Table 1

Structural features of staphylococcal and streptococcal superantigens

GroupSuperantigensMHC II bindingCystine loop (length in amino acids)Other feature
ITSST-1, SE-l X, TSST-ovineLow-affinity site α-chainNoUnique amino acid sequence
IISEB, SEC, SEG, SE-l U, SE-l W, SPE A, SSALow-affinity site α-chainYes (10–19)
IIISEA, SED, SEE, SE-I H, SE-l J, SE-l N to SE-l PLow-affinity site α-chain, high-affinity site β-chainYes (9)
IVSPE C, SPE G, SPE, J, SMEZLow-affinity site α-chain, high-affinity site β-chainNo
VSE-l I, SE-l K to SE-l M SE-l Q to SE-l T, SE-l V, SPE HLow-affinity site α-chain, high-affinity site β-chainNo15-amino acid loop insertion