MOLECULAR BIOLOGY OF P CARINII GP120

由条件致病菌卡氏肺孢子虫引起的肺炎， 获得性免疫缺陷患者死亡的主要原因 综合征，以及其他免疫功能低下的宿主。长期目标 的建议是确定获得性耐药性的基础P。 卡氏疟原虫感染，并表征抗原决定簇。 卡氏杆菌通过保护性免疫反应在分子水平上识别， 水平在对卡氏肺孢子虫的免疫应答所识别的抗原中， 被动免疫研究，针对丰富的表面， 称为糖蛋白A（gpA）的分子提供了唯一的具体实例 卡氏肺孢子虫特异性抗原， 感染该提案的近期目标将是描述 gpA的分子结构，使其可以更有效地靶向 对卡氏肺孢子虫的免疫攻击 卡氏肺孢子虫肺炎（PCP）的小鼠模型提供了唯一的实验性 免疫系统，其中免疫提供完全保护， 感染因为只有小鼠源性卡氏肺孢子虫才会建立感染 在小鼠中，免疫学分析PCP的发病机制 小鼠卡氏肺孢子虫抗原的使用。因此，第一个目标是 建议克隆和表征编码小鼠P的cDNA。 卡氏菌gpA，以推断其一级氨基酸结构并 为免疫学分析提供重组抗原来源。 使用两种单克隆抗体（MAb）之一进行被动免疫预防 对gpA具有特异性导致体内卡氏肺孢子虫的显著减少 携带各自抗原决定簇的生物体。第二个目标 建议将通过以下方式鉴定这些MAb识别的肽： 组合肽展示文库的筛选。的能力 将比较用作保护性免疫原的候选肽 被动免疫所提供的保护， mAb.候选肽也将用于表征免疫系统。 对天然gpA的响应。 完成这一建议的两个目标将产生重要的 用于卡氏肺孢子虫免疫研究的分子试剂，和 将有助于确定获得性抗感染的分子基础 对抗五氯酚

Pneumonia caused by the opportunistic pathogen Pneumocystis carinii is a primary cause of mortality in patients with acquired immunodeficiency syndrome, and in other immunocompromised hosts. The long range objective of the proposal is to determine the basis of acquired resistance to P. carinii infection, and to characterize the antigenic determinants of P. carinii recognized by the protective immune response at the molecular level. Of the antigens recognized by the immune response to P. carinii, passive immunization studies that have targeted an abundant surface molecule termed glycoprotein A (gpA) provide the only concrete examples of a specific P. carinii antigen important in protection against infection. The immediate goal of the proposal will be to characterize the molecular structure of gpA so that it may he more effectively targeted for immune attack against P. carinii. Mouse models of P. carinii pneumonia (PCP) provide the only experimental system in which immunization affords complete protection against infection. Since only mouse-derived P. carinii will establish infection in the mouse, immunological analysis of the pathogenesis of PCP mandates the use of mouse P. carinii antigens. Therefore, the first aim of the proposal will be to clone and characterize the cDNA encoding mouse P. carinii gpA, in order to deduce its primary amino acid structure and to provide a source of recombinant antigen for immunological analyses. Passive immunoprophylaxis with either of two monoclonal antibodies (MAbs) specific for gpA results in significant reduction in vivo of P. carinii organisms bearing their respective epitopes. The second aim of the proposal will be to identify peptides recognized by these MAbs through the screening of combinatorial peptide display libraries. The ability of candidate peptides to function as protective immunogens will be compared to the protection afforded by passive immunization with their respective MAb. The candidate peptides will also be used to characterize the immune response to native gpA. Completion of the two objectives of this proposal will yield important molecular reagents to be used in the study of immunity to P. carinii, and will help define the molecular basis for acquired resistance to infection against PCP.