Function analysis of chaperon and transport in antigen processing and presentation of Toxoplasma gondii-infected cells

本文分析了弓形虫感染细胞对弓形虫感染细胞特异性的CD_4、CD_8~-和CD_4、CD_8~+细胞毒性T淋巴细胞(CTL)的抗原提呈。弓形虫感染的黑色素瘤将弓形虫感染的细胞特异性抗原呈递给CD4、CD8^-GTL，而弓形虫感染的B淋巴瘤则将弓形虫感染的细胞特异性抗原呈递给CD4、CD8^-CTL。研究了热休克蛋白(HSP)70在抗原加工和呈递弓形虫感染细胞特异性细胞毒性T淋巴细胞(CTL)中的作用。用弓形虫感染P36细胞的HSP70致敏的人黑色素瘤细胞株P36和感染弓形虫的P36细胞被弓形虫感染细胞的特异性CTL裂解。细胞毒性T淋巴细胞对弓形虫感染…冲击的P36细胞的杀伤活性抗HSP70单抗可抑制更多的d P36细胞来源的HSP70，表明感染弓形虫P36的HSP70分子在抗原加工和弓形虫P36细胞呈递给T细胞的过程中起作用。此外，我们以小鼠TAP分子缺失的突变型淋巴瘤细胞系RMA.S为宿主，建立了稳定的弓形虫SAG1(弓形虫主要表面抗原)基因转染体，以诱导弓形虫感染细胞特异性的CD_4~+-CD_8~+CTL，并建立了体外基因疫苗。由于TAP转运蛋白的缺陷，RMA.S细胞不能处理从胞浆到内质网(ER)腔的自体多肽，因此RMA.S的MHC-I类分子主要结合来自含有信号序列的SAG1基因产物的多肽。用SAG1-RMA.S免疫小鼠，不仅能诱导出针对SAG1-RMA.S和弓形虫感染RMA.S的CD4~+-CD8~+CTL，还能诱导对弓形虫强毒株RH感染的保护性反应。利用专业抗原提呈细胞(APC)如朗格汉斯细胞或树突状细胞作为靶向APC来建立SAG1基因疫苗和分子伴侣的研究进展较少

Antigen presentation of Toxoplasma gondii (T.gondii)-infected cells to T.gondii-infected cell- specific CD4^+CD8^- and CD4^+CD8^- cytotoxic T lymphocytes (CTL) has been analysed. T.gondii-infected melanoma presents T.gondii-infected cell-specific antigens to CD4^+CD8^- GTL while T.gondii-infected B lymphoma presents T.gondii-infected cell-specific antigens to CD4^+CD8^- CTL.The role of heat shock protein (HSP) 70, a molecular chaperon in peptide and protein transport between cell organellas, in antigen processing and presentation of T.gondii -infected cells to cytotoxic T lymphocytes (CTL) specific for T.gondii-infected cells was investigated. Human melanoma line, P36, pulsed with HSP70 of T.gondii- infected P36 cells as well as T.gondii-infected P36 cells were lysed by a CD4^+ CTL specific for T.gondii infected cells that was generated from peripheral blood lymphocytes of a patient with chronic toxoplasmosis. The lytic activity of the CTL against P36 cells pulsed with T.gondii-infecte … More d P36 cell- derived HSP70 was inhibited by anti-HSP70 mAbs indicating that HSP70 molecules of T.gondii-infected P36 play a role in antigen processing and presentation of T.gondii-infected P36 cells to CD4^+CTL.Furthermore, we have established a stable T.gondii SAG1 (a major surface antigen of T.gondii)- gene transfectant by using RMA.S cells, a murine TAP molecule-deficient mutant lymphoma line, as a host to elicit T.gondii-infected cell-specific CD4^-CD8^+ CTL and to develope an ex-vivo gene vaccination to T.gondii-infection. RMA.S cells are unable to process self peptides from cytosol to endoplasmic reticulum (ER) lumen due to a defect of TAP transporters, so that MHC class I molecules of RMA.S dominantly bind peptides derived from the transfected SAG1gene product containig a signal sequence. Immunization of mice with the SAG1-transfected RMA.S induced CD4^-CD8^+ CTL specific for not only SAG1-transfected RMA.S but also T.gondii-infected RMA.S, and elicited protective responses to infection with a virulent T.gondii strain, RH.Establishment of gene vaccination with SAG1 and molecular chaperones by using professional antigen presenting cells (APC) such as Langerhans cells or dendritic cells as the targeting APC are underway Less