Immunogenicity of bacteriophage lambda particles displaying porcine Circovirus 2 (PCV2) capsid protein epitopes

Phage lambda particles displaying four immunodominant regions of porcine Circovirus 2 (PCV2) capsid protein (LDP–D–CAP) was shown to be immunogenic in pigs. The immunodominant regions were fused to the carboxyl-terminal of lambda head protein D. Expression of D–CAP on lambda display particles was demonstrated by ELISA and Western blots. Pigs receiving LDP–D–CAP, without incorporating adjuvant, showed significant anti-PCV2 immune response following the primary vaccination. The LDP–D–CAP preparation induced PCV2 neutralizing antibodies. Delayed type hypersensitivity (DTH) reaction scores revealed that the immunized pigs were hypersensitive to both lambda phage and PCV2 antigens. The LDP–D–CAP elicited both cellular and humoral immune responses. Neither LDP–D–CAP nor the lambda control elicited any untoward local or systemic reactions following immunization. These studies produced the first potential phage vaccine to porcine Circovirus 2.