Cross-Reactions Among Group a Streptococci

Abstract

Strains of four streptococcal types, 33, 41, 43, 52, and a nontypable strain, Ross, cross-reacted in precipitin and bactericidal tests. The homologous reactions, which determined the type, afforded the major protection and developed promptly and regularly in the serum of rabbits during immunization. The associated cross-reactions, on the other hand, appeared in the serum of certain rabbits only, were often not as strong as the associated homologous reactions, and required for their presence a longer period of immunization than the homologous reactions. Agar gel analysis of the homologous precipitin reactions revealed, as would be expected, reactions of serological identity, while those cross-reactions which were strong enough to test in this way formed bands of precipitate which joined with spur formation on the side of the homologous reaction. These experiments and others referred to in the text suggest that cross-protection, as demonstrated in bactericidal tests, is sufficiently widespread to be a factor in streptococcal immunity, if a corresponding protection occurs in vivo. Thus, streptococcal infection with one of the cross-reacting strains might confer, in addition to strong homologous protection, a certain amount of cross-protection.

The role of normal skin in the spread of streptococcal pyoderma

“…the inability to grow aero-bically on routine sheep blood agar) permitted separate analysis of these two strains. The finding that the 'other pyoderma strain' showed precipitation reactions with both types 41 and 43 M antisera is of interest in view of the recent report by Wiley & Bruno (1968) which describes precipitin and bactericidal crossreactions between types 33, 41, 43, 52 and Ross. This strain apparently has many of the characteristics of the Ross strain, but the exact nature of the precipitation reactions and possible interrelationships of these two strains will await more detailed studies.…”

New protective antigen of group A streptococci

“…Wiley and Wilson (26) later reported the occurrence of 2 M antigens on the surface of certain strains of type 14 organisms. Other similar studies reported cross-protective immune responses evoked by various antigen preparations (27,28). We now recognize that some M proteins contain cross-protective and typespecific epitopes (29).…”