• 作者： 張均昌
• 作者服務機構： 私立高雄醫學院生物化學科
• 中文摘要： 利用親和層析法，可以從抗結晶毒素(Anti-cobrotoxin)家兔血清中，不但可分離沉澱性抗體，而且亦可得到非沈澱性抗體。比較兩者間之免疫化學及物理化學性質結果，其分子大小，膠電泳分析，DEAE-Cellulose層析型，以及抗原性等皆有相似性質，但非沉澱性抗體對結合於Sepharose上之結晶毒素的結合能力較沉澱性抗體為低。 抗結晶毒素IgG或非沉澱性抗體吸著於Cobrotoxin-Sepharose上後，利用各種不同pH之緩衡液溶出之各分劃，其特異中和力價隨其結合能力之強弱而增減，但從沉澱性抗體所分離出來之各分劃則呈近似的特異中和力價，且較IgG或非沈澱性抗體之相對分劃為低。 沉澱性或非沉澱性抗體吸著於Cobrotoxin-Sepharose後分離出來之主要分劃，再經DEAF-Cellulose層析法精製，以Mercuri-papain水解後得到之Fab斷片，再經以pepsin消化後得到之消化物，利用高壓電泳法及濾紙層析法分析結果，兩者呈顯不同之peptide map，表示沉澱性及非沉澱性抗體之氨基酸組成有明顯之差異。 Polyethylene glycol對非沉澱性抗體與其抗原間之沉澱反應具有輕度之促進效果。
• 英文摘要： By using affinity chromatography, non-precipitating antibody was isolated from sera of rabbits hyperimmunized with cobrotoxin in Freund's. complete abjuvant. The physico-chemical characteristies and immunochemical properties of precipitating and non-precipitating antibodies localized in the same immunoglobulin fraction were compared. Both precipitating and non-precipitating antibodies were similar with regard to the molecular size, electrophoretic distribution, elution pattern on DEAE-cellulose column, and antigenicity for the production of homologous and cross-reactive antibodies in goats. The specific neutralizing capacity of several populations of antibodies isolated by stepwise elution of anti-cobrotoxin IgG or non-precipitaitng antibody adsorbed on cobrotoxin-Sepharose at different pH increased in order of magnitude depending on the strength of binding affinity of antibody to cobrotoxin-Sepharose. The antibodies isolated from precipitating antibody had almost the same capacity but relatively lower than that of corresponding antibodies isolated from non-precipitating antibody or IgG. The main populations of antibodies isolated from precipitating and non-precipitating antibodies by stepwise elution at different pH as described above were further purified by chromatography on DEAE-cellulose column and the main protein fractions were subjected to fragmentation by digestion with mercuripapain. The isolated Fab fragments were digested with pepsin after reduction and carboxymethylation. Striking differences in peptide maps were observed between the two preparations, suggesting that the amino acid compositions of precipitating and non-precipitating antibodies are different from each other. Polyethylene glycol slightly enhances the precipitation of non-precipitating antibody with homologous antigen.
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