Infectious bronchitis in chickens is a serious threat to the global poultry industry.Despite the availability of commercial vaccines,the epidemic has not been effectively controlled.Therefore,the development of novel vaccines may provide new ways to prevent and control this disease.In this study,BLP-S1,a bacterium-like particle displaying the S1 subunit of infectious bronchitis virus on its surface,was constructed using the GEM-PA system.The immunoprotection results showed that BLP-S1 effectively induced the production of specific IgG and sIgA in commercial chickens and provided effective protection against a heterologous strain with a protection rate of up to 90％.This study demonstrated that BLP-S1 has good immunogenicity and immunoprotection,with the poten-tial to develop a novel vaccine against infectious bronchitis.