Non-immune VH-binding specificity of human protein Fv.
The specificity of human F(ab)-binding Protein Fv (previously called Protein F), a sialoprotein released into the digestive tract mainly during hepatitis, was investigated with fragments or chains of monoclonal immunoglobulins. Protein Fv bound an unreduced H-chain dimer of a monoclonal human IgA2m(1) molecule but neither the corresponding L-chain dimer, nor several Bence-Jones molecules. Using enzymatic subfragments of F(ab)mu, or F(ab')2 gamma, a significant binding was observed with Fv fragments (VH + VL), while Fb fragments (CH1 + CL) were inactive. Taken altogether, these results prove that the structure recognized by Protein Fv is located in the VH domain. This structure probably involves discontinuous epitopes linked by a disulphide bond, which are destroyed by combined reduction and dissociation. Protein Fv does not interfere with the antigen-binding site, since there was no reciprocal inhibition with the antigen-antibody reaction.
Bouvet
J P
JP
Unité d'Immunologie Microbienne, WHO Center of Reference and Research on Viral Hepatitis, Institut Pasteur, Paris, France.
Pires
R
R
Quan
C
C
Iscaki
S
S
Pillot
J
J
D002851:Chromatography, High Pressure Liquid; D004229:Dithiothreitol / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D006526:Hepatitis C / Q000276:immunology; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000276:immunology*; D007147:Immunoglobulin Light Chains / Q000276:immunology*; D007136:Immunoglobulins / Q000187:drug effects; D008222:Lymphokines / Q000378:metabolism*; D012795:Sialoglycoproteins / Q000378:metabolism* / Q000502:physiology*
D000939:Epitopes; C089422:Fv protein, human; D006146:Guanidines; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007136:Immunoglobulins; D008222:Lymphokines; D012795:Sialoglycoproteins; D019791:Guanidine; D004229:Dithiothreitol