摘要
Coxsackievirus A6 of the D3a genotype(CVA6 D3a)is a primary pathogen causingmainland of China's hand,foot,and mouth disease(HFMD).Viral‐like particle(VLP)vaccines represent a potential candidate vaccine to prevent HFMD.This study collected Anti‐CVA6 D3a VLPs serum from BALB/c female mice immunized using CVA6 D3a VLPs.The neutralizing antibody levels were compared against the representative 14‐JX2018(D3a)and N4‐YN2015(D3b)strains between the antisera of different immune pathways.The immunoprotective effect of anti‐CVA6 D3a VLPs against these strains was monitored using pathological sections and immuno-histochemical results of lung and skeletal muscle tissues in seven‐day‐old Institute of Cancer Research(ICR)mice.Immunological protection against different branches of viruses was evaluated in 7‐day‐old(serum passive immune protection)and 14‐day‐old(VLPs active immune protection)neonatal ICR mice models.Serum‐neutralizing antibody levels were positively correlated with the number of immunizations and higher against 14‐JX2018 than against N4‐YN2015.Furthermore,these levels were significantly higher with abdominal injection than intramuscular injection.The immunized serum of 7‐day‐old ICR mice inoculated three times was 100%protected against CVA6 D3a 14‐JX2018(lethal titer:106.25 TCID 50)and CVA6 D3b N4‐YN2015(lethal titer:105.25TCID 50)fatal attacks,respectively.For ICR mice that have completed two active immunizations for 14 days,both CVA6 D3a 14‐JX2015(challenge titer:108.25 TCID 50)and CVA6 D3b N4‐YN2015(challenge titer:107.25 TCID 50)were used for the challenge,and the mice were able to survive.Overall,the CVA6 D3a VLPs prepared in this study are a potential vaccine candidate for CVA6,as it has the optimal protective effect against both CVA6 D3a and D3b evolutionary branches viruses.
基金
supported by the National Key Researchand Development Programof China (Project No.2021YFC2302003).
