Conversion of an M- group A streptococcus to M+ by transfer of a plasmid containing an M6 gene.
J Exp Med
; 164(5): 1641-51, 1986 Nov 01.
Article
in En
| MEDLINE
| ID: mdl-3534131
ABSTRACT
An M28-derived group A streptococcal strain deleted for the gene encoding M protein was converted to M+ by introduction of a plasmid carrying emm6, the structural gene for type 6 M protein from strain D471. The reconstituted M+ strain, JRS2, resists phagocytosis in human blood and is opsonized by anti-M6 hyperimmune serum, but not by anti-M28 serum. Immunofluorescent microscopy and ELISA demonstrate the presence of M protein on its surface. In addition, JRS2 removes opsonic antibodies from hyperimmune rabbit sera generated by immunization with purified ColiM6 protein and with a synthetic amino-terminal peptide derived from M6. Immunization of rabbits with JRS2 generates opsonic anti-M6 antibodies. These results indicate that the cloned emm6 gene contains the information necessary to convert a phagocytosis-sensitive streptococcus to phagocytosis resistance. Furthermore, it also contains the determinants for M type specificity and those required to elicit opsonic antibodies. It thus appears to determine all the traits associated with M protein.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Plasmids
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Streptococcus pyogenes
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Bacterial Outer Membrane Proteins
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Bacterial Proteins
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Carrier Proteins
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Conjugation, Genetic
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Genes, Bacterial
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Antigens, Bacterial
Language:
En
Journal:
J Exp Med
Year:
1986
Document type:
Article