TITLE:
MontanideTM Gel01 ST Adjuvant Enhances PRRS Modified Live Vaccine Efficacy by Regulating Porcine Humoral and Cellular Immune Responses
AUTHORS:
Xiangdong Li, Amy Galliher-Beckley, Jerome C. Nietfeld, Kay S. Faaberg, Jishu Shi
KEYWORDS:
PRRSV; MontanideTM Gel01 ST; IFN-γ; Adjuvant; IL-10; Immune Response; Vaccine
JOURNAL NAME:
World Journal of Vaccines,
Vol.3 No.1,
February
22,
2013
ABSTRACT: Porcine reproductive and
respiratory syndrome (PRRS) is a devastating disease caused by the PRRS virus.
The MontanideTM class of flexible polymeric adjuvants has recently
been shown to enhance protective immunity against PRRSV infection in piglets
when used in combination with PRRS modified live vaccines (MLV). In this study,
we explored the efficacy and immunological mechanisms of protection of
MontanideTM Gel01 ST (Gel01) adjuvanted modified live PRRSV vaccine
in pigs challenged with two genetically distinct strains of PRRSV. Gel01-MLV reduced
lymph node pathology scores in pigs challenged with VR-2332 (parental strain of
MLV vaccine) but not that in pigs challenged with MN184A (heterologous strain), when compared to that in
pigs vaccinated with un-adjuvanted MLV. Pigs vaccinated with Gel01-MLV had
higher levels of PRRS-specific antibodies, as measured by IDEXX ELISA and virus
neutralizing antibodies, after vaccination and VR-2332 challenge. In addition,
pigs vaccinated with Gel01-MLV had decreased levels of IFN-γ, IL-10, and T-regulatory lymphocytes in the blood as compared to
that in pigs vaccinated with MLV alone. Interestingly, we found that addition
of Gel01 did not change the profile of other T lymphocyte populations after
PRRSV challenge. These results demonstrate that the MLV adjuvanted with Gel01
provides enhanced protection against homologous PRRSV infection, possibly by
regulating the production of PRRSV-specific antibodies and cytokines involved
in the development of T-regulatory cells. Thus, Gel01 ST is a promising adjuvant that can
be formulated with PRRSV MLV vaccines to reduce disease severity and tissue
damage caused by PRRSV infection in pigs.