PENG Qinghua's Clinical Experience in Treating Dry Eye by the Therapeutic Method of “Maintaining with the Sweet and Restoring the Body Fluids” / 中医杂志

This paper summarized PENG Qinghua's clinical experience in treating dry eye by applying therapeutic method of maintaining with sweet medicinals and restoring the body fluids. It is believed that the spleen earth insufficiency and fluids damage transforming into dryness are the main pathogenesis of the disease， and the basic therapeutic principle is maintaining with the sweet and restoring the body fluids by mainly using sweet medicines. It is advocated to use mild-sweet herbs， such as Baibiandou （Lablab purpureus subsp. purpureus）， Fuling （Smilax glabra Roxb.）， and Yiyiren （Coix lacryma-jobi L.）， to transport spleen earth， so that qi is restored and body fluids are recovered； moderate-sweet herbs， such as Dangshen （Codonopsis pilosula ［Franch.］ Nannf.）， Taizishen （Pseudostellaria heterophylla ［Miq.］ Pax）， Shanyao （Dioscorea oppositifolia L.） and Zhigancao （Glycyrrhiza glabra L.） are suggested to cultivate earth and generate metal， so as to move qi and circulate fluid； sweet-cool herbs， such as Nanshashen （Adenophora triphylla ［Thunb.］ A.DC.）， Beishashen （Glehnia littoralis ［A.Gray］ F.Schmidt ex Miq.）， Yuzhu （Polygonatum odoratum ［Mill.］ Druce）， Tianhuafen （Trichosanthes kirilowii Maxim.） are suggested to nourish yin and increase body fluids， so as to promote fluid production to moisten dryness. In this way， when the source of fluid is restored and the fluid is circulated， the fluid can be produced continuously， which provides new ideas for the treatment of dry eyes with traditional Chinese medicine.

Peng Qinghua's Experience in the Staged Treatment of Autoimmune Uveitis / 中医杂志

This paper summarized clinical experience of Professor Peng Qinghua in the staged treatment of autoimmune uveitis （AU）. The pathogenesis of AU is always based on root-cause deficiency and manifestation excess， with weakness of healthy qi as the root， and accumulation of wind， dampness and blood stasis as the minifestation. Syndrome differentiation and treatment is usually carried out according to different stages of disease. During the acute stage， deficiency of healthy qi and stagnation of wind-dampness are the key pathomechanisms， so the treatment is to replenish qi and activate blood， dispel wind and remove dampness， and self-made Yiqi Huoxue Qufeng Chushi Decoction （益气活血祛风除湿方） can be used. During remission stage， deficiency of spleen and kidney is the key mechanism， so the treatment is to tonify the spleen and kidney， replenish the essence and brighten the eyes， and self-made Yijing Mingmu Decoction （益精明目汤） can be used. Meanwhile， it was recommened to treat early， prevent and interrupt the disease， commonly combine with Chinese patent medicine Zhengqing Fengtongning tablets （正清风痛宁缓释片）， and promote regulation of living to prevent recurrence.

Preparation of anti-VirB12 nanoantibodies, a surface protein of type Ⅳ secretory system of Brucella / 国际生物医学工程杂志

Objective:To prepare camel-derived nanoantibodies that can bind to the recombinant protein VirB12 antigen with high affinity and lay the foundation for further research.Methods:Xinjiang Bactrian camels were immunized six times with VirB12 recombinant protein, total RNA was extracted from lymphocytes isolated from peripheral blood, and the VHH gene fragment was amplified by nested PCR to construct a phage VHH display library. ELISA solid-phase affinity and enrichment methods were used for screening. After three rounds of affinity screening, the clones enriched in the second and third rounds were randomly picked out, and the binding of a nanoantibody with soluble expression to VirB12 was analyzed by ELISA. After sequence determination and multiple alignment, repetitive sequences were removed, and finally five non-redundant sequences were obtained, which were named D1, E6, H8, H9, and H10. The five identified nanoantibody genes were transformed into the WK6 strain, and the soluble expression of an intercellular substance was carried out at 16 °C. After purified expression of Ni-NTA, the binding ability and thermal stability of nanoantibodies and the antigen VirB12 protein were detected by Western Blot and ELISA.Results:Five strains of nanoantibodies were expressed in WK6 bacteria in soluble form. SDS-PAGE showed that the purity of five anti-VirB12 nanoantibodies was close to 90%, and they had high antigen-binding activity and obvious antigen-antibody concentration dependence. All four strains of nanoantibodies showed high thermal stability, and after being treated at 90 ℃, they could still retain more than 60% binding activity.Conclusions:In the study, a VHH phage display library with a capacity of 2.8×10 8 cfu/ml was constructed from Xinjiang Bactrian camel lymphocytes immunized with VirB12 recombinant protein. Five anti-VirB12 nanoantibodies with high affinity and thermal stability were obtained through solid-phase screening and enrichment and soluble monoclonal ELISA detection. These results laid the foundation for further development of VirB12 nanoantibodies.

Lumazine synthase displayed poly-nanobodies for detection of soluble PD-L1 in human serum / 国际生物医学工程杂志

Objective:To established a method for the detection of soluble programmed death ligand 1 (PD-L1) protein in serum based on the poly nanoantibody of lumazine synthase(LS).Methods:A dual nanobody-based sandwich ELISA was established with a competitive ELISA to screen nanobodies recognizing different epitopes of PD-L1 as paired antibodies. To improve sensitivity, PD-L1 nanobody P3C8 and lumazine synthase(LS) were fused, and nanobodies were obtained in polymeric forms as sPD-L1 protein captures, so as to develop an LS-displayed polymeric nanobody-based sandwich ELISA (LSNbs-ELISA) method to detect sPD-L1.Results:Compared with the Nbs-ELISA method, the LSNbs-ELISA method is approximately 11-fold more sensitive for sPD-L1 detection. The limit of detections (LODs) of Nbs-ELISA and LSNbs-ELISA for sPD-L1 in serum were 2.87 ng/ml and 0.255 ng/ml, respectively. Both assays were highly specific for the detection of sPD-L1 and did not react with structure-related proteins PD-1, CD27, CD70, CD137, and CD147 when spiked into the human serum.Conclusions:The Nbs-ELISA and LSNbs-ELISA assays both have high sensitivity and specificity for detecting sPD-L1 in serum and could have potential clinical applications.

Affinity transfer of nanobodies to a CDR3 only single-domain antibody fragment NBL42 / 国际生物医学工程杂志

Objective:To evaluate the potential of a previously identified CDR3 only single-domain antibodies (sdAbs) fragment, NBL42, as a general framework for affinity transfer.Methods:The H3 loops of VHH-A4(A4), VHH-H5(H5), cAb-Lys3(L3) and B6H12 which bind with alliinase, PD-1, lysozyme and CD47, respectively, were grafted into the corresponding loop of NBL42. The genes of the reconstituted CDR3 only sdAbs were synthesized, expressed in E. coliand purified with Ni 2+ column affinity chromatography. The antigen binding and stability of the recombinant CDR3 only sdAbs were assayed by ELISA. Results:The recombinant NBL42-A4CDR3, NBL42-H5CDR3, NBL42-L3CDR3 and NBL42-B6H12CDR3 ran as a single peak at 15, 15, 28 and 16 kDa, respectively, in SDS-PAGE as expected molecular weight. Grafted sdAbs NBL42-A4CDR3 and NBL42-H5CDR3 expressed in a soluble form and specifically bind with alliinase and PD-1, respectively, but lost about 50% of their binding activity. In contrast, the grafted sdAbs NBL42-Lys3CDR3 and NBL42-B6H12CDR3 completely lost their antigen binding capacity. NBL42 sdAbs and grafted sdAbs NBL42-A4CDR3 and NBL42-H5CDR3 retain roughly half of their binding activity after 90 ℃ heat treatment, indicating high stability. The C88Y mutation in NBL42 and the Swiss Mode 3D model predicted that the C88Y residue in FR3 may play a key role in NBL42 stability and CDR3 affinity transfer.Conclusions:The structure of NBL42 has potential as a framework for CDR3 transplantation and affinity transfer.

The potential mechanism of Yiqi Jiedu Tongluo Decoction in the treatment of liver cirrhosis based on network pharmacology and molecular docking technology / 西安交通大学学报(医学版)

【Objective】 To investigate the targets and related pathways of Yiqi Jiedu Tongluo Formula (YQJDTLF) in the treatment of liver cirrhosis based on network pharmacology and molecular docking technology, so as to predict its potential mechanism. 【Methods】 Based on the TCMSP database, the effective active ingredients and action targets of YQJDTLF were extracted, and the therapeutic targets of liver cirrhosis were obtained through Drugbank, OMIM, TTD and DisGeNET; the common targets were screened. We constructed a visualization regulatory network diagram of "drug active components-disease targets" with Cytoscape and a protein interaction network diagram (PPI) with the STRING database. Then we screened the core proteins of PPIs with Cytoscape. Finally, we made Gene Ontology (GO) function enrichment analysis and KEGG pathway enrichment analysis of the core targets by using Metascape. Finally the molecular docking was completed. 【Results】 A total of 93 active ingredients and 135 common targets were obtained. The main active compounds included quercetin, baicalein, and stigmasterol. KEGG pathway enrichment analysis revealed 135 pathways involved in cancer signaling pathways (pathways in cancer) and other pathways. Through molecular docking, it was found that the binding activity between key traditional Chinese medicine components and the key targets was good. 【Conclusion】 YQJDTLF has the characteristics of being multi-component, multi-target and multi-pathway, and can play a role in the treatment of liver cirrhosis by regulating related pathways and targets.

Construction and quality analysis of phage display library for random mutagenesis of camel nanobody / 国际生物医学工程杂志

Objective To construct phage display antibody library of artificial mutation to compare with the sequence of the natural phage display antibody library. To scientifically evaluate the quality of the artificial mutation of phage display library, and provide some references for the further transformation of the nanobody. Methods Using random mutation method, NNY fixed-point santuration mutation was performed on combine the follicle-stimulating hormone receptor (FSHR) of human nanobody. The mutant DNA sequence was connected to the vector pMECS to construct the phage display library of VHH06-CDR3 random mutation. By sequencing and analysis of DNA sequences, the diversity of the library and the amino acid distribution of CDR3 were compared between mutation library and the immune library of FSHR. The degree of enrichment of cloning was determined by six rounds of affinity screening. Results According to the NNY mutation rule ,the CDR3 regions with 16 amino acids by random mutations was synthesized and the VHH-CDR3 random mutant phage display library was constructed . The phage display library of VHH06-CDR3 random mutant size was 7.36×108 cfu/ml. Polyclonal and monoclonal phage ELISA showed that after six rounds of screening, the output phage and the combination of FSHR showed obvious enrichment, but there was no clone combined with FSHR. Conclusions Although the VHH06-CDR3 mutant phage display library has sequence diversity, it is not conducive to obtaining target antibodies in affinity screening due to the lack of functional diversity of CDR3.

Correlation of urine phthalate metabolite levels with blood pressure in first-grade children / 中国学校卫生

Objective@#To explore the correlation between blood pressure and urinary phthalandione, MMP, MEP, MnBP, MiBP, PAEs.@*Methods@#Three schools were selected from Shenzhen, China for the present study. A total of 765 firstgrade students of Han ethnicity were recruited voluntarily from the selected schools during September 2016 to June 2017. They were divided into normal blood pressure (BP) group (lower than P90 group) and high BP group (BP≥P90). Linear and Logistic regression models were used to analyze the relationships between blood pressure and urine phthalate metabolite levels.@*Results@#Urinary MMP and MnBP in students of high BP group were significantly higher than that of students in normal BP group(t=13.12, 3.97, P<0.05). Linear regression models showed that Z score increased when MMP and MnBP levels increased(P<0.05). Logistic regression model suggested that the risk of high BP increased with the increment of MMP level adjusting creatinine, sex, age and BMI(OR=1.47, P<0.05). There was no statistical significance in the differences after adjusting many factors including family income and education level of parents(P>0.05).@*Conclusion@#Urinary phthalate metabolite levels are positively associated with blood pressure in first-grade children.

Enhance the affinity of nanobodies to CD47 antigen by fusion expression of COMP48 self-folding peptide / 国际生物医学工程杂志

Objective To modify CD47 nanobody with the self-folding peptide human cartilage oligomeric matrix protein (COMP48) so as to enhance its affinity to CD47 antigen. Methods The fusion sequences of COMP48 and CD47 nanobody (VHHB1) were designed and synthesized, and the recombinant plasmid pET22b-VHHB1-COMP48 was constructed and transformed into E. coli BL21 (DE3) to induce expression of the fusion protein. The binding specificity and affinity of the fusion protein and the antigen CD47 were detected by Western Blot, indirect enzyme-linked immunosorbent assay (ELISA) and non-competitive ELISA. Results The recombinant VHHB1-COMP48 was expressed in BL21(DE3) by inducing with 1 mmol/L IPTG and purified at 90％homogenous in IMAC. Western Blot results showed that the recombinant protein VHHB1-COMP48 specifically binds to antigen CD47 but not to unrelated protein. The indirect ELISA and non-competitive ELISA results showed that the affinity of the conjugated recombinant protein VHHB1-COMP48 was enhanced compared to that of the non-conjugated nanobody, and the difference was statistically significant ( P<0 . 01 ) . Through non-competitive ELISA , the constants of affinity and dissociation constants were 6.97 ×107 L/mol and 1.434 ×10-8 mol/L, respectively. Conclusions The affinity of the nanobody for the antigen can be improved by conjugating a human cartilage matrix protein (COMP48) after the nanobody.

Preparation and identification of the nano antibodies of anti-programmed death receptor-1 / 国际生物医学工程杂志

Objective To prepare camelid-derived nano antibodies with high affinity binding to programmed death receptor-1 (PD-1) antigen,and to provide experimental basis for subsequent functional studies.Methods The PD-1-Fc recombinant protein expressed in eukaryotic expression was used to immunize Xinjiang Bactrian camel 6 times.The peripheral blood was collected and the lymphocytes were isolated.Nested PCR amplification was performed to obtain the genes in variable region of camelid heavy chain antibody (VHH),and to construct a phage display library.The phage display library was screened by solid phase enzyme-linked immunosorbent assay (ELISA).The PD-1 antigen,which was sequentially reduced in mass concentration (5.00、2.50、1.00 μg/ml),was coated in an ELISA plate,and the phage display library was subjected to 3 rounds of affinity selection.Individual clones that bind to PD-1 were further screened by soluble monoclonal ELISA.According to the results of DNA sequencing,three VHH monoclonals with multiple repeats were selected and ligated into pET22b vector,and transformed into E.coli BL21 (DE3) competent cells,and then induced by isopropyl-β3-D-thiogalactoside.The recombinant VHH antibody protein was purified by nickel column affinity chromatography,and its binding activity and affinity to PD-1 antigen were detected by Western Blot and ELISA.Results After immunization of Bactrian camel 6 times with recombinant protein PD-1-Fc,high titer specific antibody was stimulated,and the immune serum titer reached 1∶32 000.A VHH phage display library with a reservoir size of 2.6×108 cfu/ml was constructed from the immunized camel lymphocytes.After 3 rounds of affinity selection,46 VHH monoclonals with absorbance (A600) values above 0.6 were obtained by soluble monoclonal ELISA.Among them,three clones of VHH-B7,VHH-H5 and VHH-H12 had higher repeats,indicating that significant enrichment was obtained.The results of Western Blot and ELISA showed that the purified B7,H5 and H12 nanobodies had good binding activity to PD-1 antigen and had high affinity.Their affinity constants were 1.19×1011 and 1.63×1011,1.59×1011 L/mol,respectively.Conclusion The anti-PD-1 camelid-derived nanobodies were obtained by affinity selection of VHH phage display library,which can bind to the PD-1 antigen with high affinity.This study can provide an experimental basis for subsequent functional studies.

Effects of degreasing-frosting on reducing toxicity and enhancing efficacy of Periplaneta americana / 中成药

AIM To study the effects of degreasing-frosting on reducing toxicity and enhancing efficacy of Periplaneta americana L..METHODS The 95％ ethanol extracts from P.americana raw powder and processed products were extracted by petroleum ether,ethyl acetate,n-butanol and water.TLC was applied to comparing the component changes in various fractions.GC-MS was used for analyzing the kinds and contents of liposoluble constituents before and after processing.Shaking flask method combined with UV spectrophotometry method was adopted in the determination of Papp values in octanol-water and different pH values (2.23,3.28,4.22,5.23,6.12,7.24,8.23,9.10,10.15 and pure water) of buffer solutions.RESULTS After the petroleum ether fraction was processed,the colors of TLC spots became much shallower,which changed more significantly with the prolonging of processing time and increase of pressure.The TLC spots in the n-butanol and water fractions were clear without obvious changes.And no TLC spots were found in the ethyl acetate fraction.The kinds of liposoluble constituents were the same before and after processing,whose absolute contents were decreased after processing.Compared with raw powder,the Papp values of minor polypeptides in various processed products at different pH values exhibited significant differences (P ＜0.05,P ＜0.01),which also showed certain differences at the same pH values.CONCLUSION Degreasing-frosting can affect the contents of liposoluble constituents in P.americana and Papp values of minor polypeptides,which may be the mechanism of reducing toxicity and enhancing efficacy.

Auxiliary application of three-dimensional printing technology of implant fixation for tibial plateau fracture / 中国组织工程研究

BACKGROUND:In the treatment of tibial plateau fractures, because of the variety of fracture, the complexity of anatomical changes, X-ray films or three-dimensional CT scan limited by two-dimensional plane, increases the difficulty in preoperative plan and surgical treatment. The application of three-dimensional (3D) printing technology has attracted attention in the department of orthopedics. OBJECTIVE:To explore the auxiliary role of 3D printing technique in preoperative plan and treatment for tibial plateau fractures. METHODS:Thirty patients with tibial plateau comminuted fractures were enroled in this study and divided into two groups: experimental and control groups, with 15 patients in each group. In the experimental group, patients underwent 3D CT scan, which was stored in DICOM format, and processed by Mimics software. Data were converted into STL format, entered 3D printer, and a 1:1 entity size of the fracture model was made, in accordance with repair plan of 3D fracture model. Operation time and intraoperative blood loss were compared between the two groups. At 12 months after treatment, their outcomes were assessed using Rasmussen evaluation criteria. RESULTS AND CONCLUSION: The 3D printing fracture models of 1:1 ratio identified fracture type and made a repair program before surgery in the experimental group. Operation time and intraoperative blood loss were significantly less in the experimental group than in the control group (P < 0.05). After surgery, patients were folowed up for 12 to 18 months. The healing time was 3-5 months, averagely 4.3 months. At 12 months after treatment, the Rasmussen evaluation criteria results showed that the excelent and good rate was significantly higher in the experimental group than in the control group (P < 0.05). These results suggest that the fracture model of 3D can help to make the operation plan. The treatment of tibial plateau fractures is more precise, personalized and visual.

Impact of siRNA-mediated down-regulation of CD147 on human breast cancer cells / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the influence of siRNA-mediated down-regulation of CD147 on growth, proliferation and movement of human breast cancer cell line MDA-MB-231.</p><p><b>METHODS</b>The protein expression of CD147, MMP-2 and TIMP-2 of the MDA-MB-231 cells were analyzed by ABC. Lentiviral expression vector of CD147 gene was constructed and transfected into MDA-MB-231 cells. RT-PCR and Western blot were used to detect the mRNA and protein level changes of CD147 genes to identify the optimal time point, followed by detection of changes of mRNA and protein expression of MMP-2 and TIMP-2 genes. CCK-8 reagent method and cell scratch test were used to detect the proliferation and migration change of MDA-MB-231 cells. The nude mouse model of breast cancer by hypodermic injection with MDA-MB-231 cells was established to document the effect of CD147 siRNA on the tumor transplants.</p><p><b>RESULTS</b>After transfection of lentiviral expression vector of CD147 gene, protein of CD147, MMP-2 and TIMP-2 were weakly or negative expressed, significantly weaker than those of control group (P < 0.01). After 72 hours of transfection, average down-regulation rate of CD147 and MMP-2 were 96.03% ± 0.84% and 96.03% ± 0.84%, respectively. Both CD147 mRNA and MMP-2 mRNA expression were down-regulated (P < 0.05), while TIMP-2 mRNA expression showed no significant deference (P > 0.05). No less than 2 days after transfection, cell growth of MDA-MB-231 cell line was found significantly inhibited (P < 0.05). After 24 hours of transection, average migration distance of MDA-MB-231 cell line and control group were (0.64 ± 0.12) mm and (4.69 ± 0.85) mm, respectively, which indicated a lower migrate speed. Down regulation of CD147 led to reduction of volume and mass of nude mouses. The growth of the carcinoma transplant was inhibited upon siRNA-mediated down-regulation of CD147 (P < 0.05), with an average tumor mass of (1.85 ± 0.98) g and both reduction of tumor size and tumor mass.</p><p><b>CONCLUSIONS</b>CD147 may alter the MMP-2/TIMP-2 balance in MDA-MB-231 cells. CD147 gene silencing inhibits the proliferation and migration of MDA-MB-231 cells and the growth of carcinoma transplants in nude mice.</p>

Effects of CD147 gene silencing on protein expression of ANXA2, MMP-2 and TIMP-2 by thyroid medullary carcinoma TT cells and biologic characteristics / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the influence of CD147 gene silencing on the expression of ANXA2, MMP-2 and TIMP-2 of thyroid medullary carcinoma TT cells and related biological characteristics.</p><p><b>METHODS</b>Protein expression of CD147, ANXA2, MMP-2 and TIMP-2 was detected by immunocytochemistry.RNAi technology was used to identify the specific siRNA sequences and the optimal time point of effective inhibition of CD147 gene. The expression of ANXA2, MMP-2 and TIMP-2 at mRNA and protein levels was detected with RT-PCR and Western blot, respectively. MTT method was used to detect the proliferation of the TT cells, flow cytometry (FCM) to detect the cell cycle and apoptosis changes of TT cells and transwell chamber assays to document the influence of CD147 gene silencing on migration and invasion of the TT cells.</p><p><b>RESULTS</b>The protein expression of CD147, ANXA2, MMP-2 and TIMP-2 proteins was variable in the TT cells. Two siRNA sequences were identified to effectively silence CD147 gene in the TT cells, in which relative expression of MMP-2 was reduced at both mRNA and protein levels; although the expression of ANXA2 mRNA and protein did not change significantly. TIMP-2 protein expression markedly decreased in an absence of its mRNA expression. The proliferation of the TT cells was inhibited upon the CD147 gene silencing along with a significant increase of G(0)/G(1) phase cells and a decrease of G(2)/M phase cells.However, the proportion of the apoptotic cells in all experimental groups did not change. The number of the penetrating cells through the membrane filters did not show significant changes in all experimental groups in the Transwell chamber assays.</p><p><b>CONCLUSIONS</b>Through RNAi technology, two CD147 siRNA sequences are identified and shown to effectively inhibit CD147 gene expression of the TT cells. CD147 gene silencing leads to growth inhibition of the TT cells and alteration of the cell cycle. However, silencing CD147 does not significantly affect the apoptosis, migration and invasion of the TT cells.</p>

Simultaneous bilateral versus unilateral total knee arthroplasty in treatment of knee osteoarthritis / 中国组织工程研究

BACKGROUND:The safety and efficacy of simultaneous bilateral total knee replacement or selective unilateral total knee arthroplasty in patients with severe osteoarthritis of the knees are stil controversial. OBJECTIVE:To compare safety and clinical efficacy of patients with osteoarthritis knees after simultaneous bilateral total knee replacement or selective unilateral total knee replacement. METHODS:Total y 60 cases with severe osteoarthritis of the knees (90 knees) undergoing total knee replacement were divided into unilateral total knee replacement group (n=30, 30 knees), and the simultaneous bilateral total knee replacement group (n=30, 60 knees). RESULTS AND CONCLUSION:There was no significant difference in the incidence of other complications such as infection, mortality, pulmonary embolism in patients of both groups (P>0.05). The incidence of cardiovascular complications, postoperative blood loss and blood transfusion were higher in the bilateral knee group than in the unilateral knee group (P0.05). However, Visual Analogue Scale scores were significantly lower in the bilateral knee group than in the unilateral group (P<0.05). These data indicated that the risk of cardiovascular complications was high in patients receiving bilateral total knee replacement. Patients with severe cardiovascular disease should avoid simultaneous bilateral total knee arthroplasty.

Enhancement of antibodies to protective domain of surface protective antigen A of Erysipelothrix rhusiopathiae by DNA immunization with plasmids expressing spaA-chimeras / 细胞与分子免疫学杂志

AIM: DNA vaccines expressing protective domain of surface protective antigen A（spaA）of Erysipelothrix rhusiopathiae have been relatively ineffective at generating high-titer, long-lasting, neutralizing antibodies in murine models. METHODS: This paper report using a DNA vaccine expressing a fusion of the spaA protein and various elements, such as a secretion leader sequence from the highly expressed human gene encoding α1-antitrypsin (AAT), a highly soluble and stably folded domain from the rat cartilage oligomerization matrix protein (COMP), and three copies of the complement component, C3d3, to enhance the titers of neutralizing spaＡ-specific antibody. RESULTS: Analysis of titers of the antibody raised in vaccinated mice at different time points indicated that immunizations with the DNA expressing pcDNA3-AAT-COMP-spaAN-3C3d((pcD-ACSC)) had higher titers than pcDNA3-spaA_N(pcD-S) at weeks 4. Furthermore, the immune protective efficacy of the spaA-chimeras was demonstrated by lethal challenge with a virulent homologous strain 1249 against immunized mice. CONCLUSION: These results suggest that using a plasmid vector containing a strong heterologous signal sequence that mediate efficient antigen secretion in vivo and a fused piece of sequence improving antigens solubility, as well as C3d3, genetic adjuvant, could enhance the antibody responses level. This approach might be an efficient way to improve the antibody level of spaA_N DNA vaccination.