English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

SUMMARY: Strains of streptococci belonging to Lancefield groups B, C and G were found to possess an antigen which is identical with the group A type 28 M antigen in its ability to absorb group A type 28 antibodies, and to stimulate the production of type 28 antibodies. The antigen also resembles the group A type 28 antigen in its sensitivity to pepsin and trypsin, being inactivated by pepsin but not by trypsin. The antigen does not appear to be the major type-specific antigen in some of the strains not belonging to group A. Lancefield (1940) showed that the serological types of group A streptococci are each characterized by the possession of a type-specific protein antigen, the M substance. Occasionally, P-haemolytic streptococci are encountered which, although belonging to groups other than A, react with absorbed type-specific sera prepared against group A organisms. The nature of the antigen responsible for this cross-relationship has not so far been determined. It is the purpose of this paper to describe four such strains, one of which belonged to group B, two to group C and one to group G; all four strains had the M antigen char- acteristic of type 28 group A. Material and nffthods Source of strains. Strain 'Small' was Griffith's original group A type 28; strain 3962 group I3 came from a patient with a mild sore throat; strain DlO group C was also isolated from a sore throat. Strains 6074 group C and J23 group G came from the vaginae of patients with puerperal fever. Cultures. For extraction or enzyme treatment the cells after 20 hr. incuba- t.ion at 37" in 50ml. of broth (Todd & Hewitt, 1932), were collected by centrifugation. Preparation qf extracts. Crude HCI extracts were prepared as described by Lancefield (1940). These extracts contained the group-specific C substance and the type-specific M antigen. Precipitation reactions. The capillary technique of Swift, Wilson & Lancefield (1943) was used throughout. Preparation and absorption of antisera. Antisera were prepared by inoculating rabbits with formalin-killed streptococci using a slight modification of Lance- field's technique. The strains were passaged a number of times through mice, and after confirming the presence of type 28 M substance, 250 ml. amounts of Todd-Hewitt broth were inoculated and incubated for 24 hr. at 37". Formalin was then added to a concentration of 0.2 % (v/v), and the flasks were left for 48 hr. at room temperature. The cultures were then centrifuged, the deposit GMIIII 1

Occurrence of the M Substance of Type 28 Group A in Streptococci of Lancefield Groups B, G and G