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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

Complement-mediated hemolysis was inhibited by rTs-Pmy.Normal human serum (NHS) was pre-incubated with rTs-Pmy (0, 1, 2, or 4 μg) for 1 h prior to incubation with EAs. Hemolysis was measured at 412 nm for the supernatant of the reactions compared to complete lysis in water. The results shown are means ± SD and are representative of three independent experiments. BSA, C1q D and C3 D alone were added as controls. *p<0.05, **p<0.01, ***p<0.001. ns, no significant difference.
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pntd.0004310.g004: Complement-mediated hemolysis was inhibited by rTs-Pmy.Normal human serum (NHS) was pre-incubated with rTs-Pmy (0, 1, 2, or 4 μg) for 1 h prior to incubation with EAs. Hemolysis was measured at 412 nm for the supernatant of the reactions compared to complete lysis in water. The results shown are means ± SD and are representative of three independent experiments. BSA, C1q D and C3 D alone were added as controls. *p<0.05, **p<0.01, ***p<0.001. ns, no significant difference.

Mentions: To further determine whether rTs-Pmy inhibited classical complement activation, antibody-sensitized sheep erythrocytes (EAs) were incubated with fresh NHS pre-incubated with different amounts of rTs-Pmy. The classical complement-mediated hemolysis results showed that the lysis of EAs was significantly inhibited by the addition of rTs-Pmy in a dose-dependent manner (Fig 4). There was no significant hemolysis in the presence of C1q D or C3 D serum (C1q- or C3-deficient) because the classical pathway could not be activated without C1q or C3. BSA had no inhibitory effect on classical complement activation.


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)

Complement-mediated hemolysis was inhibited by rTs-Pmy.Normal human serum (NHS) was pre-incubated with rTs-Pmy (0, 1, 2, or 4 μg) for 1 h prior to incubation with EAs. Hemolysis was measured at 412 nm for the supernatant of the reactions compared to complete lysis in water. The results shown are means ± SD and are representative of three independent experiments. BSA, C1q D and C3 D alone were added as controls. *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.g004: Complement-mediated hemolysis was inhibited by rTs-Pmy.Normal human serum (NHS) was pre-incubated with rTs-Pmy (0, 1, 2, or 4 μg) for 1 h prior to incubation with EAs. Hemolysis was measured at 412 nm for the supernatant of the reactions compared to complete lysis in water. The results shown are means ± SD and are representative of three independent experiments. BSA, C1q D and C3 D alone were added as controls. *p<0.05, **p<0.01, ***p<0.001. ns, no significant difference.
Mentions: To further determine whether rTs-Pmy inhibited classical complement activation, antibody-sensitized sheep erythrocytes (EAs) were incubated with fresh NHS pre-incubated with different amounts of rTs-Pmy. The classical complement-mediated hemolysis results showed that the lysis of EAs was significantly inhibited by the addition of rTs-Pmy in a dose-dependent manner (Fig 4). There was no significant hemolysis in the presence of C1q D or C3 D serum (C1q- or C3-deficient) because the classical pathway could not be activated without C1q or C3. BSA had no inhibitory effect on classical complement activation.

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