Establishment and identification of OVA-HBsAg transgenic mice regulated by Cre recombinase

Objective　To breed OVA-HBsAg transgenic mice regulated by Cre recombinase in order to provide a better animal model for the study of HBV prevention and therapy. Methods　The OVA-HBsAg transgenic mice were generated by microinjection of OVA-HBsAg gene with LoxP sites into the pronucleus of C57BL/6J×DBA zygotes. Pups of F1 OVA-HBsAg female mice cross-fertilized with Alb-Cre male mice were assayed for the expression of HBsAg induced by Cre recombinase. PCR, ELISA and immunohistochemical methods were used to detect the integration and expression of HBsAg gene and Cre gene in the transgenic mice. Results　491 fertilized eggs were injected and a total of 337 survived. The survival rate of injection was 68.6%. 29 F0 pups were produced with 4 PCR-positive mice, and the positive rate was 13.8%. Up to now, F4 pups were obtained. The positive rates from F1 to F4 were 27.5%, 32.0%, 22.9% and 25.0%, respectively. No HBsAg-positive mice were found among these pups. Furthermore, among 16 pups of F1 OVA-HBsAg female mice crossed with Alb-Cre male mice, 6 were positive for both HBsAg and Cre as detected by PCR. There were 2 pups showed positive HBsAg by ELISA assay. The expression rate of HBsAg after Cre recombinase induction was 33.3%. Conclusion　OVA-HBsAg transgenic mice has been reproduced successfully, and it can be stably passaged. Cre recombinase can induce the expression of HBsAg in vivo. DOI: 10.11855/j.issn.0577-7402.2015.05.08