Biological activities of anti-LPS factor and LPS binding peptide from horseshoe crab amoebocytes

A first-in-class, first-in-human, phase I trial of CIGB-552, a synthetic peptide targeting COMMD1 to inhibit the oncogenic activity of NF-κB in patients with advanced solid tumors

CIGB-552 is a synthetic peptide that interacts with COMMD1 and upregulates its protein levels. The objectives of this phase I study were safety, pharmacokinetic profile, evaluation of the lymphocytes CD4+ and CD8+ and preliminary activity in patients with advanced tumors. A 3 + 3 dose-escalation design with seven dose levels was implemented. Patients were included until a grade 3 related adverse event occurred and the maximum tolerated dose was reached. The patients received subcutaneous administration of CIGB-552 three times per week for 2 weeks. Single-dose plasma pharmacokinetics was characterized at two dose levels, and tumor responses were classified by RECIST 1.1. Twenty-four patients received CIGB-552. Dose-limiting toxicity was associated with a transient grade 3 pruritic maculopapular rash at a dose of 7.0 mg. The maximum tolerated dose was defined as 4.7 mg. Ten patients were assessable for immunological status. Seven patients had significant changes in the ratio CD4/CD8 in response to CIGB-552 treatment; three patients did not modify the immunological status. Stable disease was observed in five patients, including two metastatic soft sarcomas. We conclude that CIGB-552 at dose 4.7 mg was well tolerated with no significant adverse events and appeared to provide some clinical benefits.

Delayed therapy with a polymyxin B-dextran conjugate (PMX-622) improves survival in rabbits with Gram-negative peritonitis

Polymyxin B (PMB) is an amphipathic nephrotoxic antibiotic, which has been shown to neutralize the effects of endotoxin both in vitro and in vivo. PMB-D70 (PMX-622), a covalent conjugate of PMB with dextran 70 (D70), is less nephrotoxic than the parent compound. We sought to determine whether therapy with PMB-D70, in addition to conventional antimicrobial chemotherapy, could improve survival in a model of Gram-negative peritonitis. At T = 0 h, New Zealand white rabbits were implanted intraperitoneally with 10 ml of a suspension containing hemoglobin (40 μg/ml), mucin (150 μg/ml), and 1.0 ± 0.2 x 104 cfu/kg of viable Escherichia coli (O18:K1). Beginning at T = 4 h, the rabbits were treated with gentamicin (5 mg/kg every 12 h) for five doses or until death, and infused for 24 h or until death with either D70 or PMB-D70. Two pairs of groups were studied (doses indicate cumulative amounts infused over 24 h). The PMB-D70 (low dose) group received PMB-D70 (5 mg/kg of the PMB component) and the D70 (low dose) group received an equivalent dose of D70. The PMB-D70 (high dose) group received PMB-D70 (10 mg/kg of the PMB component) and the D70 (high dose) group received an equivalent dose of D70. Results for the two PMB-D70 groups, on the one hand, and the two D70 group, on the other hand, were statistically indistiguishable and, accordingly, were pooled for all analyses. Survival at 7 days was 11/25 (44%) for rabbits treated with PMB-D70 as compared to 2/23 (9%) for animals treated with D70 ( P = 0.007). We conclude that adjuvant treatment with PMB-D70 improves survival in a clinically relevant model of Gram-negative sepsis.

Identification and expression analysis on bactericidal permeability-increasing protein (BPI)/lipopolysaccharide-binding protein (LBP) of ark shell, Scapharca broughtonii

Bactericidal permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are the numbers of the lipid transfer protein/lipopolysaccharide-binding protein family and play crucial roles in the innate immune response to Gram-negative bacteria. A novel Sb-BPI/LBP1 from ark shell Scapharca broughtonii was isolated by expressed sequence tag (EST) and RACE techniques. The Sb-BPI/LBP1 cDNA encoded a polypeptide of 484 amino acids with a putative signal peptide of 21 amino acid residues and a mature protein of 463 amino acids. The deduced amino acid sequence of Sb-BPI/LBP1 contained an N-terminal BPI/LBP/CETP domain BPI1 with three functional regions that display LPS-binding activity, and a C-terminal BPI/LBP/CETP domain BPI2. In structure and sequence, Sb-BPI/LBP1 showed highly similar to those of the BPI/LBPs from invertebrate and non-mammalian vertebrate, the LBPs and BPIs from mammal. By quantitative real-time RT-PCR, Sb-BPI/LBP1 transcripts could be detected in all normal tested tissues, including hepatopancreas, adductor muscle, mantle margin, heart, gonad, gill and hemocytes, and was universally up-regulatable at 24 h post LPS challenge. The mRNA expression of Sb-BPI/LBP1 in hemocytes was the most sensitive to LPS challenge, significantly up-regulated at 12 h post LPS challenge and peaked at 24 h (16.76-fold, P < 0.05). These results suggested that Sb-BPI/LBP1 was a constitutive and inducible acute-phase protein contributing to the host immune defense against Gram-negative bacterial infection in ark shell S. broughtonii.

Cloning and characterization of a LPS-regulatory gene having an LPS binding domain in kuruma prawn Marsupenaeus japonicus

LPS is known as an effective stimulator of the immune system in various animals, including mammals and horseshoe crabs (HSC). Both of these animal groups have suppressive regulatory proteins for the LPS response, e.g. the bactericidal/permeability increasing protein in mammals and anti-LPS factor (ALF) in HSC. Prawns are a valuable aquaculture species, but the regulatory molecules and/or mechanisms that respond to LPS are largely unknown. To investigate the molecular mechanism of the LPS response in kuruma prawns, we cloned a cDNA having a LPS binding domain. A full-length cDNA gene, denoted as M-ALF (Marsupenaeus japonicus ALF-like peptide) was cloned that consisted of 746bp and encoded 123 amino-acid residues. The 3' non-translated region of this gene had the pentamer of ATTTA repeated four times; this is known as sequences for messenger RNA stabilization. Deduced amino-acid sequences showed a 42% homology with Japanese HSC-ALF. In particular, both have clusters of basic and hydrophobic amino acids, indicating that the region is probably binding to lipid A. The mRNA expression was determined for hemocytes, lymphoid organs, hearts, intestines and gills by RT-PCR. The mRNA expression was augmented 1.5-3h after LPS administration in lymphoid organs, but then decreased to normal level at 6h. Synthetic peptides containing Cys30 to Cys51 had LPS neutralizing activity to the Limulus reaction and NO production in RAW264.7 cells. These data suggest that in kuruma prawns, M-ALF acts as a LPS regulator during the acute phase response after invasion of pathogens.

A comparison of bactericidal/permeability-increasing protein variant versus recombinant endotoxin-neutralizing protein for the treatment of Escherichia coli sepsis in rats

OBJECTIVE

To compare a recombinant bactericidal/permeability-increasing protein variant and a recombinant endotoxin-neutralizing protein.

DESIGN

Randomized, blinded, controlled study, using a rat model of sepsis.

SETTING

Animal research facility.

SUBJECTS

Male Wistar rats.

INTERVENTIONS

An inoculum of 1.5 x 10(7) to 1.8 x 10(8) Escherichia coli O18ac K1, implanted in the peritoneum, produced bacteremia in 95% of animals after 1 hr. One hour after E. coli challenge, animals received recombinant bactericidal/permeability-increasing protein variant, recombinant endotoxin-neutralizing protein, or saline intravenously, followed by ceftriaxone and gentamicin intramuscularly.

MEASUREMENTS AND MAIN RESULTS

Twenty-four (85.7%) of 28 animals receiving recombinant endotoxin-neutralizing protein (p < .001 vs. control) survived 7 days compared with nine (33.3%) of 27 recombinant bactericidal/permeability-increasing protein variant-treated (p < .001 vs. control) and two (6.5%) of 31 control animals.

CONCLUSIONS

Both recombinant endotoxin-neutralizing protein and recombinant bactericidal/permeability-increasing protein variant improved survival. Recombinant endotoxin-neutralizing protein was superior to recombinant bactericidal/permeability-increasing protein variant in its protective effect at the doses tested. Our results suggest that both proteins may be useful in the treatment of human Gram-negative sepsis.

Recombinant endotoxin neutralizing protein improves survival from Escherichia coli sepsis in rats

OBJECTIVE

A recombinant endotoxin neutralizing protein was evaluated for its ability to ameliorate the effects of Escherichia coli sepsis in rats.

DESIGN

Prospective, controlled animal trial.

SETTING

Hospital animal research laboratory.

SUBJECTS

Wistar rats, treated with gentamicin 1 hr after challenge with intraperitoneal E. coli O18ac.

INTERVENTIONS

The animals received a recombinant endotoxin neutralizing protein, in doses of 5, 25, or 50 mg/kg, either 30 or 60 mins after challenge; controls received saline.

MEASUREMENTS AND MAIN RESULTS

Geometric mean serum endotoxin concentrations in endotoxin neutralizing protein-treated animals did not differ from control animals. Tumor necrosis factor concentrations in animals treated with endotoxin neutralizing protein 30 mins after challenge were significantly lower than controls. Animals treated with 25 or 50 mg/kg of endotoxin neutralizing protein 30 mins after E. coli challenge had significant improvements in survival compared with controls. Animals treated with 50 mg/kg of endotoxin neutralizing protein 60 mins after E. coli challenge had significant improvements in survival compared with controls.

CONCLUSION

Endotoxin neutralizing protein significantly reduces mortality from Gram-negative sepsis in an antibiotic-treatment model of E. coli peritonitis and bacteremia in rats, mediated by a neutralization of the biological effects of endotoxin.