Reed S, Bouvier J, Hirata K, Que X, Pollack A S, Engel J C, Gillin F, McKerrow J H
Department of Pathology, University of California, San Diego.
Arch Med Res. 1992;23(2):181-2.
Extracellular neutral cysteine proteinases are an important virulence factor of E. histolytica. Experimental evidence supporting its role in invasion includes the ability to degrade components of the extracellular matrix and activate complement by specifically cleaving C3. We had previously reported the isolation of fragments encoding cysteine proteinase genes from HM-1 (ACP1) and a nonpathogenic strain (REF291, ACP2) by PCR using consensus sequences based on conserved structural motifs of eukaryotic cysteine proteinases. Using similar techniques, we have now identified a third gene encoding a cysteine proteinase which is present in both pathogenic and nonpathogenic strains and have correlated cysteine proteinase specific-mRNA levels with enhanced proteolytic activity and cytopathic effect on a fibroblast cell monolayer, a quantitative assay of virulence.
细胞外中性半胱氨酸蛋白酶是溶组织内阿米巴的一种重要毒力因子。支持其在侵袭中作用的实验证据包括降解细胞外基质成分以及通过特异性切割C3激活补体的能力。我们之前曾报道，利用基于真核半胱氨酸蛋白酶保守结构基序的共有序列，通过PCR从HM-1（ACP1）和非致病菌株（REF291，ACP2）中分离出编码半胱氨酸蛋白酶基因的片段。现在，我们使用类似技术鉴定出了第三个编码半胱氨酸蛋白酶的基因，该基因存在于致病和非致病菌株中，并且已将半胱氨酸蛋白酶特异性mRNA水平与增强的蛋白水解活性以及对成纤维细胞单层的细胞病变效应（一种毒力定量测定）相关联。
