An antigen-detection assay to diagnose Babesia microti infection

项目总结 人类巴贝斯虫病是一种类似疟疾的多系统疾病，主要由新近出现的微小巴贝斯虫引起。 在人类红细胞内感染和发育的顶复合体寄生虫。寄生虫被传播到 人类由扁虱传播，也可通过输血传入肩部硬体。感染 会引起流感样症状，严重的感染可能是致命的，特别是在免疫抑制和 老年人。目前巴贝斯虫病的诊断方法包括显微镜、聚合酶链式反应、间接荧光抗体和酶联免疫吸附试验。 检测患者或捐献者血清中的抗体。这些方法中的每一种都有重大限制，例如 敏感度不足、复杂性高、吞吐量低。此外，其中许多化验的结果 在活动性感染消除后的几个月或几年内保持阳性。 在这个项目的第一阶段，我们已经开发了一种捕获ELISA检测方法，可以检测寄生虫的一种蛋白质， BmGPI12/BmSAI。我们已经确定了可以用来捕获BmGPI12的成对单抗 老鼠和人类的样本。我们的初步结果表明，该方法具有良好的敏感性。 使用从感染的小鼠收集的样本，我们证明了 治疗成功后，我们的检测结果为阴性，而聚合酶链式反应和血清学检测仍为阳性。 因此，我们的检测可能有助于区分活动性感染和既往接触。 在这个项目的第二阶段，我们将进一步开发这一检测方法，目标是申请FDA的批准。我们 将对数百个动物和人类样本进行分析，以建立重要的检测特征 包括敏感性和特异性。这些第二阶段的实验旨在让我们充分了解 该检测的潜在生物学适应症和商业用途。

PROJECT SUMMARY Human babesiosis is a malaria-like multisystem disease caused primarily by Babesia microti, an emerging apicomplexan parasite that infects and develops within human erythrocytes. The parasite is transmitted to humans by the tick vector Ixodes scapularis and can also be introduced through blood transfusion. Infection can cause flu-like symptoms, and severe infection can be fatal, in particular in the immunosuppressed and the elderly. Current methods for babesiosis diagnosis include microscopy, PCR, IFA and ELISA-based methods that detect antibodies in serum from patients or donors. Each of these methods has major limitations, such as insufficient sensitivity, high complexity, and low throughput. In addition, results from many of these assays remain positive for months or years after resolution of active infection. In Phase I of this project, we have developed a capture ELISA assay that can detect a protein of the parasite, BmGPI12/BmSAI. We have identified pairs of monoclonal antibodies that can be used to capture BmGPI12 in mouse and human samples. Our preliminary results demonstrate that this assay has an excellent sensitivity. Using samples collected from infected mice, a well-established model of human disease, we demonstrated that following successful treatment, our assay gives negative results while PCR and serology remain positive. Thus, our assay may be useful in distinguishing active infection from past exposure. In Phase II of this project, we will further develop this assay with the goal of applying for FDA clearance. We will analyze several hundred animal and human samples to establish important characteristics of the assay including sensitivity and specificity. These Phase II experiments are designed to give us a full understanding of the potential biological indications and commercial usefulness of the assay.