Dengue viruses serotypes 2 and 4 exhibit distinct infection kinetics and modulation of anti-viral immune responses in human tonsil histocultures
Dengue virus (DENV) is the most prevalent mosquito-borne viral disease with over ten million cases worldwide. There are four antigenically distinct, co-circulating DENV serotypes (DENV 1-4) capable of infecting humans. Given the lack of immunocompetent animal models and the limitations of known cell culture models, more physiologically relevant experimental models are needed to recapitulate DENV infection and host immune responses. Building on previous observations that DENV-2 and DENV-4 serotypes elicit distinct innate immune responses in monocyte-derived dendritic cells (moDC) in vitro, we utilized a human tonsil histoculture (HC) model to further investigate serotype-specific differences within the physiologically relevant human lymphoid environment. We show that human tonsil HCs preserved their tissue cytoarchitecture for up to 6 days in culture, including maintaining functional germinal centers and diverse immune populations within T and B cell compartments. Exposure of tonsil HCs to DENV-2 and DENV-4 showed that DENV-4 replication peaked earlier and induced enhanced innate immune activation compared to DENV-2, consistent with previous observations in human DCs. Moreover, by leveraging the structural and cellular complexity of the HC system, we further identified that DENV E protein co-localized with HLA-DR+ antigen-presenting cells, confirming that DENV-infected cells within tonsil HCs predominantly express antigen-presenting cell markers. Altogether, these findings demonstrate that different DENV serotypes can exhibit different viral replication dynamics and induce distinct immune responses within human lymphoid tissue. This establishes human tonsil HCs as human model system with intact cytoarchitecture that closely mirrors lymph node structure and function, providing a powerful platform to study antigen-driven and virus-specific human immune responses and ultimately to evaluate vaccine candidates and antiviral therapeutics.