Production of monoclonal antibodies binding to the VP7 protein of African horse sickness virus.

Monoclonal antibodies (MAbs) against AHSV were produced by immunising BALB/c mice with AHSV serotype 9 and six clones able to recognize specifically the VP7-AHSV with a strong reactivity were selected. The specificity of the MAbs was assessed in i-ELISA against a commercial VP7-AHSV and in immunoblot against a home-made VP7-AHSV, expressed by a Baculovirus expression system; potential cross-reactions with related orbiviruses (Bluetongue virus and Epizootic Haemorrhagic Disease virus) were investigated as well. One of the six MAbs selected, MAb 7F11E14, was tested in direct immunofluorescence and reacted with all nine AHSV serotypes, but didn't cross-react with BTV and EHDV. MAb 7F11E14 was also used to develop a competitive ELISA and was able to detect AHSV antibodies in the sera of AHS infected animals.

Rapid Detection and Isolation of Escherichia coli O104:H4 from Milk Using Monoclonal Antibody-coated Magnetic Beads.

Monoclonal antibodies (MAbs) specific for the lipopolysaccharide (LPS) of Escherichia coli O104:H4 were produced by fusion of Sp2/O-Ag-14 mouse myeloma cells with spleen cells of Balb/c mice, immunized with heat-inactivated and sonicated E. coli O104:H4 bacterial cells. Four MAbs specific for the E. coli O104:H4 LPS (1E6G6, 1F4C9, 3G6G7, and 4G10D2) were characterized and evaluated for the use in a method for the detection of E. coli O104:H4 in milk samples that involves antibody conjugation to magnetic microbeads to reduce time and increase the efficiency of isolation. MAb 1E6G6 was selected and coupled to microbeads, then used for immuno-magnetic separation (IMS); the efficiency of the IMS method for E. coli O104:H4 isolation from milk was evaluated and compared to that of the EU RL VTEC conventional culture-based isolation procedure. Milk suspensions also containing other pathogenic bacteria that could potentially be found in milk (Campylobacter jejuni, Listeria monocytogenes, and Staphylococcus aureus) were also tested to evaluate the specificity of MAb-coated beads. Beads coated with MAb 1E6G6 showed a good ability to capture the E. coli O104:H4, even in milk samples contaminated with other bacteria, with a higher number of E. coli O104:H4 CFU reisolated in comparison with the official method (121 and 41 CFU, respectively, at 10(3) E. coli O104:H4 initial load; 19 and 6 CFU, respectively, at 10(2) E. coli O104:H4 initial load; 1 and 0 CFU, respectively, at 10(1) E. coli O104:H4 initial load). The specificity was 100%.

Effects of immune serum on macrophage cell cultures infected with Mycoplasma mycoides subsp. mycoides small colony: morphological analysis by scanning electron microscopy.

Macrophages are pivotal cells of the immune system and play a key role in the host defence mechanism against pathogens. To date, the importance of macrophages and the role of humoral response in eliciting macrophage activity against Mycoplasma mycoides subsp. mycoides small colony (Mmm-SC), the causative agent of contagious bovine pleuropneumonia (CBPP), have only been marginally elucidated or are almost unknown. The present study was undertaken to investigate the changes in surface morphology of macrophages after in vitro infection with Mmm-SC in the presence of bovine immune serum. Morphological analysis was performed on macrophage cultures at 6 h post infection using the three-dimensional vision of scanning electron microscopy. Non-infected macrophages in the presence of negative or immune serum and macro phages infected with Mmm-SC in the absence of serum showed only minor cell surface changes. In contrast, clear surface modifications, broad veils, fine philopodia highlighting cell activation and small aggregates of mycoplasma closely attached to the macrophage membrane, were observed in infected macrophage cultures in the presence of immune serum. Our results suggest that specific humoral response to Mmm-SC may contribute and support phagocytic activity of macrophages.