Barling P M, Hendy G N, Evans M C, O'Riordan J L
J Endocrinol. 1975 Sep;66(3):307-18. doi: 10.1677/joe.0.0660307.
Immunoassays specific for limited regions of bovine parathyroid hormone were developed in four ways. With the heterogeneous antisera produced by immunizing with intact bovine parathyroid hormone (BPTH 1-84), the specificity of radioimmunoassays could be enhanced by presaturating either with an amino-terminal (BPTH 1-34) or carboxy-terminal (BPTH 53-84) fragment. Then, the antibodies which had not been neutralized reacted exclusively with the opposite end of the molecule, even using [125I]BPTH 1-84 as tracer. With some antisera, the appropriate fragment and intact hormone reacted identically. However, with other antisera, the fragment reacted less well than the intact hormone, possibly because these antisera contain antibodies reacting with the middle of the molcule. Using the labelled fragment ([125I]BPTH 1-34) as tracer, with heterogeneous antisera, radioimmunoassays specific for the amino-terminal region were obtained. With one antiserum, BPTH 1.34 reached identically with the intact hormone, but with another antiserum, the fragment was more reactive than the intact molecule. A region-specific radioimmunoassay was also developed using antibodies produced by immunization with a fragment of the hormone. An antiserum raised against BPTH 1-34 had high affinity for the amino-terminal fragement, but reacted less well with the intact hormone. Immunoradiometric assays, specific for the amino- or carboxy-terminal regions, developed by using immunoadsorbents consisting of a fragment (either BPTH 1-34 or BPTH 53-84) coupled to cellulose. These were used to fractionate 125I-labelled antibodies. With some of these selected antibodies, the appropriate fragment was of lower reactivity than the intact hormone. This may have been due to the presence of an incomplete antigenic site on the fragment, or to conformational differences between the fragment and the corresponding region of the intact hormone. With other selected antibodies the fragment and the intact molecule reacted identically. Careful selection of antisera and of technique is necessary to obtain an assay in which a fragment and the intact hormone behave identically.
针对牛甲状旁腺激素有限区域的免疫测定法通过四种方式得以开发。用完整的牛甲状旁腺激素（BPTH 1 - 84）免疫产生的多克隆抗血清，放射免疫测定法的特异性可通过用氨基末端（BPTH 1 - 34）或羧基末端（BPTH 53 - 84）片段预饱和来提高。然后，未被中和的抗体仅与分子的另一端发生反应，即使使用[125I]BPTH 1 - 84作为示踪剂。对于一些抗血清，合适的片段和完整激素的反应相同。然而，对于其他抗血清，片段的反应不如完整激素好，这可能是因为这些抗血清含有与分子中间部分发生反应的抗体。使用标记片段（[125I]BPTH 1 - 34）作为示踪剂，利用多克隆抗血清，获得了针对氨基末端区域的放射免疫测定法。对于一种抗血清，BPTH 1 - 34与完整激素的反应相同，但对于另一种抗血清，该片段比完整分子更具反应性。还利用用激素片段免疫产生的抗体开发了一种区域特异性放射免疫测定法。针对BPTH 1 - 34产生的抗血清对氨基末端片段具有高亲和力，但与完整激素的反应较差。通过使用由与纤维素偶联的片段（BPTH 1 - 34或BPTH 53 - 84）组成的免疫吸附剂开发了针对氨基或羧基末端区域的免疫放射测定法。这些用于分离125I标记的抗体。对于其中一些选定的抗体，合适的片段的反应性低于完整激素。这可能是由于片段上存在不完全抗原位点，或者是由于片段与完整激素相应区域之间的构象差异。对于其他选定的抗体，片段和完整分子的反应相同。要获得一种片段和完整激素表现相同的测定法，仔细选择抗血清和技术是必要的。
