Regulation of immunoglobulin class switch in senescent humans

衰老人类免疫球蛋白类别转换的调节

• 批准号: 7132074
• 负责人: BONNIE B. BLOMBERG
• 金额: $ 18.77万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7132074
• 关键词: age difference; aging; aminohydrolases; chemical stability; clinical research; cytidine; enzyme linked immunosorbent assay; flow cytometry; gene rearrangement; genetic transcription; human subject; humoral immunity; immunodeficiency; immunogenetics; immunoglobulin genes; immunoglobulin isotypes; immunologic assay /test; messenger RNA; mitogen activated protein kinase; molecular genetics; nuclear factor kappa beta; tissue /cell culture; transcription factor

DESCRIPTION (provided by applicant): Aged humans have poor immune responses to infectious agents, vaccines, and cancers, which contribute to increased morbidity and mortality. Aged individuals have a qualitatively deficient antibody mediated humoral immune response with the production of antibodies of lower affinity and with increased self reactivity. Class switch recombination (CSR) of the immunoglobulin (Ig) class (or isotype) is very important for the quality and effector functions of the immune response; genetic deficiencies of CSR in patients results in respiratory tract infections, autoimmunity and failure to respond to vaccination, among others. These studies will establish whether the decreases in Ig class switch, AID (activation-induced cytidine deaminase) and E2A we have seen in age-stimulated B lymphocytes in mice is recapitulated in humans, and will then focus on the molecular and cellular mechanisms responsible for their decrease. We hypothesize that there will be a decrease in human CSR as a direct result of a decrease in AID, which is regulated by the transcription factor, E47 in humans as in mice. This proposal will compare peripheral blood B cells from aged vs. young healthy human volunteers for the presence and function of E47, AID and class switched isotypes (IgG, IgE, IgA) in vitro. In Specific Aim 1, we will determine the Ig class switch defects in aged human B cells. Purified B cells from peripheral blood mononuclear cells (PBMC) from young and old donors will be stimulated with anti- CD40 and IL-4, BAFF and IL-4 or CpG and IL-4/IL-10, and class switched phenotypes (IgG, IgE, and IgA) assayed by fluorescent cytometry for cell surface Ig, ELISA for secreted Ig and RT-PCR for germline transcripts (GLT) and circle transcripts (CTs), denoting CSR. In Specific Aim 2, the molecular mechanisms regulating class switch in young and old human B cells will be investigated. E47, AID, and NFKB expression in stimulated enriched B cells will be characterized. In Specific Aim 3, the molecular mechanisms for regulation of E47 in human B cells will be established. Studies of mRNA stability and signal transduction pathways including MAPK will be performed and will help to determine key molecular requirements for the regulation of Ig class switch in aged humans. The studies in this application will allow a better understanding, at the cellular and molecular levels, of the immune deficits in aged human subjects and will lead to improvement of these for immune response and vaccine development in the elderly population.

描述（由申请人提供）：老年人对感染剂，疫苗和癌症的免疫反应差，这有助于增加发病率和死亡率。老年个体具有质性不足的抗体介导的体液免疫反应，并产生较低亲和力的抗体并增加自我反应性。免疫球蛋白（IG）类（或同种型）的类开关重组（CSR）对于免疫反应的质量和效应子功能非常重要。患者CSR的遗传缺陷导致呼吸道感染，自身免疫性和对疫苗接种的反应等。这些研究将确定我们在人类中概括了小鼠年龄刺激的B淋巴细胞中IG类转换，AID（激活诱导的胞苷脱氨酶）和E2A的降低，然后将重点放在分子和细胞机制上，负责其降低。我们假设，人类CSR的辅助下降将下降，这是由小鼠和小鼠中人类的转录因子E47所调节的。该建议将在体外比较E47，AID和类转换的同种型（IgG，IgE，IgA）的存在和功能的年龄与年轻健康的人类志愿者的外围血液B细胞。在特定的目标1中，我们将确定年迈的人类B细胞中的IG类开关缺陷。抗CD40和IL-4，BAFF和IL-4或IL-4或CpG和IL-4/IL-10和IL-4/IL-10的纯化的B细胞（PBMC）将刺激来自年轻供体和年轻人的供体的和IL-4或IL-4/IL-10，以及类别切换表型（IgG，IgE和IgA），用于通过荧光式iig riS iigry Ig iig iigry riS iigry iigry iigry iigry iigry刺激抗CD40和IL-4，BAFF和IL-4或IL-4/IL-10。种系转录本（GLT）和圆转录本（CTS），表示CSR。在特定的目标2中，将研究调节年轻人和老年人B细胞中类别转换的分子机制。 E47，AID和NFKB在受刺激的富集B细胞中的表达将被表征。在特定的目标3中，将建立用于调节E47在人B细胞中的分子机制。将对包括MAPK在内的mRNA稳定性和信号转导途径进行研究，并有助于确定年龄人类IG类转换的关键分子要求。在本应用中的研究将使在细胞和分子水平上更好地了解人类老年受试者的免疫缺陷，并将改善这些缺陷，以改善这些人的免疫反应和老年人群的免疫反应和疫苗发育。