Murphy J W, Pahlavan N
Infect Immun. 1979 Jul;25(1):284-92. doi: 10.1128/iai.25.1.284-292.1979.
Previous studies on a cryptococcal culture filtrate (CneF) antigen have shown that the antigen is useful in detecting delayed-type hypersensitivity and that it is specific for Cryptococcus. This study further defined one more parameter of specificity, showing that the CneF antigen does not elicit delayed-type hypersensitivity responses in Cryptococcus albidus-sensitized guinea pigs. When the crude CneF antigen was subjected to ultrafiltration fractionation, the skin test active components were found to be in the 50,000 or greater molecular weight range fraction. The concentrated retentates of the XM50 ultrafiltration membrane were more sensitive antigens than the crude CneF antigens. Further fractionation of the XM50 retentate using 3% acrylamide gel electrophoresis separated the antigen into two bands. One band, the P fraction, migrated only a short distance into the gel; the fraction was carbohydrate-like and did not elicit significant skin test responses in sensitized guinea pigs. The other band, G fraction, appeared with the tracking dye, was glycoprotein-like, and elicited significantly positive skin tests in sensitized guinea pigs. G fractions prepared using three different serotypes of Cryptococcus neoformans elicited similar size indurations when used in skin testing guinea pigs sensitized with either the homologous serotype isolated of C. neoformans or the heterologous serotype isolate.
先前对隐球菌培养滤液（CneF）抗原的研究表明，该抗原可用于检测迟发型超敏反应，且对隐球菌具有特异性。本研究进一步明确了另一个特异性参数，即CneF抗原不会在白隐球菌致敏的豚鼠中引发迟发型超敏反应。当对粗制CneF抗原进行超滤分级分离时，发现皮肤试验活性成分存在于分子量为50,000或更大的分级范围内。XM50超滤膜的浓缩截留物比粗制CneF抗原更具敏感性。使用3%丙烯酰胺凝胶电泳对XM50截留物进行进一步分级分离，可将抗原分离成两条带。一条带为P级分，在凝胶中迁移距离较短；该级分类似碳水化合物，在致敏豚鼠中不会引发显著的皮肤试验反应。另一条带为G级分，与示踪染料同时出现，类似糖蛋白，在致敏豚鼠中引发显著阳性皮肤试验。使用三种不同血清型的新型隐球菌制备的G级分，在用同源血清型或异源血清型分离的新型隐球菌致敏的豚鼠进行皮肤试验时，引发的硬结大小相似。
