Improving The Sensitivity And Predictability Of Testing

提高测试的灵敏度和可预测性

• 批准号: 6837523
• 负责人: Dori R Germolec
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6837523
• 关键词: Listeria infections; Plasmodium; Streptococcus pneumoniae; cell population study; chemical carcinogen; chemical carcinogenesis; cooperative study; cytotoxic T lymphocyte; diagnosis design /evaluation; diagnosis quality /standard; disease /disorder proneness /risk; environmental toxicology; enzyme linked immunosorbent assay; flow cytometry; helper T lymphocyte; histopathology; host organism interaction; immunotoxicity; influenza; laboratory mouse; monoclonal antibody; phenotype; prostaglandin endoperoxide synthase; toxicant screening

Studies being conducted as part of an interagency agreement between NIEHS and FDA as part of the NIEHS AIDS effort are determining the relationship between decrements in immune cell phenotypes and susceptibility to infection or tumors. Studies conducted in the laboratory of Dr. James Weaver at FDA, using monoclonal antibodies (Moabs) against CD4 and CD8, to establish titration curves for the depletion of these cell subpopulations in B6C3F1 mice have been completed and published. At NIEHS, we are examining the effects of cell depletion in specific host resistance models. We are currently evaluating the effects of CD4+ cell depletion in the SA1 tumor model. It has been reported in the literature that clearance of this tumor is highly dependent on cell-mediated immune responses, although the relative contributions of CD4+ and CD8+ T cells remain to be addressed. We have also evaluated responses to influenza following depletion of specific immune cell populations and in COX deficient mice. Significant changes in body weight and temperature were observed in COX-1 null and wild type mice 1 day following influenza challenge, however the mice appeared to recover and clear the infection. In contrast, COX-2 null mice showed a lack of hypothermia and weight loss at early time points, but an accelerated response on day 3. Fifty percent of COX-2 null mice died between days 5 and 6 whereas there was no mortality in COX-1 null or wild type mice. Levels of the proinflammatory cytokines TNFalpha and IL-1beta and the anti-viral cytokine IFNgamma were dramatically reduced in bronchioalveolar lavage fluid from COX-2 deficient mice and the recruitment of neutrophils and macrophages to the airways was markedly attenuated these animals. We are currently assessing the relative viral burden in the tissues of these mice. Experimental animal data collected over the past 15 years using standardized testing panels has provided a database from which the sensitivity and predictability of a variety of tests commonly used for the screening of chemicals for immunotoxicity has been evaluated. These results have been used as guidelines for risk assessment in immunotoxicity and have been the basis for a number of regulatory activities. There has been considerable interest in the use of expanded histopathology, which focuses on examining the structural and architectural changes in lymphoid organ, as a primary screening test for immunotoxicity assessment. To determine the utility of this approach as a stand alone screen, a validation effort using data from the National Toxicology Program's immunotoxicology testing program was initiated. This study addresses the interlaboratory reproducibility of extended histopathology using a dataset of ten test chemicals and both negative and positive controls. We examined the consistency between pathologists with varied background in evaluating lesions in immune tissues and the sensitivity of the individual and combined histopathological endpoints to detect chemical effects and dose response. Agreement between pathologists was highest in the thymus, in particular with thymic cortical cellularity, and lower within all of the compartments examined in the spleen and lymph nodes. In addition, the analyses indicated that the ability to accurately identify histopathological change in lymphoid organs is dependent directly upon the experience/training that the individual possesses in immunohistology and the apparent severity of the specific lesion.

作为NIEHS和FDA之间机构间协议的一部分，作为NIEHS艾滋病工作的一部分，正在进行的研究正在确定免疫细胞表型减少与感染或肿瘤易感性之间的关系。在FDA的James Weaver博士的实验室中，使用针对CD4和CD8的单克隆抗体（Moabs）建立了B6C3F1小鼠中这些细胞亚群消耗的滴定曲线，研究已经完成并发表。在NIEHS，我们正在研究细胞损耗对特定宿主抗性模型的影响。我们目前正在评估CD4+细胞耗竭对SA1肿瘤模型的影响。据文献报道，这种肿瘤的清除高度依赖于细胞介导的免疫反应，尽管CD4+和CD8+ T细胞的相对贡献仍有待解决。我们还评估了特定免疫细胞群耗竭和COX缺陷小鼠对流感的反应。COX-1缺失型和野生型小鼠在流感攻击后1天的体重和体温发生了显著变化，但小鼠似乎恢复并清除了感染。相比之下，COX-2缺失小鼠在早期时间点没有出现体温过低和体重减轻，但在第3天反应加速。50%的COX-2缺失小鼠在第5天至第6天死亡，而COX-1缺失或野生型小鼠没有死亡。COX-2缺陷小鼠的支气管肺泡灌洗液中促炎细胞因子TNFalpha和il -1 β以及抗病毒细胞因子IFNgamma的水平显著降低，这些动物向气道募集的中性粒细胞和巨噬细胞明显减少。我们目前正在评估这些小鼠组织中的相对病毒负荷。