Comparative evaluation of four immunoassays for Plasmodium vivax serological detection using recombinant PvMSP1-42...

Serological surveillance is a vital component in the control and elimination of Plasmodium vivax, particularly during low-transmission or elimination phases. Immunoassays are core tools for malaria serological surveillance. Among them, protein arrays, dot blot, enzyme-linked immunosorbent assay (ELISA), and Western blot are widely used, each with distinct diagnostic and operational characteristics.

We evaluated a recombinant His-tagged PvMSP1-42 protein using sera from immunized mice, P. vivax-infected patients, and healthy individuals across the platforms under standardized conditions.

All immunoassays demonstrated high reproducibility but varied in sensitivity and sample requirements. Protein arrays enabled a broad detection range (3.13-200 ng/μl) with minimal protein and antibody use, with performance further enhanced using a protein stabilizing diluent. Dot blot and Western blot exhibited similar detection thresholds (6.25-200 ng/μl), although dot blot showed improved sensitivity at low serum dilutions when using Protein Microarray Spot Diluent. ELISA achieved the highest sensitivity, detecting specific antibodies at dilutions up to 1:128,000, but plateaued beyond 50 ng/μl of antigen. Apart from the dot blot, the other methods demonstrated both sensitivity and specificity exceeding 90%, whereas dot blot sensitivity remained lower at 80%.

Protein arrays offered a favorable balance between sensitivity, throughput capability and sample conservation. ELISA was the most effective for detecting low antibody titers. Dot blot and Western blot remained useful, depending on resource availability and experimental goals. These findings provide a practical reference for selecting appropriate immunoassay platforms for malaria serology and for developing scalable serosurveillance strategies in elimination-phase settings.