Xingming Ma

A novel liposome adjuvant DPC mediates Mycobacterium tuberculosis subunit vaccine well to induce cell-mediated immunity and high protective efficacy in mice.

Tuberculosis (TB) is a serious disease around the world, and protein based subunit vaccine is supposed to be a kind of promising novel vaccine against it. However, there is no effective adjuvant available in clinic to activate cell-mediated immune responses which is required for TB subunit vaccine. Therefore, it is imperative to develop new adjuvant. Here we reported an adjuvant composed of dimethyl dioctadecylammonium (DDA), Poly I:C and cholesterol (DPC for short). DDA can form a kind of cationic liposome with the ability to deliver and present antigen and can induce Th1 type cell-mediated immune response. Poly I:C, a ligand of TLR3 receptor, could attenuate the pathologic reaction induced by following Mycobacterium tuberculosis challenge. Cholesterol, which could enhance rigidity of lipid bilayer, is added to DDA and Poly I:C to improve the stability of the adjuvant. The particle size and Zeta-potential of DPC were analyzed in vitro. Furthermore, DPC was mixed with a TB fusion protein ESAT6-Ag85B-MPT64(190-198)-Mtb8.4-Rv2626c (LT70) to construct a subunit vaccine. The subunit vaccine-induced immune responses and protective efficacy against M. tuberculosis H37Rv infection in C57BL/6 mice were investigated. The results showed that the DPC adjuvant with particle size of 400 nm and zeta potential of 40 mV was in good stability. LT70 in the adjuvant of DPC generated strong antigen-specific humoral and cell-mediated immunity, and induced long-term higher protective efficacy against M. tuberculosis infection (5.41 ± 0.38log10CFU) than traditional vaccine Bacillus Calmette-Guerin (BCG) (6.01 ± 0.33log10CFU) and PBS control (6.53 ± 0.26log10CFU) at 30 weeks post-vaccination. In conclusion, DPC would be a promising vaccine adjuvant with the ability to stimulate Th1 type cell-mediated immunity, and could be used in TB subunit vaccine.

Effects of immunomodulators on liquefaction and ulceration in the rabbit skin model of tuberculosis

To better control tuberculosis (TB) epidemics in developing countries a real need exists to study the liquefaction and cavity formation that occur in pulmonary TB lesions. This report is the first to evaluate the effects of immunomodulators on these two processes in a rabbit skin model. The effects of recombinant human interferon-γ (rIFN-γ), recombinant human interleukin-2 (rIL-2), dexamethasone and cyclophosphamide (CTX) were evaluated in TB lesions produced by intradermal injection of 5 × 10(6) viable BCG bacilli. Recombinant IL-2 and rIFN-γ accelerated the liquefaction and healing of the lesions, and reduced the bacterial load. In contrast, dexamethasone inhibited the liquefaction of the lesions, and increased the bacterial load. The effect of CTX was similar to dexamethasone but not as pronounced. Serum levels of IL-2 were higher during the liquefaction and healing phases in the rIL-2 and rIFN-γ groups. Therefore, immunomodulators affect both the development of TB lesions and the survival of the mycobacteria within them. This study suggests that the rabbit skin model can be a valuable method to select therapeutic agents that could inhibit liquefaction and cavity formation in pulmonary tuberculosis.

Comparison of student perception and performance between case-based learning and lecture-based learning in a clinical laboratory immunology course

Abstract Background: Case-based learning (CBL), an educational method of problem-based learning, provides students with a venue to relate content learned in the classroom to performance in professional practice. This study compared CBL in the teaching of a clinical laboratory immunology (CLI) course to lecture-based learning (LBL), and evaluated the effect on students regarding the CBL. Methods: Data were collected from senior students (n=85; 46% males, 54% females) at Lanzhou University in China. The students were divided into two groups, one group was offered CBL, while the other LBL as a teaching instrument. After intervention, perceptions of both the groups about their respective teaching method were evaluated using questionnaires, the resulting scores were compared to those obtained in the LBL group. Results: The CBL group showed significantly better scores in course examination (p<0.05) as compared to the LBL group. Seventy-seven (90.6%) students in the CBL group opined that CBL improved their learning and clinical problem-solving skills. CBL also provided them with better understanding (90.6%) and preparation for examinations (90.6%). CBL group improved markedly in comparison to the LBL group with regard to learning motivation (p=0.040), clinical reasoning ability (p=0.023) and clinical problem-solving ability (p=0.022). Conclusions: Our findings demonstrate that CBL is a more effective teaching strategy as compared to LBL in a CLI course. Consequently, the implementation of CBL in teaching a CLI course helps students to improve their learning motivation, problem solving abilities and mastery of knowledge.

A New Rabbit-Skin Model to Evaluate Protective Efficacy of Tuberculosis Vaccines

Background: BCG protection is suboptimal and there is significant interest to develop new tuberculosis (TB) vaccines. However, there are significant limitations of the current vaccine evaluation systems in the mouse model. Here, we developed a BCG-challenge rabbit skin model as a new way to evaluate the protective efficacy of selected TB subunit vaccine candidates. Methods: Rabbits were immunized with subunit vaccines, including EAMM (ESAT6-Ag85B-MPT64<190−198>-Mtb8.4), MH (Mtb10.4-HspX), and LT70 (ESAT6-Ag85B-MPT64<190−198>-Mtb8.4-Rv2626c) three times subcutaneously every 3-weeks and challenged with the attenuated Mycobacterium bovis BCG intradermally 6-weeks after last immunization. The immune response induced by the vaccine candidates was measured, the histopathology induced by the BCG challenge was studied, and the number of bacilli in the liquefied caseum was determined. Results: The subunit vaccines generated high antigen-specific IgG antibodies and fastened the liquefaction and healing process, and significantly reduced the viable BCG load. The subunit vaccine LT70 and EAMM-MH reduced BCG bacterial load in comparison to proteins EAMM, MH, Rv2626c, and also BCG itself. The Koch phenomena induced by the LT70 and combination of EAMM-MH were the same as that produced by BCG itself and were more rapid than those induced by the other proteins and the saline controls. Conclusions: The subunit vaccines LT70 and the combination of EAMM-MH showed promising protective efficacy as expected in the rabbit skin model, which can serve as a visual and convenient new model for evaluating TB vaccines.

A flavonoid compound from Chrysosplenium nudicaule inhibits growth and induces apoptosis of the human stomach cancer cell line SGC-7901

Abstract Context: Gastric cancer remains highly prevalent, but treatment options are limited. Natural products have proved to be a rich source of anticancer drugs. Chrysosplenium nudicaule Ledeb. (Saxifragaceae) is a perennial herb that grows in the highlands of China. It has been used as a traditional Chinese medicine to treat digestive diseases for hundreds of years. Recent studies revealed that this herb had anticancer activity, and the flavonoids were speculated to be the effective components. 6,7,3′-Trimethoxy-3,5,4′-trihydroxy flavone (TTF) and 5,4′-dihydroxy-3,6,3′trimethoxy-flavone-7-O-β-d-glucoside (DTFG) are flavonoid compounds isolated from Chrysosplenium nudicaule. Objective: This study examined the effect of TTF and DTFG on SGC-7901 human stomach cancer cell in vitro to determine the anticancer and induction of apoptosis properties of TTF. Materials and methods: The proliferation of cells treated with 32, 16, 8, 4, and 2 μg/mL of TTF or DTFG for 24, 48, and 72 h was assessed by the MTT assay. After being treated with TTF, the apoptosis of SGC-7901 cells was assessed by acridine orange staining, ultrastructure, electrophoresis of DNA fragmentation, and flow cytometry. Results: Results indicated that TTF inhibited the growth of cancer cells with an IC50 value of 8.33 μg/mL after 72 h incubation. However, DTFG showed no inhibitory effect on the growth of the cancer cell. Further studies on TTF also confirmed that it was able to induce apoptosis of SGC-7901 cells at a concentration as low as 4 μg/mL. Discussion and conclusion: The apoptotic effect of TTF makes it a promising candidate for future chemotherapeutic application in treating stomach cancer.

Effects of hMASP-2 on the formation of BCG infection-induced granuloma in the lungs of BALB/c mice

Tuberculosis, caused by Mycobacterium tuberculosis, affects the functions of the lung and causes high morbidity and mortality rates worldwide. MASP-2 is an executioner enzyme, which plays an essential role in the activation of lectin pathway. In our previous studies, the MASP-2 played a dual role in promoting the progress of lesions in BCG-infected rabbit skin models. However, the really effects of MASP-2 on tuberculosis are unknown. The aim of this study was to investigate the effects of MASP-2 in granuloma formation with BCG-infected mice. Compared to the control group, rAd-hMASP-2 treated group showed increasing in survival rate of BCG-infected mice (P = 0.042), and decreasing of bacteria loads (P = 0.005) in the lung tissue. MASP-2 displayed a protective efficacy in BCG-infected mice, which promoted the activation and recruitment of macrophages and lymphocytes to the granuloma. Moreover, the data obtained from the ELISA and RT-PCR demonstrated that mRNA expression for IL-6, CCL12, CCL2 and cytokines of IFN-γ, TNF-α in lung were significantly elevated by treatment of rAd-hMASP-2. Those findings provided an evidence that MASP-2 may be as a newly immunomodulatory in targeting granuloma formation, which displayed a potential protective role in control of tuberculosis.

Subunit Vaccines Consisting of Antigens from Dormant and Replicating Bacteria Show Promising Therapeutic Effect against Mycobacterium Bovis BCG Latent Infection

To screen effective antigens as therapeutic subunit vaccines against Mycobacterium latent infection, we did bioinformatics analysis and literature review to identify effective antigens and evaluated the immunogenicity of five antigens highly expressed in dormant bacteria, which included Rv2031c (HspX), Rv2626c (Hrp1), Rv2007c (FdxA), Rv1738 and Rv3130c. Then, several fusion proteins such as Rv2007c‐Rv2626c (F6), Rv2031c‐Rv1738‐Rv1733c (H83), ESAT6‐Rv1738‐Rv2626c (LT40), ESAT6‐Ag85B‐MPT64<190‐198>‐Mtb8.4 (EAMM), and EAMM‐Rv2626c (LT70) were constructed and their therapeutic effects were evaluated in pulmonary Mycobacterium bovis Bacilli Calmette–Guérin (BCG) – latently infected rabbit or mouse models. The results showed that EAMM and F6 plus H83 had therapeutic effect against BCG latent infection in the rabbit model, respectively, and that the combination of EAMM with F6 plus H83 significantly reduced the bacterial load. In addition, the fusion proteins LT40 and LT70 consisting of multistage antigens showed promising therapeutic effects in the mouse model. We conclude that subunit vaccines consisting of both latency and replicating‐associated antigens show promising therapeutic effects in BCG latent infection animal models.

Efficacy and Safety of Different Dosages of Praziquantel for the Treatment of Schistosoma Japonicum: A Systematic Review and Meta-Analysis

Background: Praziquantel, an antischistosomal compound, is used as first-line drug for chemotherapy of Schistosoma japonicum since 1984. In this article, we conducted a systematic review and mete-analysis to evaluate the efficacy and safety of different dosages of praziquantel (PZQ) for treatment of Schistosoma japonicum. Evidence Acquisition: A number of six articles published in peer-reviewed journals before December 2012 were selected for analysis after searching the following literature databases: PubMed/Medline, the Chinese WanFang Literature Database, China National Knowledge Infrastructure (1994-2012.12), and the Chinese Biomedical Literature (1978-2012.12). Results: The meta-analyses showed that there is no statistically significant difference of the negative rate on the egg using 40 mg/kg compared to 60 mg/kg PZQ for S. japonicum treatment (RR 0.79, 95% CI 0.46 1.35; P < 0.39). The meta-analysis showed that there is no statistically significant difference of the side effects using 30 mg/kg compared with 40 mg/kg (RR 0.97, 95% CI 0.68 1.38; P = 0.87), 40 mg/kg compared with 60 mg/kg (RR 0.79, 95% CI 0.46 1.35; P = 0.39) and 50 mg/kg compared with 60 mg/kg (RR 0.89, 95% CI 0.56 1.42; P = 0.63). Conclusions: According to the results, there is no statistically significant difference in different doses of PZQ for treating S. japonicum.