A pilot study of an anti-endotoxin Ig-enriched bovine colostrum to prevent experimental sepsis.

Despite the dramatic increase in antimicrobial resistance, there is a dearth of antibiotics in development and few pharmaceutical companies working in the field. Further, any new antibiotics are likely to have a short shelf life. Ab-based interventions offer alternatives that are not likely to be circumvented by the widely prevalent antibiotic resistance genes. Bovine colostrum (BC)-the first milk after parturition, rich in nutrients and immune components-promotes gut integrity and modulates the gut microbiome. We developed a hyperimmune BC (HBC) enriched in Abs to a highly conserved LOS core region of Gram-negative bacteria by immunizing pregnant cows with a vaccine comprised of detoxified LOS from Escherichia coli O111 Rc (J5) mutant non-covalently complexed to group B meningococcal outer membrane protein (J5dLOS/OMP). This vaccine generated robust levels of anti-J5 LOS Ab in the colostrum. When given orally to neutropenic rats challenged orally with Pseudomonas aeruginosa, administration of HBC improved survival compared to non-immune rats, while both BC preparations improved survival compared to PBS controls. Elevated circulating endotoxin levels correlated with mortality. HBC and to a lesser extent non-immune BC reduced bacterial burden from the liver, lung, and spleen. We conclude that HBC and to a lesser extent BC may be effective supplements that improve outcome from lethal gut-derived disseminated infection and may reduce transmission of Gram-negative bacilli from the gastrointestinal tract.

PHARMACOLOGICAL SIRT1 ACTIVATION IMPROVES MORTALITY AND MARKEDLY ALTERS TRANSCRIPTIONAL PROFILES THAT ACCOMPANY EXPERIMENTAL SEPSIS.

The sirtuin family consists of seven NAD+-dependent enzymes affecting a broad array of regulatory protein networks by primarily catalyzing the deacetylation of key lysine residues in regulatory proteins. The enzymatic activity of SIRT1 can be enhanced by small molecule activators known as SIRT1 activator compounds (STACs). We tested the therapeutic potential of the STAC SRT3025 in two preclinical models of severe infection, the murine cecal ligation and puncture (CLP) model to induce peritonitis and intratracheal installation of Streptococcus pneumoniae to induce severe bacterial pneumonia. SRT3025 provided significant survival benefits over vehicle control in both the peritonitis and pneumococcal pneumonia models when administered with appropriate antimicrobial agents. The survival benefit of SRT3025 in the CLP model was absent in SIRT1 knockout showing the SIRT1 dependency of SRT3025's effects. SRT3025 administration promoted bacterial clearance and significantly reduced inflammatory cytokines from the lungs of animals challenged with S. pneumoniae. SRT3025 treatment was also accompanied by striking changes in the transcription profiles in multiple inflammatory and metabolic pathways in liver, spleen, small bowel, and lung tissue. Remarkably, these organ-specific changes in the transcriptome analyses were similar following CLP or pneumococcal challenge despite different sets of pathogens at disparate sites of infection. Pharmacologic activation of SIRT1 modulates the innate host response and could represent a novel treatment strategy for severe infection.

CD28 homodimer interface mimetic peptide acts as a preventive and therapeutic agent in models of severe bacterial sepsis and gram-negative bacterial peritonitis.

BACKGROUND: Severe gram-negative bacterial infections and sepsis are major causes of morbidity and mortality. Dysregulated, excessive proinflammatory cytokine expression contributes to the pathogenesis of sepsis. A CD28 mimetic peptide (AB103; previously known as p2TA) that attenuates CD28 signaling and T-helper type 1 cytokine responses was tested for its ability to increase survival in models of polymicrobial infection and gram-negative sepsis. METHODS: Mice received AB103, followed by an injection of Escherichia coli 0111:B4 lipopolysaccharide (LPS); underwent induction E. coli 018:K1 peritonitis induction, followed by treatment with AB103; or underwent cecal ligation and puncture (CLP), followed by treatment with AB103. The effects of AB103 on factors associated with and the lethality of challenge infections were analyzed. RESULTS: AB103 strongly attenuated induction of tumor necrosis factor α and interleukin 6 (IL-6) by LPS in human peripheral blood mononuclear cells. Receipt of AB103 following intraperitoneal injection of LPS resulted in survival among 73% of CD1 mice (11 of 15), compared with 20% of controls (3 of 15). Suboptimal doses of antibiotic alone protected 20% of mice (1 of 5) from E. coli peritonitis, whereas 100% (15 of 15) survived when AB103 was added 4 hours following infection. Survival among mice treated with AB103 12 hours after CLP was 100% (8 of 8), compared with 17% among untreated mice (1 of 6). In addition, receipt of AB103 12 hours after CLP attenuated inflammatory cytokine responses and neutrophil influx into tissues and promoted bacterial clearance. Receipt of AB103 24 hours after CLP still protected 63% of mice (5 of 8). CONCLUSIONS: Single-dose AB103 reduces mortality in experimental models of polymicrobial and gram-negative bacterial infection and sepsis, warranting further studies of this agent in clinical trials.

The novel immunotherapeutic oligodeoxynucleotide IMT504 protects neutropenic animals from fatal Pseudomonas aeruginosa bacteremia and sepsis.

IMT504 is a novel immunomodulatory oligonucleotide that has shown immunotherapeutic properties in early preclinical and clinical studies. IMT504 was tested in a neutropenic rat model of Pseudomonas aeruginosa bacteremia and sepsis. This animal system recapitulates many of the pathological processes found in neutropenic patients with Gram-negative, bacterial infections. The research was conducted in the setting of an academic research laboratory. The test subjects were Sprague-Dawley rats. Animals were rendered neutropenic by administration of cyclophosphamide, colonized with P. aeruginosa by oral feeding, and then randomized to receive IMT504 over a range of doses and treatment regimens representing early and late therapeutic interventions. IMT504 immunotherapy conferred a significant survival advantage over the 12-day study period compared with the results seen with placebo-treated animals when the therapy was administered at the onset of neutropenia and even in the absence of antibiotics and after the onset of fever and systemic infection. Notably, even late salvage IMT504 monotherapy was highly effective (13/14 surviving rats with IMT504 therapy versus 2/14 controls, P=<0.001). Moreover, late salvage IMT504 monotherapy was as effective as antibiotic therapy (13/14 surviving rats versus 21/21 rats, P=0.88). In addition, no antagonism or loss of therapeutic efficacy was noted with combination therapy of IMT504 plus antibiotics. IMT504 immunotherapy provides a remarkable survival advantage in bacteremia and sepsis in neutropenic animals and deserves further study as a new treatment option in patients with, or at risk for, severe Gram-negative bacterial infections and sepsis.

Burden of typhoid fever in Sulaimania, Iraqi Kurdistan.

BACKGROUND: Typhoid fever imposes a high disease burden worldwide, but resource limitations mean that the burden of typhoid fever in many countries is poorly understood. METHODS: The authors conducted a prospective surveillance study at the adult and pediatric teaching hospitals in Sulaimania, Iraqi Kurdistan. All patients presenting with an undifferentiated febrile illness consistent with typhoid were eligible for enrollment. Enrolled patients had blood cultures and Brucella serologies performed. Incidence was calculated with reference to census data. RESULTS: Both typhoid fever and brucellosis were common, and the incidence of typhoid fever was 21 cases/100 000 patient-years. Classic disease symptoms were uncommonly observed. DISCUSSION: Cost-effective surveillance projects to calculate disease burden of typhoid fever are practical and replicable. Typhoid has successfully adapted to the healthcare environment in Sulaimania. Additional work in the region should focus on antibiotic resistance and other enteric pathogens such as Brucella spp.

Evaluation of imipenem for prophylaxis and therapy of Yersinia pestis delivered by aerosol in a mouse model of pneumonic plague.

It has been previously shown that mice subjected to an aerosol exposure to Yersinia pestis and treated with ß-lactam antibiotics after a delay of 42 h died at an accelerated rate compared to controls. It was hypothesized that endotoxin release in antibiotic-treated mice accounted for the accelerated death rate in the mice exposed to aerosol Y. pestis. Imipenem, a ß-lactam antibiotic, binds to penicillin binding protein 2 with the highest affinity and produces rounded cells. The binding of imipenem causes cells to lyse quickly and thereby to release less free endotoxin. Two imipenem regimens producing fractions of time that the concentration of free, unbound drug was above the MIC (fT>MIC) of approximately 25% (6/24 h) and 40% (9.5/24 h) were evaluated. In the postexposure prophylaxis study, the 40% and 25% regimens produced 90% and 40% survivorship, respectively. In the 42-h treatment study, both regimens demonstrated a 40 to 50% survivorship at therapy cessation and some deaths thereafter, resulting in a 30% survivorship. As this was an improvement over the results with other ß-lactams, a comparison of both endotoxin and cytokine levels in mice treated with imipenem and ceftazidime (a ß-lactam previously demonstrated to accelerate death in mice during treatment) was performed and supported the original hypotheses; however, the levels observed in animals treated with ciprofloxacin (included as an unrelated antibiotic that is also bactericidal but should cause little lysis due to a different mode of action) were elevated and significantly (7-fold) higher than those with ceftazidime.

A monoclonal antibody against RAGE alters gene expression and is protective in experimental models of sepsis and pneumococcal pneumonia.

The RAGE (receptor for advanced glycation end products) is believed to play a role in sepsis by perpetuating inflammation. The interaction of RAGE with a variety of host-derived ligands that accumulate during stress and inflammation further induces the expression of RAGE. It was previously shown that a rat anti-RAGE monoclonal antibody protected mice from lethality in a cecal ligation and puncture model. We studied the effects of a humanized anti-RAGE monoclonal antibody in the murine pneumococcal pneumonia model of sepsis. Moreover, a gene expression analysis was performed in lung tissue of animals that underwent cecal ligation and puncture and treated with the rat anti-RAGE monoclonal antibody, compared with controls. Administration of humanized anti-RAGE mAb 6 h after intratracheal infection with Streptococcus pneumoniae improved mortality in BALB/c mice whether a 7.5 mg/kg (P < 0.01) or a 15 mg/kg dose (P < 0.01) was administered in combination with antibiotics. Gene expression analysis showed that many of the genes modulated by treatment with the anti-RAGE antibody were those that play an important role in regulating inflammation. Anti-RAGE monoclonal antibody offered a survival advantage to septic mice. This protective role in treated animals is supported by the observed gene expression profile changes of genes involved in sepsis and inflammation.

Inter-α inhibitor proteins: a novel therapeutic strategy for experimental anthrax infection.

Human inter-α inhibitor proteins are endogenous human plasma proteins that function as serine protease inhibitors. Inter-α inhibitor proteins can block the systemic release of proteases in sepsis and block furin-mediated assembly of protective antigen, an essential stop in the intracellular delivery of the anthrax exotoxins, lethal toxin and edema toxin. Inter-α inhibitor proteins administered on hour or up to 24 h after spore challenge with Bacillus anthracis Sterne strain protected mice from lethality if administered with antimicrobial therapy (P < 0.001). These human plasma proteins possess combined actions against anthrax as general inhibitors of excess serine proteases in sepsis and specific inhibitors of anthrax toxin assembly. Inter-α inhibitor proteins could represent a novel adjuvant therapy for the treatment of established anthrax infection.

Estrogen receptor beta agonism increases survival in experimentally induced sepsis and ameliorates the genomic sepsis signature: a pharmacogenomic study.

BACKGROUND: Nonsteroidal agonists have been developed that selectively bind to and activate estrogen receptor beta (ERbeta) rather than estrogen receptor alpha (ERalpha). ERbeta is expressed equally in both male and female mammals in multiple extragonadal tissues. Work reported elsewhere has demonstrated that ERbeta agonists have beneficial effects in multiple (but not all) models of inflammatory diseases and also increase survival in experimentally induced sepsis. METHODS: In these experiments, ERbeta agonists (ERB-041 or WAY-202196) were compared with vehicle control in the murine cecal ligation and puncture (CLP) model and in the pneumococcal pneumonia model of sepsis. The effect of WAY-202196 on the gene expression profile in the CLP model was further studied by transcriptome analysis of lung and small intestine tissue samples. RESULTS: ERbeta agonists provided a significant survival benefit in both experimental models of bacterial sepsis. This survival advantage was accompanied by reduced histologic evidence of tissue damage, reduced transcription of multiple proinflammatory proteins by transcriptome analysis and was not associated with increased bacterial outgrowth. CONCLUSIONS: ERbeta agonist administration provided a survival advantage in septic animals and appears to be a promising therapeutic modality in sepsis.

Detoxified endotoxin vaccine (J5dLPS/OMP) protects mice against lethal respiratory challenge with Francisella tularensis SchuS4.

Francisella tularensis is a category A select agent. J5dLPS/OMP is a novel vaccine construct consisting of detoxified, O-polysaccharide side chain-deficient, lipopolysaccharide non-covalently complexed with the outer membrane protein of N. meningitidis group B. Immunization elicits high-titer polyclonal antibodies specific for the highly-conserved epitopes expressed within the glycolipid core that constitutes gram-negative bacteria (e.g., F. tularensis). Mice immunized intranasally with J5dLPS/OMP exhibited protective immunity to intratracheal challenge with the live vaccine strain, as well as the highly-virulent SchuS4 strain, of F. tularensis. The efficacy of J5dLPS/OMP vaccine suggests its potential utility in immunizing the general population against several different gram-negative select agents concurrently.

Inhibition of the RAGE products increases survival in experimental models of severe sepsis and systemic infection.

INTRODUCTION: The receptor for advanced glycation end products (RAGE), a multi-ligand member of the immunoglobulin superfamily, contributes to acute and chronic disease processes, including sepsis. METHODS: We studied the possible therapeutic role of RAGE inhibition in the cecal ligation and puncture (CLP) model of polymicrobial sepsis and a model of systemic listeriosis using mice genetically deficient in RAGE expression or mice injected with a rat anti-murine RAGE monoclonal antibody. RESULTS: The 7-day survival rates after CLP were 80% for RAGE-/- mice (n = 15) (P < 0.01 versus wild-type), 69% for RAGE+/- mice (n = 23), and 37% for wild-type mice (n = 27). Survival benefits were evident in BALB/c mice given anti-RAGE antibody (n = 15 per group) over serum-treated control animals (P < 0.05). Moreover, delayed treatment with anti-RAGE antibody up to 24 hours after CLP resulted in a significant survival benefit compared with control mice. There was no significant increase in tissue colony counts from enteric Gram-negative or Gram-positive bacteria in animals treated with anti-RAGE antibody. RAGE-/-, RAGE+/-, and anti-RAGE antibody-treated animals were resistant to lethality from Listeria monocytogenes by almost two orders of magnitude compared with wild-type mice. CONCLUSION: Further studies are warranted to determine the clinical utility of anti-RAGE antibody as a novel treatment for sepsis.

Longitudinal studies of inter-alpha inhibitor proteins in severely septic patients: a potential clinical marker and mediator of severe sepsis.

OBJECTIVE: To determine the clinical relevance and prognostic significance of serial measurement of inter-alpha inhibitor proteins (IalphaIp) in severely septic patients. DESIGN: A laboratory-based study of serial plasma samples over the first 5 days of severe sepsis from a prospective clinical trial. SETTING: Small business and academic medical center research laboratories. PATIENTS: Two hundred sixty-six patients with severe sepsis from a multiple-center phase III clinical trial. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Inter-alpha inhibitor proteins serve as endogenous serine protease inhibitors in human plasma. The levels of IalphaIp were markedly reduced to a mean value of 290+/-15 microg/mL at the onset of severe sepsis compared with normal plasma levels (617+/-197 microg/mL). Failure of IalphaIp levels to recover over the first 5 days of sepsis was associated with an unfavorable outcome (p<.001). IalphaIp levels were inversely correlated with interleukin-6 levels at study entry and over the first 5 days of management of severe sepsis. IalphaIp levels were significantly lower in women, with increased age, in the presence of multiple organ failure and in patients with intra-abdominal sources of sepsis. CONCLUSIONS: Inter-alpha inhibitor proteins are markedly reduced in severe sepsis, and failure of recovery of IalphaIp levels over the course of sepsis is associated with an unfavorable outcome.

WAY-202196, a selective estrogen receptor-beta agonist, protects against death in experimental septic shock.

OBJECTIVE: To determine the effect of an estrogen receptor-beta selective agent in experimental models of systemic infection and sepsis. DESIGN: WAY-202196, a nonsteroidal selective estrogen receptor-beta agonist, was tested in the murine listeriosis model, the neutropenic rat Pseudomonas aeruginosa infection, and the mouse cecal ligation and puncture sepsis models. SETTING: University-affiliated biomedical research laboratory. SUBJECTS: BALB/c mice and Sprague-Dawley rats. INTERVENTIONS: WAY-202196 or control (vehicle) was administered orally in doses ranging from 1.5 to 50 mg/kg at various time points in the three experimental model systems. MEASUREMENTS AND MAIN RESULTS: Susceptibility of mice treated with a single oral dose of up to 50 mg/kg WAY-202196 did not differ from those treated with vehicle alone after systemic challenge by Listeria monocytogenes, suggesting a lack of generalized immunosuppression. In the neutropenic rat model, daily administration of WAY-202196 (50 mg/kg) significantly increased survival against an otherwise lethal challenge of P. aeruginosa 12.4.4 compared with the control group (83% vs. 25% survival; p < 0.05). Preservation of intestinal mucosal weight and prevention of histopathologic changes were also observed with the administration of WAY-202196. Similar results were obtained in a cecal ligation and puncture model, in which multiple oral doses of WAY-202196 (50 mg/kg) improved survival (83% vs. 0%; p < 0.05), preserved intestinal epithelial integrity, and significantly reduced systemic bacteremia and peritoneal interleukin-6 and tumor necrosis factor levels. The estrogen receptor-beta agonist provided a comparable level of protection in both male and female animals. CONCLUSION: These results indicate that oral administration of WAY-202196 preserved gastrointestinal barrier function and improved outcome in experimental models of systemic infection and inflammation. WAY-202196 and similar agents may prove useful clinically as a novel treatment strategy for the treatment or prevention of severe sepsis.

The activity of pathway-selective estrogen receptor ligands in experimental septic shock.

Estrogen receptors (ER) are widely expressed in multiple genital and nongenital tissues. Upon engagement of these receptors, multiple genes are affected in target tissues via estrogen response elements. Nonsteroidal pathway-selective ER ligands have recently been identified that inhibit NF-kappaB transcriptional activity and are devoid of conventional estrogenic activities on genital tissues. These pathway-selective ligands are potent anti-inflammatory agents in vivo and may prove to be of therapeutic utility in systemic inflammatory states. These pathway-selective ER ligands were tested in the murine listeriosis model, the neutropenic rat model, and the mouse cecal ligation and puncture model. WAY-204688 did not have any significant activity after systemic infection by Listeria monocytogenes. In the neutropenic rat model, WAY-204688 provided a significant survival benefit against an otherwise lethal challenge of Pseudomonas aeruginosa 12.4.4 compared with the control group (88% versus 25% survival; P < 0.05). Preservation of mucosal weight and prevention of histopathologic changes were observed with the administration of WAY-204688. Similar findings were observed in a cecal ligation and puncture model with WAY-204688 and a related compound WAY-169916. These results indicate that oral administration of these pathway-selective ER ligands preserved gastrointestinal barrier function and improve outcome in experimental models of systemic infection and inflammation. These agents may prove to be useful clinically as a novel treatment strategy for severe sepsis.

Active immunization with a detoxified endotoxin vaccine protects against lethal polymicrobial sepsis: its use with CpG adjuvant and potential mechanisms.

BACKGROUND: An experimental vaccine for sepsis, composed of detoxified Escherichia coli J5 lipopolysaccharide (LPS) complexed with the outer membrane protein (OMP) of Neisseria meningitidis group B, induces anti-core glycolipid antibody and has been tested in pilot studies in human volunteers. METHODS: Mice were immunized with the LPS-J5/OMP vaccine with or without synthetic oligodeoxynucleotides (ODNs) containing unmethylated CpG motifs as a vaccine adjuvant (CpG ODN). The efficacy of the vaccine-induced antibody response was tested in a cecal ligation and puncture model. RESULTS: Immunization resulted in a >20-fold increase in anti-core glycolipid antibody levels, which were further increased 5-fold by the addition of CpG ODN, compared with the levels in mice in the control group. The vaccine provided a survival advantage after a cecal ligation and puncture was performed (P < .01) and significantly decreased the levels of bacteria in organs. Immunoglobulin G (IgG) anti-core glycolipid antibodies were decreased in mice to a significantly greater extent than were levels of total circulating IgG or IgG to the OMP part of the vaccine complex, suggesting specific epitope binding and clearance. CONCLUSIONS: These results indicate that the detoxified LPS-J5/OMP vaccine induces high levels of antibody against the core glycolipid of LPS and functions in vivo to promote clearance of gram-negative bacteria and improve the outcome of experimental polymicrobial intra-abdominal sepsis.

Inter-alpha-inhibitor proteins are endogenous furin inhibitors and provide protection against experimental anthrax intoxication.

Inter-alpha-inhibitor protein (IalphaIp) functions as an endogenous serine protease inhibitor in human plasma, and IalphaIp levels diminish rapidly during acute inflammatory states. One potential target for IalphaIp is furin, a cell-associated serine endopeptidase essential for the activation of protective antigen and the formation of anthrax lethal toxin (LT). IalphaIp blocks furin activity in vitro and provides significant protection against cytotoxicity for murine peritoneal macrophages exposed to up to 500 ng/ml LT. A monoclonal antibody (MAb), 69.31, that specifically blocks the enzymatic activity of IalphaIp eliminates its protective effect against LT-induced cytotoxicity. IalphaIp (30 mg/kg of body weight) administered to BALB/c mice 1 hour prior to an intravenous LT challenge resulted in 71% survival after 7 days compared with no survivors among the control animals (P < 0.001). We conclude that human IalphaIp may be an effective preventative or therapeutic agent against anthrax intoxication.

Chloroquine enhances survival in Bacillus anthracis intoxication.

The intentional release of anthrax in the United States in 2001 resulted in 11 cases of inhalational disease, with an attendant mortality rate of 45%. Current therapeutic options for anthrax are limited; antimicrobials target only replicating organisms, thus allowing bacterial toxins to cause unchecked, devastating physiological derangements in the host. Novel approaches that target the cytotoxic effects of anthrax exotoxins are needed. Chloroquine (CQ), a commonly used antimalarial agent, endows anthrax-intoxicated murine peritoneal macrophages with a 50% and 35% marginal survival advantage at 2 and 4 h, respectively, over that of untreated control cells. The cell rescue is dose dependent and, at lower concentrations, results in delayed cell death. We subsequently studied the effect of CQ in BALB/c mice challenged with anthrax lethal toxin. CQ-treated mice demonstrated reduced tissue injury, as assessed by histopathological examination of the spleen and by peripheral blood differential cell count ratios. CQ significantly enhanced survival and may augment current treatment and prophylaxis options for this otherwise lethal infection.

Phase I study of detoxified Escherichia coli J5 lipopolysaccharide (J5dLPS)/group B meningococcal outer membrane protein (OMP) complex vaccine in human subjects.

We previously observed that a detoxified Escherichia coli O111, Rc chemotype J5 lipopolysaccharide (J5dLPS)/group B meningococcal outer membrane protein (OMP) vaccine protected animals from experimental lethal sepsis when immune antibodies were given passively as treatment at the onset of fever or when vaccine was given actively as prophylaxis. To test the safety and immunogenicity of this vaccine, we administered doses of 5, 10 and 25 microg (based on dLPS) of vaccine at days 0, 28 and 56 to 24 human subjects (8 per group). Temperatures of 100.3, 99.5 and 99.4 degrees F occurred in three subjects. At 24h, pain at the injection site was moderate in 38%, mild in 44% and not present in 18%, while at 48 h, it was 1, 25 and 73%, respectively. No alterations in baseline renal, hepatic or hematologic functions occurred. There were two to three times mean-fold increases in anti-J5dLPS IgG (range: 1.9-5.1) and IgM (range: 1.2-9.2) levels in subjects receiving the 10 and 25 microg doses. At 12-month follow-up, three of the original responders had continued elevation of antibody levels. A 25 microg booster dose of vaccine did not increase antibody levels among those responders and did not elicit antibodies among three subjects with no previous antibody response. The plasma from the six volunteers inhibited LPS-induced cytokine generation in human whole blood ex vivo. We conclude that this J5dLPS/OMP vaccine was safe and well-tolerated with transient, local pain at the injection site. Vaccine formulations with different adjuvants are currently under investigation.

Correlation between mortality and the levels of inter-alpha inhibitors in the plasma of patients with severe sepsis.

Inter-alpha inhibitor protein (IalphaIp) is an endogenous serine protease inhibitor in human plasma. Circulating IalphaIp levels were lower in 51 patients with severe sepsis than in healthy volunteers. Mean levels were 688+/-295 mg/L in patients with severe sepsis who survived (n=32), 486+/-193 mg/L in patients with sepsis who died (n=19), and 872+/-234 mg/L in control subjects (n=25). IalphaIp levels were lower in patients with shock versus those without (540+/-246 [n=33] vs. 746+/-290 [n=18] mg/L; P=.0102). IalphaIp levels were inversely correlated with 28-day mortality rates and Acute Physiology and Chronic Health Evaluation II scores and directly correlated with antithrombin III, protein C, and protein S levels. The administration of IalphaIp (30 mg/kg body weight intravenously) increased the 50% lethal dose in mice by 100-fold after an intravenous challenge of Escherichia coli. Thus, human IalphaIp may be a useful predictive marker and potential therapeutic agent in sepsis.

Effect of anti-CD14 monoclonal antibody on clearance of Escherichia coli bacteremia and endotoxemia.

OBJECTIVE: To determine the effects of an anti-CD14 monoclonal antibody on the clearance of a bacteremic Escherichia coli challenge in the presence or absence of antimicrobial agents. DESIGN: Prospective randomized animal study. SETTING: University-affiliated research laboratory. SUBJECTS: New Zealand White rabbits weighing 1.5-2.5 kg. INTERVENTIONS: Animals were pretreated with either an anti-lapine CD14 monoclonal antibody (immunoglobulin G2a, 5 mg/kg intravenously) or an isotype control monoclonal antibody. The animals then were challenged with 1 x 10(6) E. coli 018:K1 in the presence or absence of ceftazidime (50 mg/kg intravenously). There were four groups of six animals randomized to receive either anti-CD14 monoclonal antibody without ceftazidime, isotype control monoclonal antibody without ceftazidime, anti-CD14 monoclonal antibody with ceftazidime, or isotype control antibody with ceftazidime. MEASUREMENTS AND MAIN RESULTS: Serial measurement of quantitative bacteremia and endotoxemia was performed over 24 hrs after the administration of the bacterial challenge. Animals also underwent necropsy with quantitative bacterial cultures from multiple organ tissue samples. The anti-lapine CD14 monoclonal antibody significantly impaired the bloodstream clearance of E. coli (p <.01) and increased quantitative counts of E. coli in tissue culture samples when compared with isotype control antibody in the absence of simultaneous administration of ceftazidime. No differences in quantitative bacteremia, endotoxemia, or organ tissue counts were found after anti-CD14 antibody and control antibody-treated animals in the presence of ceftazidime treatment. CONCLUSIONS: Anti-CD14 monoclonal antibody has the capacity to interfere with the innate immune response and systemic microbial clearance in experimental animals with E. coli bacteremia. The concomitant administration of effective antimicrobial therapy eliminated differences in the rate of microbial clearance between the control antibody and the CD14 monoclonal antibody. These results indicate that care should be taken in clinical trials with anti-CD14 monoclonal antibodies to ensure that adequate antimicrobial therapy is administered in the presence of systemic bacterial infection.