PMC

Location of the two new superantigen-like genes in the selj and selr flanking regions. An 11,335-bp nucleotide sequence of the selr (ORF3) and selj (ORF4) flanking region was determined, and two new superantigen-like genes, ses (ORF6) and set (ORF5), were identified.

Mitogenic activity of SES and SET. PBMCs were isolated from human blood samples and incubated with a number of concentrations of rSEA, rSES, and rSET. Means and standard errors for triplicate wells from a single experiment are shown.

Phylogenetic tree of SEs and SEls, including SES and SET. The phylogenetic tree was constructed by the neighbor-joining method based on amino acid sequences. Five distinct groups can be observed. SES is most closely related to SElN and belongs to the SEA group, while SET is distinct from the SEA, SEB, and SEI groups.

Representative dot plots of Vβs for CD3-gated events from PBMCs stimulated with SES (A) and anti-CD3 (B). MAbs against Vβ9, Vβ16, and Vβ17 were labeled with phycoerythrin (PE), fluorescein isothiocyanate (FITC), or PE and FITC, respectively. Numbers indicate the percentage of T cells expressing a particular Vβ element.

Expression of ses and set. (A) Detection of ses and set mRNAs by RT-PCR. S. aureus Fukuoka 5 was cultured at 37°C and collected for RNA isolation at 0 to 7 h after inoculation. The Fukuoka 5 growth curve was graphed by determining the optical density at 600 nm (O.D.600). (B) Detection of SES and SET in culture supernatants of S. aureus strains harboring plasmid pF5 (Fukuoka 5, Fukuoka 6, and Fukuoka 7) by Western blotting.