Aston R, Cooper L, Holder A, Ivanyi J, Preece M
Mol Immunol. 1985 Mar;22(3):271-5. doi: 10.1016/0161-5890(85)90161-0.
Monoclonal antibodies (MABs) prepared against human pituitary growth hormone (hGH) have been compared for their binding to pituitary-derived and genetically engineered methionyl growth hormone (met-hGH). The antibodies bind to four non-overlapping epitopes of which two are completely shared with human choronic somatomammotropin (hCS). The determinant defined by MAB NA27 was expressed on met-hGH to a lesser degree than on hGH of pituitary origin. However, another antibody, QA68, which binds to a determinant closely related to NA27, failed to discriminate between hGH and met-hGH. A further two MABs (EB1 and NA71) were similarly ineffective in distinguishing between the two forms of the hormone. The determinant recognized by antibody EB2 was equally represented on hGH and met-hGH when assessed by a liquid-phase radioimmunoassay: however, measurement of the binding in a solid-phase assay resulted in a two-four-fold lower binding to met-hGH. Bioactivity assessed by both an in vitro cell proliferation assay and an in vivo cartilage sulphation bioassay failed to distinguish between the two hormones. It is therefore concluded that the NH2-terminal methionine on bacterially derived growth hormone results in altered antigenicity of the hormone without any measurable effect on bioactivity.
已对针对人生长激素（hGH）制备的单克隆抗体（MABs）与垂体来源的和基因工程生产的甲硫氨酰生长激素（met-hGH）的结合情况进行了比较。这些抗体与四个不重叠的表位结合，其中两个表位与人绒毛膜促生长催乳素（hCS）完全相同。由单克隆抗体NA27所确定的决定簇在met-hGH上的表达程度低于垂体来源的hGH。然而，另一种与NA27紧密相关的决定簇结合的抗体QA68，无法区分hGH和met-hGH。另外两种单克隆抗体（EB1和NA71）在区分这两种形式的激素方面同样无效。当通过液相放射免疫测定评估时，抗体EB2识别的决定簇在hGH和met-hGH上的表现相同；然而，在固相测定中测量结合情况时，发现与met-hGH的结合降低了两到四倍。通过体外细胞增殖测定和体内软骨硫酸化生物测定评估的生物活性无法区分这两种激素。因此得出结论，细菌来源的生长激素上的NH2末端甲硫氨酸导致激素抗原性改变，但对生物活性没有任何可测量的影响。
