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Prevention of experimental autoimmune myasthenia gravis by rat Crry-Ig: A model agent for long-term complement inhibition in vivo.

Hepburn NJ, Chamberlain-Banoub JL, Williams AS, Morgan BP, Harris CL - Mol. Immunol. (2007)

Bottom Line: Fusion of these domains to rat IgG2a Fc generated an effective complement inhibitor (rCrry-Ig) with a circulating half-life prolonged from 7 min for Crry alone to 53 h for rCrry-Ig.Systemic administration of rCrry-Ig over 5 weeks generated a weak immune response to the recombinant agent, however this was predominantly IgM in nature and did not neutralise Crry function or cause clearance of the agent from plasma.The long half-life and low immunogenicity of this agent will be useful for therapy in chronic models of inflammatory disease in the rat.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Biochemistry and Immunology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, United Kingdom.

ABSTRACT
Despite its vital role in innate immunity, complement is involved in a number of inflammatory pathologies and has therefore become a therapeutic target. Most agents generated for anti-complement therapy have short half-lives in plasma, or have been of mouse or human origin, thereby limiting their use either to murine models of disease or to short-term therapy. Here we describe the generation of a long-acting rat therapeutic agent based on the rat complement inhibitor, Crry. Characterisation of various soluble forms of Crry demonstrated that the amino-terminal four short-consensus repeat domains were required for full regulatory and C3b-binding activities. Fusion of these domains to rat IgG2a Fc generated an effective complement inhibitor (rCrry-Ig) with a circulating half-life prolonged from 7 min for Crry alone to 53 h for rCrry-Ig. Systemic administration of rCrry-Ig over 5 weeks generated a weak immune response to the recombinant agent, however this was predominantly IgM in nature and did not neutralise Crry function or cause clearance of the agent from plasma. Administration of rCrry-Ig completely abrogated clinical disease in a rat model of myasthenia gravis whereas soluble Crry lacking the immunoglobulin Fc domain caused a partial response. rCrry-Ig not only ablated clinical disease, but also prevented C3 and C9 deposition at the neuromuscular junction and inhibited cellular infiltration at this site. The long half-life and low immunogenicity of this agent will be useful for therapy in chronic models of inflammatory disease in the rat.

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In vivo half-life of rCrry-Ig and sCrry. Radiolabelled rCrry-Ig (■) and the sCrry reagent (▴) were administered to rats intravenously, blood was removed at specific time points and protein bound counts determined. This was expressed as a percent of protein bound counts present at 5 min post-administration and the beta phase half-life determined (Waller, 1994). Each data point represents the mean of five animals ±1S.D.
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fig4: In vivo half-life of rCrry-Ig and sCrry. Radiolabelled rCrry-Ig (■) and the sCrry reagent (▴) were administered to rats intravenously, blood was removed at specific time points and protein bound counts determined. This was expressed as a percent of protein bound counts present at 5 min post-administration and the beta phase half-life determined (Waller, 1994). Each data point represents the mean of five animals ±1S.D.

Mentions: To assess the effect the Fc had on the in vivo clearance of Crry, rCrry-Ig and sCrry were radiolabelled with 125I. A single intravenous dose of either reagent was administered to rats and samples of blood were removed at intervals and protein bound counts were measured. sCrry was rapidly cleared from the circulation with a half-life of 7 min. rCrry-Ig had a significantly prolonged half-life of 53 h (p < 0.001) (Fig. 4).


Prevention of experimental autoimmune myasthenia gravis by rat Crry-Ig: A model agent for long-term complement inhibition in vivo.

Hepburn NJ, Chamberlain-Banoub JL, Williams AS, Morgan BP, Harris CL - Mol. Immunol. (2007)

In vivo half-life of rCrry-Ig and sCrry. Radiolabelled rCrry-Ig (■) and the sCrry reagent (▴) were administered to rats intravenously, blood was removed at specific time points and protein bound counts determined. This was expressed as a percent of protein bound counts present at 5 min post-administration and the beta phase half-life determined (Waller, 1994). Each data point represents the mean of five animals ±1S.D.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2572221&req=5

fig4: In vivo half-life of rCrry-Ig and sCrry. Radiolabelled rCrry-Ig (■) and the sCrry reagent (▴) were administered to rats intravenously, blood was removed at specific time points and protein bound counts determined. This was expressed as a percent of protein bound counts present at 5 min post-administration and the beta phase half-life determined (Waller, 1994). Each data point represents the mean of five animals ±1S.D.
Mentions: To assess the effect the Fc had on the in vivo clearance of Crry, rCrry-Ig and sCrry were radiolabelled with 125I. A single intravenous dose of either reagent was administered to rats and samples of blood were removed at intervals and protein bound counts were measured. sCrry was rapidly cleared from the circulation with a half-life of 7 min. rCrry-Ig had a significantly prolonged half-life of 53 h (p < 0.001) (Fig. 4).

Bottom Line: Fusion of these domains to rat IgG2a Fc generated an effective complement inhibitor (rCrry-Ig) with a circulating half-life prolonged from 7 min for Crry alone to 53 h for rCrry-Ig.Systemic administration of rCrry-Ig over 5 weeks generated a weak immune response to the recombinant agent, however this was predominantly IgM in nature and did not neutralise Crry function or cause clearance of the agent from plasma.The long half-life and low immunogenicity of this agent will be useful for therapy in chronic models of inflammatory disease in the rat.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Biochemistry and Immunology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, United Kingdom.

ABSTRACT
Despite its vital role in innate immunity, complement is involved in a number of inflammatory pathologies and has therefore become a therapeutic target. Most agents generated for anti-complement therapy have short half-lives in plasma, or have been of mouse or human origin, thereby limiting their use either to murine models of disease or to short-term therapy. Here we describe the generation of a long-acting rat therapeutic agent based on the rat complement inhibitor, Crry. Characterisation of various soluble forms of Crry demonstrated that the amino-terminal four short-consensus repeat domains were required for full regulatory and C3b-binding activities. Fusion of these domains to rat IgG2a Fc generated an effective complement inhibitor (rCrry-Ig) with a circulating half-life prolonged from 7 min for Crry alone to 53 h for rCrry-Ig. Systemic administration of rCrry-Ig over 5 weeks generated a weak immune response to the recombinant agent, however this was predominantly IgM in nature and did not neutralise Crry function or cause clearance of the agent from plasma. Administration of rCrry-Ig completely abrogated clinical disease in a rat model of myasthenia gravis whereas soluble Crry lacking the immunoglobulin Fc domain caused a partial response. rCrry-Ig not only ablated clinical disease, but also prevented C3 and C9 deposition at the neuromuscular junction and inhibited cellular infiltration at this site. The long half-life and low immunogenicity of this agent will be useful for therapy in chronic models of inflammatory disease in the rat.

Show MeSH
Related in: MedlinePlus