Echinococcus multilocularis inoculation induces NK cell functional decrease through high expression of NKG2A in C57BL/6 mice

Abstract

Background Alveolar echinococcosis (AE) is caused by the larval stage of Echinococcus multilocularis (E. multilocularis), and considered as public health issue. Parasite-host immune interaction is pivotal during infection. As a subset of innate lymphoid cells, NK cells are known to play an important role during virus, bacteria, intra/extracellular parasitic infections and tumor progression. However, the possible role of NK cells in E. multilocularis infection in both human and murine is little known. Herein, the functional alteration of hepatic NK cells and their related molecules in E. multilocularis infected mice were studied. Methods 2000 protoscoleces (PSCs) were injected to C57BL/6 mice via the portal vein to establish secondary E. multilocularis infection. NK cells population and their related molecules (CD69, Ly49D, Ly49G2, Ly49H, Ly49I, NKG2A, NKG2D, granzyme B, IFN-γ, TNF-α) were assessed by using fluorescence-activated cell sorter (FACS) techniques and qRT-PCR. NK cell depletion was performed for further understanding the possible function of NK cells during infection. Results The total frequencies of NK cells and NK-derived IFN-γ production were significantly reduced at designated time points (2, 4, 12 weeks). The liver resident (CD49a+DX5−) NK cells are decreased at 4 weeks after inoculation and which is significantly lower than in control mice. Moreover, in vivo antibody-mediated NK cell depletion increased parasitic load and decreased peri-parasitic fibrosis. Expression of the inhibitory receptor NKG2A was negatively related to NK- derived IFN-γ secretion. Conclusions Our study showed down regulates of NK cells and upper regulates of NKG2A expression on NK cells during E. multilocularis infection. Reduction of NK cell frequencies and increased NKG2A might result in low cytotoxic activity through decreased IFN-γ secretion in E. multilocularis infection. This result might be helpful to restore NK cell related immunity against E. multilocularis infection to treat alveolar echinococcosis.

TIM-1+ B Cells are more Efficient IL-10 Producers in Liver Fibrosis Caused by Alveolar Echinococcosis

“…Mice were sacri ced at experimental timepoints (180 days after model was established) using euthanasia, which was approved by Institutional Animal Care and Use Committee. Speci cally, mice were intraperitoneally (left lower quadrant) injected with 5% chloral hydrate 0.15-0.20 ml/mouse through medical syringe needle, and peripheral blood was collected by retro-orbital bleeding after successfully anesthetized; then, whole liver and spleen samples were obtained surgically; at last, mice were euthanized using cervical dislocation [13].…”

Echinococcus multilocularis induces surface high expression of inhibitory killer immunoglobulin‐like receptor on natural killer cells

“…11,12 In AE, E. multilocularis infection inhibits the activity and proliferation of NK cells, implying that NK cells in AE patients with alveolar hydatid cannot perform normal immune surveillance functions, which leads to the formation of immune tolerance. 13,14 A recent study has demonstrated that E. multilocularis can downregulate the immune response of NK cells by inducing the overexpression of NKG2A on the surface of NK cells. In addition, some studies have also found that the sustained expression of MICA/B molecules and TGF-β may lead to the inhibition of NKG2D in NK cells, 15 thereby inhibiting NKG2D-dependent cytotoxicity, and causing immune escape of E. multilocularis in host's NK cells.…”

Development of an improved anesthesia protocol to increase CF1 mice survival in a portal vein infection with Echinococcus granulosus sensu lato protoscoleces

“…Portal vein injection is also used in murine models for the development of pathologies such as liver metastasis ( Goddard et al., 2016 ; Orci et al., 2018 ) and parasitic diseases ( Nakaya et al., 1997 ; Jarillo-Luna et al., 2002 ; Chen et al., 2017 ; Zhang et al., 2017a , 2017b ; Cortes et al., 2019 ; Abulizi et al., 2019 ). These procedures require laparotomy and therefore must be performed under anesthesia and analgesia to prevent or minimize the discomfort, pain, and/or distress of mice ( Flecknell, 2009 ).…”

“…Several researchers have reported the use of different anesthesia protocols (inhalational or injectable) to perform laparotomy and subsequent intraportal injection of an agent in mice ( Arnheiter et al., 1976 ; Nakaya et al., 1997 ; Jarillo-Luna et al., 2002 ; Chen et al., 2017 ; Kawaguchi et al., 2017 ; Zhang et al., 2017a , 2017b ; Sherman et al., 2014 ; Goddard et al., 2016 ; Orci et al., 2018 ; Abulizi et al., 2019 ; Cortes et al., 2019 ). However, only a few studies have described the use of analgesic for pain management and it was applied at the end of the surgical procedure ( Jarillo-Luna et al., 2002 ; Sherman et al., 2014 ; Goddard et al., 2016 ; Orci et al., 2018 ).…”

“…Chloral hydrate is one of the injectable drugs most used to induce anesthesia in this type of procedure ( Chen et al., 2017 ; Zhang et al., 2017a , 2017b ; Abulizi et al., 2019 ). However, it can cause adynamic ileus ( Fleischman et al., 1977 ) and it often produces only a light plane of anesthesia in rodents.…”