candidate for therapeutic allergen-specific immunotherapy.

Construction of a recombinant B-cell epitope vaccine based on a Der p1-derived hypoallergen: a bioinformatics approach.

AIM: House dust mite (HDM) allergens are important elicitors of IgE-mediated allergies. This study was aimed at constructing and characterizing a recombinant fusion protein, DpTTDp, which was based on carrier-bound Der p 1-derived peptides for HDM allergen immunotherapy. METHODS: Using the Immune Epitope Database (IEDB), we identified from Der p 1, a 34-mer hypoallergenic peptide. Two copies of the hypoallergen were then fused to a partial fragment of a tetanus toxoid molecule's N-and C terminus and expressed in Escherichia coli. After purification to homogeneity, the protein was evaluated for allergenicity and its ability to induce blocking antibodies upon immunization. RESULTS: Upon immunization of mice, DpTTDp induced high levels of protective IgG-antibodies that blocked allergic patients' IgE reactivity to HDM. In addition, DpTTDp lacked relevant IgE-reactivity, induced low T-cell proliferation and IFN-γ in peripheral blood mononuclear cells of HDM-allergic patients' sera. CONCLUSION: The protein represents a promising HDM-allergy immunotherapy candidate vaccine.