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Trichinella spiralis Paramyosin Binds Human Complement C1q and Inhibits Classical Complement Activation.

Sun R, Zhao X, Wang Z, Yang J, Zhao L, Zhan B, Zhu X - PLoS Negl Trop Dis (2015)

Bottom Line: Trichinella spiralis expresses paramyosin (Ts-Pmy) as a defense mechanism.The binding of recombinant and natural Ts-Pmy to human C1q were determined by ELISA, Far Western blotting and immunoprecipitation, respectively.Binding of recombinant Ts-Pmy (rTs-Pmy) to C1q inhibited C1q binding to IgM and consequently inhibited C3 deposition.

View Article: PubMed Central - PubMed

Affiliation: Department of Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, PR China.

ABSTRACT

Background: Trichinella spiralis expresses paramyosin (Ts-Pmy) as a defense mechanism. Ts-Pmy is a functional protein with binding activity to human complement C8 and C9 and thus plays a role in evading the attack of the host's immune system. In the present study, the binding activity of Ts-Pmy to human complement C1q and its ability to inhibit classical complement activation were investigated.

Methods and findings: The binding of recombinant and natural Ts-Pmy to human C1q were determined by ELISA, Far Western blotting and immunoprecipitation, respectively. Binding of recombinant Ts-Pmy (rTs-Pmy) to C1q inhibited C1q binding to IgM and consequently inhibited C3 deposition. The lysis of antibody-sensitized erythrocytes (EAs) elicited by the classical complement pathway was also inhibited in the presence of rTs-Pmy. In addition to inhibiting classical complement activation, rTs-Pmy also suppressed C1q binding to THP-1-derived macrophages, thereby reducing C1q-induced macrophages migration.

Conclusion: Our results suggest that T. spiralis paramyosin plays an important role in immune evasion by interfering with complement activation through binding to C1q in addition to C8 and C9.

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Related in: MedlinePlus

Classical complement activation was inhibited by rTs-Pmy.Two μg of human C1q was pre-incubated with increasing amounts of rTs-Pmy (0, 2, 4 μg) or BSA (4 μg), then added to human IgM-coated plates. After washing with PBST for three times, a total of 2% C1q-deficient serum (C1q D) was added as a source of rest complement components. The deposition of C3 was detected with anti-C3 polyclonal antibody. The NHS alone and BSA added to the activation were used as controls. The results are shown as the means ± SD for three independent experiments.* p<0.05, **p<0.01, ***p<0.001. ns, no significant difference.
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pntd.0004310.g003: Classical complement activation was inhibited by rTs-Pmy.Two μg of human C1q was pre-incubated with increasing amounts of rTs-Pmy (0, 2, 4 μg) or BSA (4 μg), then added to human IgM-coated plates. After washing with PBST for three times, a total of 2% C1q-deficient serum (C1q D) was added as a source of rest complement components. The deposition of C3 was detected with anti-C3 polyclonal antibody. The NHS alone and BSA added to the activation were used as controls. The results are shown as the means ± SD for three independent experiments.* p<0.05, **p<0.01, ***p<0.001. ns, no significant difference.

Mentions: To evaluate whether the binding of rTs-Pmy to C1q inhibits classical complement activation, we analyzed C3 deposition on plates coated with human IgM in the presence of different amounts of rTs-Pmy. The result showed that activation of C1q deficient serum (C1q D) was able to be reconstituted with the addition of C1q to the similar level of NHS by detecting C3 deposition (C1q D+C1q). However, the addition of increasing amounts of rTs-Pmy (0, 2, 4 μg) to C1q decreased C3 deposition in a dose dependent manner and the difference between the doses was significant (Fig 3). BSA (4 μg) had no any inhibitory effect with the C3 deposition similar to the group without any Ts-Pmy added (C1q D+C1q+Ts-Pmy 0 μg). C1q D itself didn’t cause significant C3 deposition without addition of C1q. The result demonstrated that activation of the classical complement pathway was inhibited by the binding of rTs-Pmy to C1q in this study.


Trichinella spiralis Paramyosin Binds Human Complement C1q and Inhibits Classical Complement Activation.

Sun R, Zhao X, Wang Z, Yang J, Zhao L, Zhan B, Zhu X - PLoS Negl Trop Dis (2015)

Classical complement activation was inhibited by rTs-Pmy.Two μg of human C1q was pre-incubated with increasing amounts of rTs-Pmy (0, 2, 4 μg) or BSA (4 μg), then added to human IgM-coated plates. After washing with PBST for three times, a total of 2% C1q-deficient serum (C1q D) was added as a source of rest complement components. The deposition of C3 was detected with anti-C3 polyclonal antibody. The NHS alone and BSA added to the activation were used as controls. The results are shown as the means ± SD for three independent experiments.* p<0.05, **p<0.01, ***p<0.001. ns, no significant difference.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4697845&req=5

pntd.0004310.g003: Classical complement activation was inhibited by rTs-Pmy.Two μg of human C1q was pre-incubated with increasing amounts of rTs-Pmy (0, 2, 4 μg) or BSA (4 μg), then added to human IgM-coated plates. After washing with PBST for three times, a total of 2% C1q-deficient serum (C1q D) was added as a source of rest complement components. The deposition of C3 was detected with anti-C3 polyclonal antibody. The NHS alone and BSA added to the activation were used as controls. The results are shown as the means ± SD for three independent experiments.* p<0.05, **p<0.01, ***p<0.001. ns, no significant difference.
Mentions: To evaluate whether the binding of rTs-Pmy to C1q inhibits classical complement activation, we analyzed C3 deposition on plates coated with human IgM in the presence of different amounts of rTs-Pmy. The result showed that activation of C1q deficient serum (C1q D) was able to be reconstituted with the addition of C1q to the similar level of NHS by detecting C3 deposition (C1q D+C1q). However, the addition of increasing amounts of rTs-Pmy (0, 2, 4 μg) to C1q decreased C3 deposition in a dose dependent manner and the difference between the doses was significant (Fig 3). BSA (4 μg) had no any inhibitory effect with the C3 deposition similar to the group without any Ts-Pmy added (C1q D+C1q+Ts-Pmy 0 μg). C1q D itself didn’t cause significant C3 deposition without addition of C1q. The result demonstrated that activation of the classical complement pathway was inhibited by the binding of rTs-Pmy to C1q in this study.

Bottom Line: Trichinella spiralis expresses paramyosin (Ts-Pmy) as a defense mechanism.The binding of recombinant and natural Ts-Pmy to human C1q were determined by ELISA, Far Western blotting and immunoprecipitation, respectively.Binding of recombinant Ts-Pmy (rTs-Pmy) to C1q inhibited C1q binding to IgM and consequently inhibited C3 deposition.

View Article: PubMed Central - PubMed

Affiliation: Department of Parasitology, School of Basic Medical Sciences, Capital Medical University, Beijing, PR China.

ABSTRACT

Background: Trichinella spiralis expresses paramyosin (Ts-Pmy) as a defense mechanism. Ts-Pmy is a functional protein with binding activity to human complement C8 and C9 and thus plays a role in evading the attack of the host's immune system. In the present study, the binding activity of Ts-Pmy to human complement C1q and its ability to inhibit classical complement activation were investigated.

Methods and findings: The binding of recombinant and natural Ts-Pmy to human C1q were determined by ELISA, Far Western blotting and immunoprecipitation, respectively. Binding of recombinant Ts-Pmy (rTs-Pmy) to C1q inhibited C1q binding to IgM and consequently inhibited C3 deposition. The lysis of antibody-sensitized erythrocytes (EAs) elicited by the classical complement pathway was also inhibited in the presence of rTs-Pmy. In addition to inhibiting classical complement activation, rTs-Pmy also suppressed C1q binding to THP-1-derived macrophages, thereby reducing C1q-induced macrophages migration.

Conclusion: Our results suggest that T. spiralis paramyosin plays an important role in immune evasion by interfering with complement activation through binding to C1q in addition to C8 and C9.

Show MeSH
Related in: MedlinePlus