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Published on: June 8, 2012
Recombinant Antigen of Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV-2) Promotes M1
Rika Wahyuningtyas1,2, Yin-Siew Lai1, Mei-Li Wu1,3
1Research Centre for Animal Biologics, National Pingtung University of Science and Technology, Neipu, Pingtung 912, Taiwan.
Abstract:
The polarization status of porcine alveolar macrophages (PAMs) determines the infectivity of porcine reproductive and respiratory syndrome virus (PRRSV). PRRSV infection skews macrophage polarization toward an M2 phenotype, followed by T-cells inactivation. CD163, one of the scavenger receptors of M2 macrophages, has been described as a putative receptor for PRRSV. In this study, we examined two types of PRRSV-2-derived recombinant antigens, A1 (g6Ld10T) and A2 (lipo-M5Nt), for their ability to mediate PAM polarization and T helper (Th1) response. A1 and A2 were composed of different combination of ORF5, ORF6, and ORF7 in full or partial length. To enhance the adaptive immunity, they were conjugated with T cells epitopes or lipidated elements, respectively. Our results showed that CD163+ expression on PAMs significantly decreased after being challenged with A1 but not A2, followed by a significant increase in pro-inflammatory genes (TNF-α, IL-6, and IL-12). In addition, next generation sequencing (NGS) data show an increase in T-cell receptor signaling in PAMs challenged with A1. Using a co-culture system, PAMs challenged with A1 can induce Th1 activation by boosting IFN-γ and IL-12 secretion and TNF-α expression. In terms of innate and T-cell-mediated immunity, we conclude that A1 is regarded as a potential vaccine for immunization against PRRSV infection due to its ability to reverse the polarization status of PAMs toward pro-inflammatory phenotypes, which in turn reduces CD163 expression for viral entry and increases immunomodulation for Th1-type response.
Insights
Recombinant antigens A1 and A2 were tested for their effects on porcine alveolar macrophages (PAMs) and T helper cell responses. Antigen A1 reversed M2 polarization, reduced CD163 expression, and promoted a Th1 immune response, indicating its potential as a PRRSV vaccine.
Area of Science:
- Veterinary Immunology
- Virology
- Macrophage Biology
Background:
- Porcine reproductive and respiratory syndrome virus (PRRSV) infection influences macrophage polarization, promoting an M2 phenotype and T-cell inactivation.
- CD163, an M2 macrophage scavenger receptor, is a potential entry receptor for PRRSV.
Purpose of the Study:
- To evaluate the immunomodulatory effects of two PRRSV-2 recombinant antigens, A1 and A2, on porcine alveolar macrophages (PAMs) and T helper 1 (Th1) responses.
- To assess the potential of these antigens as vaccine candidates against PRRSV infection.
Main Methods:
- PRRSV-2 derived recombinant antigens A1 (g6Ld10T) and A2 (lipo-M5Nt), containing different combinations of viral genes and immune-enhancing elements, were used.
- PAMs were challenged with A1 and A2, and changes in CD163 expression, pro-inflammatory gene expression (TNF-α, IL-6, IL-12), and T-cell receptor signaling were analyzed using techniques including next-generation sequencing (NGS).
- A co-culture system was employed to assess the ability of A1-challenged PAMs to induce Th1 activation, measuring IFN-γ and IL-12 secretion and TNF-α expression.
Main Results:
- Antigen A1 significantly decreased CD163+ expression on PAMs and increased pro-inflammatory genes (TNF-α, IL-6, IL-12), unlike antigen A2.
- NGS data revealed increased T-cell receptor signaling in PAMs challenged with A1.
- PAMs challenged with A1 induced Th1 activation, evidenced by boosted IFN-γ and IL-12 secretion and TNF-α expression in a co-culture system.
Conclusions:
- Antigen A1 effectively reverses PAM polarization towards pro-inflammatory phenotypes, reducing viral entry receptor CD163 expression.
- A1 promotes a Th1-type immune response, suggesting its potential as a vaccine candidate for PRRSV immunization.
- The study highlights A1's capacity to modulate both innate and T-cell-mediated immunity against PRRSV.
