Anti‐PcrV Immunization for Pseudomonas aeruginosa Pneumonia in Cystic Fibrosis

Propagation of multidrug‐resistant Pseudomonas aeruginosa, which causes endemic nosocomial infections, has become a major concern in various parts of the world. In patients with cystic fibrosis, a major cause of death is respiratory tract infections with antibiotic‐resistant P. aeruginosa. This condition has prompted medical research aimed at developing effective prophylaxis and treatments that do not rely on conventional antimicrobial agents. The pathogenesis that results in cytotoxicity and mortality in immunocompromised patients infected with P. aeruginosa is associated with the type III secretion system of this bacterium. Clinical isolates that are cytotoxic and drug‐resistant are involved in acute exacerbation of chronic infectious diseases. The P. aeruginosa V‐antigen PcrV, a Yersinia V‐antigen LcrV homolog, is involved as an indispensable component in the translocational process of type III secretory (TTS) toxins. Vaccination against PcrV ensures survival of infection‐challenged mice and decreases lung inflammation and injury. Furthermore, anti‐PcrV IgG can inhibit translocation of TTS toxins. These observations support the hypothesis that anti‐PcrV strategies have the potential as nonantibiotic immune strategies for preventing aggravation of P. aeruginosa infections in patients with cystic fibrosis

Construction and Characteristics of a Recombinant Single- Chain Antibody Fragment against Bacterial Type III Secretion

Pseudomonas aeruginosa, a Gram-negative pathogen, causes life-threatening infections. Lung injury and the development of sepsis depend largely on expression of the virulence genes associated with the type III secretion system of this bacterium. The type III secretion system functions as a molecular syringe to deliver type III secretory toxins directly into the cytosol of eukaryotic cells and also acts to inhibit innate immune mechanisms, thereby preventing bacterial clearance. Antibodies against PcrV, the cap structure in the translocational needle of type III secretory apparatus of P. aeruginosa, block toxin translocation of the type III secretion system. We have been investigating the therapeutic use of a recombinant anti-PcrV single-chain antibody. In this chapter, as a preliminary step toward an antibody-based immunotherapy against bacterial infections, we summarize our experience of constructing a recombinant single-chain antibody (called scFv166), in which the heavy (VH) and light chain (VL) variable regions of the anti-PcrV monoclonal IgG are joined by a flexible peptide linker. The practical methodologies used to make recombinant scFv166 against a bacterial protein component are described in detail

Analysis of Pharmacokinetics in the Cochlea of the Inner Ear

Sawamura S., Ogata G., Asai K., et al. Analysis of Pharmacokinetics in the Cochlea of the Inner Ear. Frontiers in Pharmacology 12, 633505 (2021); https://doi.org/10.3389/fphar.2021.633505.Hearing loss affects >5% of the global population and therefore, has a great social and clinical impact. Sensorineural hearing loss, which can be caused by different factors, such as acoustic trauma, aging, and administration of certain classes of drugs, stems primarily from a dysfunction of the cochlea in the inner ear. Few therapeutic strategies against sensorineural hearing loss are available. To develop effective treatments for this disease, it is crucial to precisely determine the behavior of ototoxic and therapeutic agents in the microenvironment of the cochlea in live animals. Since the 1980s, a number of studies have addressed this issue by different methodologies. However, there is much less information on pharmacokinetics in the cochlea than that in other organs; the delay in ontological pharmacology is likely due to technical difficulties with accessing the cochlea, a tiny organ that is encased with a bony wall and has a fine and complicated internal structure. In this review, we not only summarize the observations and insights obtained in classic and recent studies on pharmacokinetics in the cochlea but also describe relevant analytical techniques, with their strengths, limitations, and prospects

Live imaging of apoptosis in a novel transgenic mouse highlights its role in neural tube closure

Imaging of caspase activation in living mouse embryos during development suggests that caspase-mediated cell removal facilitates neural tube closure in a temporally regulated manner