Nitrated proteins in bronchoalveolar lavage fluid of patients at risk of ventilator-associated bronchopneumonia.

in European Respiratory Journal (2000), 16(2), 296-301

The study was designed to identify markers of oxidative injury, related to the nitric oxide derived cascade, in bronchoalveolar lavage (BAL) fluid from intensive care patients suspected of ventilator ... [more ▼]

The study was designed to identify markers of oxidative injury, related to the nitric oxide derived cascade, in bronchoalveolar lavage (BAL) fluid from intensive care patients suspected of ventilator-associated pneumonia (VAP) and/or acute respiratory distress syndrome (ARDS). Thirty-eight patients developing VAP and/or ARDS (VAP/ARDS group) were compared to 20 ventilated patients without VAP/ARDS (control group). Myeloperoxidase (MPO) and elastase, taken as markers of neutrophil activation were measured by enzymatic techniques, and nitrated proteins (NTPs) by an immunological method. The cytotoxicity of the BAL fluid was tested using cultured human epithelial alveolar cells by the release of pre-incorporated 51Cr. Mean NTP concentration and, MPO and elastase activities were different between the VAP/ARDS and control groups (p<0.05 for NTPs; p<0.005 for MPO; p<0.005 for elastase). NTP concentration correlated with MPO and elastase activity and neutrophil number (r=0.93, 0.91 and 0.87, respectively), but not to protein concentration and arterial oxygen tension/inspiratory oxygen fraction. The cytotoxicity of BAL correlated with NTP concentration (r=0.92) and MPO activity (r=0.89). It was concluded that the concentrations of nitrated proteins in bronchoalveolar lavage fluid correlated with the oxidant activity of neutrophils and that, bronchoalveolar lavage fluid cytotoxicity was correlated with the nitrated protein concentration and may be mediated by oxidants. [less ▲]

Study of the protective effects of hyperimmune immunoglobulins G and M against endotoxin in mice and rats

in Medical Microbiology & Immunology (1999), 188(2), 55-64

We prepared solutions of human IgM and IgG to various lipopolysaccharide (LPS) species. These were then tested, along with solutions of non-LPS specific human IgG or IgM, for their ability to confer ... [more ▼]

We prepared solutions of human IgM and IgG to various lipopolysaccharide (LPS) species. These were then tested, along with solutions of non-LPS specific human IgG or IgM, for their ability to confer passive immunity against experimental endotoxemia in two animal models. The immunoglobulins were first tested for an effect on the lethality induced by seven different LPSs in actinomycin-D sensitized mice, or by three different bacteria in normal mice. When the immunoglobulins were administered 1 h before challenge, a small protective effect was observed. This protection was dependent upon both the anti-LPS agent, the chemical composition of the LPS, or the strain of gram-negative bacteria used for injection. The anti-LPS IgM and IgG preparations reduced the mortality induced by Escherichia coli but not by Serratia marcescens or Klebsiella pneumoniae, indicating protection by strain-specific antibodies. When the antibodies were preincubated with LPS or bacteria for 30 min before administration, almost complete protection was seen. The influence of these immunoglobulin preparations or of human albumin (as a control) on the hypotensive and vascular-permeabilizing effects of LPS in rats was then studied. A dose-dependent inhibitory effect was observed with IgG preparations and albumin. At 200 mg/kg, anti-LPS IgG reduced the effects of LPS, while at 400 mg/kg, both anti-LPS and normal IgG preparations showed protection, as did human albumin used at the same dose. The IgM-enriched preparation worsened the initial hypotensive phase after LPS, whereas the anti-LPS IgM significantly reduced the second phase of the hypotension, but only at the largest dose of 400 mg/kg. In this second model using the rat, a clear difference between the activity of IgG and IgM was thus observed. We conclude that pretreatment with human immunoglobulins from large plasma pools modestly, but significantly, attenuated the effects of murine and rat Gram-negative sepsis, but that protection was incomplete. Our results suggest that single regimen intervention strategies may not be sufficient to influence the course of the disease. [less ▲]

Screening and characterization of specific anti-lipopolysaccharide antibodies in Belgian blood donors by enzyme-linked immunosorbent assays

in European Journal of Clinical Investigation (1996), 26(12), 1134-1142

The goal of this project was to find and collect high concentrations of endotoxin-specific antibodies for therapeutic IgG- or IgM-enriched preparations. Various enzyme-linked immunosorbent assays (ELISAs ... [more ▼]

The goal of this project was to find and collect high concentrations of endotoxin-specific antibodies for therapeutic IgG- or IgM-enriched preparations. Various enzyme-linked immunosorbent assays (ELISAs) were developed to perform longitudinal studies of the serological response to a large panel of smooth and rough purified lipopolysaccharide (LPS) extracts in a population of healthy blood donors. To accomplish this, 1612 human serum samples from volunteer blood donors collected by seven different blood banks in Belgium were screened and specific IgM and IgG activities were measured. Approximately 17% of the donors had anti-LPS concentrations higher than 40 mg L-1. Of these, 10.9% had anti-smooth LPS antibodies, 3.7% had anti-rough LPS antibodies and 2.8% were found to be positive towards both types of LPS. The mean anti-LPS antibody concentration was 8 mg L-1 for rough LPS and 14 mg L-1 for smooth LPS. Age- and sex-related distributions of the activities indicated that the greatest prevalence of high anti-LPS concentration was in women aged 40-49 years and in men older than 60 years. Differential absorption experiments showed that the pooled serum of selected blood donors contained a mixture of specific and cross-reacting antibodies. We detected predominantly anti-LPS activities due to the IgG1 and IgG2 subclasses. The range of specificities to different LPS was increased by the pooling of selected sera. It was concluded that pools of naturally occurring specific anti-LPS immunoglobulin antibodies may be obtained in Belgium by screening blood donors using ELISAs that we have developed. [less ▲]

Sequential anti-core glycolipid immunoglobulin antibody activities in patients with and without septic shock and their relation to outcome

in Annals of Surgery (1993), 217(3), 300-306

OBJECTIVE: This study follows the sequential changes in anti-lipopolysaccharide antibodies in infected patients with and without septic shock. SUMMARY BACKGROUND DATA: A relation between high endogenous ... [more ▼]

OBJECTIVE: This study follows the sequential changes in anti-lipopolysaccharide antibodies in infected patients with and without septic shock. SUMMARY BACKGROUND DATA: A relation between high endogenous levels of anti-LPS antibodies and protection against bacteremia and septic shock in at-risk patient groups has been observed. However, information on the daily follow-up and kinetics of apparition or disappearance of anti-LPS antibody activities and their relations with the protective properties of the different immunoglobulin classes has not been clearly investigated. METHODS: Two hundred and five septic surgical patients were studied during their stay in the intensive care unit during a period of 3 years. Among these patients, septic shock developed in 54 and 47 died. A sensitive ELISA was used to study circulating IgM and IgG antibodies to the core glycolipid (CGL) region of Salmonella minnesota R595. The activities were measured each day when sepsis occurred and every hour during septic shock. RESULTS: Anti-CGL IgM activity was found in 32% of the septic patients. This response, however, most often appeared to be transient. A strong correlation was observed between the occurrence of septic shock and the absence of anti-CGL IgM activity on admission to the ICU (p < 0.02). Anti-CGL IgG activity was detected in 82% of the patients and better correlated with outcome for patients with high or rising activities during their hospitalization (p < 0.0005). In patients with septic shock or irreversible organ failure, a fall in the anti-CGL IgG activity was observed before death, suggesting that the IgG antibodies were consumed during this acute event. Therefore, the anti-CGL IgG activity measured by ELISA could be used as a marker of the evolution of the illness. CONCLUSIONS: Our observations demonstrate the interest to follow-up the evolution of the anti-CGL antibodies during sepsis. The fall of these antibodies during septic shock and in patients who died was an additional argument to perform, as an additive form, passive antibody therapy to decrease lethality in this group of patients. [less ▲]

Production of heterobispecific monoclonal antibodies by mouse hybrid hybridomas (quadromas)

in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1988), 96