Crandall I, Sherman I W
University of California, Riverside 92521.
Parasitology. 1994 Apr;108 ( Pt 3):257-67. doi: 10.1017/s0031182000076101.
Murine monoclonal antibodies (Mabs) were produced by vaccination of Balb/c mice with live Plasmodium falciparum-infected red cells (iRBC). The iRBC Mabs recognized altered forms of the human erythrocyte membrane protein band 3; however, these Mabs did not recognize the band 3 molecule in uninfected or ring-infected red cells. The location of epitopes was determined by studying the binding of the iRBC Mabs after selective proteolysis of band 3 as well as by the reactivity of these Mabs to synthetic peptides that corresponded to putative exofacial regions of band 3. Treatment of uninfected red cell membranes with trypsin under low ionic strength conditions resulted in exposure of cryptic epitopes of band 3 which were recognized by the iRBC Mabs. Several of the anti-iRBC Mabs (two of which were described previously) inhibited the in vitro adherence of infected erythrocytes to C32 amelanotic melanoma cells. A mouse polyclonal serum against a synthetic peptide based on an amino acid sequence motif of band 3 reacted (by immunostaining) only with the surface of iRBC and blocked adhesion. Thus, it appears that cryptic residues of the band 3 protein become exposed upon parasitization, and their presence contributes to the increased adhesiveness of the P. falciparum-infected red cell.
通过用感染恶性疟原虫的活红细胞（iRBC）免疫Balb/c小鼠来制备鼠单克隆抗体（Mabs）。这些iRBC单克隆抗体识别出人类红细胞膜蛋白带3的改变形式；然而，这些单克隆抗体不能识别未感染或环状感染红细胞中的带3分子。通过研究带3选择性蛋白酶解后iRBC单克隆抗体的结合情况以及这些单克隆抗体与对应于带3假定胞外区域的合成肽的反应性，确定了表位的位置。在低离子强度条件下用胰蛋白酶处理未感染的红细胞膜，导致带3隐蔽表位的暴露，这些表位可被iRBC单克隆抗体识别。几种抗iRBC单克隆抗体（其中两种先前已有描述）抑制了感染红细胞在体外对C32无黑色素黑色素瘤细胞的黏附。一种基于带3氨基酸序列基序的合成肽的小鼠多克隆血清仅与iRBC表面发生反应（通过免疫染色）并阻断黏附。因此，似乎带3蛋白的隐蔽残基在被寄生后会暴露，并且它们的存在有助于恶性疟原虫感染红细胞黏附性的增加。
