Immunogen
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Human J chain is a polypeptide folded within the polymeric structure of the immunoglobulin. J chain isolated form human polymeric IgA and IgM are identical by criteria of composition, peptide maps and antigenicity. Human J chain has been established as distinct from all other component chains of polymeric IgA and IgM. It has a unique primary structure. Antisera to light chains or heavy chains of human Immunoglobulins do not react with J chain. J chain is released from dimeric human myeloma IgA by sulphitolysis and purified by ion exchange chromatography in urea and gel filtration in guanidine. Its purity is tested in alkaline urea polyacrylamide gel electrophoresis, in immunodiffusion and immunoelectrophoresis, showing it to be free of IgA, heavy or light chain contaminants. Freund's complete adjuvant is used in the first step of the immunization procedure.
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Isotype
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IgG
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Specificity
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The reactivity of the antiserum is restricted to J chain as tested in immunoelectrophoresis and radial immunodiffu-sion. The antiserum shows a single precipitation reaction with totally reduced and alkylated polyclonal and monoclonal polymeric IgA and IgM. No reaction is obtained with the intact polyclonal or monoclonal IgA, IgM and IgG. There is also no detectable reaction with normal human serum, normal human milk, purified Ig heavy and light chains and secretory component. However a single precipitin line can be obtained with human serum after two hours incubation with 9 M urea and 0. 2 M mercaptoethanol at pH 8. 6, and this shows a reaction of identity with the precipitin line obtained with the purified immunogen
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Characteristics
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Precipitating polyclonal rabbit antiserum to human J chain Total protein and IgG concentrations in the antiserum are comparable to those of pooled normal rabbit serum. Antibody titre: Precipitin titre 1:32 when tested in agar-block immunodiffusion titration against a 1 % solution of puri
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Purification
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Delipidated, heat inactivated, lyophilized, stable whole antiserum Immunoaffinity adsorbed using insolubilized antigens as required, to eliminate antibodies reacting with other serum proteins. The use of insolubilized adsorption antigens prevents the presence of excess adsorbent protein or immune complexes in the antiserum.
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