RESUMO
The purpose of this work was to obtain genus-specific monoclonal antibodies against the Legionella spp. recombinant PAL protein, which will subsequently allow to use them as a basis for the development of new express tests for pathogenic legionella detection. A short three-week immunization protocol for Wistar rats was used to generate rat-mouse heterohybridomas producing antibodies against PAL. Mouse myeloma cell line Sp2/0-Ag14 served as the fusion partner. Hybridization was performed using two methods: PEG-mediated fusion and electrofusion. Subsequent screening was performed by indirect solid-phase ELISA against the target protein rPAL. Specificity analysis was performed by dot-blot using a panel of lysates obtained from 39 pure cultures of different strains, which included closely related and heterologous microorganisms among others. No difference in the efficiency of stable hybridoma clones production by the two indicated cell-fusion methods was detected. Twelve clones producing specific rat monoclonal antibodies were obtained based on the screening results. The obtained rat monoclonal antibodies are highly specific towards the PAL protein of L. pneumophila of different serological groups and other pathogenic legionella and are good candidates to be used as the components of diagnostic test systems for the detection of pathogenic representatives of the Legionella genus.
RESUMO
Neutralization of the lethal toxin of Bacillus anthracis is an important topic of both fundamental medicine and practical health care, regarding the fight against highly dangerous infections. We have generated a neutralizing monoclonal antibody 1E10 against the lethal toxin of Bacillus anthracis and described the stages of receptor interaction between the protective antigen (PA) and the surface of eukaryotic cells, the formation of PA oligomers, assembly of the lethal toxin (LT), and its translocation by endocytosis into the eukaryotic cell, followed by the formation of a true pore and the release of LT into the cell cytosol. The antibody was shown to act selectively at the stage of interaction between Bacillus anthracis and the eukaryotic cell, and the mechanism of toxin-neutralizing activity of the 1E10 antibody was revealed. The interaction between the 1E10 monoclonal antibody and PA was found to lead to inhibition of the enzymatic activity of the lethal factor (LF), most likely due to a disruption of true pore formation by PA, which blocks the release of LF into the cytosol.
RESUMO
The evolution of the beam distribution in a double-rf system with a phase modulation on either the primary or secondary rf cavity was measured. We find that the particle diffusion process obeys the Einstein relation if the phase space becomes globally chaotic. When dominant parametric resonances still exist in the phase space, particles stream along the separatrices of the dominant resonance, and the beam width exhibits characteristic oscillatory structure. The particle-tracking simulations for the double-rf system are employed to reveal the essential diffusion mechanism. Coherent octupolar motion has been observed in the bunch beam excitation. The evolution of the longitudinal phase space in the octupole mode is displayed.
