Dengue is a mosquito-borne viral disease causing significant health and economic burdens globally. The dengue virus (DENV) comprises four serotypes (DENV1-4). Usually, the primary infection is asymptomatic or causes mild dengue fever (DF), while secondary infections with a different serotype increase the risk of severe dengue disease (dengue hemorrhagic fever, DHF). Complement system activation induces inflammation and tissue injury, contributing to disease pathogenesis. However, in asymptomatic or primary infections, protective immunity largely results from the complement system’s lectin pathway (LP), which is activated through foreign glycan recognition. Differences in N-glycans displayed on the DENV envelope membrane influence the lectin pattern recognition receptor (PRR) binding efficiency. The important PRR, mannan binding lectin (MBL), mediates DENV neutralization through (1) a complement activation-independent mechanism via direct MBL glycan recognition, thereby inhibiting DENV attachment to host target cells, or (2) a complement activation-dependent mechanism following the attachment of complement opsonins C3b and C4b to virion surfaces. The serum concentrations of lectin PRRs and their polymorphisms influence these LP activities. Conversely, to escape the LP attack and enhance the infectivity, DENV utilizes the secreted form of nonstructural protein 1 (sNS1) to counteract the MBL effects, thereby increasing viral survival and dissemination.

Background: Specific binding to target protein epitopes by a mouse monoclonal antibody (mAb) relies on its variable domains. However, the isolation of functional variable gene transcripts is sometimes hindered by co-expression of aberrant transcripts in hybridoma cells. Objective: To develop general strategies for identifying the functional variable transcripts of both heavy (V-H) and kappa light (V-kappa) chains from mouse hybridomas. Methods: V-H and V-kappa genes of anti-dengue hybridoma clones were PCR-amplified using set of degenerate primers covering all mouse immunoglobulin families. V-kappa amplicons were additionally digested with BciVI to eliminate aberrant V-kappa transcripts. The productive V-H and V-kappa sequences were identified by Immunogenetics (IMGT) database analysis and cloned into a dual human IgG expression vector to generate chimeric antibodies (chAbs) in mammalian cells. The reactivity of chAbs was tested by immunoblot and immunofluorescent assays. Results: Among 17 tested hybridoma clones, 400 bp V-kappa amplicons were obtained using eight different V-kappa primers. Amplicons from productive V-kappa transcripts are resistant to BciVI digestion, whereas BciVI-digested amplicons indicated aberrant V-kappa transcripts. 500-bp productive V-H amplicons could be obtained from all clones using a set of five V-H primers. The productive V-H/V-kappa genes of three anti-dengue NS1 mAbs (m2G6, m1F11 and m1A4) were cloned and mouse-human chAbs were generated. The binding reactivities of the chAbs to dengue NS1 were similar to the original mAbs. Conclusions: A general protocol to identify productive/functional V-H and V-kappa genes was demonstrated. The method is useful for producing chAbs and genetic archiving of valuable hybridoma cell lines.

The non-structural protein 1 (NS1) of dengue virus (DENV) plays a multifaceted role in viral pathogenesis and immune modulation. Although vaccine strategies have traditionally focused on neutralizing antibodies against the envelope (E) protein, recent evidence highlights the protective potential of anti-NS1 antibodies—particularly those that mediate Fc-dependent effector functions. These functions include antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC), which collectively bridge adaptive antibody responses with innate immune activation. However, the outcomes of anti-NS1 responses are context-dependent: certain antibody specificities confer protection, while others may contribute to immunopathology. In this review, I synthesize current evidence on the roles of anti-NS1 antibodies in modulating Fc receptor engagement, subclass-specific responses, glycosylation patterns, and their effector functions. Understanding these mechanisms is essential for guiding rational vaccine design and the development of antibody-based diagnostics and therapeutics. By integrating the findings from both innate and adaptive immunology, this review emphasizes the importance of NS1 as a multifunctional immune determinant in dengue virus infection.

The non-structural protein 1 (NS1) of dengue virus (DENV) plays a multifaceted role in viral pathogenesis and immune modulation. Although vaccine strategies have traditionally focused on neutralizing antibodies against the envelope (E) protein, recent evidence highlights the protective potential of anti-NS1 antibodies—particularly those that mediate Fc-dependent effector functions. These functions include antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC), which collectively bridge adaptive antibody responses with innate immune activation. However, the outcomes of anti-NS1 responses are context-dependent: certain antibody specificities confer protection, while others may contribute to immunopathology. In this review, I synthesize current evidence on the roles of anti-NS1 antibodies in modulating Fc receptor engagement, subclass-specific responses, glycosylation patterns, and their effector functions. Understanding these mechanisms is essential for guiding rational vaccine design and the development of antibody-based diagnostics and therapeutics. By integrating findings from both innate and adaptive immunology, this review emphasizes the importance of NS1 as a multifunctional immune determinant in dengue virus infection.