Generation of a new strain of NOD/SCID/IL2Rγ mice with targeted disruption of Prkdc and IL2Rγ genes using CRISPR/Cas9 system / 南方医科大学学报

<p><b>OBJECTIVE</b>The NOD/SCID/IL2Rγ (NSG) mouse strain is the most widely used immunodeficient strain for xenograft transplantation. However, the existing SCID mutation is a spontaneous mutation of the Prkdc gene, which leads to leaky T cell developmental block and difficulty in genotyping. It is therefore important to develop a new strain of NSG mice with targeted disruption of Prkdc and IL2Rγ genes.</p><p><b>METHODS</b>Targeted disruption of Prkdc and IL2Rγ genes was achieved using the CRISPR/Cas9 system. By intercrossing the knockout and NOD mice, we obtained a novel strain of NOD/SCID/IL2Rγ(NSG) mice, denoted as cNSG (Chinese NSG) mice.</p><p><b>RESULTS</b>In addition to the NOD mutation, cNSG mice exhibited a complete absence of T cells, B cells and NK cells. cNSG mice allowed more efficient engraftment of human cancer cells than the commonly used immunodeficient nude mice.</p><p><b>CONCLUSION</b>cNSG mice will provide an important xenotransplantation model for biomedical research.</p>

Detection of interferon-induced transmembrane-1 gene expression for clinical diagnosis of colorectal cancer / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression of the interferon-induced transmembrane-1 (IFITM1) gene in colorectal cancer (CRC) tissue and the serum anti-IFITM1 antibody responses of the patients and assess their value in clinical diagnosis of CRC.</p><p><b>METHODS</b>Semi-quantitative RT-PCR was performed to detect IFITM1 mRNA expression in the specimens of normal colonic mucosa, CRC tissue, inflammatory polyps, adenomatous polyps, gastric cancer, esophageal carcinoma and liver cancer tissues. Serum samples were collected from the patients to detect anti-IFITM1 antibody responses using Western blotting. The clinicopathological features of the carcinoma expressing IFITM1 gene were analyzed.</p><p><b>RESULTS</b>IFITM1 mRNA was expressed in 47.4 % (18/38) of the CRC specimens, a rate significantly higher than that in adenomatous polyps [15% (3/20)] and gastric cancer [4.8% (1/21)]; no obvious IFITM1 expression was found in normal colonic mucosa, inflammatory polyp, esophageal carcinoma or liver cancer tissues (P<0.001 or P<0.05). IFITM1 mRNA was strongly expressed in CRC at the expression level of 0.8048-/+0.2273, which was significantly higher than that in adenomatous polyps (0.4447-/+0.0989, P<0.001). No anti-IFITM1 antibody response was detected in healthy human sera, but in the CRC patients, the serum antibody response was detected at the rate of 36.8% (14/38), significantly higher than the rate of 9.5% (2/21) in gastric cancer (P<0.05). No antibody response was detected in esophageal carcinoma, liver cancer, inflammatory polyp or adenomatous polyps. Most of the IFITM1-expressing CRC had a diameter exceeding 5 cm, often invading the serous membrane with metastasis to the lymph nodes and the distant organs; these tumors were identified mostly as well-differentiated adenocarcinoma in Dukes stage C or D.</p><p><b>CONCLUSION</b>IFITM1 gene may play an important role in the pathogenesis, development and metastasis of CRC, and may serve as a potential biomarker for clinical diagnosis of CRC.</p>

Oral immunization of mice with vaccine of attenuated Salmonella typhimurium expressing Helicobacter pylori urease B subunit / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To prepare the live recombinant vaccine of attenuated Salmonella typhimurium SL3261 expressing Helicobacter pylori (H. pylori) B subunit (UreB) and to determine whether it could be used as an oral vaccine against H. pylori infection.</p><p><b>METHODS</b>Using genomic DNA of H. pylori Sydney strain (SSI) as template, the H. pylori UreB gene fragment was amplified by PCR and subcloned into the expression vector pTC01. The recombinant plasmid pTC01-UreB was then transferred into LB5000 to obtain modified forms, and further conversed into the attenuated Salmonella typhimurium SL3261 to obtain recombinant SL3261/pCT01-UreB as an oral immunization reagent, which was then used to orally immunize Balb/c mice twice at a three-week interval. Twelve weeks later, anti-UreB IgA antibodies in intestinal fluid and IgG antibodies in sera were determined by ELISA. The relating data in control groups (including body weight, gastric inflammation, etc.) were also collected.</p><p><b>RESULTS</b>The sequencing analysis showed that the UreB gene fragment amplified by PCR was consistent with the sequence of the H. pylori UreB gene. The restriction enzyme digestion revealed that the correct pTC01-UreB was obtained. SDS-PAGE and Western blot showed that a 61KD protein was expressed in SL3261/pTC01-UreB, which could be recognized by anti-H. pylori UreB antiserum and was absent in the control containing only Salmonella typhimurium SL3261 strain. The multiple oral immunization with SL3261/pTC01-UreB could significantly induce H. pylori specific mucosal IgA response as well as serum IgG responses. IFN-gamma and IL-10 levels were significantly increased in SL3261/pTC01-UreB group, and no obvious side effect and change in gastric inflammation were observed.</p><p><b>CONCLUSION</b>The attenuated vaccine of Salmonella typhimurium expressing H. pylori UreB can be used as an oral vaccine against H. pylori infection.</p>