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Borrelia valaisiana resist complement-mediated killing independently of the recruitment of immune regulators and inactivation of complement components.

Schwab J, Hammerschmidt C, Richter D, Skerka C, Matuschka FR, Wallich R, Zipfel PF, Kraiczy P - PLoS ONE (2013)

Bottom Line: Among the investigated isolates, growth of ZWU3 Ny3 was not affected while growth of VS116 and Bv9 was strongly inhibited in the presence of 50% human serum.In contrast, no surface-deposited components and no aberrations in cell morphology were detected for serum-resistant ZWU3 Ny3.Taken together, these findings suggest that certain B. valaisiana isolates differ in their capability to resist complement-mediating killing by human serum.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt, Frankfurt, Germany.

ABSTRACT
Spirochetes belonging to the Borrelia (B.) burgdorferi sensu lato complex differ in their resistance to complement-mediated killing, particularly in regard to human serum. In the present study, we elucidate the serum and complement susceptibility of B. valaisiana, a genospecies with the potential to cause Lyme disease in Europe as well as in Asia. Among the investigated isolates, growth of ZWU3 Ny3 was not affected while growth of VS116 and Bv9 was strongly inhibited in the presence of 50% human serum. Analyzing complement activation, complement components C3, C4 and C6 were deposited on the surface of isolates VS116 and Bv9, and similarly the membrane attack complex was formed on their surface. In contrast, no surface-deposited components and no aberrations in cell morphology were detected for serum-resistant ZWU3 Ny3. While further investigating the protective role of bound complement regulators in mediating complement resistance, we discovered that none of the B. valaisiana isolates analyzed bound complement regulators Factor H, Factor H-like protein 1, C4b binding protein or C1 esterase inhibitor. In addition, B. valaisiana also lacked intrinsic proteolytic activity to degrade complement components C3, C3b, C4, C4b, and C5. Taken together, these findings suggest that certain B. valaisiana isolates differ in their capability to resist complement-mediating killing by human serum. The molecular mechanism utilized by B. valaisiana to inhibit bacteriolysis appears not to involve binding of the key host complement regulators of the alternative, classical, and lectin pathways as already known for serum-resistant Lyme disease or relapsing fever borreliae.

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Determination of the C5 proteolytic activity of B. valaisiana.(A) Schematic representation of the α-, and β-chain of C5. (B) Degradation of C5 by an intrinsic proteolytic activity of spirochetes (5×108) was analyzed by detection of potential cleavage products after incubation of cells with purified C5. B. burgdorferi LW2, B. garinii G1, B. valaisiana isolates Bv9, VS116, ZWU3 Ny3, and B. duttonii LA1 were incubated with 1 µg C5 for 60 min and 120 min at 37°C. After centrifugation, supernatants were subjected to 10% tris/tricine SDS-PAGE and transferred onto a nitrocellulose membrane. The C5 fragments were visualized by Western blotting using a polyclonal goat anti-human C5 antiserum. As a negative control, purified C5 (1 µg) was incubated under the same conditions. The mobility of the 118 kDa α-chain and the 74 kDa β-chain is indicated.
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pone-0053659-g007: Determination of the C5 proteolytic activity of B. valaisiana.(A) Schematic representation of the α-, and β-chain of C5. (B) Degradation of C5 by an intrinsic proteolytic activity of spirochetes (5×108) was analyzed by detection of potential cleavage products after incubation of cells with purified C5. B. burgdorferi LW2, B. garinii G1, B. valaisiana isolates Bv9, VS116, ZWU3 Ny3, and B. duttonii LA1 were incubated with 1 µg C5 for 60 min and 120 min at 37°C. After centrifugation, supernatants were subjected to 10% tris/tricine SDS-PAGE and transferred onto a nitrocellulose membrane. The C5 fragments were visualized by Western blotting using a polyclonal goat anti-human C5 antiserum. As a negative control, purified C5 (1 µg) was incubated under the same conditions. The mobility of the 118 kDa α-chain and the 74 kDa β-chain is indicated.

Mentions: In order to test the inactivation capacity on complement component C5, spirochetes were incubated with purified C5 for 60 and 120 min. After centrifugation, supernatants were subjected to SDS-PAGE and C5 cleavage products were analyzed by Western blotting using a goat anti-C5 antibody. No degradation fragments of the 118-kDa α-chain or of the 74-kDa β-chain were detected indicating that spirochetes lacked proteolytic activity for the cleavage of C5 (Fig. 7).


Borrelia valaisiana resist complement-mediated killing independently of the recruitment of immune regulators and inactivation of complement components.

Schwab J, Hammerschmidt C, Richter D, Skerka C, Matuschka FR, Wallich R, Zipfel PF, Kraiczy P - PLoS ONE (2013)

Determination of the C5 proteolytic activity of B. valaisiana.(A) Schematic representation of the α-, and β-chain of C5. (B) Degradation of C5 by an intrinsic proteolytic activity of spirochetes (5×108) was analyzed by detection of potential cleavage products after incubation of cells with purified C5. B. burgdorferi LW2, B. garinii G1, B. valaisiana isolates Bv9, VS116, ZWU3 Ny3, and B. duttonii LA1 were incubated with 1 µg C5 for 60 min and 120 min at 37°C. After centrifugation, supernatants were subjected to 10% tris/tricine SDS-PAGE and transferred onto a nitrocellulose membrane. The C5 fragments were visualized by Western blotting using a polyclonal goat anti-human C5 antiserum. As a negative control, purified C5 (1 µg) was incubated under the same conditions. The mobility of the 118 kDa α-chain and the 74 kDa β-chain is indicated.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3539980&req=5

pone-0053659-g007: Determination of the C5 proteolytic activity of B. valaisiana.(A) Schematic representation of the α-, and β-chain of C5. (B) Degradation of C5 by an intrinsic proteolytic activity of spirochetes (5×108) was analyzed by detection of potential cleavage products after incubation of cells with purified C5. B. burgdorferi LW2, B. garinii G1, B. valaisiana isolates Bv9, VS116, ZWU3 Ny3, and B. duttonii LA1 were incubated with 1 µg C5 for 60 min and 120 min at 37°C. After centrifugation, supernatants were subjected to 10% tris/tricine SDS-PAGE and transferred onto a nitrocellulose membrane. The C5 fragments were visualized by Western blotting using a polyclonal goat anti-human C5 antiserum. As a negative control, purified C5 (1 µg) was incubated under the same conditions. The mobility of the 118 kDa α-chain and the 74 kDa β-chain is indicated.
Mentions: In order to test the inactivation capacity on complement component C5, spirochetes were incubated with purified C5 for 60 and 120 min. After centrifugation, supernatants were subjected to SDS-PAGE and C5 cleavage products were analyzed by Western blotting using a goat anti-C5 antibody. No degradation fragments of the 118-kDa α-chain or of the 74-kDa β-chain were detected indicating that spirochetes lacked proteolytic activity for the cleavage of C5 (Fig. 7).

Bottom Line: Among the investigated isolates, growth of ZWU3 Ny3 was not affected while growth of VS116 and Bv9 was strongly inhibited in the presence of 50% human serum.In contrast, no surface-deposited components and no aberrations in cell morphology were detected for serum-resistant ZWU3 Ny3.Taken together, these findings suggest that certain B. valaisiana isolates differ in their capability to resist complement-mediating killing by human serum.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt, Frankfurt, Germany.

ABSTRACT
Spirochetes belonging to the Borrelia (B.) burgdorferi sensu lato complex differ in their resistance to complement-mediated killing, particularly in regard to human serum. In the present study, we elucidate the serum and complement susceptibility of B. valaisiana, a genospecies with the potential to cause Lyme disease in Europe as well as in Asia. Among the investigated isolates, growth of ZWU3 Ny3 was not affected while growth of VS116 and Bv9 was strongly inhibited in the presence of 50% human serum. Analyzing complement activation, complement components C3, C4 and C6 were deposited on the surface of isolates VS116 and Bv9, and similarly the membrane attack complex was formed on their surface. In contrast, no surface-deposited components and no aberrations in cell morphology were detected for serum-resistant ZWU3 Ny3. While further investigating the protective role of bound complement regulators in mediating complement resistance, we discovered that none of the B. valaisiana isolates analyzed bound complement regulators Factor H, Factor H-like protein 1, C4b binding protein or C1 esterase inhibitor. In addition, B. valaisiana also lacked intrinsic proteolytic activity to degrade complement components C3, C3b, C4, C4b, and C5. Taken together, these findings suggest that certain B. valaisiana isolates differ in their capability to resist complement-mediating killing by human serum. The molecular mechanism utilized by B. valaisiana to inhibit bacteriolysis appears not to involve binding of the key host complement regulators of the alternative, classical, and lectin pathways as already known for serum-resistant Lyme disease or relapsing fever borreliae.

Show MeSH
Related in: MedlinePlus