Mingari M C, Moretta L, Moretta A, Ferrarini M, Preud'homme J L
J Immunol. 1978 Aug;121(2):767-70.
The susceptibility to proteolysis and the mode of re-expression of receptors for IgM or IgG present on two different subpopulations of human T lymphocytes (T.M and T.G cells, respectively) have been investigated. The IgM receptor was highly susceptible to both trypsin and pronase, whereas the IgG receptor was resistant to trypsin and sensitive only to high concentrations of pronase. The receptors have been removed by treating purified human T cells with pronase and their reappearance on the cell surface has been followed in vitro. The IgM receptors on the cell surface were detectable within 2 hr and the resynthesis was completed in 6 hr. IgG receptors were detectable in 4 to 6 hr and the resynthesis completed within 12 hr. When protein synthesis was inhibited by culturing the cells in the presence of cycloheximide for up to 12 hr, only the IgM receptor (which had a higher turnover rate) failed to be expressed. Whereas interaction of IgG immune complex with the IgG receptors was previously shown to induce a modulation of the receptors, contact with antigen-IgM antibody complexes did not alter the mode of expression of IgM receptors.
对人类T淋巴细胞的两个不同亚群（分别为T.M和T.G细胞）上存在的IgM或IgG受体的蛋白水解敏感性及重新表达模式进行了研究。IgM受体对胰蛋白酶和链霉蛋白酶均高度敏感，而IgG受体对胰蛋白酶有抗性，仅对高浓度链霉蛋白酶敏感。通过用链霉蛋白酶处理纯化的人类T细胞去除受体，并在体外追踪其在细胞表面的重新出现情况。细胞表面的IgM受体在2小时内可检测到，重新合成在6小时内完成。IgG受体在4至6小时内可检测到，重新合成在12小时内完成。当在放线菌酮存在的情况下培养细胞长达12小时以抑制蛋白质合成时，只有IgM受体（其周转率较高）未能表达。虽然先前已表明IgG免疫复合物与IgG受体的相互作用会诱导受体的调节，但与抗原-IgM抗体复合物的接触并未改变IgM受体的表达模式。
