A novel peptide inhibitor of classical and lectin complement activation including ABO incompatibility.
Previous experiments from our laboratories have identified peptides derived from the human astrovirus coat protein (CP) that bind C1q and mannose binding lectin (MBL) inhibiting activation of the classical and lectin pathways of complement, respectively. The purpose of this study was to evaluate the function of these coat protein peptides (CPPs) in an in vitro model of complement-mediated disease (ABO incompatibility), preliminarily assess their in vivo complement suppression profile and develop more highly potent derivatives of these molecules. E23A, a 30 amino acid CPP derivative previously demonstrated to inhibit classical pathway activation was able to dose-dependently inhibit lysis of AB erythrocytes treated with mismatched human O serum. Additionally, when injected into rats, E23A inhibited the animals' serum from lysing antibody-sensitized erythrocytes, providing preliminary in vivo functional evidence that this CPP can cross the species barrier to inhibit serum complement activity in rodents. A rational drug design approach was implemented to identify more potent CPP derivatives, resulting in the identification and characterization of a 15 residue peptide (polar assortant (PA)), which demonstrated both superior inhibition of classical complement pathway activation and robust binding to C1q collagen-like tails. PA also inhibited ABO incompatibility in vitro and demonstrated in vivo complement suppression up to 24h post-injection. CPP's ability to inhibit ABO incompatibility in vitro, proof of concept in vivo inhibitory activity in rats and the development of the highly potent PA derivative set the stage for preclinical testing of this molecule in small animal models of complement-mediated disease.
Department of Pediatrics, Eastern Virginia Medical School, 855 West Brambleton Avenue, Norfolk, VA 23510, United States.
Clifford T
CT
Mauriello
Haree K
HK
Pallera
Julia A
JA
Sharp
Jon L
JL
Woltmann
Shizhi
S
Qian
Pamela S
PS
Hair
Pieter
P
van der Pol
Cees
C
van Kooten
Nicole M
NM
Thielens
Frank A
FA
Lattanzio
Kenji M
KM
Cunnion
Neel K
NK
Krishna
D000017:ABO Blood-Group System / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D001787:Blood Group Incompatibility / Q000188:drug therapy*; D036022:Capsid Proteins / Q000737:chemistry / Q000494:pharmacology*; D003171:Complement Pathway, Classical / Q000187:drug effects*; D037582:Complement Pathway, Mannose-Binding Lectin / Q000187:drug effects*; D006801:Humans; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D020349:Surface Plasmon Resonance
D000017:ABO Blood-Group System; D036022:Capsid Proteins; D010455:Peptides