Mutant chemokine receptor (CCR-5) and its relevance to HIV infection in Arabs.

(st4529, st4547, st4532, st4545, and st3018, with accession numbers AF060368, AF052426, AF077666, AF077668, and AF077669, respectively). The newly found group A st4545 sequence was more similar to various group G streptococcal emm sequences than to known group A emm sequences. One group G isolate had a previously found group G 5' emm sequence (stLG6, accession number U25741). The nongroupable Streptococcus had an emm sequence previously associated with group L Streptococcus (Beall and Facklam, unpub. data). These results demonstrate the usefulness of emm typing in areas where specific M-typing antisera are not available. Identifying 6 (25%) of 24 GAS with new emm types provides further evidence of new M serotypes of GAS in Malaysia. The deduced amino acid sequences of the mature hypervariable N termini of ST4529, ST4532, ST4547, and ST3018 ranged from 43% to 82% identity to M proteins of known sequence (data not shown). The M nontypability of these isolates suggests unique serologic specificity. ST4547, ST4532, and ST3018 had 70% to 82% identity over the first 55-variable-region amino acids, with their closest matching known M proteins (M70, M27, and M22, respectively), but whether antibodies against any of these proteins would cross-protect against strains expressing these M proteins is unknown. Even though the M70 protein is 70% identical over its first 50 variable N terminal amino acids to the M33 protein, antibodies against the M70 and M33 proteins do not crossprotect, which suggests that no cross-protection would occur. The new deduced M protein with the lowest similarity to any known M protein was ST4529, whose closest match had a 43% identity over the N-terminal 55 residues of the M5 protein. st4529 likely encodes a new serospecifically unique M protein. These findings potentially affect vaccine development. Although new emm sequences were identified in a survey in the United States (5), the percentage of new strains with new emm sequences was much lower (6%) than was found with these Malaysian isolates. emm typing of a larger number of strains from rheumatic fever– and rheumatic heart disease–endemic areas is required to deduce amino acid sequences for the development of a suitable M protein– based vaccine. Acknowledgments We thank Sukeri Kasni and Theresa Hoenes for technical assistance.