[Genetic polymorphism of NFKB1 gene in Chinese Han of Chengdu and Thai populations]

OBJECTIVE

To investigate the single nucleotide polymorphisms (rs3774963 C>G and rs11722146 A>G) of NFKB1 gene between the Chinese Han of Chengdu and Thai populations, and simultaneously to compare distributions of genotype and allelic frequencies of NFKB1 among different ethnic groups from the International Haplotype Map Project.

METHODS

The genotypes and allele frequencies of NFKB1 gene rs3774963 C>G and rs11722146 A>G were analyzed in 118 healthy Chinese Han of Chengdu and 101 Thai individuals using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy and DNA sequencing.

RESULTS

The frequencies of the CC, CG, and GG genotypes of rs3774963 C>G were 15.3%, 43.2%, and 41.5% in Chinese Han of Chengdu, and 25.7%, 47.5%, and 26.7% in Thai population, respectively. The frequencies of the C and G alleles were 36.9% and 63.1% in Chinese Han of Chengdu, and 49.5% and 50.5% in Thai population, respectively. There were significant differences in the genotypes and allele frequencies between the two groups. The frequencies of the AA, AG, and GG genotypes of rs11722146 A>G were 22.9%, 50.0%, and 27.1% in Chinese Han of Chengdu, and 18.8%, 53.5%, and 27.7% in Thai population, respectively. The frequencies of the A and G alleles were 47.9%, 52.1% in Chinese Hen of Chengdu, and 54.5%, 45.5% in Thai population, respectively. However, no statistically significant difference was observed between the two populations. Interestingly, when compared with the data from the International Haplotype Map Project, the genotypes and allele frequencies of NFKB1 gene rs11722146 A>G but not rs3774963 C>G in the Chinese Han of Chengdu were significantly different from those among European and Sub-Saharan African populations.

CONCLUSION

NFKB1 gene polymorphism in diverse populations is significantly different.

[An expression plasmid encoding recombinant immunotoxin IP10-DT390 suppresses the experimental autoimmune encephalomyelitis]

Experimental autoimmune encephalomyelitis (EAE) is an autoimmune disease of the central nervous system (CNS); it serves as a model for the human multiple sclerosis (MS). In mice, EAE is mediated by T cells specific for various myelin basic proteins which migrate from the periphery to the CNS. In search of a way to prevent the induction and progression of EAE, we observed the effects of recombinant immunotoxin IP10-DT390 on blocking or eliminating the active T cells in the EAE model. In this paper is presented an experimental gene therapy-based model in which the mice were made resistant to EAE induction by plasmid DNA encoding recombinant immunotoxin that was injected into the leg muscles of mice. The new immuno-biological construct could selectively impair autoreactive T-cell homing while the duration of clinical signs is shorter, and the new construct would not affect other components of the immune response. These data demonstrated the effectiveness of the constructs in the treatment of EAE and suggested its usefulness in the treatment of other autoimmune diseases.

[Therapeutic effect of a new recombinant immunotoxin mMIP-1alpha-DT390 on experimental autoimmune encephalomyelitis]

OBJECTIVE

To evaluate the therapeutic effect of a new recombinant immunotoxin mMIP-1alpha-DT390 on experimental autoimmune encephalomyelitis (EAE).

METHODS

EAE was induced in the low-sensitive strain C57BL/6 mice with intraperitoneal injection of myelin basic protein (MBP) to simulate the human disease multiple sclerosis, followed by intramuscular injection of cationic liposome carrying the plasmid DNA SRalpha-mMIP-1alpha-DT390 in the leg muscle to elicit resistance to EAE development. The mice were then examined daily for clinical signs of EAE by an observer blind to the treatment protocol. For immunohistochemistry the mice were anesthetized and perfused with sterile PBS and paraformaldehyde, and the cerebrum, cerebellum, medulla and spinal cord were removed for preparation of serial sections. The mononuclear cells (MNCs) from the EAE mouse spleens were prepared for three-color flow cytometry analysis of the surface markers with appropriate antibodies following the BD Pharmingen cytokine staining protocol.

RESULTS

EAE model was successfully established by active MBP immunization in C57BL/6 mice. Administration of the immunotoxin mMIP-1alpha-DT390 significantly delayed the disease onset and lowered the mean clinical score for EAE as compared with the control mice. Immunohistochemistry demonstrated much less CCR5(+) infiltrating cells in the central nervous system in mMIP-1alpha-DT390-treated mice than in the control. The treatment also eliminated reactive T cells in the periphery blood without affecting the number of B cells.

CONCLUSION

The immunotoxin mMIP-1alpha-DT390 can attenuate the disease activity of EAE in mice, suggesting its potential use in the treatment of other autoimmune disorders.

[The research on construction and expression of eukaryotic expression plasmid for a recombinant immunotoxin mMIP-1alpha-DT390]

OBJECTIVE

To construct a novel recombinant immunotoxin (IT) expression vector by fusing mouse macrophage inflammatory protein-1alpha gene (mMIP-1alpha) into a truncated diphtheria toxin gene (DT390), and examine the expression of mMIP-1alpha-DT390 fusion protein in NIH3T3 cells.

METHODS

mMIP-1alpha cDNA was cloned from mouse liver tissue through reverse transcription-polymerase chain reaction (RT-PCR), and inserted in the expression plasmid SRalpha, that includes the DT390 gene, to form the recombinant vector SRa-mMIP-1alpha-DT390. The positive recombinant plasmid was identified by PCR, the restriction endonucleases digestion and DNA sequencing, and then by liposome protocol, the identified positive plasmid was transferred into NIH3T3 cells for observing the fusion protein expression by immunofluorescence, with detecting the activities of the immunotoxin in vitro through MTT.

RESULTS

We have successfully constructed a recombinant immunotoxin expression vector named as SRalpha-mMIP-1alpha-DT390. The immunofluorescence photograph sourced from fluorescence immunocytochemical method showed that the fusion gene could express in the cytomembrane and cytoplasm of NIH3T3 cells. In the bioactivity detection assay, the supernatant of the transfected cell culture was observed to have the obvious cytotoxic activity to activated T-lymphocyte.

CONCLUSION

The SRalpha-mMIP-1alpha-DT390 recombinant immunotoxin expression vector will provide the basis of studying the targeted cytotoxic activity to inflammatory cells, and may have some potential value for clinical application.

[Analysis of the multi-amplified 5 STR loci and their allelic distribution in both Han populations in Chengdu City and Yunnan province]

OBJECTIVE

To illuminate the multi-amplified 5 STR loci and their allelic distribution in Hans by means of STR-DNA typing with improved efficiency and decreased cost.

METHODS

We have established an allelic ladder of D7S820, D13S317, D5S818, D3S1358 and Amelogenin loci via the cloning techniques. With this homemade allelic ladder, we established successfully a multiplexing polymerase chain reaction (PCR) method, followed by denaturing polyacrylamide gel electrophoresis (PAGE) and silver staining. DNA samples collected from 130 unrelated Han individuals in Yunnan and Chengdu were analyzed. The non-overlapping of the allelic fragments of the five loci allowed the detection to be accomplished successfully.

RESULTS

No difference of the genotyping results of the single locus amplification and multiplexing was observed. The genotype distributions of 4 STR were in accordance with the Hardy-Weinberg equilibrium. 7, 7, 8 and 8 alleles of D7S820, D13S317, D5S818, and D3S1358 loci were observed in Yunnan Han population, as well as 8, 7, 8 and 7 alleles in Chengdu Han population respectively. No significant difference in the allele distribution of these loci was seen between these two Han populations.

CONCLUSION

This multiplexing system with home-made allelic ladder has a high combined discrimination power and exclusion power. It is a valuable tool in forensic science practice.

[Construction and functional analysis of a novel eukaryotic expression plasmid of recombinant immunotoxin DT390-Rantes]

OBJECTIVE

To construct a novel eukaryotic expression plasmid for recombinant immunotoxin DT390-Rantes and perform preliminary analysis of its function.

METHODS

The gene fragment coding for Rantes was obtained from the liver tissues of C57BL/6 mice using RT-PCR, and inserted into the eukaryotic expression plasmid SRalpha containing DT390 gene to construct the recombinant plasmid DT390-Rantes-SRalpha, which was transformed into E. coli JM109, followed by selection of the positive clones containing the target inserts. The eukaryotic expression plasmid was analysed by PCR, restriction endonuclease digestion and DNA sequencing. The recombinance plasmid DT390-Rantes-SRalpha was transfected into NIH3T3 cells and its expression was observed by immunofluorescence detection. The activity of the expressed DT390-Rantes in vitro was evaluated by MTT assay.

RESULTS

The gene fragment of Rantes was correctly inserted into the eukaryotic expression plasmid SRalpha as verified by restriction endonuclease digestion and DNA sequencing, and could be expressed in NIH3T3 cells. MTT assay confirmed that the expression product DT390-Rantes could kill activated T cells in vitro.

CONCLUSIONS

The recombinant eukaryotic expression plasmid DT390-Rantes-SRalpha is successfully constructed and expressed in eukaryotic cells. The expressed product can specifically kill activated T cells in vitro.

[A multiplex for simultaneous amplification of three Y-STR loci using modified primers]

OBJECTIVE

To develop a multiplex method for simultaneous detection of Y-STR loci.

METHODS

The primers of Y-STR loci were devised for use in the simultaneous amplification of three Y-STR loci (DYS390, DYS391, DYS393).

RESULTS

Simultaneous amplification of the three Y-STR loci was successfully performed using the modified primers in which the fragment length of DYS391 was shortened from 279-287 bp to 142-150 bp, and at the same time, the virile specificity of DYS393 was enhanced.

CONCLUSION

The use of new-devised primers of Y-STR loci is a valid approach to rapid detection of multiple Y-STRs loci; it is worthy to be recommended in the field of forensic science.

[Construction and prokaryotic expression of a recombinant immunotoxin fused with mouse interleukin 18 and truncated Pseudomonas exotoxin]

OBJECTIVE

To construct a new recombinant immunotoxin expression vector by fusion of mouse interleukin 18 (mIL-18) gene and a truncated form of A (PE38) gene, and examine the expression of IL-18-PE38 fusion protein in Escherichia coli.

METHODS

mIL-18 cDNA was cloned from mouse liver tissue through reverse transcription-polymerase chain reaction (RT-PCR). The mIL-18 cDNA was subcloned into a PE38 gene inserted fusion protein expression plasmid. The recombinant vector was identified by restriction endonucleases digestion, PCR and DNA sequencing. After transformed into E. coli BL21 and induced by IPTG, the expressed product was obtained and detected the molecular weight and specificity by SDS-PAGE and Western-blotting.

RESULTS

The new recombinant immunotoxin expression vector was constructed successfully. The IL-18-PE38 fusion protein was expressed in E. coli BL21, and the molecular weight of the expression product was identical to the expected value. In addition, the protein expressed could react with the specific antibody against mIL-18.

CONCLUSION

IL-18-PE38 recombinant immunotoxin expression vector will provide the basis for study on the targeted cytotoxic activity to Th1 cell and may have some potential value in the treatment of autoimmune disease and T cell leukemias.

[Study on the genetic polymorphisms of D8S1132 locus in Chinese Han, Mongolian and Thai populations]

OBJECTIVE

The aim of the present study was to obtain the population genetic data of short tandem repeat (STR) locus D8S1132 and study the difference of allelic frequency distributions among different populations.

METHODS

A sample of 380 unrelated individuals from 3 populations (Han, Mongolian, Thai) were studied using single PCR followed by polyacrylamide gel electrophoresis and silver staining.

RESULTS

Eleven allels and 42 genotypes were observed. The observed heterozygosity and the discrimination power were 85.0%-89.5% and 94.1%-95.5%, respectively. The genotype distributions of D8S1132 locus in 3 populations were in accordance with Hardy-Weinberg equilibrium and the difference of allelic frequency distributions among 3 populations was obvious.

CONCLUSION

The methods established are easy-to-perform and sensitive. The discrimination power and exclusion chances of this locus are desirable for forensic analysis.