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Mannose-binding lectin-deficient mice are susceptible to infection with Staphylococcus aureus.

Shi L, Takahashi K, Dundee J, Shahroor-Karni S, Thiel S, Jensenius JC, Gad F, Hamblin MR, Sastry KN, Ezekowitz RA - J. Exp. Med. (2004)

Bottom Line: The mannose-binding lectin (MBL, also known as mannose-binding protein) is an oligomeric serum molecule that recognizes carbohydrates decorating a broad range of infectious agents including S. aureus.Circumstantial evidence in vitro and in vivo suggests that MBL plays a key role in first line host defense.Furthermore, we demonstrated that neutrophils and MBL are required to limit intraperitoneal infection with S. aureus.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, JRG 1402, Boston, MA 02114, USA.

ABSTRACT
Gram-positive organisms like Staphylococcus aureus are a major cause of morbidity and mortality worldwide. Humoral response molecules together with phagocytes play a role in host responses to S. aureus. The mannose-binding lectin (MBL, also known as mannose-binding protein) is an oligomeric serum molecule that recognizes carbohydrates decorating a broad range of infectious agents including S. aureus. Circumstantial evidence in vitro and in vivo suggests that MBL plays a key role in first line host defense. We tested this contention directly in vivo by generating mice that were devoid of all MBL activity. We found that 100% of MBL- mice died 48 h after exposure to an intravenous inoculation of S. aureus compared with 45% mortality in wild-type mice. Furthermore, we demonstrated that neutrophils and MBL are required to limit intraperitoneal infection with S. aureus. Our study provides direct evidence that MBL plays a key role in restricting the complications associated with S. aureus infection in mice and raises the idea that the MBL gene may act as a disease susceptibility gene against staphylococci infections in humans.

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Generation and characterization of MBL- mice. (a) MBL-C targeting construct. Genomic organization of MBL-C is shown and compared with the targeting vector and homologous recombinant. (b) RT-PCR analysis of transcript for MBL-A, MBL-C, and serum amyloid protein (SAP) in liver. (c) Serum levels of MBL-A and MBL-C in WT, MBL-C KO, and MBL- mice. •, individual mice; bars, the mean value for each group. (d) C4 cleaving activity of serum. The capacity of serum to activate C4 via the MBL complement pathway (left) or classical pathway (right) was assayed as described above. •, individual mice; bars, the mean value for each group. (e) C4 cleaving activity. Comparison of rhMBL with purified MBL-A and MBL-C. •, rhMBL; ○, MBL-A; ▾, MBL-C.
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fig1: Generation and characterization of MBL- mice. (a) MBL-C targeting construct. Genomic organization of MBL-C is shown and compared with the targeting vector and homologous recombinant. (b) RT-PCR analysis of transcript for MBL-A, MBL-C, and serum amyloid protein (SAP) in liver. (c) Serum levels of MBL-A and MBL-C in WT, MBL-C KO, and MBL- mice. •, individual mice; bars, the mean value for each group. (d) C4 cleaving activity of serum. The capacity of serum to activate C4 via the MBL complement pathway (left) or classical pathway (right) was assayed as described above. •, individual mice; bars, the mean value for each group. (e) C4 cleaving activity. Comparison of rhMBL with purified MBL-A and MBL-C. •, rhMBL; ○, MBL-A; ▾, MBL-C.

Mentions: A genomic DNA clone encoding MBL-C was isolated from a 129SvJ library in Lambda Fix II vector (Stratagene) and mapped (54). The MBL-C gene was disrupted by introducing the neomycin resistance gene (neor) into exon 6. The MBL-C gene-targeting construct consists of a 4.5-kb PmeI-NotI fragment toward the 5′ end followed by neor, and then a 1.5-kb PacI-SrfI fragment toward the 3′ end in a KO3 vector (see Fig. 1 a; provided by K. Moore, Massachusetts General Hospital, Boston, MA). 17 out of 111 embryonic stem cell clones underwent homologous recombination. This was confirmed by Southern blot analysis (not depicted). The positive embryonic stem cell clones were injected into C57Bl/6J blastocysts at the Transgenic and Knockout Mouse Core Facility at Massachusetts General Hospital, directed by Dr. E. Li. Genotyping was performed by PCR. A colony of MBL-C KO mice was expanded and some were crossed with MBL-A KO (48) mice to create MBL- mice. All animal experiments were performed under a protocol approved by the Subcommittee on Research Animal Care at Massachusetts General Hospital.


Mannose-binding lectin-deficient mice are susceptible to infection with Staphylococcus aureus.

Shi L, Takahashi K, Dundee J, Shahroor-Karni S, Thiel S, Jensenius JC, Gad F, Hamblin MR, Sastry KN, Ezekowitz RA - J. Exp. Med. (2004)

Generation and characterization of MBL- mice. (a) MBL-C targeting construct. Genomic organization of MBL-C is shown and compared with the targeting vector and homologous recombinant. (b) RT-PCR analysis of transcript for MBL-A, MBL-C, and serum amyloid protein (SAP) in liver. (c) Serum levels of MBL-A and MBL-C in WT, MBL-C KO, and MBL- mice. •, individual mice; bars, the mean value for each group. (d) C4 cleaving activity of serum. The capacity of serum to activate C4 via the MBL complement pathway (left) or classical pathway (right) was assayed as described above. •, individual mice; bars, the mean value for each group. (e) C4 cleaving activity. Comparison of rhMBL with purified MBL-A and MBL-C. •, rhMBL; ○, MBL-A; ▾, MBL-C.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211809&req=5

fig1: Generation and characterization of MBL- mice. (a) MBL-C targeting construct. Genomic organization of MBL-C is shown and compared with the targeting vector and homologous recombinant. (b) RT-PCR analysis of transcript for MBL-A, MBL-C, and serum amyloid protein (SAP) in liver. (c) Serum levels of MBL-A and MBL-C in WT, MBL-C KO, and MBL- mice. •, individual mice; bars, the mean value for each group. (d) C4 cleaving activity of serum. The capacity of serum to activate C4 via the MBL complement pathway (left) or classical pathway (right) was assayed as described above. •, individual mice; bars, the mean value for each group. (e) C4 cleaving activity. Comparison of rhMBL with purified MBL-A and MBL-C. •, rhMBL; ○, MBL-A; ▾, MBL-C.
Mentions: A genomic DNA clone encoding MBL-C was isolated from a 129SvJ library in Lambda Fix II vector (Stratagene) and mapped (54). The MBL-C gene was disrupted by introducing the neomycin resistance gene (neor) into exon 6. The MBL-C gene-targeting construct consists of a 4.5-kb PmeI-NotI fragment toward the 5′ end followed by neor, and then a 1.5-kb PacI-SrfI fragment toward the 3′ end in a KO3 vector (see Fig. 1 a; provided by K. Moore, Massachusetts General Hospital, Boston, MA). 17 out of 111 embryonic stem cell clones underwent homologous recombination. This was confirmed by Southern blot analysis (not depicted). The positive embryonic stem cell clones were injected into C57Bl/6J blastocysts at the Transgenic and Knockout Mouse Core Facility at Massachusetts General Hospital, directed by Dr. E. Li. Genotyping was performed by PCR. A colony of MBL-C KO mice was expanded and some were crossed with MBL-A KO (48) mice to create MBL- mice. All animal experiments were performed under a protocol approved by the Subcommittee on Research Animal Care at Massachusetts General Hospital.

Bottom Line: The mannose-binding lectin (MBL, also known as mannose-binding protein) is an oligomeric serum molecule that recognizes carbohydrates decorating a broad range of infectious agents including S. aureus.Circumstantial evidence in vitro and in vivo suggests that MBL plays a key role in first line host defense.Furthermore, we demonstrated that neutrophils and MBL are required to limit intraperitoneal infection with S. aureus.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Developmental Immunology, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, JRG 1402, Boston, MA 02114, USA.

ABSTRACT
Gram-positive organisms like Staphylococcus aureus are a major cause of morbidity and mortality worldwide. Humoral response molecules together with phagocytes play a role in host responses to S. aureus. The mannose-binding lectin (MBL, also known as mannose-binding protein) is an oligomeric serum molecule that recognizes carbohydrates decorating a broad range of infectious agents including S. aureus. Circumstantial evidence in vitro and in vivo suggests that MBL plays a key role in first line host defense. We tested this contention directly in vivo by generating mice that were devoid of all MBL activity. We found that 100% of MBL- mice died 48 h after exposure to an intravenous inoculation of S. aureus compared with 45% mortality in wild-type mice. Furthermore, we demonstrated that neutrophils and MBL are required to limit intraperitoneal infection with S. aureus. Our study provides direct evidence that MBL plays a key role in restricting the complications associated with S. aureus infection in mice and raises the idea that the MBL gene may act as a disease susceptibility gene against staphylococci infections in humans.

Show MeSH
Related in: MedlinePlus