Porcine Parvovirus virus-like particle vaccine induces long-term humoral immunity by recruiting T follicular helper and germinal center B cell responses

Porcine parvovirus (PPV) is a major pathogen causing reproductive disorders in sows and remains widely prevalent worldwide. In recent years, PPV has undergone rapid mutations and frequently co-infects with other pathogens, making vaccination the most effective preventive measure. Our previous study showed that co-expression of the chaperone protein Tf16 and VP2 in prokaryotic cells could produce highly immunogenic PPV virus-like particles (VLPs). However, whether these VLP vaccines can induce durable immune memory through sustained antibody recall responses has not been fully elucidated. In this study, mice were immunized with VLPs formulated with ISA 201 VG adjuvant, and the responses of follicular helper T cells (Tfh) and germinal center B cells (GC B cells) were analyzed. The results demonstrated that recombinant VLPs significantly enhanced Tfh and GC B cell responses after the third immunization compared to a commercial inactivated vaccine. More importantly, PPV VLPs effectively induced the generation of specific long-lived plasma cells (LLPCs) and memory B cells (MBCs). These findings enhance our understanding of PPV VLP immunogenicity and may inform the design of more efficacious PPV vaccines.