Influence of sialic contents on the chemiluminescent response of human leucocytes to group B streptococci.

The sialic acid content in reference strains of various Group B streptococci serotypes was studied before and after serial passages in mouse to enhance the virulence. The passages in mouse strongly increased the sialic acid content but the neuraminidase treatment reduced the to comparable values in reference and in virulent strains. The chemiluminescent response of human polymorphonuclear leucocytes to different GBS strains was higher for reference strains and lower for virulent strains. Sialic acid removal by neuraminidase increased the chemiluminescent response in virulent and in reference strains. Negative correlation between sialic acid content and chemiluminescence was demonstrated in strains of the same serotype, before and after passages in mouse and neuraminidase treatment for types Ic, II and III but no correlation was found considering the sialic acid content in strains belonging to different serotypes.