Retention of neutralising activity by recombinant anti-pneumolysin antibody fragments.
The variable domains of a neutralising (prevents erythrocyte lysis) anti-pneumolysin monoclonal antibody have been cloned and expressed as functional protein in Escherichia coli. Purification of the anti-pneumolysin single-chain antibody fragment, via antibody-affinity or metal-chelate affinity chromatography, resulted in product that was predominantly in a dimeric or monomeric form, respectively. The dimeric single-chain antibody fragment showed a higher sensitivity and affinity for immobilised antigen in both ELISA and BIAcore studies. The dimeric single-chain antibody fragment was as effective at protecting erythrocytes from lysis as the parent monoclonal. The monomeric, low affinity single-chain antibody fragment, showed reduced neutralising potency. As antibiotic resistant Streptococcus pneumoniae strains continue to show an increasing word-wide distribution, recombinant, neutralising antibody fragments, may provide an additional class of molecules useful in the treatment of toxaemia.
Garcia
M
M
Department of Molecular and Cell Biology, Institute of Medical Sciences, Foresterhill, Aberdeen, UK.
Strachan
G
G
Porter
A J
AJ
Harris
W J
WJ
D000818:Animals; D000907:Antibodies, Bacterial / Q000235:genetics / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology; D000915:Antibody Affinity; D000937:Antigen-Antibody Reactions; D001426:Bacterial Proteins; D003001:Cloning, Molecular; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007128:Immunoglobulin Fragments / Q000235:genetics / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000276:immunology; D007147:Immunoglobulin Light Chains / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D011994:Recombinant Proteins / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000276:immunology*; D013301:Streptolysins / Q000276:immunology*
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D007128:Immunoglobulin Fragments; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D011994:Recombinant Proteins; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae