Amir J, Scott M G, Nahm M H, Granoff D M
Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri.
J Infect Dis. 1990 Jul;162(1):163-71. doi: 10.1093/infdis/162.1.163.
Complement-mediated bactericidal and opsonic activity of IgG1 and IgG2 antibodies to Haemophilus influenzae type b polysaccharide (polyribosyl ribitol phosphate [PRP]) were investigated. The antibody sources were IgG1 or IgG2 subclass polyclonal antibody fractions prepared by immunoabsorption of sera from adults immunized with PRP or PRP-diphtheria toxoid conjugate vaccine or clonally purified anti-PRP antibodies from eight adults immunized with PRP vaccine. In bactericidal assays using an inoculum of 3 x 10(3) colony-forming units (cfu)/ml, twofold lower concentrations of IgG1 compared with IgG2 antibody were required for 50% killing. With approximately 10(6) cfu/ml, IgG1 antibody killed 3 logs more of bacteria than were killed by comparable concentrations of IgG2 antibody. The IgG1 antibody also required lower concentrations of complement than did the IgG2 antibody for comparable bacteriolytic activity. Clonally purified IgG1 and IgG2 anti-PRP antibodies from most individuals showed similar relative differences in bactericidal activity. IgG1 anti-PRP antibody was also more efficient than IgG2 anti-PRP antibody in enhancing the uptake of radiolabeled type b H. influenzae by human polymorphonuclear leukocytes in the presence of complement and in protecting infant rats from developing bacteremia. However, the differences in opsonic or protective activity of the two subclasses were smaller than the differences in bactericidal activity. Thus, IgG1 anti-PRP antibody is functionally more effective than IgG2 antibody, but it is likely that both subclasses can confer protection against disease.
研究了针对b型流感嗜血杆菌多糖（多核糖基核糖醇磷酸酯[PRP]）的IgG1和IgG2抗体的补体介导的杀菌和调理活性。抗体来源为通过免疫吸附来自用PRP或PRP-白喉类毒素结合疫苗免疫的成人血清制备的IgG1或IgG2亚类多克隆抗体组分，或来自8名用PRP疫苗免疫的成人的克隆纯化抗PRP抗体。在使用3×10³菌落形成单位（cfu）/ml接种物的杀菌试验中，与IgG2抗体相比，IgG1抗体达到50%杀菌所需浓度低两倍。在大约10⁶cfu/ml时，IgG1抗体杀死的细菌比相同浓度的IgG2抗体多3个对数。对于相当的溶菌活性，IgG1抗体所需的补体浓度也低于IgG2抗体。来自大多数个体的克隆纯化IgG1和IgG2抗PRP抗体在杀菌活性上显示出相似的相对差异。在补体存在下，IgG1抗PRP抗体在增强人多形核白细胞对放射性标记的b型流感嗜血杆菌的摄取以及保护幼鼠免于发生菌血症方面也比IgG2抗PRP抗体更有效。然而，这两个亚类在调理或保护活性上的差异小于杀菌活性上的差异。因此，IgG1抗PRP抗体在功能上比IgG2抗体更有效，但很可能这两个亚类都能提供疾病保护。
