Interaction of group A streptococcal lipoteichoic acid with bovine myelin basic protein.

Group A streptococcal lipoteichoic acid (LTA), a polyglycerol phosphate ester linked with fatty acids, formed precipitin lines in agar gels with the positively charged myelin basic protein (MBP) isolated from bovine brain. The LTA-MBP complexes were formed with deacylated teichoic acid and were not inhibited by monomeric glycerol phosphate, a finding indicating the participation of the polyglycerol phosphate (PGP) backbone of LTA in the reaction. Following interaction with PGP, MBP inhibited the agglutination of LTA-sensitized erythrocytes by induction of antibodies to LTA, directed against the PGP antigenic determinant. The amplification of the humoral immune response to the insoluble complex of LTA and MBP was of particular interest in view of the lack of immunogenicity of either LTA or MBP alone.