Role of galectin-3 in genital tract immunosuppression

描述（申请人提供）：人精浆含有多种免疫抑制因子，可下调女性生殖道先天免疫。这些免疫抑制因子的作用是保护精子免受女性免疫系统的侵害。然而，免疫抑制作用可能增加女性生殖道对性传播疾病（包括艾滋病毒）感染的易感性。我们实验室的初步研究发现，半乳糖凝集素-3存在于前列腺体和精浆中的膜囊中，可抑制白细胞功能。值得注意的是，半乳糖凝集素-3受体在白细胞上表达，半乳糖凝集素-3具有免疫调节特性，半乳糖凝集素-3在病原体-宿主细胞相互作用中起作用。因此，我们假设半乳糖凝集素-3有助于前列腺小体的免疫抑制特性，并促进性传播感染。当前项目的总体目标是研究半乳糖凝集素-3在前列腺体中的功能，特别是在免疫抑制方面。本项目的目的是通过微序列分析确定前列腺小体中特定的半乳糖凝集素-3结合配体，并研究半乳糖凝集素-3在前列腺小体中的定位和功能。利用免疫电镜和流式细胞术研究半乳糖凝集素-3及其配体在前列腺小体上的表面定位。半乳糖凝集素-3在前列腺体-白细胞粘附中的作用将通过荧光显微镜和流式细胞术进行评估。功能分析将研究半乳糖凝集素-3在前列腺体介导的淋巴细胞增殖抑制和中性粒细胞活性氧（ROS）产生中的作用。研究人员将研究半乳糖凝集素-3在前列腺小体中截断型半乳糖凝集素-3功能的潜在调控机制。我们预计，对精浆免疫抑制因子及其对女性生殖道先天免疫和适应性免疫的影响的进一步了解将为性病/艾滋病的传播和发病机制提供重要的见解，并将对未来的性病预防策略产生重大影响。

DESCRIPTION (provided by applicant): Human seminal plasma contains multiple immunosuppressive factors that down-regulate innate immunity in the female reproductive tract. These immunosuppressive factors function to protect spermatozoa from the female immune system. However, the immunosuppressive effects potentially increase susceptibility of the female genital tract to infection by sexually transmitted diseases, including HIV. Preliminary studies from our laboratory identified galectin-3 on prostasomes, membranous vesicles in seminal plasma that inhibit leukocyte function. Significantly, galectin-3 receptors are expressed on leukocytes, galectin-3 exhibits immunomodulatory properties, and galectin-3 functions in pathogen-host cell interactions. Therefore, we hypothesize that galectin-3 contributes to the immunosuppressive properties of prostasomes and facilitates sexually transmitted infections. The overall goal of the current project is to investigate galectin-3 function in prostasomes with specific regard to immunosuppression. The aims of the proposed project are to identify the specific galectin-3 binding ligands in prostasomes by microsequence analysis and to investigate the localization and function of galectin-3 in prostasomes. Surface localization of galectin-3 and its ligands on prostasomes will be investigated using immunoelectron microscopy and flow cytometry. The role of galectin-3 in prostasome-leukocyte adhesion will be evaluated using fluorescence microscopy and flow cytometry. Functional assays will investigate the role of galectin-3 in prostasome-mediated inhibition of lymphocyte proliferation and of reactive oxygen species (ROS) production in neutrophils. A potential regulatory mechanism of galectin-3 function in prostasomes involving a truncated galectin-3 variant will be investigated. We anticipate that improved understanding of immunosuppressive factors in seminal plasma and their effects on innate and adaptive immunity in the female genital tract will provide significant insights into STD/HIV transmission and pathogenesis and will have significant implications for future STD prevention strategies.