Research Article The Effect of Bacteriophage Preparations on Intracellular Killing of Bacteria by Phagocytes Ewa JoNczyk-Matysiak, 1 Marzanna Ausiak-Szelachowska, 1 Marlena KBak, 1 Barbara Bubak, 1 Ryszard Miwdzybrodzki, 1,2,3 Beata Weber-Ddbrowska, 1,2 Maciej gaczek, 1 Wojciech Fortuna, 1,2 PaweB Rogóh, 2 SBawomir Letkiewicz, 2 Krzysztof Szufnarowski, 2 and Andrzej Górski 1,2,3 1 Bacteriophage Laboratory, Ludwik Hirszfeld Institute of Immunology and Experimental Terapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland 2 Phage Terapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Terapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland 3 Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw, Nowogrodzka 59, 02-006 Warsaw, Poland Correspondence should be addressed to Ewa Jo´ nczyk-Matysiak; ewa.jonczyk@iitd.pan.wroc.pl Received 6 July 2015; Revised 17 November 2015; Accepted 18 November 2015 Academic Editor: Peirong Jiao Copyright © 2015 Ewa Jo´ nczyk-Matysiak et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Intracellular killing of bacteria is one of the fundamental mechanisms against invading pathogens. Impaired intracellular killing of bacteria by phagocytes may be the reason of chronic infections and may be caused by antibiotics or substances that can be produced by some bacteria. Terefore, it was of great practical importance to examine whether phage preparations may infuence the process of phagocyte intracellular killing of bacteria. It may be important especially in the case of patients qualifed for experimental phage therapy (approximately half of the patients with chronic bacterial infections have their immunity impaired). Our analysis included 51 patients with chronic Gram-negative and Gram-positive bacterial infections treated with phage preparations at the Phage Terapy Unit in Wroclaw. Te aim of the study was to investigate the efect of experimental phage therapy on intracellular killing of bacteria by patients’ peripheral blood monocytes and polymorphonuclear neutrophils. We observed that phage therapy does not reduce patients’ phagocytes’ ability to kill bacteria, and it does not afect the activity of phagocytes in patients with initially reduced ability to kill bacteria intracellularly. Our results suggest that experimental phage therapy has no signifcant adverse efects on the bactericidal properties of phagocytes, which confrms the safety of the therapy. 1. Introduction Intracellular killing of bacteria (IKB) is one of the fundamen- tal defense mechanisms against invading pathogens. Phago- cytic cells (neutrophils, monocytes, tissue macrophages, and dendritic cells) are a component of innate immunity [1]. Tey are involved in nonspecifc defense of the body against external pathogens and substances produced by them, for example, toxins, which consists of antigen uptake and for- mation of a phagosome and then the destruction of the antigens there, due to the presence of degrading enzymes [2, 3]. High efectiveness in killing bacteria is achieved in neutrophils by combining the action of reactive oxygen species (ROS) and substances contained in the granules of these cells (proteins that mediate the antibacterial activity of phagocytes in anaerobic conditions) [4]. Innate immune defciencies, antibiotic therapy, and the development of strategies allowing bacteria to survive inside the phagocyte are possible causes of defects in the IKB, which is one of the key steps of phagocytosis [5]. Bacterial infections, including those caused by antibiotic-resistant bacterial strains, are a major cause of morbidity in patients Hindawi Publishing Corporation Journal of Immunology Research Volume 2015, Article ID 482863, 13 pages http://dx.doi.org/10.1155/2015/482863