Isolation and Characterization of Recombinant Variable Domain of Heavy Chain Anti-idiotypic Antibodies Specific to Aflatoxin B_1

Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain （VHH）. The recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. In particular, they might be very useful for molecular mimicry. The present study demonstrated an alpaca immunized with the F（ab＇）z fragment of anti-aflatoxin B1 mAb and developed an important anti-idiotypic （anti-ld） responses. Antigen-specific elution method was used for panning private anti-ld VHHs from the constructed alpaca VHH library. The selected VHHs were expressed, renatured, purified, and then identified by a competitive enzyme-linked immunosorbent assay （ELISA）. Our findings indicated that the VHH would be an alternative tool for haptens mimicry studies.

Cloning, expression, purification, and characterization of LC-1 ScFv with GFP tag

Total RNA was isolated from the hybridoma cell line （LC- 1 ）, which secretes anti-lung adenocarcinoma monoclonal antibody, and was transferred into cDNA. Based on the FRl （framework region l） and FR4 conserved regions of LC-1 gene, the variable regions of heavy chain （Vh） and light chain （Vl） were amplified, and the Vh and modified Vl were connected to single chain Fv （ScFv） by SOE-PCR （splice overlap extension PCR）. The modified ScFv was fused with green fluorescent protein （GFP） and introduced into E. coli JM109. The fusion protein induced by lPTG （Isopropylthiogalactoside） was about 57000 on a 10% SDS-PAGE gel （10% Sds Polyacrylamide Gel Electrophoresis）, and primarily manifested as inclusion bodies. The renatured protein purified by Ni-NTA Superflow resins showed ability to bind to antigen on SPC-A-l lung adenocarcinoma. In addition, the induced host cells fluoresced bright green under 395 nm wavelength, which indicated that the expected protein with dual activity was expressed in the prokaryotic system. The ScFv with GFP tag used in this research can be applied as a new reagent to detect immunological dye, and provide a feasible way to detect adenocarcinoma in a clinical setting.

Cloning, sequencing and analyzing of the heavy chain V region genes of human polyreactive antibodies

The heavy chain variable region genes of 5 human polyreactive mAbs generated in our laboratory have been cloned and sequenced using polymerase chain reaction (PCR) technique. We found that 2 and 3 mAbs utilized genes of the VHIV and VHIII families, respectively. The former 2 VH segments were in germline configuration. A common VH segment, with the best similarity of 90.1 % to the published VHIII germline genes, was utilized by 2 different rearranged genes encoding the V regions of other 3 mAbs. This strongly suggests that the common VH segment is a unmutated copy of an unidentified germline VHIII gene. All these polyreactive mAbs displayed a large NDN region (VH-D-JH junction). The entire H chain V regions of these polyreactive mAbs are unusually basic. The analysis of the charge properties of these mAbs as well as those of other poly- and mono- reactive mAbs from literatures prompts us to propose that the charged amino acids with a particular distribution along the H chain V region,especially the binding sites (CDRs), may be an important structural feature involved in antibody polyreactivity.

Screening of scFvs against cTnI from Phage Display Antibody Library and Their Expression in E.coli Rosetta

The single chain variable fragments of antibodies(scFvs) against cTnI were screened from the phage display antibody library by using cTnI as the target antigen. After four rounds of panning, four clones(H2, G5, A9, B9) from the phage display antibody library were verified to show higher binding affinity for cTnI by ELISA and to contain the variable region genes of the light and heavy chains of scFvs by sequencing. The variable region genes of scFvs H2 and G5 were successfully amplified by polymerase chain reactions(PCR) and cloned into expression vector pPELB and expressed as a soluble protein in E.coli Rosetta, whose expression yield was about 2% of total proteins. The expressed proteins were purified by nickel(Ni) affinity chromatography and a single band is shown in the position of 28 kDa on SDS-PAGE. The western blot analysis result verifies that the expressed scFv proteins are capable of binding with monoclonal antibodies against hexa-histidine, indicating that they are hexa-histidin-tagged aim proteins. The immunoassay demonstrates that the expressed scFv proteins are able to specifically react with cTnI molecules. The association constant(K_A) values range from 1.2×10 4 to 1.7 ×10 5 L/mol that are correspondent to the affinities of polyclonal antibodies against cTnI from rabbits. These antibodies can be valuable reagents for the immunoassay of cTnI.

Davana： A New Host Plant for Ralstonia solanacearum from India

Ralstonia solanacearum infecting Davana （Artemisia pallens Wall.） from commercial nurseries in India was isolated on modified semi selective media （SMSA）. Here, we report a new host for Ralstonia solanacearum i.e. davana. It has huge demand in medicinal and aromatic industries. Isolate was confirmed as race-l, biovar-3 by morphological, physiological, biochemical and pathogenicity studies. Two sets of primers （OLI 1 ＆ Y2 and Y 1 ＆ Y2） were used in this study. Further, the identity of the isolate was confirmed by serological diagnostic kit obtained from International Potato Research Center, Lima, Peru and single chain variable fragment antibody specific to Ralstonia solanacearum used to confirm the casual organism.

Chronic Lymphocytic Leukemia Prognostic Index： A New Inteorated Scorino System to Predict the Time to First Treatment in Chinese Patients with Chronic Lymphocytic Leukemia

Background： The established clinical staging systems （Rai/Binet） of chronic lymphocytic leukemia （CLL） cannot accurately predict the appropriate treatment of patients in the earlier stages. In the past two decades, several prognostic factors have been identified to predict the outcome of patients with CLL, but only a few studies investigated more markers together, To predict the time to first treatment （TTFT） in patients of early stages, we evaluated the prognostic role of conventional markers as well as cytogenetic abnormalities and combined them together in a new prognostic scoring system, the CLL prognostic index （CLL-PI）. Methods： Taking advantage of a population of 406 untreated Chinese patients with CLL at early and advanced stage of disease, we identified the strongest prognostic markers of TTFT and, subsequently, in a cohort of 173 patients who had complete data for all 3 variables, we integrated the data of traditional staging system, cytogenetic aberrations, and mutational status of immunoglobulin heavy chain variable region （1GI：tV） in CLL-PI. The median follow-up time was 45 months and the end point was TTFT. Results： The median TTFT was 38 months and the 5-year overall survival was 80%. According to univariate analysis, patients of advanced Rai stages （P 〈 0.001） or with 11q- （P = 0.002）, 17p- （P 〈 0.001）, unmutated IGHV （P 〈 0.001）, negative 13q- （P = 0.007） and elevated lactate dehydrogenase levels （P = 0.001 ） tended to have a significantly shorter TTFT. And subsequently, based on multivariate Cox regression analysis, three independent factors for TTFT were identified： advanced clinical stage （P = 0.002）, 17p- （P = 0.050） and unmutated 1GHV （P = 0.049）. Applying weighted grading of these independent factors, a CLL-PI was constructed based on regression parameters, which could categorize tbur different risk groups （low risk [score 0], intermediate low [score 1], intermediate high [score 2] and high risk [score 3-6]） with significantly different TTFT （median TTFT of not reached （NR）, 65.0 months, 36.0 months and 19.0 months, respectively, P 〈 0.001 ）. Conclusions： This study developed a weighted, integrated CLL-PI prognostic system of CLL patients which combines the critical genetic prognostic markers with traditional clinical stage. This novel modified PI system could be used to discriminate among groups and may help predict the TTFT and prognosis of patients with CLL.

Engineering a cell-penetrating hyperstable antibody scFv(Ras)-An extraordinary approach to cancer therapeutics

In the modern pharmaceutical industry,monoclonal antibodies are often used as therapeutic agents.However,they are restricted to cell surface antigens due to their inability to penetrate the outer cell membrane and maintain normal function in the reducing environment.Additionally,it can lead to cytotoxicity since it attacks cancerous cells by mimicking the human immune system.As an alternative,this study modifies the hyperstable single-chain fragment variable(scFv)antibody to eliminate cancer using its linear shape.The scFv(F8)antibody model was modified to recognize human Ras protein by altering residues in the antigen-binding site.Furthermore,a cell-penetrating peptide(CPP)was attached to the scFv(Ras)antibody model to allow entrance to the cell,creating CPP-scFv(Ras).Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE),western blotting,and the binding assay were performed to prove its effectiveness.As a result,CPP-scFv(Ras)was successfully engineered and bound to the antigen,HRas(G12V).

Option Pricing under the Double Exponential Jump-Diffusion Model with Stochastic Volatility and Interest Rate

This paper proposes an efficient option pricing model that incorporates stochastic interest rate(SIR),stochastic volatility(SV),and double exponential jump into the jump-diffusion settings.The model comprehensively considers the leptokurtosis and heteroscedasticity of the underlying asset’s returns,rare events,and an SIR.Using the model,we deduce the pricing characteristic function and pricing formula of a European option.Then,we develop the Markov chain Monte Carlo method with latent variable to solve the problem of parameter estimation under the double exponential jump-diffusion model with SIR and SV.For verification purposes,we conduct time efficiency analysis,goodness of fit analysis,and jump/drift term analysis of the proposed model.In addition,we compare the pricing accuracy of the proposed model with those of the Black-Scholes and the Kou(2002)models.The empirical results show that the proposed option pricing model has high time efficiency,and the goodness of fit and pricing accuracy are significantly higher than those of the other two models.