title: In vitro reduction of endotoxin concentrations with the 5S fragment of immunoglobulin G.
abstract: Endotoxin has long been implicated as an inducer for the development and progression of gram-negative sepsis. Accordingly, antiendotoxin therapy has been considered one of the major targets for the treatment of sepsis. To investigate the influence of a human immunoglobulin G (IgG) derivative, the 5S fragment of IgG (5S-IgG; Gamma-Venin, Centeon Pharma GmbH, Frankfurt-Niederrad, Germany), on endotoxin release during bacterial proliferation and under antibiotic bactericidal action, time-kill studies were performed by using Escherichia coli ATCC 25922 starting inocula of 10(3), 10(5), and 10(7) CFU/ml with cefotaxime (120 microg/ml) alone and in combination with 5S-IgG (2,100 microg/ml). Samples were collected for bacterial colony count and endotoxin concentration determinations; the area under the free endotoxin concentration curve (AUFEC) was calculated by using the trapezoidal rule. Colony counts showed that cefotaxime had a rapid bactericidal effect because it achieved greater than a 4-log decrease in the numbers of E. coli CFU per milliliter over the first 2 h; the addition of 5S-IgG did not appear to alter the kinetics of killing. Comparison of the AUFEC revealed that the addition of 5S-IgG resulted in a mean reduction of 50, 66, and 27% in the free endotoxin concentration at starting inocula of 10(3), 10(5), and 10(7) CFU/ml, respectively. Moreover, experiments were conducted with a starting inoculum of 10(5) CFU/ml and various amounts of 5S-IgG (2 to 20 mg/ml) to further investigate the dose-effect relation of 5S-IgG on endotoxin release. Decreased AUFECs were observed with increasing concentrations of 5S-IgG, suggesting the dose-dependent antiendotoxin activity of 5S-IgG. Further study is required to investigate the mechanism(s) responsible for this observation, the biological significance of this antiendotoxin activity, and the potential utility of 5S-IgG as an adjuvant therapy in the treatment of gram-negative sepsis.
authors.affiliation: Section of Pharmacy Research, Hartford Hospital, Connecticut 06102, USA.
authors.forename: D
authors.initials: D
authors.lastname: Xuan
authors.forename: D P
authors.initials: DP
authors.lastname: Nicolau
authors.forename: P R
authors.initials: PR
authors.lastname: Tessier
authors.forename: L
authors.initials: L
authors.lastname: Bow
authors.forename: R
authors.initials: R
authors.lastname: Quintiliani
authors.forename: C H
authors.initials: CH
authors.lastname: Nightingale
mesh_terms: D002439:Cefotaxime / Q000627:therapeutic use; D002511:Cephalosporins / Q000627:therapeutic use; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000187:drug effects*; D006801:Humans; D007128:Immunoglobulin Fragments / Q000627:therapeutic use*; D007074:Immunoglobulin G / Q000737:chemistry / Q000627:therapeutic use*; D007700:Kinetics; D008070:Lipopolysaccharides / Q000378:metabolism*; D008826:Microbial Sensitivity Tests
chemical_list: D002511:Cephalosporins; D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D002439:Cefotaxime