CD20 DEPLETION IN SIVAGM-INFECTED AGMS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 体液免疫应答在控制HIV/SIV感染中的作用仍在争论中。本研究的目的是调查抗体应答对急性和慢性SIVagm复制的结果的影响。本研究使用10个接种SIVagm的AGM。从SIVagm.sab感染后第-7天开始，每21天用50 mg/kg的抗-CD 20抗体（Rituxan，由Genentech赠送）处理4只动物，6只AGM仅接受SIVagm.sab。采用实时荧光定量PCR和原位杂交技术检测血浆和组织中的病毒载量。用流式细胞仪检测外周血、淋巴结和肠道中主要淋巴细胞亚群的动态变化。流式细胞术和免疫组化法检测T细胞的免疫活化、增殖和凋亡。血清学检查比较两组抗SIV抗体的差异。如通过流式细胞术测量的CD 20+和CD 79 a细胞的动力学所示，用Rituxan处理的所有动物成功地耗尽外周血、LN和肠中的CD 20细胞。CD 20缺失的AGM和对照猴之间的VL无显著差异：峰值VL范围为107-108拷贝/ml。在感染的慢性期，两组显示出相似的VL控制（设定点值范围为104至105 SIV RNA拷贝/ml）。与VL相关，我们确定了治疗和未治疗动物肠道中相同程度的急性CD 4 T细胞耗竭。与对照组相比，CD 20缺失的AGM中SIVagm血清转化延迟。与对照组相比，CD 20耗尽的AGM中中和抗体应答的时间和幅度均存在显著差异。总之，我们的研究表明，体液免疫反应在控制SIV病毒复制在急性和慢性SIVagm感染的自然宿主中没有显着的作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The role of humoral immune responses in controlling HIV/SIV infection is under debate. The aim of this study was to investigate the impact of antibody responses on the outcome of acute and chronic SIVagm replication in AGMs. Ten AGMs inoculated with SIVagm were used for this study. Four animals were treated with 50 mg/kg of an anti-CD20 antibody (Rituxan, gift from Genentech) every 21 days, starting from day -7 post-SIVagm.sab infection and six AGMsreceived SIVagm.sab only. Viral loads (VLs) in plasma and tissues were determined by real-time PCR and in situ hybridization (ISH). Dynamics of the major lymphocyte subsets were measured in peripheral blood, lymph nodes (LNs) and intestine by flow-cytometry. Immune activation, proliferation and apoptosis of T-cells were investigated by flow-cytometry and immunohistochemistry (IHS). Serology was performed to compare the differences in emergence of anti-SIV antibodies between the two groups. All the animals treated with Rituxan were successfully depleted of CD20 cells in peripheral blood, LNs and intestine, as illustrated by the dynamics of CD20+ and CD79a cells measured by both flow-cytometry. There was no significant difference in VLs between CD20-depleted AGMs and control monkeys: peak VLs ranged 107-108 copies/ml. During the chronic phase of infection, both groups showed similar control of VL (set-point values ranging from 104 to 105 SIV RNA copies/ml). Correlated to the VLs we determined the same degree of acute CD4 T-cell depletion in the intestine in treated and non-treated animals. SIVagm seroconversion was delayed in the CD20-depleted AGMs compared to controls. There was a significant difference in both timing and magnitude of neutralizing antibody responses in CD20-depleted AGMs compared to controls. In conclusion, our study shows that humoral immune responses play no significant role in the control of SIV viral replication during acute and chronic SIVagm infection in the natural host.