A novel method for depletion of dengue virus non-structural protein 1 antibodies to determine serotype exposure history.

UNLABELLED: Nearly 4 billion people worldwide reside in dengue virus (DENV) endemic areas. Primary dengue infection generates both type-specific and cross-reactive immunity. While serotype-specific immunity provides long-term protection against homologous virus challenge, cross-reactive immunity is short-lived and, upon subsequent heterotypic exposure, can increase the risk of severe clinical outcomes. Therefore, it is critical to measure type-specific immunity. The current resource-intensive and technically demanding approach of removing antibodies using purified whole virions and subsequently assessing type-specific immunity through neutralization assays is practical only for small-scale studies. We developed a novel, straightforward method that uses transfected suspension cells stably expressing DENV non-structural protein 1 (NS1) de novo to selectively deplete targeted serotype-specific and cross-reactive NS1 antibodies from plasma and serum samples. The same cell lines are then used to establish an antibody profile of the depleted plasma to uncover type-specific serotype exposure history. This approach to antibody depletion offers several advantages over column- and bead-based depletion methods, such as (i) ease of antigenic substrate production; (ii) simplicity of the depletion procedure; and (iii) interpretability of the data.

IMPORTANCE

Accurately determining dengue serotype exposure remains challenging because current serotyping methods are labor-intensive, costly, and often rely on engineered viral antigens or antibodies to capture native immune components. We developed a streamlined approach that removes NS1-specific antibodies from dengue convalescent plasma using transfected cells that express NS1 de novo. This procedure enables the characterization of the depleted sample for the antibodies left behind to understand the relative levels of different antibody specificities and uncover an individual's dengue exposure history. The knowledge of viral antigen-antibody profiles refines the interpretation of downstream functional assays and establishes a practical framework for dissecting dengue immunity with greater precision.