Biomarkers: in combination they may do better

The field of biomarkers is a growing one, particularly in osteoarthritis (OA). OA is the most common disabling condition in older persons and a major cause of morbidity. While the debate continues about which of the involved tissues - cartilage, bone or synovium - is the most important in OA aetiology, there is no doubt that the three develop abnormalities in concert; perhaps a truly useful biomarker will reflect just that. While efforts continue to identify reliable biomarkers useful for characterising the status, prognosis and measurement of treatment response in OA, combining existing biomarkers to improve their accuracy looks promising.     

Tumor-specific targeting of a cell line with natural killer cell activity by asialoglycoprotein receptor gene transfer

Targeting of immunological effector cells to tumor cells could be an efficient strategy of adoptive immunotherapy. The success of this strategy depends on the specificity of the effector cells and their availability in sufficient numbers. The aim of this study was to target the human natural killer cell line YT specifically to tumor cells. The cell line was modified by transfection with the cDNA of the human asialoglycoprotein receptor (ASGPR). This C-type lectin recognizes carbohydrates containing terminal galactosyl (Gal) residues, including the beta1-Gal bearing Thomsen-Friedenreich (TF) antigen, which is found on tumor cells. Binding assays revealed that the ASGPR-gene-transfected YT cell line binds significantly higher to tested target tumor cell lines than the mock-transfected control cells. Cytolytic activity against the tumor cell lines Raji, Jurkat and the TF-positive KG1 subline was increased. Genetic modification of YT cells could provide a useful tool for tumor targeting in immunotherapy.     

Identification of immunogenic polypeptides from a <Emphasis Type="Italic">Mycoplasma hyopneumoniae</Emphasis> genome library by phage display

The identification of immunogenic polypeptides of pathogens is helpful for the development of diagnostic assays and therapeutic applications like vaccines. Routinely, these proteins are identified by two-dimensional polyacrylamide gel electrophoresis and Western blot using convalescent serum, followed by mass spectrometry. This technology, however, is limited, because low or differentially expressed proteins, e.g. dependent on pathogen-host interaction, cannot be identified. In this work, we developed and improved a M13 genomic phage display-based method for the selection of immunogenic polypeptides of Mycoplasma hyopneumoniae, a pathogen causing porcine enzootic pneumonia. The fragmented genome of M. hyopneumoniae was cloned into a phage display vector, and the genomic library was packaged using the helperphage Hyperphage to enrich open reading frames (ORFs). Afterwards, the phage display library was screened by panning using convalescent serum. The analysis of individual phage clones resulted in the identification of five genes encoding immunogenic proteins, only two of which had been previously identified and described as immunogenic. This M13 genomic phage display, directly combining ORF enrichment and the presentation of the corresponding polypeptide on the phage surface, complements proteome-based methods for the identification of immunogenic polypeptides and is particularly well suited for the use in mycoplasma species.     

Determination of acid α-naphthyl acetate esterase enzyme activity in peripheral blood leukocytes of gazelles (Gazella subgutturosa)

We examined gazelle peripheral blood leucocytes using the α-Naphthyl acetate esterase (ANAE) staining technique (pH 5.8). Our purpose was to determine the percentage of ANAE positive lymphocytes. The proportion of ANAE positive T-lymphocytes was 72%. T-lymphocytes showed an ANAE positive reaction, but eosinophilic granulocytes and monocytes also showed a positive reaction. By contrast, no reaction was detected in B-lymphocytes, neutrophil granulocytes or platelets. The reaction observed in T-lymphocytes was a red-brown coloration, usually 1–2 granules, but enough granules to fill the cytoplasm were detected rarely. As a result of ANAE enzyme staining, we concluded that the staining technique can be used as a cytochemical marker for gazelle T-lymphocytes.     

Development of neutralizing scFv-Fc against botulinum neurotoxin A light chain from a macaque immune library

Botulinum toxins (BoNTs) are among the most toxic substances on earth, with serotype A toxin being the most toxic substance known. They are responsible for human botulism, a disease characterized by flaccid muscle paralysis that occurs naturally through food poisoning or the colonization of the gastrointestinal tract by BoNT-producing clostridia. BoNT has been classified as a category A agent by the Centers for Disease Control, and it is one of six agents with the highest potential risk of use as bioweapons. Human or human-like neutralizing antibodies are thus required for the development of anti-botulinum toxin drugs to deal with this possibility. In this study, Macaca fascicularis was hyperimmunized with a recombinant light chain of BoNT/A. An immune phage display library was constructed and, after multistep panning, several scFv with nanomolar affinities that inhibited the endopeptidase activity of BoNT/A1 in vitro as scFv-Fc, with a molar ratio (ab binding site:toxin) of up to 1:1, were isolated. The neutralization of BoNT/A-induced paralysis by the SEM120-IID5, SEM120-IIIC1 and SEM120-IIIC4 antibodies was demonstrated in mouse phrenic nerve-hemidiaphragm preparations with the holotoxin. The neutralization observed is the strongest ever measured in the phrenic nerve-hemidiaphragm assay for BoNT/A1 for a monoclonal antibody. Several scFv-Fc inhibiting the endopeptidase activity of botulinum neurotoxin A were isolated. For SEM120-IID5, SEM120-IIIC1, and SEM120-IIIC4, inhibitory effects in vitro and protection against the toxin ex vivo were observed. The human-like nature of these antibodies makes them promising lead candidates for further development of immunotherapeutics for this disease.     

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

Background and methods

Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.

Results

We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 10⁵ viral copies/ml in nasal lavage and 1.88 × 10⁵ viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.

Conclusion

HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely.     

Development of human antibody fragments using antibody phage display for the detection and diagnosis of Venezuelan equine encephalitis virus (VEEV)

Background  

Venezuelan equine encephalitis virus (VEEV) belongs to the Alphavirus group. Several species of this family are also pathogenic to humans and are recognized as potential agents of biological warfare and terrorism. The objective of this work was the generation of recombinant antibodies for the detection of VEEV after a potential bioterrorism assault or an natural outbreak of VEEV.