Anti-tumor effect of cisplatin combined with DC vaccine on tumor-bearing mice / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the anti-tumor mechanism of the combination of cisplatin with DC vaccine in tumor-bearing mice.</p><p><b>METHODS</b>B16 melanoma cells were treated with cisplatin at the final concentration of 20 µg/ml in vitro for 24 h. The expression of HMGB1, Hsp70 and TGF-β were detected by Western blot. B16 tumor-bearing mouse models were generated. The therapeutic effect of the combination of cisplatin (100 µg/mouse i.p., for sequential 3 days) and intratumoral injection of DC cells (3×10(6)/mouse, twice with a 7-day interval) in the tumor-bearing mouse models was evaluated. Expression of MHC II, ICAM-1 and CD86 was analyzed by flow cytometry. The mice were sacrificed at 28 days after tumor cell inoculation. The tumors were removed and weighed, and tissue samples were taken for pathological examination. Tumor infiltrating lymphocytes (TIL) were isolated by discontinuous gradient centrifugation. The distribution of T-reg and CD8(+) T cells in the TIL was analyzed by flow cytometry, and the ratio of CD8(+) T/T-reg was determined. The activity of cytotoxic lymphocytes (CTL) was determined by microcytotoxicity assay.</p><p><b>RESULTS</b>Cisplatin enhanced both the B16 cell apoptosis and HMGB1 expression. After loading with cisplatin-treated cell lysate, the expression of MHC II, ICAM-1 and CD86 on DC cells were (47.5 ± 8.8)%, (35.5 ± 8.3)% and (36.2 ± 9.2)%, respectively. At 28 days after tumor cell inoculation, the tumor weight of the control group was (2.1 ± 0.6) g, that of the cisplatin group was (0.3 ± 0.2) g and that of cisplatin + DC vaccine group was (0.5 ± 0.2) g, showing a significant inhibition of tumor growth (P < 0.01). Furthermore, the CD8(+) T/T-reg ratio and CTL activity in TIL were also significantly enhanced in the tumor-bearing mice treated with cisplatin + DC vaccine. When the effector-to-target ratio was 20:1, 10:1 and 5:1, the CTL activity in the cisplatin + DC vaccine treated mice was (25.0 ± 5.0)%, (22.0 ± 6.0)% and (14.0 ± 4.0)%, respectively, significantly higher than (8.2 ± 3.6)%, (6.7 ± 1.8)% and (3.6 ± 1.9)%, respectively, in the control group (all P < 0.01).</p><p><b>CONCLUSION</b>Cisplatin promotes the anti-tumor effect of DC vaccine by down-regulating T-reg cells and enhancing the CTL activity in tumors.</p>

Clone and Expression of Loop1 and Loop2 Gene of Hexonof Infectious Canine Hepatitis Virus / 中国生物工程杂志

The mainly antigenic sites for the adenovirus neutraliation are present on Loop1 and Loop2 of hexon.Majority research were focus in the human adenovirus.Little was known on infectious canine hepatitis virus (ICHV), which was also called canine adenovirus typeⅠ.Here,ICHV (the isolated strain) DNA was isolated and purified from the cultured MDCK cells.The Loop1 and Loop2 fragments were amplified by polymerase chain reaction(PCR) method,and then was connected by ligase T4.The target fragment was then connected with vector pET28a.The nucleotide sequence ecoding Loop1 and Loop2 was determined.The nucleotide sequence identity of Loop1 region between the isolated strain and CLL, RI261 and Toronto A26/61 strains is 100%, 100% and 83.8%, and the nucleotide sequence identity of Loop2 region between the isolated strain and CLL, RI261 and Toronto A26/61 strains is 88.1% , 88.1% and 99.3%, and amino acid identity is 93.6%, 93.6% and 98.6%.The recombinant Loop protein was expressed in E.coli and was approximately 36kDa in size,and then was purified. Then BALB/c mice were injected subcutaneously in the back and armpit with the recombinant Loop protein.The anti-ICHV antibody titers of immunized serum was tested by indirect ELISA and the titers were up to 1:320.Western blot demonstrated that immunized sera could specifically combine with ICHV. The research laid a foundation for creating new genetic engineering products of infectious canine hepatitis virus.

Study on Purification and Identification of Streptavidin / 微生物学通报

The aim of this research is to refine the protocol of purification of SA and identify the character of SA. By utilizing the cold-denaturing method, most of other kinds of protein were screened out and SA was purified from the fermentation broth of L-183 by using the refined affinity chromatography method. The rate of recollection was checked to be 75%～85%. By identification, it is indicated that the molecular weight of self-made SA was 74.5kD, the biotin-combining number 3.2, the activity 11.2u/mg, the pI around 7.4. So, the essential characters of SA are same as described by documents.