Molecular characterization of the humoral responses to Cryptococcus neoformans infection and glucuronoxylomannan-tetanus toxoid conjugate immunization.
Molecular characterization of the humoral responses to Cryptococcus neoformans infection and glucuronoxylomannan-tetanus toxoid conjugate immunization.
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DOI：
10.1084/jem.177.4.1105
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发表时间：
1993-04-01
期刊：
影响因子：
--
通讯作者：
Scharff MD
中科院分区：
文献类型：
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作者：
Mukherjee J;Casadevall A;Scharff MD
对血清型A新型隐球菌感染的体液免疫应答的分子特征与隐球菌葡糖醛酸甘露聚糖-破伤风类毒素（GXM-TT）结合物引起的应答进行了比较。从这两种反应中分离的抗隐球菌单克隆抗体（mAb）先前已被证明可以识别隐球菌GXM的相同抗原决定簇。Southern印迹和序列分析表明，从每个反应中分离的杂交瘤只产生于少数前体B细胞。从感染的和GXM-TT缀合物免疫的小鼠产生的所有mAb利用相同的VH 7183家族成员：JH 2/JH 4、v κ 5.1和J κ 1;由不同B细胞产生的mAb具有由具有共同序列基序的7个氨基酸组成的互补决定区3（CDR 3）。因此，对这些产生抗隐球菌单克隆抗体的杂交瘤的分子分析表明，对隐球菌感染和缀合物免疫的应答是寡克隆的，并且在免疫球蛋白基因利用方面受到高度限制。GXM-TT缀合物主要刺激同种型转换和克隆增殖，并且不导致表达额外免疫球蛋白库的杂交瘤。来自两种应答的mAb在CDR 2的5'端具有许多置换突变，其似乎是抗原驱动选择的结果。体细胞突变还导致一种mAb 13 F1的表位特异性改变。被动施用来自响应于GXM-TT缀合物产生的不同克隆的代表性mAb延长了致死性感染小鼠的存活。
The molecular characteristics of the humoral immune response to a serotype A Cryptococcus neoformans infection were compared with the response elicited by a cryptococcal glucuronoxylomannan-tetanus toxoid (GXM-TT) conjugate. Anticryptococcal monoclonal antibodies (mAbs) isolated from both responses have previously been shown to recognize the same antigenic determinant of cryptococcal GXM. Southern blot and sequence analyses indicate that the hybridomas isolated from each response arose from only a few precursor B cells. All the mAbs generated from the infected and GXM-TT conjugate-immunized mice utilize the same VH7183 family member: JH2/JH4, v kappa 5.1, and J kappa 1; mAbs generated by different B cells had complementarity-determining region 3's (CDR3s) composed of seven amino acids with a common sequence motif. Thus, the molecular analysis of these anticryptococcal mAb- producing hybridomas indicated that the response to both cryptococcal infection and conjugate immunization was oligoclonal and highly restricted with regard to immunoglobulin gene utilization. The GXM-TT conjugate primarily stimulated isotype switching and clonal proliferation, and did not result in hybridomas expressing additional immunoglobulin repertoires. The mAbs from both responses had a number of replacement mutations at the 5' end of CDR2 that appear to be the result of antigen-driven selection. Somatic mutation also resulted in altered epitope specificity for one mAb, 13F1. Passive administration of representative mAbs from different clones generated in response to the GXM-TT conjugate prolonged survival of lethally infected mice.