Recombinant Trichinella Spiralis Excretory-secretory Antigen 53ku Protein Alleviates Acute Lung Injury in Septic Mice via Polarization of M2 Macrophages / 中山大学学报(医学科学版)

[Objectives]To investigate the protective effects of recombinant Trichinella spiralis excretory-secretory 53ku pro-tein(rTsP53)on acute lung injuries in mice.[Methods]Thirty Balb/c mice were randomly divided into normal group. ALI group and rTsP53 group(n=10,respectively). Macrophages were harvested by bronchoalveolar lavage. Mortality in 72 hours was counted and compared. Pathological damage of lung tissues was observed by HE staining and graded by Smith score. Wet/dry ratio was measured. The bronchoalveolar lavage fluid concertration of IL-6 and IL-4 was measured by ELISA. The mRNA expression of TNF-α,iNOS, IL-10 and Arg-1 in alveolar lavage macrophages was detected by RT-PCR.[Results]72 h mortality of ALI mice was 70%,which was reduced to 30% in mice received rTsP53 treatment. Compared with ALI mice,the pathological damage of in rTsP53 treated-mice was improved and Smith score was declined ,combined with descending W/D ratio. IL-6 level of alveolar lavage fluid was elevated in ALI mice compared with normal group. And alveolar lavage macrophage was polarized to M2 sub-type,appeared as higher mRNA expression of TNF-α and iNOS and lower level of IL-10 and Arg-1. Bronchoalveolar lavage fluid concentration of IL-6 was declined and IL-4 was elevated in rTsP53-treated mice compared with ALI group. The macrophages of alveolar wash had higher mRNA expression of IL-10 and Arg-1,while lower level of TNF-α and iNOS,manifesting M2 polarization characteristics.[Conclusion]Recombinant T.spiralis P53 protein could protect mice from acute lung injuries induced by LPS via modulating M2 macrophage polarization,which play a role in depression of inflammatory reaction and tissue repairment.

Immunomodulatory potential of particular Trichinella spiralis muscle larvae excretory-secretory components.

Excretory-secretory antigens of Trichinella spiralis muscle larvae can induce the semi-matured status of rat dendritic cells. This may at least partly be the consequence of transient activation of extracellular signal-regulated kinases 1/2 (ERK1/2). Here we investigated the potential of several components of excretory-secretory antigens (native fraction containing 45, 49 and 53kDa proteins and recombinant Tsp53, representing one of the constituents of this fraction) to demonstrate previously observed effects of excretory-secretory antigens on dendritic cells in vitro, characterised by establishment of a particular phenotype (very low MHC II expression, moderate CD86 expression and significant ICAM-1 expression) and functional properties (low production of pro-inflammatory cytokine IL-12p70, and high production of IL-10 and TGF-ß). Dendritic cells activated by these components were able to provoke proliferation of naïve T cells and their polarisation towards Th2 and anti-inflammatory responses. The investigated antigens had almost the same capacity to induce IL-4 and IL-10 production from T cells as excretory-secretory antigens, but failed to induce significant TGF-ß synthesis. It could be concluded that the investigated excretory-secretory antigens components can largely reproduce the immunomodulatory effects of the complete excretory-secretory antigens and therefore may be considered as molecules important for creation of the anti-inflammatory milieu achieved by the parasite.

Effect of rTsP53 on the M1/M2 activation of bone-marrow derived macrophage in vitro.

We investigated that if rTsP53 could be used to activate bone-marrow derived macrophage (BMDM) into M2 macrophage and stop M1 macrophage activation. After 72 h incubation in blank culture medium, cells with PE-CCR7 (-) and FITC-CD206 (-) was extracted and its mean proportion was 92.30 ± 0.22%. With the stimulation of 20 µg/ml IFN-γ for 72 h, cells with PE-CCR7 (+) was extracted and its mean proportion was 16.24 ± 0.82%. With the stimulation of IL-3/IL-14 (both 10 µg/ml) for 72 h, cells with FICT-CD206 (+) was extracted and its mean proportion was 87.32 ± 4.29%. Co-incubation with different dose of rTsP53 (0.001 µg/ml, 0.01 µg/ml, 0.1 µg/ml, 1 µg/ml, 2 µg/ml, 5 µg/ml, 10 µg/ml, respectively) for 72 h, FITC-CD206 (+) macrophage was extracted. The mean proportion in each group was 1.09 ± 0.22%, 2.13 ± 0.13%, 4.91 ± 0.07%, 5.48 ± 0.29%, 9.81 ± 0.06%, 12.83 ± 0.55%, 17.87 ± 0.02%, respectively. The dose of rTsP53 was significantly positive correlated to the proportion of FITC-CD206 (+) macrophage. Co-incubation with 20 µg/ml IFN-γ and 5 µg/ml rTsP53 for 72 h, cells with PE-CCR7 (+) was extracted and its mean proportion was 10.60 ± 0.19%. Compared to that of mere co-incubation with IFN-γ, there was significant difference between the two groups. ELISA showed that Th1 cytokines' (IFN-γ, IL-6 and TNF-α) level decreased in the culture medium supernatant of BMDM co-incubated with rTsP53. There was negative correlation between the Th1 cytokines' level and the dose of rTsP53. Both Th2 cytokines (IL-4 and IL-13) and regulatory cytokines in the culture medium increased. There was positive correlation between the Th2 cytokines' level and the dose of rTsP53. There was also positive correlation between the regulatory cytokines' level and the dose of rTsP53. Compared to that of BMDM co-incubated with IFN-γ, levels of TNF-α and IL-6 were significant lower than that of BMDM co-incubated with both IFN-γ and rTsP53 (both P < 0.05), while the levels of IL-4 and TGF-ß were significant higher (both P < 0.05). There was no significant difference in the levels of IL-13 and IL-10 between the two groups.