Recombinant human complement component C2 produced in a human cell line restores the classical complement pathway activity in-vitro: an alternative treatment for C2 deficiency diseases

Paolo G.v Martini ,Birgitta Gullstrand,Knut Langsetmo,Kate J Zaleski,Jason Lottherand,Lennart Truedsson,Scott Alderucci,Nancy Savioli,Göran Jönsson,Christian Lood ,Dianna Lundberg ,Michael W Heartlein ,Michael F Concino ,Jessica M Powell ,Angela W Norton ,Lynette Cook ,John Gill ,Charles Bédard ,Susan Fish ,Arthur O Tzianabos

doi:10.1186/1471-2172-11-43

Paolo G.v Martini , Birgitta Gullstrand + Show 18 more

Open Access

https://doi.org/10.1186/1471-2172-11-43

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Abstract

BackgroundComplement C2 deficiency is the most common genetically determined complete complement deficiency and is associated with a number of diseases. Most prominent are the associations with recurrent serious infections in young children and the development of systemic lupus erythematosus (SLE) in adults. The links with these diseases reflect the important role complement C2 plays in both innate immunity and immune tolerance. Infusions with normal fresh frozen plasma for the treatment of associated disease have demonstrated therapeutic effects but so far protein replacement therapy has not been evaluated.ResultsHuman complement C2 was cloned and expressed in a mammalian cell line. The purity of recombinant human C2 (rhC2) was greater than 95% and it was characterized for stability and activity. It was sensitive to C1s cleavage and restored classical complement pathway activity in C2-deficient serum both in a complement activation ELISA and a hemolytic assay. Furthermore, rhC2 could increase C3 fragment deposition on the human pathogen Streptococcus pneumoniae in C2-deficient serum to levels equal to those with normal serum.ConclusionsTaken together these data suggest that recombinant human C2 can restore classical complement pathway activity and may serve as a potential therapeutic for recurring bacterial infections or SLE in C2-deficient patients.

Highlights

Complement complement component C2 (C2) deficiency is the most common genetically determined complete complement deficiency and is associated with a number of diseases
When mannose-binding lectin (MBL) or ficolins in complex with MBL-associated serine protease (MASP) molecules bind to relevant carbohydrate molecules, this leads to activation of MASP-2 which may cleave both C2 and C4 thereby forming the same C3 convertase as in classical pathway activation [5]
Protein Cloning and Expression The recombinant human C2 (rhC2) was highly expressed in human cells and shown to be purified very efficiently by a 2-step column chromatography process (Figure 1A) based on a modification and improvement of a procedure previously described [14,15]

Summary

Introduction

Complement C2 deficiency is the most common genetically determined complete complement deficiency and is associated with a number of diseases. Most prominent are the associations with recurrent serious infections in young children and the development of systemic lupus erythematosus (SLE) in adults The links with these diseases reflect the important role complement C2 plays in both innate immunity and immune tolerance. Deficiencies of complement components of the classical activation pathway, C1, C2 and C4, all lead to increased susceptibility to bacterial infections [2] and increased risk of developing autoimmune disease, systemic lupus erythematosus (SLE) [3]. C2 is an important component of both the classical and the lectin pathways of complement activation and is involved in first line defense against microbial infection that is essential for detection and clearance of the invading pathogens [6]

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