Administration of anti-CTLA-4 monoclonal antibody augments protective immunity induced by Schistosoma japonicum glutathione-S-transferase.

AIMS: The aim of this study was to evaluate the effect of anti-CTLA-4 monoclonal antibody (mAb) on 26-kDa glutathione-S-transferase (GST) vaccine-induced immunity against Schistosoma japonicum infection. METHODS AND RESULTS: Mice immunized with GST before infection with S japonicum cercariae were injected with anti-CTLA-4 mAb. Worm reduction rate of GST was increased from 25.41% in mice with GST immunization to 52.48% in mice with GST plus anti-CTLA-4 mAb. The percentages of regulatory T cells (Tregs) were significantly higher following administration of both GST and anti-CTLA-4 mAb, or anti-CTLA-4 mAb alone. Elevated levels of IFN-γ, IL-2, IL-4 and IL-5 were observed. CONCLUSION: These results demonstrated that CTLA-4 may inhibit the protective effect of GST vaccine, and anti-CTLA-4 mAb may be used as an adjuvant to enhance the immune protection conferred by the GST vaccine by enhancing Th1- and Th2-type immune response.

Anti-CTLA-4 monoclonal antibody improves efficacy of the glyceraldehyde-3-phosphate dehydrogenase protein vaccine against Schistosoma japonicum in mice.

Schistosomiasis is a devastating disease caused by Schistosoma infection. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has emerged as a candidate vaccine component against Schistosoma japonicum, but only confers partial protection. Cytotoxic T lymphocyte antigen-4 (CTLA-4) regulates T cell activation and shows negative effects on vaccine-induced immune protection; however, its potential influence on the protective effects of a GAPDH vaccine against S. japonicum and the underlying mechanism remain unclear. In this study, we established a mouse model of S. japonicum infection, and the mice were randomly divided into uninfected, infected control, anti-CTLA-4 monoclonal antibody (anti-CTLA-4 mAb), GAPDH, and GAPDH combined with anti-CTLA-4 mAb groups to compare the protective effects against infection and the consequent tissue damage. The worm reduction rate in the GAPDH-treated infected mice was 26.58%, which increased to 54.61% when combined with anti-CTLA-4 mAb. The frequency of regulatory T cells (Tregs) was significantly higher in the anti-CTLA-4 mAb group and was lower in the GAPDH group. However, both anti-CTLA-4 mAb and GAPDH elevated the levels of the cytokines IFN-γ, IL-2, IL-4, and IL-5 in the spleens of infected mice, and their combination further enhanced cytokine production. The diameter of egg granuloma in the anti-CTLA-4 mAb group and combined treatment group increased significantly compared to that of the other groups. These results suggest that anti-CTLA-4 mAb can be used as an adjuvant to enhance the immune protection of the GAPDH vaccine via inducing the Th1 immune response, although this comes at the cost of enhanced body injury.

Glutathione S-transferase influences the fecundity of Schistosoma japonicum.

The aim of this study was to investigate the effect of Schistosoma japonicum glutathione S-transferase (SjGST) on the developmental stages of the parasite. We found that the mRNA levels of GST were higher in schistosomula obtained from the host and the eggs than that in other developmental stages. SjGST was mainly distributed in the egg shells, teguments of the worms, and part of the parenchyma of the worms. GST knockdown with RNA interference in S. japonicum worms resulted in a silencing rate higher than 80%. The egg reduction rate (18%) and abnormal egg ratio (28%) were significantly higher (P < 0.05) in the GST-silenced group than in the negative control group. These results indicate that SjGST plays an important role in the fecundity of S. japonicum, specifically in egg formation.

[Impurity analysis and their structure determination of gatifloxacin].

AIM: To analyse the impurities of gatifloxacin. METHODS: The impurity of gatifloxacin were analysized and determinated by RP-HPLC/electrospray ionization mass spectrometry with a Zorbax SB-C18(4.6 mm x 150 mm ID, 5 microns). The mobile phase was 3% acetic acid/acetonitrile-3% acetic acid/water (15:85). The two compounds were synthesized: 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-methoxy-7-(1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMP) and 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-hydro-7-(3-methy-1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMO). Their liquid chromatogram, UV, MS were compared with those of the impurity of gatifloxacin. RESULTS: The mass of the impurity was 14 less than that of gatifloxacin. It means the impurity was CH2 less than gatifloxacin. The tR (HPLC), UV and MS of DMP were the same as those of the impurity of gatifloxacin. CONCLUSION: Based on the tR (HPLC), UV and MS, the impurity of gatifloxacin is confirmed as DMP.

[Determination of first-order structure of somatostatin by electrospray ionization mass spectrometry].

AIM: To determine the molecular weight and first-order structure of somatostatin. METHODS: The molecular weight of somatostatin was determined by electrospray ionization mass spectrometry. Somatostatin was deoxidized by 2-mercaptoethanol. A series of typical fragment ions of deoxidized product were obtained by insource collision-induced dissociation (CID). RESULTS: The m/z of quasi-molecular ion [M + H]+ of somatostatin was 1,637.8 and [M + Na]+ was 1,659.5. The m/z of double-charge ion [M + 2H]2+ was 819.5 and [M + H + Na]2+ was 830.3. It showed that the molecular weight of somatostatin was 1,636.7. The y and b series of fragment ions of deoxidized product were obtained by adjusting the fragmentor voltage. It was determined that the first-order structure of deoxidized product of somatostatin was A-G-C-K-N-F-F-W-K-T-F-T-S-C. CONCLUSION: The molecular weight and first-order structure of somatostatin were confirmed.

[Analysis of impurity in caderofloxacin].

AIM: To analyse the main impurity of caderofloxacin. METHODS: The impurity of caderofloxacin was analysed and determinated by RP-HPLC/ESI/MS with a Zorbax SB-C18 (150 mm x 4.6 mm ID, 5 microns) column. The mobile phase was acetonitrile-0.5% acetic acid solution (17:83). A compound was synthesized: 1-cyclopropyl-8-(difluoromethoxy)-6-fluoro-1, 4-dihydro-7-(1-piperazinyl)-4-oxo-3-quinoline carboxylic acid (DMCA). Its HPLC chromatogram, UV and MS spectrum were compared with those of the impurity in caderofloxacin. RESULTS: The molecular weight of the impurity was 14 less than that of caderofloxacin. It means the impurity was a CH2-group less than caderoflixacin. The tR, UV and MS of DMCA were the same as those of the impurity in caderofloxacin. CONCLUSION: Based on the tR (HPLC), UV and MS, the impurity of caderofloxacin is confirmed as DMCA.

[Detection of hepatotoxic pyrrolizidine alkaloids in Ligularia Cass. with LC/MSn].

AIM: To detect the hepatotoxic pyrrolizidine alkaloids (HPA) in the genus Ligularia Cass.. METHODS: The alkaloid extracts of Ligularia plant materials were detected and analyzed by the method of combination of TLC, and LC/MSn. RESULTS: Among 22 species of Ligularia Cass., HPA were detected in 18 species with LC/MSn, and no HPA was detected in the remaining 4 species. CONCLUSION: HPA was first detected with LC/MSn in L. tongelensis and other 15 species of Ligularia Cass.; HPA from these plants should be isolated, separated and identified and it is necessary to study the activities and toxicities of the HPA. The types and kinds of HPA from different species and sources are different, they should be detected separately.

[Study on the fingerprints of the alkaloids in Sophora flavescens].

OBJECTIVE: To establish a method for HPLC fingerprint determination of the alkaloids in S. flavescens. METHOD: RP-HPLC, linear gradient elution, LC/MS, etc. were used to determine the fingerprint and identify the main peaks in the HPLC fingerprint. RESULT: A satisfactory method for HPLC fingerprint determination of the alkaloids in S. flavescens. was established, and 5 peaks in the HPLC fingerprint were identified. CONCLUSION: The perfect fingerprint can be obtained and the method can be used for quality control of S. flavescens.