title: Preparation and description of high-molecular-weight soluble surface antigens from a group A Streptococcus.
abstract: High-molecular-weight proteins having M protein reactivity were isolated without acid or alkaline digestion. Treatment of a heat-killed group A Streptococcus with sonic vibration released antigens which reacted strongly and specifically with absorbed type-specific antiserum. This antigen preparation was released without diminishing the total yield of acid-extractable M protein of the original heat-killed cells. Fractionation of the sonic preparation on a sucrose gradient yielded four peaks of M reactivity. When these fractions were placed on Sephadex G-200 columns, the M reactive material of three fractions appeared in the void volumes, suggesting that the active material in each had a molecular weight greater than 300,000. The reactivity of the fourth fraction followed closely the void volume of Sephadex G-100. Chemical analysis revealed heterogeneity of the fractions. Spectral analysis showed virtual absence of nucleic acid in three of the fractions and a moderate amount in the fourth. Bactericidal inhibition tests showed activity of three of the four fractions. Analysis of the fractions by Ouchterlony double-diffusion technique revealed that each of the four fractions had several antigenic constituents. All four contained M antigen. T antigen and a third unnamed antigen were present in some of the fractions. Group reactivity was present in all fractions, but did not reside on the M molecule. The enhanced potential of sonically released antigens to induce high-titer specific precipitating antibodies to M protein is discussed.
mesh_terms: D000941:Antigens / Q000032:analysis / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000302:isolation & purification; D002499:Centrifugation, Density Gradient; D005779:Immunodiffusion; D008970:Molecular Weight; D013297:Streptococcus pyogenes / Q000032:analysis*; D014465:Ultrasonics
chemical_list: D000941:Antigens; D001426:Bacterial Proteins