Genetically engineered bacterial-like particles induced specific cellular and humoral immunity as effective tick-borne encephalitis virus vaccine

Tick-borne encephalitis(TBE)is a natural focal disease with fatal encephalitis induced by tick-borne encephalitis virus(TBEV),seriously threatening human and public health.Protection of TBE depends on vaccination with inactivated vaccine,which requires high cost and multiple immunizations.Here,we construct genetically engineered bacterial-like particles(BLPs)as an effective TBEV vaccine with simplified immunizations and improved immune efficacy.The TBEV BLPs involve the combination of the gram-positive enhancer matrix from Lactococcus lactis,and TBEV envelope(E)protein expressed by genetically engineered recombinant baculovirus.The prepared TBEV BLPs can effectively stimulate the activation of dendritic cells to present the TBEV E proteins to T and B cells,leading to strong and durable cellular and humoral immune responses in mice.Surprisingly,the serum levels of specific IgG antibodies in mice remain about 10^(6)at 6 months after the secondary immunization.Overall,the TBEV BLPs can be used as a potent vaccine candidate,laying the foundation for developing novel TBEV genetically engineered vaccines.