Cross protective immune responses in nursing piglets infected with a US spike-insertion deletion porcine epidemic diarrhea virus strain and challenged with an original US PEDV strain

Thavamathi Annamalai,Linda J Saif,Zhongyan Lu,Qiuhong Wang,Xiang Gao,Chun-Ming Lin,Xinsheng Liu

doi:10.1186/s13567-017-0469-7

Thavamathi Annamalai, Linda J Saif + Show 5 more

Open Access

https://doi.org/10.1186/s13567-017-0469-7

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Journal: Veterinary Research	Publication Date: Oct 6, 2017
Citations: 41	License type: open-access

Affiliation: The Ohio State University

Abstract

We investigated cross-protective immunity of a US spike-insertion deletion porcine epidemic diarrhea virus (PEDV) Iowa106 (S-INDEL) strain against the original US PEDV (PC21A) strain in nursing piglets. Piglets were inoculated orally with S-INDEL, PC21A or mock. At 20–29 days post-inoculation (dpi), all pigs were challenged with the PC21A strain. The S-INDEL-inoculated pigs had lower ileal IgA antibody secreting cells, serum IgA and neutralizing antibody titers compared with PC21A-inoculated pigs. No pigs in the PC21A-group developed diarrhea, whereas 81 and 100% of pigs in the S-INDEL and mock-groups had diarrhea post challenge, respectively. S-INDEL induced partial protective immunity against the original US PEDV strain.

Highlights

We investigated cross-protective immunity of a US spike-insertion deletion porcine epidemic diarrhea virus (PEDV) Iowa106 (S-INDEL) strain against the original US PEDV (PC21A) strain in nursing piglets
Studies from our laboratory, as well as from other laboratories, showed that S-INDEL PEDV strains cause less severe infection compared with the original PEDV strains [7, 8]
Whether the differences in severity of infection between those PEDV strains have any impact on eliciting protective immunity is unknown

Summary

Ɵters of piglets a c a b a a

PEDV specific serum virus neutralization antibody titers were significantly lower in the S-INDEL Iowa106 group compared with the original US PEDV-inoculated piglets at pre-challenge (0 dpc) (Figure 1B). Virus specific IgA ASC responses were significantly lower in the S-INDEL Iowa106-inoculated piglets compared with the original US PEDV-inoculated piglets at 0 DPC (Figure 2A). No differences in virus specific IgG and IgM ASC responses were observed between S-INDEL Iowa106 and original US PEDV-inoculated piglets pre-challenge (Figure 2A). The sows of piglets inoculated with the S-INDEL Iowa106 and the original US PEDV strains showed similar virus neutralization antibody responses in the serum pre-challenge (0 dpc) (Figure 3A). Virus specific IgA antibody titers as determined by ELISA in whey were similar between the sows of piglets inoculated with the S-INDEL Iowa106 and the original US PEDV strains (Figure 3D)

Discussion

Findings

Serum geometric mean PEDV IgA anƟbody Ɵters of sows