Chicken Egg Yolk Igy Antibodies In The Diagnosis Of Falciparum Malaria

Malaria is one of the three major infectious diseases in the world.There were an estimated 247 million malaria cases among 3.3 billion people at risk in tropical and sub-tropical regions.In malaria patients,a prompt and accurate diagnosis is the key to effective disease management,services.Compared to traditional microscopy,the main disadvantages of currently available RDTs are:lack of sensitivity and specificity at low levels of parasitaemia;Cross-reactivity with rheumatoid factor in blood;inability to quantify parasite density;inability to differentiate between P.vivax,P.ovale,P.malariae and P.knowlesi;exaction on the storage conditions and environmental conditions.Use of rapid diagnostic tests for Plasmodium falciparum was limited in remote areas as a result of those shortcomings of the above.In the previous work,we developed a novel diagnostic kit for Plasmodium falciparum,by combining random tandem with epitope shuffling technology and birds IgY antibody technique.We have constructed polyepitope DNA libraries with epitope shuffling technology.The artificial random multi-epitope recombinant antigens,named M.RC Ag-1/2,had been obtained by high-throughput screening.These M.RC Ag can induce hens producing extremely strong humoral immunity,which means IgY antibody in yolk can effectively recognized the natural Plasmodium falciparum.The newly developed Sandwich-ELISA by adopting this IgY antibody instead of the mammalian monoclonal IgG antibody had been tested for M.RC Ag standards(detection limit reached 1.95ng/ml) and plasmodium falciparum culture (the minimum parasite densities of mixed and ring-stage-rich parasite culture were 0.0001%and 0.001%respectively).Furthermore,the whole blood of the malaria patients, which diagnosed by microscopy,was investigated by the Sanwich-ELISA as well, showing 56.7%of sensitivity.Moreover,the IgY-based immunochromatographic strip as a trial,was reaching 10ng/ml as the highest limit for M.RC Ag standards and the lowest rate was 0.5%for plasmodium falciparum culture.In addition,the condition of egg yolk IgY purification had been optimized and the process of chromatography had been developed.Another study was carried out to compare the efficacy of adjuvant,and ultimately Montanide ISA 50 was considered the most suitable one for immunization of hens.These results provide the possibility of rapid diagnositic test of malaria and rapid diagnositic test platform for other diseases especially infectious diseases.