title: Immunogenicity and characteristics of M protein released by phage-associated lysin from group-A streptococci types 1 and 23.
abstract: A phage-associated lysin (PAL) was used to release M protein from goup-A streptococci of types 1 and 23. Much of the lysin-released-M protein (LYSIN-M) of both types was of high molecular weight, since LYSIN-M appeared just after the void volume on Sephadex G-200 gel-filtration. Some of the LYSIN-M appeared just after the void volume on Sephadex G-200 gel-filtration. Some of the LYSIN-M of both types was found to be firmly attached to group-A carbohydrate. Type-1 LYSIN-M was partially purified by ammonium-sulfate precipitation followed by absorption and elution from an immunoabsorbent column containing antibody for group-A carbohydrate. Type-23 LYSIN-M was partially purified by precipitation at its isoelectric point, pH 4-9. Rabbits immunised in the footpads with either type-1 or type-23 LYSIN-M responded by producing both precipitins and bactericidal (opsonising) antobodies. Some of the antiesera were absorbed and rendered specific for homologous acid extracts. The LYSIN-M preparations of both types 1 and 23 were originally contaminated with heat-labile antigen(s). Antibodies to these heat-labile antigen(s), which cross-react from type to type, were found in the type-specific antisera distributed by the Center for Disease Control. The specificity of Lancefield typing antisera depends on their being tested with extracts of streptococci prepared at pH 2 and 100 degree C for 10 min. Although LYSIN-M is more difficult to prepare and purify then acid-heat released M protein, it might prove useful for studying the nature of native streptococcal M protein.
mesh_terms: D000942:Antigens, Bacterial / Q000302:isolation & purification*; D001426:Bacterial Proteins; D001433:Bacteriolysis / Q000187:drug effects; D001435:Bacteriophages / Q000378:metabolism; D003851:Deoxyribonucleases; D007106:Immune Sera; D008239:Lysine / Q000096:biosynthesis / Q000494:pharmacology; D011234:Precipitins; D013297:Streptococcus pyogenes / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007106:Immune Sera; D011234:Precipitins; D003851:Deoxyribonucleases; D008239:Lysine