Mechanisms of antibacterial action in the respiratory system

Chronic Ethanol Exposure: Pathogenesis of Pulmonary Disease and Dysfunction

Ethanol (EtOH) is the world’s most commonly used drug, and has been widely recognized as a risk factor for developing lung disorders. Chronic EtOH exposure affects all of the organ systems in the body and increases the risk of developing pulmonary diseases such as acute lung injury and pneumonia, while exacerbating the symptoms and resulting in increased mortality in many other lung disorders. EtOH and its metabolites inhibit the immune response of alveolar macrophages (AMs), increase airway leakage, produce damaging reactive oxygen species (ROS), and disrupt the balance of antioxidants/oxidants within the lungs. In this article, we review the role of EtOH exposure in the pathogenesis and progression of pulmonary disease.

Möglichkeiten der Vakzinierung mit inaktiviertem Virus über den Respirationstrakt untersucht am System Aujeszky-Virus - weiße Maus1

Zusammenfassung

Mit einer Äthyläthylenimin‐inaktivierten und konzentrierten Aujeszky‐Virusvakzine wurden Mäuse i. m., i. n. und per Aerosol vakziniert. Mit allen drei Verabreichungsformen wurde eine unterschiedliche Immunität erzielt. Der Grad der induzierten Immunität und ihre Bestimmung waren abhängig von der Art der Applikation sowohl der Vakzinen als auch des Testinfektionsvirus. Gegenüber einer parenteralen Infektion erwies sich die i. m. Vakzination der i. n. Impfung deutlich überlegen, nach i. n. Testinfektion war die i. n. durchgeführte Immunisierung aber zumindest der i. m. gleichwertig. Eine Aerosolvakzination mit inaktiviertem Aujeszky‐Virus induzierte nur mit Adjuvanszusatz einen signifikanten Schutz, der aber im Vergleich zu den beiden anderen Applikationsarten wesentlich geringer war.

Die i. n. Impfung reduzierte die Vermehrung und Ausbreitung des i. n. applizierten Testinfektionsvirus fast vollständig. Die Vakzination per Aerosol verringerte gegenüber den Kontrollen sowohl die Zahl der Lungen‐ und Gehirnisolate als auch die Virustiterhöhe in den Lungen.

Neutralisierende Antikörper konnten nur im Serum i. m. und i. n. geimpfter Mäuse, aber nicht nach Aerosolvakzination nachgewiesen werden. In Lungenspülflüssigkeiten und Lungenextrakten wurden in keinem Fall neutralisierende Antikörper gefunden.

Summary

Possibilities of vaccination with inactivated virus via the respiratory tract studied in the Aujeszky virus — white mouse system

Using an ethylethelenimin‐inactivated and concentrated Aujeszky disease virus vaccine, mice were vaccinated i. m., i. n. and by aerosol. A different immunity resulted from all three routes. The grade of immunity induced and its disposition depended both on the method of application of the vaccine and of the challenge virus. Against parenteral challenge i. m. vaccination was superior to i. n. vaccination. Using i. n. challenge i. n. vaccination was at least as good as i. m. vaccination. Aerosol vaccination with inactivated virus gave significant protection only when adjuvant was included and was in any case less effective than the other two methods of vaccination.

I. n. vaccination reduced the spread and multiplication of the i. n. challenge dose almost completely. Aerosol vaccination reduced the number of lung and brain isolations and also the lung virus titres compared with the controls.

Neutralizing antibodies could be found only in the sera of mice vaccinated i. m. and i. n. and not in mice vaccinated with aerosol. In lung washings and extracts no evidence of neutralizing antibodies was found on any occasion.

Résumé

Possibilité d'une vaccination par voie aérogène avec un virus inactivé de la maladie d'Aujeszky chez la souris blanche

Des souris ont été vaccinées par voies i. m., i. n. et par aérosols avec un vaccin du virus d'Aujeszky concentré et inactivé à l'éthyléthylénimine. Une immunité différente fut obtenue avec les trois formes d'application. Le degré d'immunité induite et sa détermination ont dépendu du mode d'application, des vaccins et du virus de l'infection‐test. La vaccination i. m. fut supérieure à l'i. n. par rapport à une infection parentérale; l'immunisation i. n. faite après une infection‐test i. n. fut égale à l'i. m. La vaccination par aérosols avec un virus d'Aujeszky inactivé n'a donné une protection qu'avec l'addition d'un adjuvant et fut moins efficace que les deux autres méthodes.

La vaccination i. n. diminua presque complètement la multiplication et l'extension du virus appliqué dans l'infection‐test. La vaccination par aérosols diminua le nombre des isolements à partir des poumons et du cerveau ainsi que la hauteur du titre viral dans les poumons par rapport aux témoins. Des anticorps neutralisants n'ont été trouvés que chez des souris vaccinées i. m. et i. n. et non chez celles vaccinées par aérosols. On n'a absolument pas trouvé d'anticorps neutralisants dans des lavages de poumons et des extraits de poumons.

Resumen

Posibilidades de vacunación con virus inactivado a través del tracto respiratorio estudiadas en el sistema virus de Aujeszky‐ratón blanco

Se vacunaron ratones blancos por las vías im., in. y con aerosoles mediante una virusvacuna de Aujeszky inactivada con etiletilenimina y concentrada. Con todas las tres formas de administración se logró una inmudidad diferente. El grado de inmunidad inducida y su valuación dependían del tipo de aplicación, tanto de las vacunas como del virus de infección de prueba. Frente a la infección parenteral se reveló la vacunación im. muy superior a la vacunación in., pero tras la infección in. de prueba era la inmunización lograda por vía in. equivalente al menos a la im. La vacunación aerosólica con virus inactivado de Aujeszky inducía solo con adición de adyuvante una protección significativa, la cual, sin embargo, era bastante inferior en comparación con los otros tipos de aplicación.äLa vacunación in. reducía asi por completo la multiplicación y difusión del virus de infección de prueba aplicado por vía in. La vacunación por medio de aerosoles disminuía frente a los testigos tanto el número de aislamientos en pulmones y cerebros como el nivel de los títulos virósicos pulmonares.

Solo se pudieron identificar anticuerpos neutralizantes en el suero sanguíneo de ratones vacunados por las vías im. e in., ya que no tras vacunación aerosólica. En los líquidos de lavado pulmonar y en extractos pulmonares no se hallaron en ningún caso anticuerpos neutralizantes.

Contrasting effects of CCR5 and CCR2 deficiency in the pulmonary inflammatory response to influenza A virus

The immune response to influenza A virus is characterized by an influx of both macrophages and T lymphocytes into the lungs of the infected host, accompanied by induced expression of a number of CC chemokines. CC chemokine receptors CCR5 and CCR2 are both expressed on activated macrophages and T cells. We examined how the absence of these chemokine receptors would affect pulmonary chemokine expression and induced leukocyte recruitment by infecting CCR5-deficient mice and CCR2-deficient mice with a mouse-adapted strain of influenza A virus. CCR5(-/-) mice displayed increased mortality rates associated with acute, severe pneumonitis, whereas CCR2(-/-) mice were protected from the early pathological manifestations of influenza because of defective macrophage recruitment. This delay in macrophage accumulation in CCR2(-/-) mice caused a subsequent delay in T cell migration, which correlated with high pulmonary viral titers at early time points. Infected CCR5(-/-) mice and CCR2(-/-) mice both exhibited increased expression of the gene for MCP-1, the major ligand for CCR2(-/-) and a key regulator of induced macrophage migration. These studies illustrate the very different roles that CCR5 and CCR2 play in the macrophage response to influenza infection and demonstrate how defects in macrophage recruitment affect the normal development of the cell-mediated immune response.

Alterations in macrophage functions by environmental chemicals

The establishment of infectious diseases is rarely entirely attributed to a single entity, but instead is the result of a primary stress and one or more secondary factors that interfere with homeostasis and the ability of the host to cope with the primary etiologic assault. Any environmental chemical that can suppress the normal functioning of the host's body defenses would be expected to increase the risk of the host to such diseases. Within the lung, the alveolar macrophages are the crucial elements responsible for defending the body against such airborne viable agents. The effects of inhaled gases and particulates on these defense cells are a major concern of the environmental health scientist since such chemicals have the capability of adversely affecting the integrity and functioning of these pulmonary defense cells. The objective of this report is to provide an overview that will improve our understanding of how a variety of environmental chemicals can alter the biochemical, physiological and immunological functioning of these cells.

The pulmonary clearance of Pasteurella haemolytica in calves infected with bovine virus diarrhea or Mycoplasma bovis

Based on current literature which commonly associates bovine virus diarrhea virus and Mycoplasma bovis with "pneumonic pasteurellosis," an investigation was conducted into the effect of these two pathogens on the capacity of bovine lung to clear inhaled Pasteurella haemolytica. There was no significant effect (p less than 0.05) of either bovine virus diarrhea virus or M. bovis on the mean clearance rate of P. haemolytica, nor did the time interval of three, five or seven days between the first inoculation and exposure to P. haemolytica and adversely affect the lung clearance rates. However, it was found that the left lungs and a higher bacterial retention (p less than 0.05) than the right lungs.

A review of infectious bovine rhinotracheitis, shipping fever pneumonia and viral-bacterial synergism in respiratory disease of cattle

Unanswered questions on the etiology and prevention of shipping fever pneumonia have allowed this disease to remain one of the most costly to the North American cattle industry. Research in this area has indirected that while Pasteurella haemolytica and, to a lesser extent, P. multocida are involved in most cases, they seem to require additional factors to help initiate the disease process. Bovine herpes virus 1 has been shown experimentally to be one such factor. This review examines in some detail the topics of infectious bovine rhinotracheitis, shipping fever, and viral-bacterial interactions in the production of respiratory disease in various species. It deals with history, definitions, etiologies, clinical signs and lesions, and considers exposure levels, transmission and various pathogenetic mechanisms that are postulated or known to occur.

Use of experimental airborne infections for monitoring altered host defenses

The success or failure of the respiratory system to defend itself against airborne infectious agents largely depends upon the efficiency of the pulmonary defenses to maintain sterility and to dispose of unwanted substances. Both specific and nonspecific host defenses cooperate in the removal and inactivation of such agents. Several studies have shown that these defenses are vulnerable to a wide range of environmental agents and that there is a good relationship between exposure to pollutant and the impaired resistance to pulmonary disease. There are numerous immunological, biochemical and physiological techniques that are routinely used to identify and to characterize individual impairments of these defenses. Based on these effects, various hypotheses are proposed as to what health consequences could be expected from these effects. The ultimate test is whether the host, with its compromised defense mechanisms, is still capable of sustaining the total injury and continuing to defend itself against opportunistic pathogens. This paper describes the use of an experimental airborne infectious disease model capable of predicting subtle changes in host defenses at concentrations below which there are any other overt toxicological effects. Such sensitivity is possible because the model measure not just a single "health" parameter, but instead is capable of reflecting the total responses caused by the test chemical.

Pulmonary infection of mice with Staphylococcus aureus

The survival of Staphylococcus aureus in the lungs of mice was studied under various conditions. Doses of 10(7) to 10(9) washed staphylococci were quantitatively introduced into the lungs after intratracheal inoculation in mice under either ether or sodium pentobarbital anesthesia. Mice were sacrificed at intervals, the lungs were excised and homogenized, and the cocci were enumerated by plate count. The 50% lethal dose was 6 x 10(8) cocci per mouse, and mice died within 24 h but without proliferation of the inoculum. Mice given 10(8) cocci intratracheally under pentobarbital anesthesia regularly survived and eliminated the organisms over a 48-h period. The use of ether anesthesia resulted in persistence of the inoculum for up to 48 h, but the organisms were then eliminated. Inability to proliferate did not appear to result from a lack of iron because pretreatment of the mice with ferric ammonium citrate or Imferon did not alter inoculum survival. Staphylococci inoculated intratracheally in mice infected with influenza virus 3 to 21 days previously showed no enhanced persistence or multiplication. Cocci preclumped with fibrinogen, inocula mixed with 10 times the number of Formalin-killed staphylococci, or inocula of the encapsulated Smith strain did not survive any better than conventional inocula, suggesting that phagocytosis might not be the sole mechanism for elimination. However, a sedimentable fraction from normal or infected lung homogenates proved either inhibitory or cidal for staphylococci in vitro.

[The patient as a source of bacteria in intensive care units: influence of antibiotics and tracheal intubation (author's transl)]

133 patients in an intensive care unit, who prior to admission had not shown any signs of bacterial infection and had not received antibiotic treatment, were assigned to two groups at random. One group received antibiotic prophylaxis with penicillins or cephalosporins (+Pat.), the other group did not receive antibiotics (-Pat.). Staph. aureus was the most frequent facultative pathogen in tracheal secretions and in the environment of "-Pat.". This organism was significantly more frequent in "-Pat." than in "+Pat." in both the tracheal secretions and the environment. Klebsiella spp. outnumbered all other species in "+Pat.". They were significantly more frequent in tracheal secretions of "+Pat." than of "-Pat.". In the first week of hospitalisation marked changes were seen in bacterial flora of tracheal secretions of "+Pat.". Colonization with grammnegative bacteria rose to nearly 100%, the frequency of Staph. aureus diminishing at the same time. Monitoring by contact cultures revealed that gramnegative rods were significantly more numerous in the environment of "+Pat." than of "-Pat.". Matching bacterial strains cultured from tracheal secretions and from the environment of the patients proved that "+Pat. spread significantly higher numbers of their gramnegative bacteria into the environment. The same is true of "-Pat." for Staph. aureus. Intubation had no noticeable effect on the degree of contamination of the surroundings with Staph. aureus. Gramnegative rods were significantly more frequent in tracheal secretions of patients with intubation than in patients without. The same trend was observed for environmental contamination. As the clinical results of this study have shown, antibiotic prophylaxis does not protect patients from infections to the extent expected. Patients, and particularly intubated patients, receiving antibiotic treatment have to be considered as sources of highly resistant gramnegative organisms.

Effects of oxygen exposure on it vitro function of pulmonary alveolar macrophages

Bacterial infection may complicate pulmonary oxygen (O2) toxicity, and animals exposed to high O2 concentrations show depressed in vivo pulmonary bacterial inactivation. Therefore, in vitro studies were undertaken to define the mechanism by which O2 alters pulmonary antibacterial activity. Normal and BCG pretreated rabbits were exposed to 100% O2 for 24, 48, and 72-h periods. Pulmonary alveolar macrophages (PAM) were obtained from the experimental animals and from nonoxygen exposed controls by bronchopulmonary lavage. O2 exposure did not alter cell yield or morphology. PAMs were suspended in 10% serum-buffer, and phagocytosis of (14C)Staphylococcus aureus 502A and (14C)Pseudomonas aeruginosa was measured. Comparison of the precent uptake of the 14C-labeled S. aureus after a 60-min incubation period demonstrated that normal PAMs exposed to O2 for 48 h showed a statistically significant increase in phagocytosis when compared to their controls (43.5 vs. 29.2%). A similar, but smaller increase was seen after 24-h O2 exposures. 48 and 72-h O2 exposures produced no significant changes in phagocytosis in PAMs from BCG-stimulated rabbits. Normal PAMs also showed an increased phagocytosis of Ps. aeruginosa after 48-h oxygen exposure. No impairment of in vitro bactericidal activity against either S. aureus 502A or Ps. aeruginosa could be demonstrated in PAMs from normal rabbits exposed to O2 for 48 h. These results indicate that the in vitrophagocytic and bactericidal capacity of the rabbit PAM is relatively resistant to the toxic effects of oxygen, and that imparied in vivo activity may possibly be mediated by effects other than irreversible metabolic damage to these cells. The mechanism for the observed stimulation of phagocytosis remains to be determined.

Variations in pulmonary antibacterial defenses among experimental animals

Intrapulmonary killing of Staphylococcus aureus proceeded at equal rates in guinea pigs, hamsters, rats, and mice. In the lung of guinea pigs and hamsters, Proteus mirabilis was killed at virtually the same rate as S. aureus as compared with half the rate of inactivation in the lungs of rats and mice.

Pulmonary alveolar macrophage. Defender against bacterial infection of the lung

The rate of ingestion of inhaled bacteria by pulmonary alveolar macrophages is an important determinant of host defense. This parameter was investigated by infecting rats with finely dispersed aerosols bearing Staphylococcus aureus in high concentrations (about 10(s) bacteria/ft(3)/min). These aerosols deposited more than 10(6) bacteria/murine lung. At 0, 2(1/2), and 5 h after infection, bacterial clearance rates were measured in the left lung, and the intracellular or extracellular location of 100 bacteria was determined histologically in the right lung (perfused in situ). The clearance rates at 2(1/2) and 5 h were 44.5% and 76.9%, respectively. The percentages of intracellular bacteria were: 0 h, 54.8%; 2(1/2) h, 87.1%: 5 h, 91.9%. When rats were exposed for 4 h to 2.5 ppm of ozone (O(3)), bacterial clearance did not occur - 15.3%, although 78.7% of the bacteria were intracellular. Clumps of more than 10 bacteria-usually intracellular-were also present. These experiments demonstrate that phagocytic ingestion is an exceedingly rapid process, that in this experimental model the inactivation of inhaled staphylococci results almost entirely from phagocytosis, and that ozone-induced reductions in bacterial clearance are due to severe impairment of intrapulmonary killing mechanisms and minor impairment of bacterial ingestion.

Pulmonary infection due to disruption of the pharyngeal bacterial flora by antibiotics in hamsters

An animal model was used to determine the effect of oxacillin on the pharyngeal bacterial flora and the relationship of this flora to pneumonia. The pharyngeal bacterial flora of 68 healthy Golden Syrian hamsters was determined. A quantitative comparison between Streptococci and Escherichia, Proteus, Klebsiella and Enterobacter from 70 hamsters was made before and at 4, 24, 48 and 72 hours after oxacillin administration. Lung cultures were positive in 22 of 25 hamsters, yielding K pneumoniae type 1 most frequently. Lung histology from 25 hamsters revealed bronchopneumonia. Intestinal postmortem cultures of treated and untreated animals were similar. The importance of throat cultures in diagnosing pneumonia and the value of the hamster model to study the effect of other antibiotics on the temporary flora are demonstrated.

The effect of edema, hydrocortisone acetate, concurrent viral infection and immunization on the clearance of Pasteurella hemolytica from the bovine lung

The influence of pulmonary edema, hydrocortisone, immunization against Pasteurella hemolytica and concurrent infection with parainfluenza-3 virus upon pulmonary clearance of aerosolized P. hemolytica was studied in 31 calves. Following the various treatments calves were challenged with an aerosol of P. hemolytica. One control calf was killed immediately after the aerosol and the numbers of bacteria in the lung taken as 100%. Two calves were killed four hours after challenge and the numbers of bacteria in the lungs were compared to the 100% of the control calf. The result was the percentage clearance of bacteria at four hours. PULMONARY EDEMA WAS INDUCED BY THREE DIFFERENT METHODS: by an aerosol of histamine, by intravenous injection of endotoxin and by intravenous injection of croton oil emulsion. The edema impaired the clearance of P. hemolytica, which was reflected in high numbers of P. hemolytica present in the lungs at four hours after challenge: 260% after histamine, 300% and 400% after endotoxin and 92% after croton oil. SIX DAYS OF TREATMENT OF FOUR CALVES WITH HIGH DOSES OF HYDROCORTISONE ACETATE PRODUCED INCONSISTENT RESULTS: two calves treated with a higher daily dose (36 mg/kg) had normal clearance whereas two calves treated with a lower dose had pulmonary edema and displayed lowered clearance with 111% and 31% respectively of P. hemolytica retained in the lungs four hours after challenge. Immunization of calves by three different methods, a subcutaneously injected bacterin of P. hemolytica (2 calves), single aerosol (2 calves) and four aerosols (4 calves) of live P. hemolytica was reflected in an accelerated pulmonary clearance of P. hemolytica (with a mean of 1.55% of bacteria retained at four hours). Concurrent infection with parainfluenza-3 virus did not lower the clearance of P. hemolytica in the lungs of 12 calves over 15 days except on the first day following the exposure to parainfluenza-3 virus. These calves had hemagglutinating antibodies against P. hemolytica before exposure.

Prevention of gram-negative bacillary pneumonia using aerosol polymyxin as prophylaxis. I. Effect on the colonization pattern of the upper respiratory tract of seriously ill patients

A prospective study used polymyxin B by aerosol to reduce colonization of the upper respiratory tract with nosocomial gram-negative bacilli. 58 high-risk patients from the Respiratory-Surgical Intensive Care Unit entered the trial. 33 were randomly selected to receive 2.5 mg/kg/day of polymyxin B by hand atomizer into the pharynx, and tracheal tube if present. 17 of 25 control patients became colonized with gram-negative bacilli as compared with 7 of 33 polymyxin-treated patients (p < 0.01). Control patients became colonized with a total of 33 gram-negative bacilli: 3 were Pseudomonas aeruginosa, 21 were species of Enterobacteriaceae. The polymyxin-treated patients became colonized with a total of 11 gram-negative bacilli: no P. aeruginosa and only 3 species of Enterobacteriaceae were recovered. Colonization increased with duration in Respiratory-Surgical Intensive Care Unit and with time of required controlled ventilation. Polymyxin most effectively prevented the increase in colonization in treated patients who stayed in the Respiratory-Surgical Intensive Care Unit for longer than 1 wk and who required controlled ventilation for at least 72 h.

Use of technetium ( 99m Tc) as a bacterial label in lung clearance studies

The suitability of technetium ((99m)Tc), a gamma emitter, for labeling of Diplococcus pneumoniae in studies of lung bacterial clearance was examined. A killed bacterial slurry with high specific activity was obtained with a ferric ascorbate reducing system. Approximately 5.5% of radioactive counts dissociated from labeled bacteria in 6 h. Rats were exposed to a uniformly mixed aerosol of untagged, viable pneumococci and killed, (99m)Tc-tagged pneumococci. The aerodynamic behavior of labeled and unlabeled pneumococci was similar. Viable bacterial counts and radioactive counts were determined in lung homogenates at intervals following exposure, and rates of bacterial killing and disappearance of radioactive counts were plotted. Radioactive counts did not increase in the liver during the period of observation, suggesting that the decrease in lung radioactivity represents mucociliary clearance and not release of isotope to the systemic circulation. The use of (99m)Tc for bacterial labeling provides advantages of technical simplicity and personnel safety compared to the use of beta-emitting isotopes.

Use of technetium ( 99m Tc) as a bacterial label in lung clearance studies

The suitability of technetium ((99m)Tc), a gamma emitter, for labeling of Diplococcus pneumoniae in studies of lung bacterial clearance was examined. A killed bacterial slurry with high specific activity was obtained with a ferric ascorbate reducing system. Approximately 5.5% of radioactive counts dissociated from labeled bacteria in 6 h. Rats were exposed to a uniformly mixed aerosol of untagged, viable pneumococci and killed, (99m)Tc-tagged pneumococci. The aerodynamic behavior of labeled and unlabeled pneumococci was similar. Viable bacterial counts and radioactive counts were determined in lung homogenates at intervals following exposure, and rates of bacterial killing and disappearance of radioactive counts were plotted. Radioactive counts did not increase in the liver during the period of observation, suggesting that the decrease in lung radioactivity represents mucociliary clearance and not release of isotope to the systemic circulation. The use of (99m)Tc for bacterial labeling provides advantages of technical simplicity and personnel safety compared to the use of beta-emitting isotopes.

The pulmonary clearance of bacteria by calves and mice

Using a modified aerosol generator, white mice and calves were exposed to aerosols of viable Staphylococcus aureus and Pasteurella haemolytica and the clearance of the inhaled organisms by the lungs of the experimental animals was measured. Fifty-seven percent of inhaled S. aureus were cleared in two hours by the mouse lungs, 79% were cleared in four hours and 93% were cleared in eight hours. Fifty-six percent of inhaled P. haemolytica were cleared in two hours by the mouse lungs, 76% were cleared in four hours and 93% were cleared in eight hours. Seventy percent of inhaled S. aureus were cleared in two hours by the calf lungs, 90% were cleared in four hours and 95% were cleared in eight hours. Seventy-five percent of inhaled P.haemolytica were cleared in two hours by the calf lungs, 90% were cleared in four hours and 92% were cleared in eight hours.

The human alveolar macrophage: isolation, cultivation in vitro, and studies of morphologic and functional characteristics

Human alveolar macrophages were lavaged from surgically resected lungs and from lungs of normal subjects. Macrophages that had been purified by glass adherence were maintained in tissue culture for as long as 54 days. After 3-4 wk in vitro they underwent transformation into multinucleated giant cells. These aged cells had more than 30 times the phagocytic capacity that the same group of cells had had after 1 day in vitro. Phagocytosis of heat-killed Candida albicans was inhibited by iodoacetate, sodium fluoride, potassium cyanide, and low partial pressures of oxygen, suggesting that these cells require both oxidative and glycolytic energy sources for maximal particle ingestion. Alveolar macrophages and monocyte-derived macrophages killed Listeria monocytogenes with similar efficiency, but neutrophils were more efficient than either of the other cell types. Bacterial killing is probably not dependent upon myeloperoxidase in the monocyte-derived macrophage or in the alveolar macrophage since histochemical stains for peroxidase do not stain either cell type. C. albicans blastospores, which are killed by neutrophils and monocytes that contain myeloperoxidase, were not killed by human alveolar macrophages during the 4 hr of observation. Large cells with supernormal phagocytic capacity were recovered from patients with postobstructive pheumonia and from one patient with recurrent bacterial pneumonia, indicating that macrophage function can be altered in certain disease states. Human alveolar macrophages are unique human phagocytes in their dependence on an oxygen tension greater than 25 mm HG for maximal phagocytosis. Carbon dioxide tensions as high as 70 mm Hg did not alter phagocytosis when the pH of the medium was held constant. These data suggest that the increased susceptibility to pneumonia of patients with chronic bronchitis or atelectasis may be in part related to suboptimal phagocytosis by macrophages in areas of the lung with depressed oxygen tension.

Comparison of the pulmonary bactericidal capacity of mice and rats aganist strains of Pseudomonas aeruginosa

After aerosol deposition of Pseudomonas aeruginosa strains in mice and rats, completely different patterns of pulmonary bacterial clearance were observed in each animal species.

Human alveolar macrophages: comparison of phagocytic ability, glucose utilization, and ultrastructure in smokers and nonsmokers

Phagocytic ability, glucose utilization, and ultrastructural morphology were studied in human alveolar macrophages in smokers and nonsmokers. The macrophages were obtained by bronchopulmonary lavage and the studies were carried out in vitro in the absence of smoke. Phagocytic ability was measured as the decrease in the number of viable Staphylococcus albus organisms incubated with the macrophages. Measurements of (14)CO(2) formation from glucose-U-(14)C were made in a resting state. 90-95% of the cells obtained by lavage were large mononuclear macrophages of which approximately 90% remained viable at the end of the experiment. Smokers yielded many more macrophages per lavage (mean 46.4 x 10(6) +/-7.4) compared to the nonsmokers (mean 10.2 x 10(6) +/-2.3). The decline in viable organisms was the same in each group, indicating phagocytic competence of alveolar macrophages removed from smokers. However, the mean glucose utilization for the smokers was 4.3 +/-0.2 mmumoles/10(6) cells and 1.4 +/-0.7 mmumoles/10(6) cells for the nonsmokers. This very significant difference (P < 0.0001) suggests that smokers' macrophages have a higher resting energy requirement than those of nonsmokers. Comparison of the ultrastructural morphology of the alveolar macrophages from each group reveals that the cells from smokers differ from those of nonsmokers in that they are slightly larger, and contain more golgi vesicles, endoplasmic reticulum, and residual bodies. The residual bodies in smokers' cells contain distinctive fiber-like inclusions.