Opsonization of Cryptococcus neoformans by a family of isotype-switch variant antibodies specific for the capsular polysaccharide
Opsonization of Cryptococcus neoformans by a family of isotype-switch variant antibodies specific for the capsular polysaccharide
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DOI：
10.1128/iai.58.6.1914-1918.1990
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发表时间：
1990-06
影响因子：
3.1
通讯作者：
Annette M. Schlageter;T. Kozel
中科院分区：
文献类型：
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作者：
Annette M. Schlageter;T. Kozel
免疫球蛋白同种型转换变体的家族是通过同胞选择从鼠杂交瘤中分离的，所述鼠杂交瘤产生对新型隐球菌的荚膜多糖具有特异性的免疫球蛋白G亚类1（IgG1）抗体。IgG1，IgG2a，和IgG2b同种型的抗体具有相似的血清型特异性模式，在双重免疫扩散试验，使用多糖的四种隐球菌血清型作为抗原。在免疫双扩散试验中观察到同种型与多糖形成沉淀的能力的定量差异，并在定量沉淀素试验中证实。抗体的相对沉淀活性为IgG2a大于IgG1，远大于IgG2b。通过酶联免疫吸附试验分析三种同种型与隐球菌多糖的反应性，显示出相同的滴度和斜率，表明类别转换抗体的可变区未改变。该系统允许我们检查抗体的Fc部分对封装的隐球菌的调理作用的影响。用每种同种型的抗体预包被酵母细胞，并与鼠巨噬细胞或培养的人单核细胞一起孵育。所有三种同种型的抗体对人和鼠吞噬细胞的吞噬作用表现出剂量依赖性调理作用。抗体的相对调理活性为IgG2a大于IgG1大于IgG2b。
A family of immunoglobulin isotype-switch variants was isolated by sib selection from a murine hybridoma which produced an immunoglobulin G subclass 1 (IgG1) antibody specific for the capsular polysaccharide of Cryptococcus neoformans. Antibodies of the IgG1, IgG2a, and IgG2b isotypes had similar serotype specificity patterns in double immunodiffusion assays which used polysaccharides of the four cryptococcal serotypes as antigens. A quantitative difference in the ability of the isotypes to form a precipitate with the polysaccharide was observed in a double immunodiffusion assay and confirmed in a quantitative precipitin assay. The relative precipitating activity of the antibodies was IgG2a greater than IgG1 much greater than IgG2b. Analysis by enzyme-linked immunosorbent assay of the reactivity of the three isotypes with cryptococcal polysaccharide showed identical titers and slopes, suggesting that the variable region of the class-switch antibodies was unaltered. This system allowed us to examine the effect of the Fc portion of the antibody on opsonization of encapsulated cryptococci. Yeast cells were precoated with antibodies of each isotype and incubated with murine macrophages or cultured human monocytes. Antibodies of all three isotypes exhibited a dose-dependent opsonization for phagocytosis by both human and murine phagocytes. The relative opsonic activity of the antibodies was IgG2a greater than IgG1 greater than IgG2b.