Cox R A, Dolan M J, Magee D M, Galgiani J N
Department of Research Immunology, San Antonio State Chest Hospital, Texas 78223.
Infect Immun. 1993 May;61(5):1895-9. doi: 10.1128/iai.61.5.1895-1899.1993.
Antigen 2 (Ag2) has been implicated as a T-cell-reactive component of the pathogenic fungus Coccidioides immitis. We report the production of a murine monoclonal antibody (MAb) of the immunoglobulin G2a isotype that recognizes an epitope specific to C. immitis Ag2. This specificity was evidenced by the finding that the MAb did not recognize other antigens present in coccidioidin or spherulin and did not show reactivity with antigenic extracts from Histoplasma capsulatum or Blastomyces dermatitidis. The epitope was labile to enzymatic digestion with pronase but resistant to treatment with glycolytic enzymes and to periodate oxidation. This peptide epitope appears to require conformational structure on the basis that it was not recognized by the MAb in immunoblots of antigen that had been electrophoresed in polyacrylamide gels under denaturing, reducing conditions. Immunoaffinity chromatography of spherulin on columns containing the MAb established that the MAb was effective as a ligand for isolating Ag2 from heterogeneous extracts. The production of a MAb which recognizes an Ag2-specific epitope and its utility as a ligand for isolating Ag2 will provide a valuable reagent for studies of this immunologically important antigen.
抗原2（Ag2）被认为是致病性真菌粗球孢子菌的一种T细胞反应性成分。我们报告了一种免疫球蛋白G2a同种型的鼠单克隆抗体（MAb）的产生，该抗体识别粗球孢子菌Ag2特有的一个表位。该单克隆抗体不识别球孢子菌素或球孢子菌溶菌素中存在的其他抗原，也不与荚膜组织胞浆菌或皮炎芽生菌的抗原提取物发生反应，这一发现证明了其特异性。该表位对链霉蛋白酶的酶消化不稳定，但对糖酵解酶处理和高碘酸盐氧化具有抗性。基于在变性、还原条件下于聚丙烯酰胺凝胶中电泳的抗原免疫印迹中该单克隆抗体不识别该肽表位这一情况，该肽表位似乎需要构象结构。在含有该单克隆抗体的柱上对球孢子菌溶菌素进行免疫亲和层析表明，该单克隆抗体作为从异质提取物中分离Ag2的配体是有效的。一种识别Ag2特异性表位的单克隆抗体的产生及其作为分离Ag2的配体的用途将为研究这种具有免疫学重要性的抗原提供一种有价值的试剂。
