| Autor: |
Fleury, Be´ne´dicte, Bergonier, Dominique, Berthelot, Xavier, Schlatter, Yvonne, Frey, Joachim, Vilei, Edy M. |
| Zdroj: |
Journal of Clinical Microbiology; August 2001, Vol. 39 Issue: 8 p2814-2822, 9p |
| Abstrakt: |
ABSTRACTThe gene for a 30-kDa immunodominant antigen, P30, ofMycoplasma agalactiaewas cloned from type strain PG2 and expressed in Escherichia coli. P30 is encoded on a monocistronic operon determined by two -10 boxes and a possible -35 region constituting the potential promoter, and a transcription termination site. The gene for the 266-amino-acid protein is preceded by a polypurine-rich region designed as the consensus sequence for a ribosome-binding site. Analysis of the amino acid sequence of P30 revealed the presence of a recognition site for a prokaryotic signal peptidase II at amino acid (aa) 24, indicating that P30 is a transmembrane protein. Moreover, Triton X-114 phase partitioning ofM. agalactiaePG2 total antigen revealed that P30 is strongly hydrophobic and hence a possible membrane component. Immunoblot analysis using the monospecific polyclonal anti-P30-His serum indicated that P30 is specific to M. agalactiae. Furthermore, PCR amplification with specific primers forp30and Southern blot analysis revealed the presence of the gene in all M. agalactiaestrains tested and its absence in the other mycoplasma species. Among 27 strains of M. agalactiaestudied,20 strains belonging to the common serotypes A to D, including PG2, expressed P30 or part of it as detected by the monospecific polyclonal anti-P30 antibodies. The other seven strains belonging to the rarely isolated serotypes E to H were negative for P30. The p30gene was sequenced in 15 strains of M. agalactiae, 10 of which expressed P30 or at least part of it and 5 of which did not express P30. The negative strains carried mutations in both -10 boxes of the promoters. These mutations seem to be responsible for the lack of P30 expression in these strains. Analysis of sera from sheep that were experimentally infected with M. agalactiaerevealed that P30 induced a strong and persistent immune response which was still very high two months after infection. In contrast, currently used enzyme-linked immunosorbent assay serology gave only low titers. |
| Databáze: |
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