Thymic stromal lymphopoietin improves protective immunity of the SARS-CoV-2 subunit vaccine by inducing dendritic cell-dependent germinal center response

The current development and implementation of subunit vaccines in clinical practice encounter a number of challenges. The most significant difficulties are the scarcity of effective adjuvants and the fact that most vaccination programs rely on non-mucosal injections, which frequently fail to establish mucosal adaptive immunity and hence restrict the potential to protect against respiratory viral infections. Our research indicates that TSLP can effectively boost SARS-CoV-2 subunit vaccine-specific systemic and mucosal humoral immunity in mice after intranasal immunization, protecting them from SARS-CoV-2 wild-type and Delta variant infection. The mucosal adjuvant effects of TSLP depend on DC migration and activation, which boosts germinal center responses. Therefore, supplementation of mucosal subunit vaccines with TSLP should be considered in vaccine development, particularly when the vaccine is administered to children and the elderly. Our findings provide new evidence for the development of mucosal adjuvants for infectious diseases, potentially facilitating future vaccine development.