Human T cell responses against the major cysteine proteinase (cruzipain) of Trypanosoma cruzi: role of the multifunctional alpha 2-macroglobulin receptor in antigen presentation by monocytes.
Human T cell responses against the major cysteine proteinase (cruzipain) of Trypanosoma cruzi: role of the multifunctional alpha 2-macroglobulin receptor in antigen presentation by monocytes.
复制标题
人类 T 细胞对克氏锥虫主要半胱氨酸蛋白酶（cruzipain）的反应：多功能 α2-巨球蛋白受体在单核细胞抗原呈递中的作用。
DOI：
10.1093/intimm/9.6.825
复制
发表时间：
1997
影响因子：
4.4
通讯作者：
Scharfstein,J
中科院分区：
文献类型：
--
作者：
Morrot,A;Strickland,DK;Higuchi,MdeL;Reis,M;Pedrosa,R;Scharfstein,J
查加斯病患者（CDP）对来自克氏锥虫的主要半胱氨酸蛋白酶（cruzipain）产生体液和细胞免疫应答。在这里，我们证明了由cruzipain和α 2-巨球蛋白（α 2 M）形成的复合物被人单核细胞有效地内化，并且该过程导致cruzipain肽从CDP向CD 4 + T细胞的提呈增强。纯化的或血清α 2 M结合多态cruzipains，但只有一小部分的蛋白酶成为共价连接。一旦与α 2 M结合，荧光素标记的cruzipain（FITC-cruzipain）或[125 I]cruzipain更有效地被正常外周血单核细胞（PBMC）或单核细胞内化;这种作用通过（I）用受体相关蛋白（rRAP）（一种已知的α 2 M受体拮抗剂）预处理细胞而消除（α 2 MR/LRP），和（II）在与α 2 M反应之前使[125 I]cruzipain的活性位点失活，表明α 2 M复合物上的受体结合位点的暴露需要诱饵区切割。然后，我们试图确定单核细胞对α 2 M：cruzipain的α 2 MR/LRP依赖性摄取是否导致PBMC-CDP的CD 4 + T细胞应答增加（n = 13）。这些作用仅在从PBMC-CDP中耗尽CD 19 + B淋巴细胞后才显示;与单独的抗原相比，在用α 2 M：cruzipain刺激的培养物中T细胞刺激的阈值低得多。用抗cruzipain或抗α 2 MR/LRP（CD 81+）单克隆抗体对慢性心肌病CDP的心肌标本（3次尸检）进行免疫组化分析。cruzipain的细胞外储库位于炎性单核细胞浸润中，其中部分含有CD 91+巨噬细胞样细胞。正在进行的研究应澄清，如果T。cruzi半胱氨酰蛋白酶在南美锥虫心脏病的发病机制中起作用。
Chagas' disease patients (CDP) develop both humoral and cellular immune responses against the major cysteine proteinase (cruzipain) from Trypanosoma cruzi. Here we demonstrate that complexes formed by cruzipain and alpha 2-macroglobulin (alpha 2M) are efficiently internalized by human monocytes, and that this process results in enhanced presentation of cruzipain peptides to CD4+ T cells from CDP. Purified or serum alpha 2M binds to polymorphic cruzipains, but only a fraction of the proteinases become covalently linked. Once bound to alpha 2M, fluorescein-labeled cruzipain (FITC-cruzipain) or [125I]cruzipain were more efficiently internalized by normal peripheral blood mononuclear cells (PBMC) or monocytes; this effect was abolished by (I) pre-treating the cells with receptor-associated protein (rRAP), a known antagonist the of alpha 2M receptor (alpha 2MR/LRP), and (II) inactivating [125I]cruzipain's active site prior to the reaction with alpha 2M, indicating that the exposure of receptor binding sites on alpha 2M complexes required bait region cleavage. We then sought to determine if the alpha 2MR/LRP-dependent uptake of alpha 2M:cruzipain by monocytes resulted in increased CD4+ T cell responses of PBMC-CDP (n = 13). These effects were only revealed after depletion of CD19+ B lymphocytes from PBMC-CDP; the threshold of T cell stimulation was far lower in cultures stimulated with alpha 2M:cruzipain, as compared to antigen alone. Myocardial specimens from CDP with chronic myocardiopathy (three necropsies) were analyzed by immunohistochemistry with mAb anti-cruzipain or anti-alpha 2MR/LRP (CD81+). Extracellular depots of cruzipain were localized amidst inflammatory mononuclear infiltrates, part of which contained CD91+ macrophage-like cells. Ongoing studies should clarify if T. cruzi cysteinyl proteinases play a role in the pathogenesis of Chagas' heart disease.