Malaria is a life-threatening disease caused by Plasmodium parasites transmitted to people through the bites of infected female Anopheles mosquitoes. In 2017, it was estimated that nearly half of the world population was at risk of contracting the disease, with the highest number of cases and deaths reported in sub-Saharan Africa. In the same year the WHO reported 219 million malaria cases worldwide and 435,000 deaths.
Despite considerable funding, efforts to eradicate the disease have so far produced limited results. A part of this effort is directed at developing an effective vaccine that could become a potent weapon in the fight for the elimination of the disease. The complexity of the organisms, the multi-stage lifecycle and its impressive arsenal of immune evasion mechanisms contribute to the limited success thus far obtained. The authors of this study designed a novel protein microarray with the aim to accelerate the identification and validation of potential new vaccine targets for further evaluation in clinical trials. An extensive evaluation of existing data regarding P. Falciparum proteins known for their immunogenicity potential has been conducted to identify a panel of potential vaccine candidates. A selected number of immunogenic new proteins were also added to the list. Proteins selected to be included in this study are known to be associated with the surface of the merozoite (the parasites released in the bloodstream), involved in erythrocyte invasion or demonstrated to correlate with protection from clinical malaria.
Recombinant full-length purified proteins were arrayed on ONCYTE Supernova microarray slides and probed with malaria immune serum alongside malaria naïve and sample buffer (2% BSA/ 0.1% Tween 20 HBS) controls.T he results are very encouraging as the array was demonstrated to offer many advantages that could effectively boost the identification and prioritization of vaccine candidates. The array features:
- Low intra and inter assay variability
- Long term stability of printed proteins (at least 3 months)
- Low volume of sera needed to test more than a 100 potential target proteins
- Convenient storage at 4 C with desiccant
- Wider dynamic range when compared to conventional ELISA
Therefore, the malaria microarray was demonstrated to be a flexible and portable method to analyze serum levels of malaria antibodies.