CD4 T CELL DEPENDENT B CELL ACTIVATION IN AIDS LYMPHOMAS

慢性艾滋病毒感染的一个常见后果是 与艾滋病相关的淋巴瘤的发展。这些都是统一的高等级 B淋巴细胞的恶性肿瘤，可分为三种组织学类型 分类：(I)小的、未分裂的细胞；(Ii)大的 免疫母细胞/浆细胞样细胞；(3)大细胞淋巴瘤。 爱泼斯坦-巴尔病毒(Epstein-Barr Virus，EBV)常见于 免疫母细胞瘤，而其他类型的肿瘤表现为常见的c- P53抑癌基因的MYC重排和突变。而当 在HIV感染者中观察到EBV+免疫母细胞性淋巴瘤。 在PBL-SCID小鼠中，其他与艾滋病相关的淋巴瘤尚未见报道。 我们建议研究HIV感染和慢性B细胞之间的联系 使用来自HIV感染者的PBL以及 正常PBL感染在Hu-PBL-SCID模型的背景下。这个 该项目的具体目标是确定休息的反应， 外周血B细胞或扁桃体、生发中心B细胞向T细胞转化 或感染HIV或表达HIV gp120或gp41的T细胞克隆。CD_4 T细胞克隆将根据细胞因子的产生情况进行选择 表示Th0、Th1或Th2子集。精选组合 T细胞克隆和B细胞将被引入SCID小鼠以评估 体内B细胞增殖、分化和发生率的程度 肿瘤的形成。外周血B细胞、扁桃体B细胞和 滤泡树突状细胞将来自正常供者和外周血淋巴细胞 来自正常的和艾滋病毒血清阳性的捐赠者。EBV血清阳性的捐赠者 不会引起自发性肿瘤的就会用到。我们还将检查 可能阻断细胞凋亡的B细胞基因的表达 不同背景下向恶性转化的第一步 Aim中概述的T细胞刺激条件1.bcl2的表达 以及Epstein-Barr病毒基因LMP(反式激活bcl2 表达)、EBNA-2和斑马将通过敏感的RNase进行分析 保护性化验。EBV阳性患者的PBL和生发中心B细胞 EBV阴性的捐赠者将被比较。最后，我们将确定 不同HIV-1毒株与病毒特异性激活的关系 表达VH3免疫球蛋白可变区的B细胞。初步 有证据表明，用于感染人类的艾滋病毒毒株之间存在相关性。 PBL-SCID小鼠、CD4T细胞损失率和VH3程度 B细胞刺激。这些数据表明，不同的gp120分子 可能与表达VH3的B细胞上的Ig受体相互作用不同， 和/或HIV感染后CD4T细胞活化的程度 不同毒株之间差异显著。

One of the frequent consequences of chronic HIV infection is the development of AIDS associated lymphomas. These are uniformly high grade malignancies of B lymphocytes, and they fall into three histological categories: (i) small, noncleaved cell; (ii) large immunoblastic/plasmacytoid cell; and (3), large cell lymphoma. Involvement of Epstein-Barr virus (EBV) is frequently seen in the immunoblastic tumors, while the other tumor categories show frequent c- myc rearrangements and mutations of the p53 tumor suppressor gene. While EBV+ immunoblastic lymphomas have been observed in HIV infection of hu- PBL-SCID mice, the other AIDS-associated lymphomas have not been seen. We propose to study the link between HIV infection and chronic B cell activation, using PBL derived from HIV-infected individuals as well as normal PBL infected in the context of the hu-PBL-SCID model. The specific aims of the project are to determine the response of resting, peripheral blood B cells or tonsillar, germinal center B cells to T cells or T cell clones infected with HIV or expressing HIV gp120 or gp41. CD4 T cell clones will be chosen on the basis of cytokine production to represent either the Th0, Th1, or Th2 subset. Selected combinations of T cell clones and B cells will be introduced into SCID mice to assess the extent of in vivo B cell proliferation, differentiation, and incidence of tumor formation. Peripheral blood B cells, tonsilar B cells, and follicular dendritic cells will be derived from normal donors and PBL from normal and HIV-seropositive donors. EBV seropositive donors who do not give rise to spontaneous tumors will be used. We will also examine expression of B cell genes that might block apoptosis and represent the first step towards malignant transformation under the differing conditions of T cell stimulation outlined in Aim 1. Expression of bcl-2 and the Epstein-Barr virus genes LMP (which transactivates bcl-2 expression), EBNA-2, and ZEBRA will be analyzed by a sensitive RNase protection assay. PBL and germinal center B cells from EBV-positive and EBV-negative donors will be compared. Finally, we will determine the relationship between different HIV-1 strains and specific activation of B cells expressing the VH3 immunoglobulin variable region. Preliminary evidence shows a correlation between the HIV strain used to infect hu- PBL-SCID mice, the rate of CD4 T cell depletion, and the extent of VH3 B cell stimulation. These data suggest that different gp120 molecules may interact differently with the Ig receptor on VH3-expressing B cells, and/or that the extent of CD4 T cell activation following HIV infection differs markedly among different virus strains.