Primary characterization of the immune response in pigs infected with Trichinella spiralis

Nan Wang,Mingyuan Liu,Xuenong Luo,Hongbin Yan,Xiaolei Liu,Xue Bai,Hong Jia,Xuelin Wang,Yong Yang,Bin Tang,Hongfei Zhu

doi:10.1186/s13567-020-0741-0

Abstract

Trichinellosis, which is caused by Trichinella spiralis (T. spiralis), is a serious zoonosis. Pigs play an important role in the transmission of human trichinellosis. Characterizing the immune response to T. spiralis infection is key to elucidating host–parasite interactions. However, most studies on the immune response to T. spiralis infection have employed murine models. In this study, we investigated the immune response to T. spiralis infection in pigs. The results showed that the average numbers of larvae per gram (lpg) for the 100-muscle larvae (ML), 1000-ML, and 10 000-ML groups were 1.502, 35.947, and 398.811, respectively. The percentages of CD3+ T cells, B cells, CD4+ T cells, Treg cells, and Th17 cells were elevated in the infection groups compared to the control animals. In contrast, CD8+ T cell percentages were reduced after infection in the low-dose group. The number of neutrophils was increased at 3–17 days post-infection (dpi). Th1 cytokine IL-2 levels were significantly decreased at 7 dpi, and Th2 cytokine IL-4 levels were significantly elevated at 3 dpi. Treg cytokine IL-10 levels were significantly elevated between 7 dpi and 30 dpi. Th17 cytokine IL-17A levels were significantly increased beginning at 11 dpi. These results confirmed that pigs infected with T. spiralis predominantly induced Th2 and Treg immune responses, which suppress the Th1 immune responses. This study provides novel insights into the immune response of pigs infected with T. spiralis.

Highlights

Trichinellosis is a frequently occurring zoonosis that leads to significant economic loss in pork production
T. spiralis muscle larvae (ML) could live in the host for various years, the host immune system is activated to accelerate worm expulsion from the intestine
Another possibility is that the parasite could moderate the host immune response to facilitate parasite survival using secretory products and surface antigens [12, 17]

Summary

Introduction

Trichinellosis is a frequently occurring zoonosis that leads to significant economic loss in pork production This disease is distributed worldwide and has a notable impact on human health, with approximately 10 000 cases occurring each year [1]. T. spiralis and its secretory products can suppress inflammatory responses and induce Th2-type immune responses, as determined by the elevated Th2-associated cytokine levels observed in infected animals [17, 18]. Treg-type immune responses play a key role in the anti-inflammatory effects of helminth infection and exist in the ML phase [22, 23]. Th1, Th2, Treg, and Th17 cells play important roles in the infection of T. spiralis. We studied the dynamics of T lymphocytes in pigs infected with T. spiralis

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Results

Conclusion