The Journal of Medical Microbiology, Vol 10, Issue 2 179-194, Copyright © 1977 by Society for General Microbiology
Immunogenicity and characteristics of M protein released by phage-associated lysin from group-A streptococci types 1 and 23
J. O. Cohen, H. Gross and W. K. Harrell
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.
