Restoration of alveolar macrophage function in HIV patients: A clinical study.

描述（由申请人提供）：HIV以淋巴细胞和巨噬细胞为宿主细胞。大多数研究将艾滋病的进展仅仅等同于T细胞监视功能的丧失。然而，有人认为，由于HIV寄生于巨噬细胞，病毒可以直接损害吞噬细胞的杀微生物能力。利用新的检测吞噬体成熟的方法，我们已经证明HIV感染会降低吞噬体的水解能力，并损害超氧化物的产生。考虑到巨噬细胞作为微生物入侵的主要屏障的作用，这将产生严重的后果，特别是在粘膜表面，如呼吸道。在本研究中，我们建议解决以下3个问题。

DESCRIPTION (provided by applicant): HIV targets both lymphocytes and macrophages as host cells. Most studies equate progression to AIDS solely as the loss of T cell surveillance. However, it has been suggested that because HIV parasitizes macrophages, the virus could impair the microbicidal capacity of the phagocyte directly. Exploiting novel assays for phagosomal maturation we have demonstrated that HIV infection diminishes the hydrolytic capacity of the phagosome and impairs superoxide production. Given the macrophage's role as the primary barrier against microbial invasion this will have serious consequences, particularly at mucosal surfaces such as the respiratory tract. In this study we propose to address the following 3 questions. 1. To what extent does HIV infection compromise the anti-microbial capacity of macrophages? HIV-infected, PBMC-derived macrophages will be subjected to a panel of physiological assays to determine the extent to which phagocyte function is impaired i.e. phagosome acidification, the acquisition of lysosomal hydrolases, the generation of reactive oxygen and nitrogen intermediates, and the capacity of the HIV-infected cells to limit growth of a panel of model bacterial pathogens. 2. Do alveolar macrophages from HIV-infected patients demonstrate similar subversion of phagocyte function? Following in vitro validation, these assays will be repeated on broncholavage cells from HIV-infected patients at the Queen Elizabeth Hospital in Malawi. In addition, samples will be acquired for electron microscopy and for immuno-electron microscopy, and total nucleic acid will be extracted for retrospective identification of possible co-infections. 3. How does HIV impair macrophage function and can this be reversed chemotherapeutically? a. We propose functional studies to determine how HIV modulates the microbicidal capacity of the phagosome. b. We will conduct high-throughput screens to identify small molecules that counteract the suppressive activity of HIV. c. We will assay these compounds for their ability to reverse the suppression of phagocyte function in alveolar macrophages from HIV-infected patients. PUBLIC HEALTH RELEVANCE: The progression to AIDS is almost universally correlated with the loss of immune surveillance. However, we have found that HIV-infected macrophages exhibit impaired phagosomal function that reduces their microbicidal capacity, thus directly increasing the likelihood of opportunistic infections. In a prospective clinical study on alveolar macrophages from HIV-infected patients we will parallel our in vitro experiments to pursue both the mechanism and the identification of compounds that reverse the HIV-mediated suppression of macrophage function.