Experimental evaluation of P.berghei sporozoites in light of selected innate immune components

Abstract

Known as polymorphonuclear leukocytes (PMNs), neutrophils have been shown to play a regulatory role in healing injuries and resolving infections. Although the immune response (IR) of neutrophils in bacterial and fungal infections is well understood, their impact during sporozoite infection is much less studied. This project investigates the role of neutrophils in recognizing Plasmodium berghei sporozoites in an effort to understand the mechanism of sporozoites’ IR evasion and spread of malaria infection in the blood circulation. Plasmodium berghei GFP-expressing sporozoites were purified from infected mosquitoes by manual dissection of salivary glands and exposed to antibiotics for decontamination. Processed and post-thaw cryopreserved sporozoites were assessed for viability using LSM and quantified using hematocytometer. Viable sporozoites were then incubated with human host blood, mimicking in vivo infection, and evaluated using the neutrophil function test (NFT) and spectral resolution. NFT results showed an activation rate of neutrophils of about 70% and incomplete loss of GFP signal upon incubation with sera complement proteins. This output delineates a partial early IR induced by neutrophils, leaving space for ambiguous queries related to the factors hindering a complete protective efficacy.