The central region of the msp gene of Treponema denticola has sequence heterogeneity among clinical samples, obtained from patients with periodontitis.
BACKGROUND
Treponema denticola is an oral spirochete involved in the pathogenesis and progression of periodontal disease. Of its virulence factors, the major surface protein (MSP) plays a role in the interaction between the treponeme and host. To understand the possible evolution of this protein, we analyzed the sequence of the msp gene in 17 T. denticola positive clinical samples.


METHODS
Nucleotide and amino acid sequence of MSP have been determined by PCR amplification and sequencing in seventeen T. denticola clinical specimens to evaluate the genetic variability and the philogenetic relationship of the T. denticola msp gene among the different amplified sequence of positive samples. In silico antigenic analysis was performed on each MSP sequences to determined possible antigenic variation.


RESULTS
The msp sequences showed two highly conserved 5' and 3' ends and a central region that varies substantially. Phylogenetic analysis categorized the 17 specimens into 2 principal groups, suggesting a low rate of evolutionary variability and an elevated degree of conservation of msp in clinically derived genetic material. Analysis of the predicted antigenic variability between isolates, demonstrated that the major differences lay between amino acids 200 and 300.


CONCLUSIONS
These findings showed for the first time, the nucleotide and amino acids variation of the msp gene in infecting T. denticola, in vivo. This data suggested that the antigenic variability found in to the MSP molecule, may be an important factor involved in immune evasion by T. denticola.
Department of Hematology and Oncology L, and A, Seragnoli, University St, Orsola-Malpighi Hospital, V, Massarenti 9, Bologna, Italy. paolo.gaibani@unibo.it
Paolo
P
Gaibani
Maria Teresa
MT
Pellegrino
Giada
G
Rossini
Gualtiero
G
Alvisi
Luisa
L
Miragliotta
Carlo
C
Prati
Vittorio
V
Sambri
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D010518:Periodontitis / Q000382:microbiology*; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D048373:Treponema denticola / Q000235:genetics* / Q000302:isolation & purification; D014211:Treponemal Infections / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics*
D001425:Bacterial Outer Membrane Proteins; D004269:DNA, Bacterial; D037521:Virulence Factors