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The immunoglobulin M-degrading enzyme of Streptococcus suis, IdeSsuis, is involved in complement evasion.

Seele J, Beineke A, Hillermann LM, Jaschok-Kentner B, von Pawel-Rammingen U, Valentin-Weigand P, Baums CG - Vet. Res. (2015)

Bottom Line: Furthermore, expression of Ide(Ssuis) reduced IgM-triggered complement deposition on the bacterial surface.Bactericidal assays confirmed a positive effect of Ide(Ssuis) expression on bacterial survival in porcine blood in the presence of high titers of specific IgM.In conclusion, this study demonstrates that Ide(Ssuis) is a novel complement evasion factor, which is important for bacterial survival in porcine blood during the early adaptive (IgM-dominated) immune response.

View Article: PubMed Central - PubMed

Affiliation: Institute for Microbiology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, 30173, Hannover, Germany. jana_seele@gmx.de.

ABSTRACT
Streptococcus (S.) suis is one of the most important pathogens in pigs causing meningitis, arthritis, endocarditis and serositis. Furthermore, it is also an emerging zoonotic agent. In our previous work we identified a highly specific IgM protease in S. suis, designated Ide(Ssuis) . The objective of this study was to characterize the function of Ide(Ssuis) in the host-pathogen interaction. Edman-sequencing revealed that Ide(Ssuis) cleaves the heavy chain of the IgM molecule between constant domain 2 and 3. As the C1q binding motif is located in the C3 domain, we hypothesized that Ide(Ssuis) is involved in complement evasion. Complement-mediated hemolysis induced by porcine hyperimmune sera containing erythrocyte-specific IgM was abrogated by treatment of these sera with recombinant Ide(Ssuis) . Furthermore, expression of Ide(Ssuis) reduced IgM-triggered complement deposition on the bacterial surface. An infection experiment of prime-vaccinated growing piglets suggested attenuation in the virulence of the mutant 10Δide(Ssuis). Bactericidal assays confirmed a positive effect of Ide(Ssuis) expression on bacterial survival in porcine blood in the presence of high titers of specific IgM. In conclusion, this study demonstrates that Ide(Ssuis) is a novel complement evasion factor, which is important for bacterial survival in porcine blood during the early adaptive (IgM-dominated) immune response.

No MeSH data available.


Related in: MedlinePlus

IdeSsuispromotes survival in opsonophagocytosis assays including purified porcine neutrophilic granulocytes and serum with specific IgM titers. (A) Survival of strain 10 (wt), 10ΔideSsuis (Δ), 10ΔideSsuis_homologue (Δ_h) and 10ΔideSsuis_C-terminus (Δ_C) in opsonophagocytosis assays with serum from a piglet with specific IgM. (B) Attenuation of 10ΔideSsuis in opsonophagocytosis assays depends on active complement and adaptive immunity. The ratios of the survival factors of 10ΔideSsuis to the respective survival factors of wt are shown. A ratio of 1 is depicted by the horizontal line and refers to a lack of attenuation. To access the impact of complement, the post immune serum with specific IgM used for experiments shown in (A) was heat-inactivated or treated with zymosan. Samples with active and heat-inactivated serum from a colostrum-deprived pig were included to investigate whether this IdeSsuis-mediated phenotype depends on adaptive immunity. Bars and error bars represent mean values and standard deviations, respectively. Significant differences between strains and ratios of survival factors in (A) and (B), respectively, are indicated (* p < 0.05, ** p < 0.01).
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Fig5: IdeSsuispromotes survival in opsonophagocytosis assays including purified porcine neutrophilic granulocytes and serum with specific IgM titers. (A) Survival of strain 10 (wt), 10ΔideSsuis (Δ), 10ΔideSsuis_homologue (Δ_h) and 10ΔideSsuis_C-terminus (Δ_C) in opsonophagocytosis assays with serum from a piglet with specific IgM. (B) Attenuation of 10ΔideSsuis in opsonophagocytosis assays depends on active complement and adaptive immunity. The ratios of the survival factors of 10ΔideSsuis to the respective survival factors of wt are shown. A ratio of 1 is depicted by the horizontal line and refers to a lack of attenuation. To access the impact of complement, the post immune serum with specific IgM used for experiments shown in (A) was heat-inactivated or treated with zymosan. Samples with active and heat-inactivated serum from a colostrum-deprived pig were included to investigate whether this IdeSsuis-mediated phenotype depends on adaptive immunity. Bars and error bars represent mean values and standard deviations, respectively. Significant differences between strains and ratios of survival factors in (A) and (B), respectively, are indicated (* p < 0.05, ** p < 0.01).

Mentions: As rIdeSsuis interfered with complement activation using sera with specific antibodies, we hypothesized that expression of the IgM protease IdeSsuis contributes to survival in opsonophagocytosis assays including a porcine serum with specific IgM and comparatively low specific IgG titers (αS. suis IgM: 29.2 ELISA-units and for comparison: αMRP IgG: 12.8 ELISA-units). Phenotypic analysis of S. suis was conducted in this study using the mutant 10ΔideSsuis [6] and two new in frame deletion mutants expressing truncated IdeSsuis constructs. These new mutants, designated 10ΔideSsuis_C-terminus and 10ΔideSsuis_homologue, expressed the N-terminal part homologous to IdeS and the large C-terminal part lacking homologies, respectively (Additional file 4). Noteworthy, 10ΔideSsuis _C-terminus released IgM protease activity in the supernatant in contrast to 10ΔideSsuis and 10ΔideSsuis_homologue (Additional file 4). As shown in Figure 5A 10ΔideSsuis and 10ΔideSsuis_homologue had a significant lower survival factor compared to the wt strain and the survival factor for 10ΔideSsuis_C-terminus was also found to be lower compared to the wt strain. The extent of attenuation of 10ΔideSsuis was significantly lower in opsonophagocytosis assays including serum from a colostrum-deprived piglet in comparison to assays including specific IgM. Inhibition of complement reduced the attenuation of the mutant 10ΔideSsuis significantly (Figure 5B).Figure 5


The immunoglobulin M-degrading enzyme of Streptococcus suis, IdeSsuis, is involved in complement evasion.

Seele J, Beineke A, Hillermann LM, Jaschok-Kentner B, von Pawel-Rammingen U, Valentin-Weigand P, Baums CG - Vet. Res. (2015)

IdeSsuispromotes survival in opsonophagocytosis assays including purified porcine neutrophilic granulocytes and serum with specific IgM titers. (A) Survival of strain 10 (wt), 10ΔideSsuis (Δ), 10ΔideSsuis_homologue (Δ_h) and 10ΔideSsuis_C-terminus (Δ_C) in opsonophagocytosis assays with serum from a piglet with specific IgM. (B) Attenuation of 10ΔideSsuis in opsonophagocytosis assays depends on active complement and adaptive immunity. The ratios of the survival factors of 10ΔideSsuis to the respective survival factors of wt are shown. A ratio of 1 is depicted by the horizontal line and refers to a lack of attenuation. To access the impact of complement, the post immune serum with specific IgM used for experiments shown in (A) was heat-inactivated or treated with zymosan. Samples with active and heat-inactivated serum from a colostrum-deprived pig were included to investigate whether this IdeSsuis-mediated phenotype depends on adaptive immunity. Bars and error bars represent mean values and standard deviations, respectively. Significant differences between strains and ratios of survival factors in (A) and (B), respectively, are indicated (* p < 0.05, ** p < 0.01).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Fig5: IdeSsuispromotes survival in opsonophagocytosis assays including purified porcine neutrophilic granulocytes and serum with specific IgM titers. (A) Survival of strain 10 (wt), 10ΔideSsuis (Δ), 10ΔideSsuis_homologue (Δ_h) and 10ΔideSsuis_C-terminus (Δ_C) in opsonophagocytosis assays with serum from a piglet with specific IgM. (B) Attenuation of 10ΔideSsuis in opsonophagocytosis assays depends on active complement and adaptive immunity. The ratios of the survival factors of 10ΔideSsuis to the respective survival factors of wt are shown. A ratio of 1 is depicted by the horizontal line and refers to a lack of attenuation. To access the impact of complement, the post immune serum with specific IgM used for experiments shown in (A) was heat-inactivated or treated with zymosan. Samples with active and heat-inactivated serum from a colostrum-deprived pig were included to investigate whether this IdeSsuis-mediated phenotype depends on adaptive immunity. Bars and error bars represent mean values and standard deviations, respectively. Significant differences between strains and ratios of survival factors in (A) and (B), respectively, are indicated (* p < 0.05, ** p < 0.01).
Mentions: As rIdeSsuis interfered with complement activation using sera with specific antibodies, we hypothesized that expression of the IgM protease IdeSsuis contributes to survival in opsonophagocytosis assays including a porcine serum with specific IgM and comparatively low specific IgG titers (αS. suis IgM: 29.2 ELISA-units and for comparison: αMRP IgG: 12.8 ELISA-units). Phenotypic analysis of S. suis was conducted in this study using the mutant 10ΔideSsuis [6] and two new in frame deletion mutants expressing truncated IdeSsuis constructs. These new mutants, designated 10ΔideSsuis_C-terminus and 10ΔideSsuis_homologue, expressed the N-terminal part homologous to IdeS and the large C-terminal part lacking homologies, respectively (Additional file 4). Noteworthy, 10ΔideSsuis _C-terminus released IgM protease activity in the supernatant in contrast to 10ΔideSsuis and 10ΔideSsuis_homologue (Additional file 4). As shown in Figure 5A 10ΔideSsuis and 10ΔideSsuis_homologue had a significant lower survival factor compared to the wt strain and the survival factor for 10ΔideSsuis_C-terminus was also found to be lower compared to the wt strain. The extent of attenuation of 10ΔideSsuis was significantly lower in opsonophagocytosis assays including serum from a colostrum-deprived piglet in comparison to assays including specific IgM. Inhibition of complement reduced the attenuation of the mutant 10ΔideSsuis significantly (Figure 5B).Figure 5

Bottom Line: Furthermore, expression of Ide(Ssuis) reduced IgM-triggered complement deposition on the bacterial surface.Bactericidal assays confirmed a positive effect of Ide(Ssuis) expression on bacterial survival in porcine blood in the presence of high titers of specific IgM.In conclusion, this study demonstrates that Ide(Ssuis) is a novel complement evasion factor, which is important for bacterial survival in porcine blood during the early adaptive (IgM-dominated) immune response.

View Article: PubMed Central - PubMed

Affiliation: Institute for Microbiology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, 30173, Hannover, Germany. jana_seele@gmx.de.

ABSTRACT
Streptococcus (S.) suis is one of the most important pathogens in pigs causing meningitis, arthritis, endocarditis and serositis. Furthermore, it is also an emerging zoonotic agent. In our previous work we identified a highly specific IgM protease in S. suis, designated Ide(Ssuis) . The objective of this study was to characterize the function of Ide(Ssuis) in the host-pathogen interaction. Edman-sequencing revealed that Ide(Ssuis) cleaves the heavy chain of the IgM molecule between constant domain 2 and 3. As the C1q binding motif is located in the C3 domain, we hypothesized that Ide(Ssuis) is involved in complement evasion. Complement-mediated hemolysis induced by porcine hyperimmune sera containing erythrocyte-specific IgM was abrogated by treatment of these sera with recombinant Ide(Ssuis) . Furthermore, expression of Ide(Ssuis) reduced IgM-triggered complement deposition on the bacterial surface. An infection experiment of prime-vaccinated growing piglets suggested attenuation in the virulence of the mutant 10Δide(Ssuis). Bactericidal assays confirmed a positive effect of Ide(Ssuis) expression on bacterial survival in porcine blood in the presence of high titers of specific IgM. In conclusion, this study demonstrates that Ide(Ssuis) is a novel complement evasion factor, which is important for bacterial survival in porcine blood during the early adaptive (IgM-dominated) immune response.

No MeSH data available.


Related in: MedlinePlus