IgA antibody production by intrarectal immunization of mice using recombinant major capsid protein of hamster polyomavirus

Automated determination of 8-OHdG in cells and tissue via immunofluorescence using a specially created antibody

Despite powerful DNA repair systems, oxidative damage/modification to DNA is an inevitable side effect of metabolism, ionizing radiation, lifestyle habits, inflammatory pathologies such as type-2 diabetes or metabolic syndrome, cancer and natural aging. One of the most common oxidative DNA modifications is 8-OHdG (8‑hydroxy-2'-deoxyguanosine), which is the most widely used marker in research and clinical diagnostics. 8-OHdG is easily and specifically detectable in various samples such as urine, plasma, cells and tissues via a large variety of methods like ELISA, HPLC, chromatographic methods, and immunochemistry. Formed by oxidation of guanine and being representative for the degree of DNA damage, 8-OHdG can be also used as biomarker for risk assessment of various cancers as well as degenerative diseases. Here, we present a highly specific, self-developed 8-OHdG antibody in successful comparison to a commercially one, tested in cells (FF95, HCT116, and HT22) and intestinal tissue, focusing on automatized evaluation via fluorescence/confocal microscopy.

Serological diagnosis and prognosis of severe acute pancreatitis by analysis of serum glycoprotein 2

BACKGROUND

Glycoprotein 2 (GP2), the pancreatic major zymogen granule membrane glycoprotein, was reported to be elevated in acute pancreatitis in animal models.

METHODS

Enzyme-linked immunosorbent assays (ELISAs) were developed to evaluate human glycoprotein 2 isoform alpha (GP2a) and total GP2 (GP2t) as specific markers for acute pancreatitis in sera of 153 patients with acute pancreatitis, 26 with chronic pancreatitis, 125 with pancreatic neoplasms, 324 with non-pancreatic neoplasms, 109 patients with liver/biliary disease, 67 with gastrointestinal disease, and 101 healthy subjects. GP2a and GP2t levels were correlated with procalcitonin and C-reactive protein in 152 and 146 follow-up samples of acute pancreatitis patients, respectively.

RESULTS

The GP2a ELISA revealed a significantly higher assay accuracy in contrast to the GP2t assay (sensitivity ≤3 disease days: 91.7%, specificity: 96.7%, positive likelihood ratio [LR+]: 24.6, LR-: 0.09). GP2a and GP2t levels as well as prevalences were significantly elevated in early acute pancreatitis (≤3 disease days) compared to all control cohorts (p<0.05, respectively). GP2a and GP2t levels were significantly higher in patients with severe acute pancreatitis at admission compared with mild cases (p<0.05, respectively). Odds ratio for GP2a regarding mild vs. severe acute pancreatitis with lethal outcome was 7.8 on admission (p=0.0222). GP2a and GP2t levels were significantly correlated with procalcitonin [Spearman's rank coefficient of correlation (ρ)=0.21, 0.26; p=0.0110, 0.0012; respectively] and C-reactive protein (ρ=0.37, 0.40; p<0.0001; respectively).

CONCLUSIONS

Serum GP2a is a specific marker of acute pancreatitis and analysis of GP2a can aid in the differential diagnosis of acute upper abdominal pain and prognosis of severe acute pancreatitis.

Generation of Murine Monoclonal Antibodies by Hybridoma Technology

Monoclonal antibodies are universal binding molecules and are widely used in biomedicine and research. Nevertheless, the generation of these binding molecules is time-consuming and laborious due to the complicated handling and lack of alternatives. The aim of this protocol is to provide one standard method for the generation of monoclonal antibodies using hybridoma technology. This technology combines two steps. Step 1 is an appropriate immunization of the animal and step 2 is the fusion of B lymphocytes with immortal myeloma cells in order to generate hybrids possessing both parental functions, such as the production of antibody molecules and immortality. The generated hybridoma cells were then recloned and diluted to obtain stable monoclonal cell cultures secreting the desired monoclonal antibody in the culture supernatant. The supernatants were tested in enzyme-linked immunosorbent assays (ELISA) for antigen specificity. After the selection of appropriate cell clones, the cells were transferred to mass cultivation in order to produce the desired antibody molecule in large amounts. The purification of the antibodies is routinely performed by affinity chromatography. After purification, the antibody molecule can be characterized and validated for the final test application. The whole process takes 8 to 12 months of development, and there is a high risk that the antibody will not work in the desired test system.

A novel monoclonal antibody suitable for the detection of leukotriene B4

Leukotriene B4 as an inflammatory mediator is an important biomarker for different respiratory diseases like asthma, chronic obstructive pulmonary disease or cystic lung fibrosis. Therefore the detection of LTB4 is helpful in the diagnosis of these pulmonary diseases. However, until now its determination in exhaled breath condensates suffers from problems of accuracy. Reasons for that could be improper sample collection and preparation methods of condensates and the lack of consistently assay specificity and reproducibility of the used immunoassay detection system. In this study we describe the development and the characterization of a specific monoclonal antibody (S27BC6) against LTB4, its use as molecular recognition element for the development of an enzyme-linked immunoassay to detect LTB4 and discuss possible future diagnostic applications.

Characterizing seamless ligation cloning extract for synthetic biological applications

Synthetic biology aims at designing and engineering organisms. The engineering process typically requires the establishment of suitable DNA constructs generated through fusion of multiple protein coding and regulatory sequences. Conventional cloning techniques, including those involving restriction enzymes and ligases, are often of limited scope, in particular when many DNA fragments must be joined or scar-free fusions are mandatory. Overlap-based-cloning methods have the potential to overcome such limitations. One such method uses seamless ligation cloning extract (SLiCE) prepared from Escherichia coli cells for straightforward and efficient in vitro fusion of DNA fragments. Here, we systematically characterized extracts prepared from the unmodified E. coli strain DH10B for SLiCE-mediated cloning and determined DNA sequence-associated parameters that affect cloning efficiency. Our data revealed the virtual absence of length restrictions for vector backbone (up to 13.5 kbp) and insert (90 bp to 1.6 kbp). Furthermore, differences in GC content in homology regions are easily tolerated and the deletion of unwanted vector sequences concomitant with targeted fragment insertion is straightforward. Thus, SLiCE represents a highly versatile DNA fusion method suitable for cloning projects in virtually all molecular and synthetic biology projects.

Multiplex localization of sequential peptide epitopes by use of a planar microbead chip

Epitope mapping is crucial for the characterization of protein-specific antibodies. Commonly, small overlapping peptides are chemically synthesized and immobilized to determine the specific peptide sequence. In this study, we report the use of a fast and inexpensive planar microbead chip for epitope mapping. We developed a generic strategy for expressing recombinant peptide libraries instead of using expensive synthetic peptide libraries. A biotin moiety was introduced in vivo at a defined peptide position using biotin ligase. Peptides in crude Escherichia coli lysate were coupled onto streptavidin-coated microbeads by incubation, thereby avoiding tedious purification procedures. For read-out we used a multiplex planar microbead chip with size- and fluorescence-encoded microbead populations. For epitope mapping, up to 18 populations of peptide-loaded microbeads (at least 20 microbeads per peptide) displaying the primary sequence of a protein were analyzed simultaneously. If an epitope was recognized by an antibody, a secondary fluorescence-labeled antibody generated a signal that was quantified, and the mean value of all microbeads in the population was calculated. We mapped the epitopes for rabbit anti-PA28γ (proteasome activator 28γ) polyclonal serum, for a murine monoclonal antibody against PA28γ, and for a murine monoclonal antibody against the hamster polyoma virus major capsid protein VP1 as models. In each case, the identification of one distinct peptide sequence out of up to 18 sequences was possible. Using this approach, an epitope can be mapped multiparametrically within three weeks.

Identification of whole pathogenic cells by monoclonal antibodies generated against a specific peptide from an immunogenic cell wall protein

We selected the immunogenic cell wall ß-(1,3)-glucosyltransferase Bgl2p from Candida albicans as a target protein for the production of antibodies. We identified a unique peptide sequence in the protein and generated monoclonal anti- C. albicans Bgl2p antibodies, which bound in particular to whole C. albicans cells.