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The inflammation in cystic fibrosis (CF) patients with chronic Pseudomonas aeruginosa lung infection is dominated by polymorphonuclear neutrophils (PMNs). There seems to be a relationship between the PMN-dominated inflammation, pronounced antibody production and a Th2-dominated response. Apart from mobilizing monocytes and PMNs from the bone marrow, GM-CSF, G-CSF and IL-3 select subsets of dendritic cells, which subsequently induce distinct Th responses. Therefore, the present study examines the correlation between the mobilizing cytokines in serum and the Th responses. The IFN-gamma and IL-4 production by peripheral blood mononuclear cells, and the concentrations of GM-CSF and G-CSF in serum as well as lung function, were determined in 37 CF patients with and 6 CF patients without chronic P. aeruginosa lung infection. The GM-CSF/G-CSF ratio correlated both with the IFN-gamma production and good lung function. In addition, an inverse correlation between IL-3 and IFN-gamma was observed. The results indicate involvement of endogenous GM-CSF, G-CSF and IL-3 in the skewed Th response in CF, and change to a Th1-dominated response might be achieved with GM-CSF treatment.

In infections with intracellular microorganisms such as mycobacteria and Leishmania parasites as well as certain extracellular chronic infections such as Pseudomonas aeruginosa a Th1 response with activation of macrophages is desirable. Several studies indicate that such a response is associated with better recovery from infection, improved course of the chronic infection, and higher survival rate. In Th1 responses there is increased interferon-gamma (IFN-gamma) and interleukin-12 (IL-12) production, whereas that of interleukin-10 (IL-10) is decreased. The present study indicated that Ginseng modulation of stimulated peripheral blood mononuclear cells (PBMC) results in a higher IL-12 production. The enhanced IL-12 production could induce a stronger Th1 response, resulting in better protection against infection with a variety of pathogens.

Most cystic fibrosis (CF) patients with chronic Pseudomonas aeruginosa lung infection have a persistent acute type lung inflammation dominated by polymorphonuclear neutrophils (PMN) and a pronounced antibody response against P. aeruginosa. We speculated whether this immune response in CF is of the Th2 type and whether a change to a Th1 type immune response could improve the prognosis. Therefore, we studied 14 CF patients with (CF +P) and 14 CF patients without (CF -P) chronic P. aeruginosa lung infection. The specific production of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) by peripheral blood mononuclear cells was determined. Cells from CF +P patients had lower IFN-gamma (p

The ability to consume complement and activate neutrophils was investigated for staphylococci adherent to silicone surfaces and non-adherent staphylococci. Staphylococcus epidermidis strain ATCC 14990 and Staphylococcus aureus strain E 2371 were used in this study. The bacteria were allowed to adhere to silicone catheter segments for 2 h at 37 degrees C. Complement consumption was measured by reduction in serum haemolytic activity against sheep red blood cells. The induction of chemiluminescence was measured after opsonization of the staphylococci in 20% AB-positive human serum for 60 min at 37 degrees C. The bacteria consumed complement to approximately the same extent when adherent to the catheter segments, but more slowly in comparison with planktonic bacteria. When planktonic bacteria were compared, complement was consumed more quickly by S. epidermidis than by S. aureus. Measuring the induction of chemiluminescence by planktonic bacteria, S. epidermidis induced a lower response than S. aureus, while when adherent to the catheter segments the bacteria induced similar responses. These responses were only 15 to 20% of those induced by planktonic bacteria and only slightly higher than the spontaneous chemiluminescence by the neutrophils. Inter-strain variation was found, but all strains induced about the same low chemiluminescence when adherent to the catheter segments. The reduction in inflammatory response caused by adherence of staphylococci to catheter segments may interfere with phagocytosis and elimination of S. epidermidis during the early establishment of a foreign body infection.

Crude preparations of Leishmania donovani proteins were separated by preparative SDS-polyacrylamide gel electrophoresis. Fractions of separated proteins were recovered by electroelution directly from the gel into separate chambers. The isolated protein fractions were tested for induction of proliferation and interferon-gamma (IFN-gamma) production in cultures of peripheral blood mononuclear cells (PBMC) from individuals who had recovered from visceral leishmaniasis caused by L. donovani. The release of interleukin-4 (IL-4) by PBMC stimulated with the isolated L. donovani antigen fractions was measured after treatment with phorbol-myristate-acetate and ionomycin. The cells proliferated in response to all protein fractions with molecular weights in the range < 12 kDa to 85 kDa. In general, IFN-gamma was secreted in response to stimulation with all the protein fractions, whereas IL-4 production was infrequently observed. The results show that T cells from individuals who have been cured of visceral leishmaniasis recognize and respond to a wide range of leishmanial antigens. There was no evidence of particular fractions constantly giving either IFN-gamma or IL-4-producing responses.

In the present study the effect of Leishmania major surface protease Gp63 on the chemotaxis and oxidative burst response of human peripheral blood monocytes and neutrophils was investigated. It was shown that prior incubation of cells with Gp63 inhibited chemotaxis of neutrophils but not monocytes towards the chemotactic peptide f-met-leu-phe. On the other hand, chemotaxis of both neutrophils and monocytes towards zymosan-activated serum containing C5a was inhibited by Gp63. Monocyte and neutrophil chemiluminescence response to opsonized zymosan was reduced by preincubation of the cells with Gp63 in a concentration-dependent manner. Notably, monocytes were inhibited to a much greater degree than neutrophils by a given concentration of Gp63, and they were also inhibited at much lower concentrations of the protease. The inhibitory effect of Gp63 on chemotaxis and chemiluminescence was completely abolished by heat inactivation of the protease at 70 degrees C for 15 min. Neither neutrophil nor monocyte chemiluminescence was inhibited by Gp63 when cells were stimulated with PMA. Our data suggest that the major surface protease Gp63 might play an important role in the initial stages of Leishmania/macrophage interactions and the intracellular survival of the parasite.

Leishmania parasites cause human diseases ranging from self-healing cutaneous ulcers to fatal systemic infections. In addition, many individuals become infected without developing disease. In mice the two subsets of CD4+ T cells, Th1 and Th2, have different effects on the outcome of experimental Leishmania infections. Th1 cells producing interferon-gamma (IFN-gamma) mediate resistance, whereas Th2 cells producing interleukin-4 (IL-4) and IL-10 are associated with susceptibility and exacerbation. Evidence is accumulating that a Th1/Th2 dichotomy in the T-cell response to Leishmania exists also in humans, and that the balance between subsets of parasite-specific T cells may play an important regulatory role in determining the outcome of the infections.

The ability of staphylococci adherent to silicone surfaces to induce superoxide anion (O2-) production by polymorphonuclear leukocytes (PMNs) was investigated and compared with the same activity induced by planktonic bacteria. The responses to Staphylococcus aureus strain E 2371 and Staphylococcus epidermidis strain ATCC 14990 were compared. The staphylococci were allowed to adhere to silicone catheters for 2 h at 37 degrees C. After opsonization of adherent bacteria in 30% human AB-positive serum, the induction of superoxide anion production by PMNs was measured in a cytochrome C reduction assay. Both bacterial strains, when adhered to the surfaces, were able to induce superoxide anion production by PMNs to about the same extent. Comparing adherent and planktonic bacteria with these two bacterial strains, it was found that planktonic S. epidermidis induced one to three times higher superoxide anion production than the adherent bacteria, whereas planktonic S. aureus induced four to seven times higher superoxide anion production than the adherent bacteria. Interstrain variation between the response to adherent and planktonic staphylococci was found. The lower phagocytic response to adherent staphylococci as compared to the response to planktonic organisms may interfere with the killing process and thereby contribute to poor clearance of these bacteria when adherent to foreign bodies such as catheters.

Persistence of bacteria in spite of a normal host immune system and relevant antibiotic treatment is a key problem in many chronic infections, such as the bronchopulmonary P. aeruginosa infection in cystic fibrosis patients. The capability of bacteria to establish themselves in microcolonies or biofilms is an important protective mechanism of the microorganisms. We examined the human PMN oxidative burst response to P. aeruginosa in biofilm and in planktonic form. The PMN chemiluminescence response to P. aeruginosa in biofilms was reduced to 30.5-47.5% (p less than 0.04) and the superoxide response to 85.9% (p less than 0.02) of the response to equivalent numbers of planktonic bacteria. Mechanical disruption of the biofilms before the assays elicited a significantly increased response in the chemiluminescence experiments and to nonopsonized biofilms in the superoxide anion experiments. We conclude that biofilm bacteria, although able to stimulate the PMN, result in a reduced, suboptimal response leading to lack of efficient eradication of the bacteria in the chronic infection.

The ability of peptidoglycan from Staphylococcus epidermidis and Staphylococcus aureus to generate in human serum chemoattractant for peripheral blood neutrophils was studied. It was shown that PG from the two bacteria was able to induce chemotactic activity in normal human serum. Sonication of PG was required to generate this activity. Very little or no activity was generated in heat-treated or C5-deficient human serum by PG, indicating that PG treatment of serum resulted in generation of chemoattractants by activation of complement. Kinetics studies employing C2-deficient or MgEGTA-chelated serum revealed that S. epidermidis induced chemotactic activity by activating the alternative complement pathway. The alternative complement activation induced by S. epidermidis occurred rapidly and was completed after 15 min, whereas S. aureus activated the alternative pathway much more slowly, with activation reaching a maximum at 60 min. The rapid activation of the alternative complement pathway by S. epidermidis PG may partly explain why this bacterium does not normally cause infections in healthy individuals.

Actinobacillus species are usually not considered as being human pathogens apart from A. actinomycetemcomitans. However, single cases of human meningitis, septicemia, and empyema caused by Actinobacillus lignieresii have been reported in the literature. This is the first reported case of Actinobacillus hominis giving rise to pleural-empyema in a patient with carcinoma of the lung. The function of peripheral blood neutrophils, serum opsonic activity and specific precipitating antibodies were investigated. Neutrophils from the patient exhibited an enhanced oxidative burst response measured by chemiluminescence assay. Furthermore, the opsonic activity of the serum from the patient was higher than that of a healthy control person. Several precipitating antibodies to various antigens of Actinobacillus hominis were demonstrated in the serum of the patient by crossed immunoelectrophoresis.

The spontaneous binding of both piliated and non-piliated E. coli to human lymphocytes, monocytes, and polymorphonuclear leukocytes (PMN) was investigated. It was found that the piliated E. coli showed a higher binding percentage to lymphocytes than the nonpiliated bacteria. A specific antiserum raised in rabbit against E. coli strongly inhibited the binding of the homologous E. coli strain to lymphocytes and monocytes. On the other hand there was no difference in the binding of piliated and non-piliated E. coli to PMNs, and the specific E. coli antiserum did not inhibit the binding. The binding of E. coli to human lymphocytes obtained from healthy donors was investigated in a 3-week follow-up experiment. It was shown that there were significant differences between the binding of cells from different individuals, whereas there were no differences in the binding ability of the cells from the same individual in the 3-week follow up.

The effect of rhamnolipid purified from culture supernatant of Pseudomonas aeruginosa on human peripheral blood neutrophil and monocyte function was studied. It was shown that rhamnolipid at concentrations of up to 100 micrograms/ml did not affect neutrophil and monocyte chemotaxis towards various chemoattractants. The rhamnolipid by itself did not show chemotactic activity and did not induce any oxidative burst response. Preincubation of monocytes with rhamnolipid enhanced the oxidative burst response of these cells to phorbol myristate acetate (PMA) and to opsonized zymosan by 2 to 5 fold. The priming effect was observed both in a superoxide assay and in a chemiluminescence assay. However, rhamnolipid did not prime the neutrophil oxidative burst response. Monocytes/macrophages are involved in the inflammatory process in the lung infections caused by P. aeruginosa and oxygen radicals are known to cause tissue damage. Therefore the priming by rhamnolipid of monocytes for enhanced generation of oxygen radicals may play a role in the pathogenesis of tissue damage in the lungs of cystic fibrosis patients with P. aeruginosa infections.