title: Pharmacokinetics and immunologic consequences of repeated administrations of purified heterologous and homologous butyrylcholinesterase in mice.
abstract: OBJECTIVE
  To assess the consequences of repeated administrations of purified human serum butyrylcholinesterase (Hu BChE) and mouse serum (Mo) BChE into mice.
  
  
  METHODS
  Purified Hu BChE and Mo BChE isolated from the sera of CD-1 mice were administered into Balb/c or CD-1 mice. The enzymes were delivered by i.m. injections of approximately 100U (0.15mg) on day 1 and on day 28, respectively. The effects of two injections were monitored by following blood BChE and anti-BChE IgG levels.
  
  
  RESULTS
  Hu BChE displayed a mean residence time (MRT) of 50h, and an area under the curve (AUC) of 1220U/ml.h in Balb/c or CD-1 mice. Mo BChE exhibited an MRT of 78h and an AUC of 1815U/ml.h in Balb/c mice; the AUC increased to 2504U/ml.h in CD-1 mice. A second injection of Hu BChE in both strains exhibited a marked reduction in circulatory stability. The circulatory stability of the second injection of Mo BChE was reduced in Balb/c mice, but was almost identical to the first injection in CD-1 mice. Consistent with these observations, circulating anti-BChE IgGs were observed in mice injected with Hu BChE; low levels of anti-BChE IgGs were observed only in Balb/c mice injected with Mo BChE. No antibody response was detected in CD-1 mice following either injection of homologous Mo BChE.
  
  
  CONCLUSIONS
  The identical pharmacokinetic profiles and the absence of an immunologic response following a second administration of homologous BChE support the development of Hu BChE as a detoxifying drug in humans.
authors.affiliation: Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.forename: Chunyuan
authors.initials: C
authors.lastname: Luo
authors.forename: Ramachandra S
authors.initials: RS
authors.lastname: Naik
authors.forename: Bhupendra P
authors.initials: BP
authors.lastname: Doctor
authors.forename: Ashima
authors.initials: A
authors.lastname: Saxena
mesh_terms: D000818:Animals; D002091:Butyrylcholinesterase / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000097:blood* / Q000187:drug effects; D007273:Injections, Intramuscular; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D013045:Species Specificity; D013997:Time Factors
chemical_list: D007136:Immunoglobulins; D002091:Butyrylcholinesterase