Neutrophil Bactericidal Function Research Articles

Prenylcysteine oxidase 1 like protein is required for neutrophil bactericidal activities

The bactericidal function of neutrophils is dependent on a myriad of intrinsic and extrinsic stimuli. Using systems immunology approaches we identify microbiome- and infection-induced changes in neutrophils. We focus on investigating the Prenylcysteine oxidase 1 like (Pcyox1l) protein function. Murine and human Pcyox1l proteins share ninety four percent aminoacid homology revealing significant evolutionary conservation and implicating Pcyox1l in mediating important biological functions. Here we show that the loss of Pcyox1l protein results in significant reductions in the mevalonate pathway impacting autophagy and cellular viability under homeostatic conditions. Concurrently, Pcyox1l CRISPRed-out neutrophils exhibit deficient bactericidal properties. Pcyox1l knock-out mice demonstrate significant susceptibility to infection with the gram-negative pathogen Psuedomonas aeruginosa exemplified through increased neutrophil infiltrates, hemorrhaging, and reduced bactericidal functionality. Cumulatively, we ascribe a function to Pcyox1l protein in modulation of the prenylation pathway and suggest connections beween metabolic responses and neutrophil functionality.

Features of the development of the mucosal immune system of the upper respiratory tract in ferrous metallurgy workers

Introduction. The exposure to industrial aerosols triggers the response of the adaptive and innate mucosal immunity in the upper airways. Objective: To analyze the impact of work-related risk factors on the development of local mucosal immunity in workers engaged in extraction of vanadium-bearing iron ore, and cast iron and steel production. Materials and methods. We examined one thousand five hundred forty seven male workers of two mining and metallurgical industries. The first cohort included 788 vanadium-bearing iron ore miners and the second cohort comprised 719 cast iron and steel production workers, both standardized by age and years of employment. Occupational risk factors identified in both cohorts included the exposure to fibrous aerosols and aliphatic hydrocarbons, and poor microclimate (high or low air temperature) at workplaces. The workers of the second cohort were also exposed to manganese compounds, vanadium (V) oxide, chromium, nickel, and iron compounds. The control group consisted of 40 engineering and technical personnel. Results. A significant increase in secretory immunoglobulin A (sIgA) was detected in the miners exposed to aliphatic hydrocarbons and low air temperature. In the ferrous metallurgy workers, the exposure to low air temperature, crystalline silicon, and aliphatic hydrocarbons caused a significant decrease in the level of sIgA while the exposure to manganese oxides induced a decrease in the bactericidal function of neutrophils. Limitations. The main limitations of the research were related to the selected criterion of inclusion in the merged occupational cohorts with account for exposure to adverse microclimate parameters, silicon-containing aerosols, aliphatic hydrocarbons, and manganese compounds. In view of the multiplicity of occupational risk factors in the industry, it is important to conduct additional studies of a larger sample for qualitative and quantitative presentation of convincing evidence of health effects of other factors of the work environment. Conclusions: We established a multidirectional response of the mucosal immunity to production factors in the examined workers. A combined exposure to chemical and physical occupational factors has a stronger health effect than a single one. Differences in the level of sIgA in workers exposed to different occupational hazards prove the advisability of an in-depth immunological examination combined with an assessment of the functional status as indicators of occupational adaptation.

Нейроендокринно-імунний супровід діуретичного ефекту бальнеотерапії на курорті Трускавець

Мета: виявити супутні зміни параметрів нейроендокринно-імунного комплексу і мікробіоценозу товстого кишечника, що супроводжують діуретичний ефект бальнеотерапії на курорті Трускавець. Результати. У спостереженні за 22 чоловіками, хворими на хронічний пієлонефрит в поєднанні з холециститом, виявлено, що 10–12-денний курс бальнеотерапії (пиття біоактивної води «Нафтуся», аплікації озокериту, мінеральні ванни) збільшує добовий діурез на 28 % (p < 0,001). Це поєднується із збільшенням екскреції фосфатів на 103 % (p < 0,001), кальцію — на 76 % (p < 0,01), креатиніну — на 32 % (p < 0,02), сечової кислоти — на 29 % (p < 0,001), сечовини — на 21 % (p < 0,01), магнію — на 19 % (p = 0,05) при відсутності суттєвих змін екскреції хлориду, калію і натрію. При цьому знижується рівень у плазмі креатиніну на 14 % (p < 0,001) і сечовини на 11 % (p < 0,01). Лейкоцитурія зменшується на 16 % (p < 0,02). Екскреторно-депураційний і протизапальний ефекти бальнеотерапії супроводжуються відчутною модуляцією параметрів нейроендокринно-імунного комплексу. Зокрема, зменшується як абсолютна, так і відносна щільність спектральної потужності (PSD) δ- і α-ритмів (p < 0,05–0,01), і підвищується відносна PSD β-ритму (p < 0,05–0,02) базальної електроенцефалограми. Разом з тим знижуються індекси варіабельності ритму серця: (VLF + LF)/HF — на 34 % (p < 0,05) і LF/HF — на 32 % (p > 0,05) за рахунок підвищення PSD HF більшою мірою, ніж LF. Базальний рівень у плазмі кортизолу знижується на 20 % (p < 0,01), тестостерону — на 15 % (p = 0,01), натомість підвищується рівень трийодтироніну — на 4 % (p < 0,05) і особливо кальцитонінової активності — на 92 % (p < 0,001), розрахованої за екскрецією з сечею фосфатів і кальцію. Лейкоцитарний індекс адаптації Поповича зростає на 46 % (p < 0,02). Стосовно параметрів фагоцитарної функції нейтрофілів констатовано підвищення зниженого індексу кілінгу ними Staphylococcus aureus на 19 % (p < 0,001) і Escherichia coli на 18 % (p < 0,01) за відсутності змін початково нормальних фагоцитарних індексів. Мікробне число стосовно Staphylococcus aureus залишається нормальним, а початково підвищена на 15 % інтенсивність фагоцитозу Escherichia coli знижується на 8 % (p < 0,05). Стосовно параметрів імунітету виявлено значуще підвищення рівня в крові лише CD16+ лімфоцитів (+17 %, p < 0,01) при відсутності змін рівнів CD3+CD4+ і CD3+CD8+ Т-лімфоцитів і CD19+ В-лімфоцитів. Не змінюються суттєво ні рівні в сироватці Ig G, M, A, ні циркулюючих імунних комплексів. Імунотропний ефект супроводжується редукцією проявів дисбактеріозу: вміст Bifidumbacter зростає на 19 % (p < 0,02), Lactobacter — на 20 % (p < 0,05), а Escherichia coli — на 48 % (p < 0,01), при цьому доля штамів з ослабленими ферментативними властивостями зменшується на 47 % (p < 0,001), з гемолітичними властивостями — на 77 % (p < 0,01). Висновок. Бальнеотерапія на курорті Трускавець чинить відчутний діуретичний ефект, що поєднується з активацією екскреторної і депураційної функцій нирок та бактерицидної функції нейтрофілів, редукцією дисбактеріозу товстого кишечника, лейкоцитурії і нейроендокринних проявів стресу.

Human Placental MSC-Secreted IL-1β Enhances Neutrophil Bactericidal Functions during Hypervirulent Klebsiella Infection

Hypervirulent Klebsiella pneumoniae (hvKP) causes severe infections even in healthy individuals by escaping surveillance and killing from polymorphonuclear neutrophils (PMNs), the first-line leukocytes in bacterial infections; moreover, the emergence of multidrug-resistant strains further limits treatment options. We therefore assess whether multilineage mesenchymal stem cells (MSCs), best known for immunomodulation toward Tcells, could be therapeutic for highly virulent bacterial infections via modulation of PMNs. We find that both bone marrow MSCs and placental MSCs (PMSCs) preserve invitro PMN survival, but only PMSCs significantly enhance multiple PMN bactericidal functions, including phagocytosis, through secretion of interleukin-1β (IL-1β). PMSC treatment of hvKP-infected mice suppresses T and natural killer (NK) cell responses as expected but can preferentially recruit PMNs and enhance antibacterial functions to allow for disease survival; IL-1β knockdown in PMSCs significantly decreases hvKP clearance, worsening survival and resulting in 100% lethality. Our data strongly implicate the possible use of PMSCs for infections of PMN-resistant hvKP strains.

Serum amyloid A3 confers protection against acute lung injury in Pseudomonas aeruginosa-infected mice.

Pseudomonas aeruginosa is a gram-negative bacterium associated with serious illnesses, including ventilator-associated pneumonia and various sepsis syndromes in humans. Understanding the host immune mechanisms against P. aeruginosa is, therefore, of clinical importance. The present study identified serum amyloid A3 (SAA3) as being highly inducible in mouse bronchial epithelium following P. aeruginosa infection. Genetic deletion of Saa3 rendered mice more susceptible to P. aeruginosa infection with decreased neutrophil superoxide anion production, and ex vivo treatment of mouse neutrophils with recombinant SAA3 restored the ability of neutrophils to produce superoxide anions. The SAA3-deficient mice showed exacerbated inflammatory responses, which was characterized by pronounced neutrophil infiltration, elevated expression of TNF-α, KC/CXCL1, and MIP-2/CXCL2 in bronchoalveolar lavage fluid (BALF), and increased lung microvascular permeability compared with their wild-type littermates. BALF neutrophils from Saa3 knockout mice exhibited reduced superoxide anion production compared with neutrophils from wild-type mice. Adoptive transfer of SAA3-treated neutrophils to Saa3 knockout mice ameliorated P. aeruginosa-induced acute lung injury. These findings demonstrate that SAA3 not only serves as a biomarker for infection and inflammation, but also plays a protective role against P. aeruginosa infection-induced lung injury in part through augmentation of neutrophil bactericidal functions.

The Impact of Hypoxia on the Host-Pathogen Interaction between Neutrophils and Staphylococcus aureus.

Neutrophils are key to host defence, and impaired neutrophil function predisposes to infection with an array of pathogens, with Staphylococcus aureus a common and sometimes life-threatening problem in this setting. Both infiltrating immune cells and replicating bacteria consume oxygen, contributing to the profound tissue hypoxia that characterises sites of infection. Hypoxia in turn has a dramatic effect on both neutrophil bactericidal function and the properties of S. aureus, including the production of virulence factors. Hypoxia thereby shapes the host–pathogen interaction and the progression of infection, for example promoting intracellular bacterial persistence, enabling local tissue destruction with the formation of an encaging abscess capsule, and facilitating the establishment and propagation of bacterial biofilms which block the access of host immune cells. Elucidating the molecular mechanisms underlying host–pathogen interactions in the setting of hypoxia will enable better understanding of persistent and recalcitrant infections due to S. aureus and may uncover novel therapeutic targets and strategies.

English

Nitroblue Tetrazolium Test Is One Of The Simplest And Cost-Effective Methods In The Assessment Of Neutrophil Bactericidal Function. This Has Also Been Used As A Method Of Early Diagnosis In Bacterial Infection. Neutrophilic Leucocytosis Is Considered As An Indirect Evidence Of Acute Inflammation And Acute Infections Though It Is Seen In Several Other Conditions. To Combat Any Infectious Process, Apart From The Rise In Leucocyte Counts, A Normal Neutrophil Function Is Also Essential. Patients With A Neutrophilic Response On Exposure To Infectious Agents Need Not Necessarily Possess Normal Neutrophil Functions Like Chemotaxis, Phagocytosis, Killing And Degradation. Diabetes Mellitus Is A Common Disease In Which Neutrophil Functions Are Altered 1,2,3 A Battery Of Tests Are Available To Assess Neutrophil Functions Which Include NBT Test, Flow Cytometry, Spectrophotometric Assays, Chemotaxis Assays, Superoxide Assays And Immunoblotting4 Which Though Accurate Require Expertise And Monetary Consideration While The NBT Test Is Inexpensive And Technically Less Demanding . This Prospective Study Focuses On The Utility Of NBT Test To Study Neutrophil Function In Diabetics And To Reiterate Its Role As A Supplement In The Diagnosis Of Bacterial Infections.

Frontline Science: Employing enzymatic treatment options for management of ocular biofilm-based infections.

Pseudomonas aeruginosa‐induced corneal keratitis is a sight‐threatening disease. The rise of antibiotic resistance among P. aeruginosa keratitis isolates makes treatment of this disease challenging, emphasizing the need for alternative therapeutic modalities. By comparing the responses to P. aeruginosa infection between an outbred mouse strain (Swiss Webster, SW) and a susceptible mouse strain (C57BL6/N), we found that the inherent neutrophil‐killing abilities of these strains correlated with their susceptibility to infection. Namely, SW‐derived neutrophils were significantly more efficient at killing P. aeruginosa in vitro than C57BL6/N‐derived neutrophils. To interrogate whether the distinct neutrophil killing capacities were dependent on endogenous or exogenous factors, neutrophil progenitor cell lines were generated. The in vitro differentiated neutrophils from either SW or C57BL6/N progenitors retained the differential killing abilities, illustrating that endogenous factors conferred resistance. Consistently, quantitative LC‐MS/MS analysis revealed strain‐specific and infection‐induced alterations of neutrophil proteomes. Among the distinctly elevated proteins in the SW‐derived proteomes were α‐mannosidases, potentially associated with protection. Inhibition of α‐mannosidases reduced neutrophil bactericidal functions in vitro. Conversely, topical application of α‐mannosidases reduced bacterial biofilms and burden of infected corneas. Cumulatively, these data suggest novel therapeutic approaches to control bacterial biofilm assembly and improve bacterial clearance via enzymatic treatments.

Efficacy and clinical safety of pegbovigrastim for preventing naturally occurring clinical mastitis in periparturient primiparous and multiparous cows on US commercial dairies.

Periparturient dairy cows experience impaired immune function, exhibited as a transient decrease in neutrophil function. This decrease in immune competence is associated with an increase in susceptibility to bacterial infections, including mastitis and metritis. Bovine granulocyte colony stimulating factor (bG-CSF) is an endogenous protein that enhances neutrophil bactericidal functions and increases the production of neutrophils from bone marrow precursors. Administration of pegbovigrastim (recombinant bG-CSF covalently bound to polyethylene glycol) around the time of calving has been shown to reduce the incidence of new clinical mastitis cases in a natural disease model system. To further explore the application of pegbovigrastim under herd management systems typical of those found in the US dairy industry, we conducted a multicenter field study to evaluate the efficacy and clinical safety of pegbovigrastim administered to multiparous cows and heifers approximately 7 d before calving and within 24 h of calving. Responses of treated cows were compared with those of animals treated with sterile saline. Animals treated with pegbovigrastim exhibited 4- to 5-fold increases in circulating neutrophil numbers within 24 h of treatment initiation, and this increase persisted at least a week beyond the second dose. Pegbovigrastim-treated animals exhibited a 35% decrease in the incidence of clinical mastitis relative to the controls during the first 30 d of lactation. Animals treated with pegbovigrastim also exhibited a 52% reduction in failure to return to visual estrus within 80 d of calving. We observed no differences in somatic cell count or milk composition between treated and control animals. We also found no differences in the duration of pregnancy or proportion of viable calves in treated cows relative to control animals. These results indicate that administration of pegbovigrastim provides a well-tolerated, novel approach to overcoming periparturient immune suppression, resulting in reduced susceptibility to clinical mastitis during early lactation.

Bordetella parapertussis Circumvents Neutrophil Extracellular Bactericidal Mechanisms.

B. parapertussis is a whooping cough etiological agent with the ability to evade the immune response induced by pertussis vaccines. We previously demonstrated that in the absence of opsonic antibodies B. parapertussis hampers phagocytosis by neutrophils and macrophages and, when phagocytosed, blocks intracellular killing by interfering with phagolysosomal fusion. But neutrophils can kill and/or immobilize extracellular bacteria through non-phagocytic mechanisms such as degranulation and neutrophil extracellular traps (NETs). In this study we demonstrated that B. parapertussis also has the ability to circumvent these two neutrophil extracellular bactericidal activities. The lack of neutrophil degranulation was found dependent on the O antigen that targets the bacteria to cell lipid rafts, eventually avoiding the fusion of nascent phagosomes with specific and azurophilic granules. IgG opsonization overcame this inhibition of neutrophil degranulation. We further observed that B. parapertussis did not induce NETs release in resting neutrophils and inhibited NETs formation in response to phorbol myristate acetate (PMA) stimulation by a mechanism dependent on adenylate cyclase toxin (CyaA)-mediated inhibition of reactive oxygen species (ROS) generation. Thus, B. parapertussis modulates neutrophil bactericidal activity through two different mechanisms, one related to the lack of proper NETs-inducer stimuli and the other one related to an active inhibitory mechanism. Together with previous results these data suggest that B. parapertussis has the ability to subvert the main neutrophil bactericidal functions, inhibiting efficient clearance in non-immune hosts.

Toll-Like Receptor 4 Agonistic Antibody Promotes Host Defense against Chronic Pseudomonas aeruginosa Lung Infection in Mice.

Chronic lower respiratory tract infection with Pseudomonas aeruginosa is difficult to treat due to enhanced antibiotic resistance and decreased efficacy of drug delivery to destroyed lung tissue. To determine the potential for restorative immunomodulation therapies, we evaluated the effect of Toll-like receptor 4 (TLR4) stimulation on the host immune response to Pseudomonas infection in mice. We implanted sterile plastic tubes precoated with P. aeruginosa in the bronchi of mice, administered the TLR4/MD2 agonistic monoclonal antibody UT12 intraperitoneally every week, and subsequently analyzed the numbers of viable bacteria and inflammatory cells and the levels of cytokines. We also performed flow cytometry-based phagocytosis and opsonophagocytic killing assays in vitro using UT12-treated murine peritoneal neutrophils. UT12-treated mice showed significantly enhanced bacterial clearance, increased numbers of Ly6G(+) neutrophils, and increased concentrations of macrophage inflammatory protein 2 (MIP-2) in the lungs (P < 0.05). Depletion of CD4(+) T cells eliminated the ability of the UT12 treatment to improve bacterial clearance and promote neutrophil recruitment and MIP-2 production. Additionally, UT12-pretreated peritoneal neutrophils exhibited increased opsonophagocytic killing activity via activation of the serine protease pathway, specifically neutrophil elastase activity, in a TLR4-dependent manner. These data indicated that UT12 administration significantly augmented the innate immune response against chronic bacterial infection, in part by promoting neutrophil recruitment and bactericidal function.

Protein Energy Malnutrition and Susceptibility to Viral Infections as Zika and Influenza Viruses

Infection and malnutrition have constantly been intricately related. Malnutrition is the primary motive of immunodeficiency worldwide, and we're getting to know more and more about the pathogenesis of this interaction. Malnutrition is the main cause of immunodeficiency international, with infants, children, youth, and the aged most affected. There is a strong courting between malnutrition, contamination and mortality, due to the fact bad nutrients leading to kids underweight, weakened, and susceptible to infections, mainly considering that of epithelial integrity and irritation. The most consistent changes in immune competence in protein energy malnutrition are in cellmediated immunity, the bactericidal function of neutrophils, the complement system, the secretory immunoglobins A, and antibody response. This direct relationship between malnutrition and immunodeficiency reflected on susceptibility to infection by influenza and Zika viruses.

Neuroendocrine-immune and metabolic accompaniments of cholecystokinetic effects of balneotherapy on SPA Truskavets’

Marfiyan O M, Korolyshyn T A, Barylyak L G, Kovbasnyuk M M, Yavors’kyi O V, Zukow W, Popovych I L . Neuroendocrine-immune and metabolic accompaniments of cholecystokinetic effects of balneotherapy on SPA Truskavets’ . Journal of Education, Health and Sport. 2015;5(5):21-30. ISSN 2391-8306. DOI: 10.5281/zenodo.17307 http://ojs.ukw.edu.pl/index.php/johs/article/view/2015%3B5%285%29%3A21-30 https://pbn.nauka.gov.pl/works/556532 http://dx.doi.org/10.5281/zenodo.17307 Formerly Journal of Health Sciences. ISSN 1429-9623 / 2300-665X. Archives 2011 – 2014 http://journal.rsw.edu.pl/index.php/JHS/issue/archive Deklaracja. Specyfika i zawartośc merytoryczna czasopisma nie ulega zmianie. Zgodnie z informacją MNiSW z dnia 2 czerwca 2014 r., ze w roku 2014 nie bedzie przeprowadzana ocena czasopism naukowych; czasopismo o zmienionym tytule otrzymuje tyle samo punktow co na wykazie czasopism naukowych z dnia 31 grudnia 2014 r. The journal has had 5 points in Ministry of Science and Higher Education of Poland parametric evaluation. Part B item 1089. (31.12.2014). © The Author (s) 2015; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland and Radom University in Radom, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 15.02.2015. Revised 27.03.2015. Accepted: 15.04.2015. NEUROENDOCRINE-IMMUNE AND METABOLIC ACCOMPANIMENTS OF CHOLECYSTOKINETIC EFFECTS OF BALNEOTHERAPY ON SPA TRUSKAVETS’ O M Marfiyan 1,2 , T A Korolyshyn 3 , L G Barylyak 1,3 , M M Kovbasnyuk 1,3 , O V Yavors’kyi 1 , W Zukow 4 , I L Popovych 1,3 1 JSC “Truskavets’kurort”, Truskavets’, Ukraine olenka80@meta.ua 2 Department of Pediatry, OO Bohomolets’ National Medical University, Kyiv, Ukraine 3 Laboratory of Balneology, OO Bohomolets’ Institute of Physiology, Truskavets’-Kyiv, Ukraine i.popovych@ukr.net 4 Faculty of Physical Education, Health and Tourism, Kazimierz Wielki University, Bydgoszcz, Poland w.zukow@ukw.edu.pl SUMMARY Objective. Ability balneofactors spa Truskavets’ (Ukraine), including bioactive water Naftussya, affect Gall-bladder motility has long been known. We set a goal to identify changes related neuroendocrine-immune complex and metabolism accompanying cholecystokinetic effect of balneotherapy on spa. Results. In observation of 22 men with chronic cholecystitis in combination with pyelonephritis, found that 10-12-day course of balneotherapy (drinking of bioactive water Naftussya, application of ozokerite, mineral baths) reduces Gall-bladder volume fasting by 16% (p 0,05), by increasing PSD HF greater extent than LF. The basal levels of plasma cortisol decreased by 20% (p 0,2) and 8% (p<0,05) respectively. Regarding immunity parameters revealed significant increase in blood CD16 + lymphocytes only (+17%, p<0,01) in the absence of changes in levels of CD3 + CD4 + and CD3 + CD8 + T cells and CD19 + B lymphocytes. Do not change significantly either serum Igg G, M, A, or circulating immune complexes. Finally, stated a slight but significant increase electrokinetic index cell nuclei of buccal epithelium, indicating the rejuvenation of the body. Conclusion : balneotherapy on spa Truskavets’ be significantly cholecystokinetic effect, combined with the activation excretory and depurative kidney functions and neutrophil bactericidal function against a background of lower levels of neuroendocrine markers of stress. Keywords: Truskavets’, balneotherapy, cholekinetic, diuresis, neuroendocrine-immune complex.

EFFECTS OF PROTEIN-ENERGY MALNUTRITION ON THE IMMUNE SYSTEM

Protein-Energy Malnutrition (PEM) is believed to lead to an increased susceptibility to infection, or cause impaired immunity. Infection, occurring with malnutrition, is a major cause of morbidity in all age groups and is responsible for two-thirds of all death under 5 yr of age in developing countries. Many cells of the immune system are known to depend for their function on metabolic pathways that employ various nutrients as critical factors. The most consistent changes in immune competence in PEM are in cell-mediated immunity, the bactericidal function of neutrophils, the complement system, the secretory immunoglobin A, and antibody response. Keywords: protein-energy malnutrition, immune system, cell mediated immunity, amino acid deficiency, antibody responses Introduction

Altered Human Neutrophil Function in Response to Acute Psychological Stress

To examine the effects of an acute laboratory psychological stress task on neutrophil function, specifically phagocytosis of Escherichia coli and stimulated superoxide production in human neutrophils. There is mounting evidence that acute stress is associated with short-term increases in a number of immune indices. Participants were 40 (n = 20 females) university students (mean age, 25.9 ± 4.56 years). Blood samples to determine neutrophil function by flow cytometry were taken at the end of resting baseline, during an acute stress task, and during recovery. The stress task was a 10-minute time-pressured mental arithmetic challenge with social evaluation. There was an acute increase in phagocytic ability, p = .047, η(2)p = 0.076, and a reduction of superoxide production, p = .026, η(2)p = 0.101, associated with the stress task relative to baseline. These findings suggest that neutrophil bactericidal function may be sensitive to mental challenge tasks that provoke acute psychological stress. Further research is needed to replicate the observed psychological stress-induced changes in neutrophil function.

Taurine modulates neutrophil function but potentiates uropathogenic E. coli infection in the murine bladder

Eradication of a urinary tract infection (UTI) appears to be related to a number of innate host defence mechanisms and their interactions with invading bacteria. Recurrent UTIs (rUTIs) pose a difficult problem in that these bacteria use both host and bacterial factors to evade elimination. Neutrophil bactericidal function is depressed, both systemically and in urine, in patients with a history of recurrent UTI. Taurine is a semi-essential amino acid and is successful in preserving neutrophil bactericidal function in urine. Taurine may preserve neutrophil function at the urothelium and thus aid UTI resolution. Adult female (6 weeks old) C57Bl/6 mice were randomised into three groups: a saline gavage only control group, a saline gavage + E. coli group, and a taurine gavage + E. coli group [21 g/70 kg taurine in 0.9% normal saline (N/S) for 5 days]. Whilst taurine gavage pre-treatment resulted in increased serum neutrophils respiratory burst activity, at the urothelial-endothelial interface it caused higher colony forming units in the urine and a higher incidence of E. coli invasion in the bladder wall with no evidence of increased bladder wall neutrophils infiltration on MPO assay of histological assessment. Histologically there was also evidence of reduced bladder inflammation and urothelial cell apoptosis. In conclusion, taurine effectively increases neutrophils activity but given its anti-inflammatory properties, at the expense of decreased urothelial-endothelial activation thus preventing clearance of active E. coli infection in the bladder. Despite the negative results, this study demonstrates the importance of modulating interactions at the urothelial interface.

Effect of 2‐hydroxyethyl‐methacrylate (HEMA) on the phagocytic and respiratory burst activity of human neutrophils and monocytes

Neutrophils and monocytes/macrophages (MØ), found in oral mucosa and gingival sulcus, phagocytose and kill bacteria using products produced during a respiratory burst. 2-Hydroxyethyl-methacrylate (HEMA) is a major component released from resin glass ionomer and dental adhesives. Hence, in pulp and gingiva, phagocytes can come into contact with unpolymerized HEMA monomers. The aim of this study was to examine the effects of exposure to HEMA on neutrophil and monocyte bactericidal function. Blood collected from five female volunteers was exposed in vitro to HEMA for 2 h and then phagocytosis, respiratory burst, and cellular integrity were measured using flow cytometry. Respiratory burst was quantified by measuring fluorescent rhodamine 123 generated via oxidation of dihydrorhodamine 123. Cellular membrane integrity was evaluated by staining with propidium iodide. The respiratory burst activity of the neutrophils was significantly decreased by exposure to 7.5 and 15 mM HEMA. No significant effect of HEMA was seen on the number of granulocytes or monocytes capable of performing respiratory burst. Furthermore, there was no significant effect of HEMA on the phagocytic activity of the monocytes or the granulocytes. In conclusion, HEMA did not affect the phagocytosis activity of neutrophils; however, the ability of the cells to kill internalized prey was significantly reduced.

Neutrophil bactericidal function is defective in patients with recurrent urinary tract infections.

Urinary tract infection (UTI), most frequently caused by Escherichia coli, is one of the most common bacterial infections in humans. It is a host inflammatory response to bacterial invasion in which large numbers of neutrophils are recruited into the bladder in response to cytokines secreted by the infected bladder epithelium. We hypothesise that an impaired host neutrophil response leads to susceptibility to recurrent UTI (rUTI). Therefore, the neutrophil inflammatory response of patients with a history of rUTI was compared to healthy controls. No difference in neutrophil adhesion receptor expression or complement receptor expression following bacterial stimulus was detected between the two groups. However, the expression of the IgG receptor CD16, bacterial phagocytosis and reactive oxygen intermediate (ROI) production were significantly reduced in UTI patient neutrophils compared to controls. Neutrophils from rUTI patients have a significantly reduced bactericidal function when compared to healthy controls, with the former showing a reduced capacity for activation. This reduced neutrophil function may result in defective bacterial clearance and lead to susceptibility to recurrent infection.

Galectin-8 modulates neutrophil function via interaction with integrin alphaM.

The members of the galectin family are associated with diverse cellular events, including immune response. We investigated the effects of galectin-8 on neutrophil function. Human galectin-8 induced firm and reversible adhesion of peripheral blood neutrophils but not eosinophils to a plastic surface in a lactose-sensitive manner. Other human galectins, galectins-1, -3, and -9, showed low or negligible effects on neutrophil adhesion. Confocal microscopy revealed actin bundle formation in the presence of galectin-8. Cytochalasins inhibited both actin assembly and cell adhesion induced by galectin-8. Affinity purification of galectin-interacting proteins from solubilized neutrophil membrane revealed that N-terminal carbohydrate recognition domain (CRD) of galectin-8 bound promatrix metalloproteinase-9 (proMMP-9), and C-terminal CRD bound integrin alphaM/CD11b and proMMP-9. A mutant galectin-8 lacking the carbohydrate-binding activity of N-terminal CRD (galectin-8R69H) retained adhesion-inducing activity, but inactivation of C-terminal CRD (galectin-8R233H) abolished the activity. MMP-3-mediated processing of proMMP-9 was accelerated by galectin-8, and this effect was inhibited by lactose. Galectins-1 and -3 did not affect the processing. Superoxide production, an essential event in bactericidal function of neutrophils, was stimulated by galectin-8 to an extent comparable to that induced by fMLP. Galectin-8R69H but not galectin-8R233H could stimulate superoxide production. Taken together, these results suggest that galectin-8 is a novel factor that modulates the neutrophil function related to transendothelial migration and microbial killing.

G-CSF and GM-CSF for treating or preventing neonatal infections.

The colony stimulating factors (CSFs), granulocyte-macrophage colony stimulating factor (GM-CSF) and granulocyte colony stimulating factor (G-CSF), are naturally occurring cytokines that stimulate the production and antibacterial function of neutrophils and monocytes. Two strategies have been adopted for exploring whether CSFs can provide clinical benefit for preterm infants. The first has investigated their use as a treatment to improve outcome in established systemic infection, especially when complicated by a low neutrophil count. The alternative strategy has been to use CSFs prophylactically, to prevent sepsis prospectively through stimulation of neutrophil production and bactericidal function. To determine the efficacy and safety of the haemopoietic colony stimulating factors (G-CSF or GM-CSF) in newborn infants, when used for:a) treatment of suspected or proven systemic infection to reduce mortality, orb) prophylaxis, to prevent systemic infection in infants at high risk of nosocomial infection. To determine, in subgroup analysis, the influence of pre-existing or high risk of neutropenia on the outcome of therapy. PubMed, EMBASE, MEDLINE and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2003) were searched in April 2003 using the keywords: G-CSF, GM-CSF, infant newborn, with and without the limit Clinical Trial. In addition, reference lists of identified RCTs, meta-analyses and personal files were searched. The criteria used to select studies for inclusion were: RCT. Newborn infants in intensive care. G-CSF or GM-CSF given as treatment in conjunction with antibiotics for suspected or microbiologically proven systemic infection. G-CSF or GM-CSF given as prophylaxis with the aim of reducing the incidence of systemic infection. Treatment studies reporting all cause mortality. Prophylaxis studies reporting subsequent incidence of sepsis and / or mortality. Relative risks (RR) and risk differences (RD) with 95% confidence intervals (CI) using the fixed effect model are reported. Number needed to treat (NNT) was calculated for the outcomes that showed a statistically significant reduction in RR. Seven treatment studies of 257 infants with suspected systemic bacterial infection and three prophylaxis studies comprising 359 neonates are analysed. Treatment studies: There is no evidence that the addition of G-CSF or GM-CSF to antibiotic therapy in preterm infants with suspected systemic infection reduces immediate all cause mortality. No significant survival advantage was seen at 14 days from the start of therapy [typical RR 0.71 (95% CI 0.38,1.33); typical RD -0.05 (95% CI -0.14, 0.04)]. However all seven of the treatment studies were small, the largest recruiting only 60 infants. The subgroup analysis of 97 infants from three treatment studies who, in addition to systemic infection, had clinically significant neutropenia (< 1.7 x 10(9)/l) at trial entry, does show a significant reduction in mortality by day 14 [RR 0.34 (95% CI 0.12, 0.92); RD -0.18 (95% CI -0.33, -0.03); NNT 6 (95% CI 3-33)]. Prophylaxis studies have not demonstrated a significant reduction in mortality in neonates receiving GM-CSF [RR 0.59 (95% CI 0.24,1.44); RD -0.03 (95% CI -0.08,0.02)]. The identification of sepsis as the primary outcome of prophylaxis studies has been hampered by inadequately stringent definitions of systemic infection. However, data from one study suggest that prophylactic GM-CSF may provide protection against infection when given to preterm infants who are neutropenic or at high risk of developing postnatal neutropenia. There is currently insufficient evidence to support the introduction of either G-CSF or GM-CSF into neonatal practice, either as treatment of established systemic infection to reduce resulting mortality, or as prophylaxis to prevent systemic infection in high risk neonates. No toxicity of CSF use was reported in any systemic infection to reduce resulting mortality, or as prophylaxis to prevent systemic infection in high risk neonates. No toxicity of CSF use was reported in any study included in this review. The limited data suggesting that CSF treatment may reduce mortality when systemic infection is accompanied by severe neutropenia should be investigated further in adequately powered trials which recruit sufficient infants infected with organisms associated with a significant mortality risk.