Monitoring of the effects of transfection with baculovirus on Sf9 cell line and expression of human dipeptidyl peptidase IV.

Human dipeptidylpeptidase IV (hDPPIV) is an enzyme that is in hydrolase class and has various roles in different parts of human body. Its deficiency may cause some disorders in the gastrointestinal, neurologic, endocrinological and immunological systems of humans. In the present study, hDPPIV enzyme was expressed on Spodoptera frugiperda (Sf9) cell lines as a host cell, and the expression of hDPPIV was obtained by a baculoviral expression system. The enzyme production, optimum multiplicity of infection, optimum transfection time, infected and uninfected cell size and cell behavior during transfection were also determined. For maximum hDPPIV (269 mU mL(-1)) enzyme, optimum multiplicity of infection (MOI) and time were 0.1 and 72 h, respectively. The size of infected cells increased significantly (P < 0.001) after 24 h post infection. The results indicated that Sf9 cell line was applicable to the large scale for hDPPIV expression by using optimized parameters (infection time and MOI) because of its high productivity (4.03 mU m L(-1) h(-1)).

Co-expression of the Bcl-xL antiapoptotic protein enhances the induction of Th1-like immune responses in mice immunized with DNA vaccines encoding FMDV B and T cell epitopes.

Foot-and-mouth disease (FMD) is one of the most devastating animal diseases, affecting all cloven-hoofed domestic and wild animal species. Previous studies from our group using DNA vaccines encoding FMD virus (FMDV) B and T cell epitopes targeted to antigen presenting cells, allowed demonstrating total protection from FMDV homologous challenge in those animals efficiently primed for both humoral and cellular specific responses (Borrego et al. Antivir Res 92:359-363, 2011). In this study, a new DNA vaccine prototype expected to induce stronger and cross-reactive immune responses against FMDV which was designed by making two main modifications: i) adding a new B-cell epitope from the O-serotype to the B and T-cell epitopes from the C-serotype and ii) using a dual promoter plasmid that allowed inserting a new cistron encoding the anti-apoptotic Bcl-xL gene under the control of the internal ribosomal entry site (IRES) of encephalomyocarditis virus aiming to increase and optimize the antigen presentation of the encoded FMDV epitopes after in vivo immunization. In vitro studies showed that Bcl-xL significantly prolonged the survival of DNA transfected cells (p < 0.001). Accordingly, vaccination of Swiss out-bred mice with the dual promoter plasmid increased the total IgG responses induced against each of the FMDV epitopes however no significant differences observed between groups. The humoral immune response was polarized through IgG2a in all vaccination groups (p < 0.05); except peptide T3A; in correspondence with the Th1-like response observed, a clear bias towards the induction of specific IFN-γ secreting CD4⁺ and CD8⁺ T cell responses was also observed, being significantly higher (p < 0.05) in the group of mice immunized with the plasmid co-expressing Bcl-xL and the FMDV B and T cell epitopes.

Purification of alginate and feasible production of monoclonal antibodies by the alginate-immobilized hybridoma cells.

Alginate has an extensive usage in the immobilization of many cell types. Although they have high biocompatibility, commercial alginates contain various degrees of contaminants such as polyphenols, endotoxins and proteins. Thus, these alginates show cytotoxicity against sensitive cell types such as hybridoma cells. In the studies so far, owing to this fact, commercially purchased high-priced ultrapure alginates have been used in the immobilization of hybridoma cells for monoclonal antibody production. However in this study, as a novelty, low-priced commercial alginate was purified, and then the cultivation of alginate-immobilized hybridoma cells was performed for feasible monoclonal antibody production. Low-priced commercial alginate was purified with a profitability ratio of 40%. Then, an optimized immobilization procedure was conducted effectively by using the purified alginate. During more than 25 days of cultivation, serum concentration was kept low, and approximately 2 times greater monoclonal antibody production was achieved, in comparison with its free suspended counterpart. The results showed that the efficiency of monoclonal antibody production via alginate-immobilized hybridoma cultivation can be increased by performing a proved in-house purification method. By shedding light on the efficiency of the in-house purification method, the results also indicated a feasible way of monoclonal antibody production.

Production of monoclonal antibody against Salmonella H: g,m flagellar antigen and potential diagnostic application.

In this study, the flagella antigen was detached at high speed by shaking vigorously with glass pearl beads, from Salmonella enteritidis in a yield of 3.9 mg/mL(-1) after being concentrated with polyethylene glycol (PEG). A monoclonal antibody (MAb), designated D7 clone, was generated from Balb/c mice immunized with Salmonella enteritidis flagella using the conventional hybridoma method. The D7 clone secreting MAb was classified as IgG2a isotype. ELISA analyses of D7 MAb to Salmonella-specific flagella demonstrated that the antibody reacted with H: m. However, Western immunoblot analyses of D7 clone appear to be secreting heavy chain of IgG2a antibody, which was eligible for the diagnosis of Salmonella enteritidis.

Production of monoclonal antibodies in a mouse model via lipopolysaccharide conjugates with synthetic polymers specific to Salmonella Enteritidis O antigen.

Monoclonal antibodies (Mabs) specific for lipopolysaccharide (LPS) of Salmonella Enteritidis were evaluated in a model of LPS conjugated synthetic polymer immunization of Balb/c mice by conventional hybridoma method. Nine hybridoma cell lines were determined as antibody positive against LPS. The clone 5A8 secreting the highest antibody was selected for further characterization. Evaluated results indicate that the synthetic polymer can be used as an effective adjuvant in immunization with LPS, because the 5A8 Mab were obtained using synthetic polymer as an adjuvant. 5A8 Mab was classified as IgG2a isotype by antibody capture enzyme-linked immunosorbent assay. The reactivity of the Mab against lipid A and different LPS of Salmonella were investigated using an indirect enzyme-linked immunosorbent assay. Mab presented a wide spectrum of reactivity, coupling with antigens against Salmonella. The hybridoma 5A8 determined in this study has a great potential to be used in the development of diagnostic, prophylactic, and therapeutic agents specific for Salmonella Enteritidis and Salmonella LPS.