Chhatwal G S, Dutra I S, Blobel H
Microbiol Immunol. 1986;30(2):155-64. doi: 10.1111/j.1348-0421.1986.tb00930.x.
Human beta 2-microglobulin (beta 2-m) was isolated from urine samples of patients with tubular dysfunctions and aggregated with glutaraldehyde. Four aggregates with molecular weights of 800,000, 480,000, 260,000, and 60,000 were separated by filtration on Sephacryl S-300. The aggregates and monomeric beta 2-m (11,800 MW) were subsequently labeled with 125I and tested for binding to streptococci. Group A streptococci bound only aggregated beta 2-m with a mean binding of 44.5%. Most of the group G streptococci, on the other hand, bound only monomeric beta 2-m with a mean binding of 58%. Among group B streptococci the serotypes with protein antigens interacted mainly with monomeric beta 2-m and those without protein antigens preferentially with aggregated beta 2-m. Nontypable group B streptococcal serotypes did not bind monomeric or aggregated beta 2-m. Of the streptococci belonging to group C, S. equisimilis reacted with monomeric beta 2-m and S. dysgalactiae with aggregated beta 2-m. S. equi did not interact with monomeric beta 2-m or aggregated beta 2-m. Bindings of monomeric beta 2-m and aggregated beta 2-m were saturable and could be inhibited by the respective unlabeled forms of beta 2-m. Fibrinogen, fibronectin, alpha 2-macroglobulin, haptoglobin, or immunoglobulin G did not inhibit the binding of either form of beta 2-m. The binding sites for monomeric beta 2-m were more susceptible to trypsin than those for aggregated beta 2-m. Treatment of streptococci with pronase destroyed their binding activities for monomeric and aggregated beta 2-m. Both monomeric beta 2-m and aggregated beta 2-m binding sites were sensitive to heat. The Scatchard plots of monomeric beta 2-m and aggregated beta 2-m were linear with Kd of 1.29 X 10(-9) M and 1.9 X 10(-9) M respectively. The number of binding sites per bacterium were estimated to be 81,000 for monomeric beta 2-m and 1,210 for aggregated beta 2-m.
从肾小管功能障碍患者的尿液样本中分离出人β2-微球蛋白（β2-m），并用戊二醛使其聚集。通过在Sephacryl S - 300上过滤，分离出分子量分别为800,000、480,000、260,000和60,000的四种聚集体。随后，将聚集体和单体β2-m（分子量11,800）用125I标记，并测试其与链球菌的结合情况。A组链球菌仅结合聚集的β2-m，平均结合率为44.5%。另一方面，大多数G组链球菌仅结合单体β2-m，平均结合率为58%。在B组链球菌中，具有蛋白质抗原的血清型主要与单体β2-m相互作用，而没有蛋白质抗原的血清型则优先与聚集的β2-m相互作用。不可分型的B组链球菌血清型不结合单体或聚集的β2-m。在属于C组的链球菌中，马链球菌与单体β2-m反应，而停乳链球菌与聚集的β2-m反应。马链球菌不与单体β2-m或聚集的β2-m相互作用。单体β2-m和聚集的β2-m的结合是可饱和的，并且可以被各自未标记形式的β2-m抑制。纤维蛋白原、纤连蛋白、α2-巨球蛋白、触珠蛋白或免疫球蛋白G均不抑制任何一种形式的β2-m的结合。单体β2-m的结合位点比聚集的β2-m的结合位点对胰蛋白酶更敏感。用链霉蛋白酶处理链球菌会破坏它们对单体和聚集的β2-m的结合活性。单体β2-m和聚集的β2-m的结合位点都对热敏感。单体β2-m和聚集的β2-m的Scatchard图呈线性，Kd分别为1.29×10(-9)M和1.9×10(-9)M。估计每个细菌的单体β2-m结合位点数量为81,000个，聚集的β2-m结合位点数量为1,210个。
