Malaria invasion: Red cell receptor /ligand interactions

疟疾寄生虫入侵红细胞是一个多步骤的过程，涉及红细胞(RBC)上的受体和特定寄生虫配体之间的几个特定相互作用。通过抑制裂殖子对红细胞的入侵，可以防止感染，进而预防疾病。因此，对参与这一过程的分子的鉴定和表征对于新药的开发至关重要，或者对参与这一过程的分子的表征对于新药或疫苗的开发至关重要。间日疟原虫裂殖子主要通过单一途径侵入网织红细胞，部分利用Duffy抗原和间日疟原虫侵入网织红细胞。另外两种间日疟原虫网织红细胞结合蛋白参与了间日疟原虫对网织红细胞的特异性识别，但相应的网织红细胞受体(S)尚未确定。我们将克隆和鉴定网织红细胞受体(S)，从而支持该受体(S)与Duffy蛋白功能关系的理解，最终有助于建立间日疟原虫转基因小鼠模型。恶性疟原虫有三种侵袭选择，涉及GPA、GPB和未知受体‘X’，其中只有GP与寄生虫配体EBA-175的相互作用已被很好地描述。恶性疟原虫与GPB或‘X’特异结合的配体以及其他入侵途径的分子基础尚不清楚。因此，这项拟议研究的另一个目的是识别受体(S)‘X’，并克隆和表征参与两种不同入侵途径的寄生虫分子。我们将识别受体(S)‘X’，并克隆和鉴定参与两种不同入侵途径的寄生虫分子。我们将通过评估三个新发现的含有已知在其他BC/寄生虫相互作用中起作用的结合基序的寄生虫基因的结合特异性，以及分离与GPB和受体(S)‘X’特异结合的配体来鉴定新的寄生虫配体(S)。然后是克隆。这些假定的配体在入侵中的作用以及它们的功能结合结构域将在寄生虫在RBC中的发展过程中得到表征。为了识别受体‘X’，我们将分别在侵袭和结合试验中使用表达胰酶敏感血液抗原的RBC突变体或转化细胞。GBP和受体(S)‘X’与其对应的寄生虫特异性配体的功能结合域将通过结合分析和抑制与特定抗体或多肽的结合来确定。

Invasion of erythrocytes by the malaria parasite is a multi-step process involving several specific interactions between receptors on the red blood cells (RBCs) and specific parasite ligands. Inhibition of RBC invasion by the merozoites would prevent infection and consequently disease. Therefore, identification and characterization of the molecules involved in this process is critical for the develop of new drugs or characterization of the molecules involved in this process is critical for the development of new drugs or vaccines. P. vivax merozoites invade primarily the reticulocytes via a single pathway utilizing in part the Duffy antigen and the P. vivax into reticulocytes. Two other P. vivax reticulocyte-binding proteins were implicated in the specific recognition of the reticulocytes by P. vivax, however, the corresponding reticulocyte receptor(s) have not been identified. We will clone and characterize the reticulocyte receptor(s) and thus support the understanding of the functional relationship of this receptor(s) with the Duffy protein, ultimately helping to establish a transgenic mouse model for P. vivax. P. falciparum was three invasion options involving GPA, GPB and an unknown receptor 'X', of which only the interaction of GP with the parasite ligand EBA- 175 has been well characterized. The P. falciparum ligands that bind specifically to GPB or 'X' and the molecular basis for the alternative pathways of invasion are unknown. Thus, another aim of the proposed research is to identify the receptor(s) 'X' and to clone and characterize the parasite molecules involved in the two alternative pathways of invasion. We will identify receptor(s) 'X' and to clone and characterize the parasite molecules involved in the two alternative pathways of invasion. We will identify novel parasite ligand(s) by evaluating the binding specificity of three newly identified parasite genes containing binding motifs known to function in other BC/parasite interactions, and by isolating biochemically ligands that bind specifically to GPB and receptor(s) 'X'. Followed by cloning. The role of the putative ligands in invasion, and their functional binding domains will be characterized during parasite development in the RBC. To identify receptor 'X' we will use RBC mutants or transformed cells that express trypsin sensitive blood antigens in invasion and binding assays, respectively. The functional binding domains of GBP and receptor(s) 'X' with their corresponding parasite specific ligands will be defined using binding assays and inhibition of binding with specific antibodies or peptides.