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At least 19 recordsLinked to original sources
PubMed1957

Long chain formation by strains of group A streptococci in the presence of homologous antiserum: a type-specific reaction.

Strains of group A streptococci, types 30 and 12, were observed to grow in extremely long chains in liquid media to which homologous antiserum was added. Addition to the media of antisera to heterologous types of streptococci failed to produce long chain growth. The long chain effect was destroyed by absorption of the antiserum with organisms of homologous type but was unaffected by absorption with organisms of heterologous types. The reaction disappeared at concentrations of antisera smaller than 0.25 per cent and was independent of complement or other heat-labile serum factors. Addition of trypsin to the culture to remove M protein from cells prevented long chain formation. The long chain effect depended upon the constant presence of antibody to the media. In its absence, the organisms promptly reverted to short chain growth. The phenomenon appears to have general applicability to those strains rich in M protein with only an occasional strain not responding as described. Further studies are in progress to determine the cause of this atypical response. The applicability of this phenomenon in detecting type-specific antibody using indicator strains of a variety of streptococcal types is discussed.

Antibodies↗
PubMed1957

Studies on bacteriophages of hemolytic streptococci. I. Factors influencing the interaction of phage and susceptible host cell.

The host ranges of bacteriophages for group A, types 1, 6, 12, and 25 and group C streptococci have been determined. The findings indicate that the susceptibility to these phages is primarily a group-specific phenomenon, although it is modified by several factors such as the hyaluronic acid capsule, lysogeny, and possibly the presence of surface proteins. Phage antibody studies indicate that while the group A phages are antigenically related, they are distinct from the group C phage. This is in agreement with the observation that group A phages are not specific for their homologous streptococcal types. The purified group C carbohydrate inactivates group C phage but not the group A phages, thus suggesting that the carbohydrate, a component of the cell wall, may serve as the phage receptor site. It has not been possible to inactivate the group A phages with group A carbohydrate. Phage lysis of groups A and C streptococci is accompanied by fragmentation of the cell wall since the C carbohydrate has been identified serologically and chemically in the supernate of centrifuged lysates. The immediate lysis of groups A and C hemolytic streptococci and their isolated cell walls by an accesory heat-labile lytic factor in fresh group C lysates is also described.

Antigens↗
PubMed1957

Differentiation of group A streptococci with a common R antigen into three serological types, with special reference to the bactericidal test.

In further study of streptococci having the R antigen, the bactericidal test has been used instead of the mouse protection test in investigating the type-specific M antigens of these organisms. The results have been confirmed by M anti-M precipitin tests, and a correlation between the M and T antigens of the strains has been shown. On the basis of a specific M antigen, type 28 has been shown to comprise Griffith's strain Small and four other R-containing strains. A number of other strains previously thought to belong to type 28 on the basis of R antigen reactions have now been identified as belonging either to type 2 or to a new type, designated 48, which shows a one-way cross-relationship to type 13. The bactericidal test is suggested as a useful method for assessing M antigen in group A streptococci and for establishing type-specificity by means of a biological test which is more widely applicable than the standard mouse protection test.

Animals↗
PubMed1958

Further studies on the chemical basis for serological specificity of Group A streptococcal carbohydrate.

Azoproteins prepared with p-aminophenyl-beta-N-acetyl-glucosaminide react in precipitin tests with Group A streptococcal antisera. The reaction is nonreciprocal, and antisera to the azoprotein do not react with Group A carbohydrate. Phenyl-N-acetyl-glucosaminides inhibit the reaction of Group A carbohydrate with homologous antisera and with antisera to the azoprotein. The beta-anomer is more effective as an inhibitor than the alpha-anomer. Formation by a soil bacillus of the enzyme which removes N-acetyl-glucosamine from Group A carbohydrate is induced by phenyl-beta-N-acetyl-glucosaminide but not by the alpha-compound. The enzyme, like the glucosaminidase of emulsin, appears to be specific for beta-glucosaminides. Neither the induced enzyme nor emulsin effectively remove all of the N-acetyl-glucosamine from the azoprotein antigens. The findings support the view that beta-N-acetyl-glucosaminide side chains represent the major antigenic determinant of Group A streptococcal carbohydrate.

Antigens↗
PubMed1958

Occurrence of R antigen specific for Group A type 3 streptococci.

Approximately 50 per cent of Group A, Type 3 streptococci contain a hitherto undescribed antigen found only in Group A, Type 3 organisms. It is serologically distinct from Type 3 M antigen and is designated as 3 R antigen. Strains containing 3 R antigen but no Type 3 M antigen are "glossy," avirulent Type 3 variants. These strains can be obtained by repeated transfers of virulent M-containing streptococci in artificial media under unfavorable conditions of growth. These degraded streptococci recover Type 3 M antigen during serial passage through mice. The amount of 3 R antigen in a strain is not affected by a decrease or increase in M antigen. The 3 R antigen is unrelated to virulence. Antibodies to this antigen do not protect mice against infection or promote phagocytosis in bactericidal tests. The 3 R antigen-antibody system can give rise to confusion in M-precipitin reactions. In all these properties 3 R antigen is similar to 28 R antigen, although in certain other properties the two R antigens are not identical. They are serologically distinct. Virulence and ability to grow in normal human blood under the conditions of the bactericidal test are correlated with the presence of M antigen of Group A, Type 3 streptococci. Mouse protection and specific inhibition of growth of Type 3 streptococci by phagocytosis in bactericidal tests are associated with the presence of Type 3 anti-M antibodies.

Animals↗
PubMed1958

Accessory plasma factors involved in the bactericidal test for type-specific antibody to group A streptococci. I. A typical behavior of some human and rabbit bloods.

The bloods of two apparently healthy human beings, of 25 studied, failed to produce a strong bactericidal test for type-specific antibody to the M protein of group A streptococci under in vitro conditions wherein most human blood leukocytes rapidly phagocytize and destroy virulent organisms in the presence of anti-M antibody and accessory plasma factors. The defect in bactericidal activity of these two individuals is associated with the plasma rather than with the blood leukocytes. Leukocytes suspended in these atypical plasmas showed a characteristic delay in the rate of activation of phagocytosis. Although previously the bloods of laboratory animals (except monkeys) had been reported to be much less active than human blood in this system, occasional exceptions were encountered in rabbits in this study. Two rabbits were found whose bloods were as strongly bactericidal against streptococci, in the presence of type-specific antibody, as the blood of the average "normal" human being. The atypical behavior of some human and rabbit bloods in the bactericidal test may be explained by variations in accessory plasma factors that are as yet unidentified and that influence the rate of phagocytosis of virulent streptococci in vitro in the presence of type-specific antibody.

Animals↗
PubMed1958

Studies on the bacteriophages of hemolytic streptococci. II. Antigens released from the streptococcal cell wall by a phage-associated lysin.

The lysis of cell walls of hemolytic streptococci by a phage-associated lysin has been described. A method is presented for preparing the lysin from Group C streptococcal phage lysates. Following lysis almost all of the cell wall carbohydrate is recovered in solution. This material has the serological reactivity, physical-chemical properties, and values for nitrogen, rhamnose, and glucosamine similar to those of the carbohydrate isolated from the cell walls by the Streptomyces albus enzyme. Group C carbohydrate isolated by either enzyme inactivates Group C bacteriophage. The protein liberated by the lysin from Group A Type 6 cell walls gives a type-specific precipitin reaction with homologous rabbit antiserum. Preliminary data are presented on the ammonium sulfate fractionation and the electrophoretic separation of a protein fraction with the serological reactivity of M protein.

Animals↗
PubMed1960

Factors affecting the chain length of group A streptococci. I. Demonstration of a metabolically active chain-splitting system.

Group A streptococci which grew in long chains in the presence of homologous anti-M antibody were split into their original length by the addition of an excess of homologous M protein to the culture. The chain-splitting reaction showed temperature and pH optima (37 degrees C., 7.5) and was completely inhibited at 0 degrees C. or by heat-killing the long chains at 56 degrees C. prior to the addition of M protein. Addition of sublethal doses of HgCl(2), or of penicillin, inhibited the chain-splitting reaction. Pneumococci behaved in entirely comparable fashion to streptococci in similar experiments. Virulent strains of streptococci formed the shortest chains when broth media was enriched with serum. The chain-shortening effect of serum enrichment of the media was most apparent with encapsulated strains and under cultural conditions that favored capsule formation. Loss of capsules by mutation or by unfavorable growth conditions resulted in increase in chain length. The activity of the chain-splitting mechanism seemed to be independent of M protein, however, since encapsulated M-negative variants also formed very short chain in serum-enriched media. The physical presence of the capsule was not essential for chain shortening since enzymatic removal of the capsule with hyaluronidase during growth did not affect chain length. These results strongly suggest that chain-splitting of streptococci and pneumococci occurs by an active metabolic mechanism, presumably enzymatic, which is inhibited by the union of surface antigens with specific antibody.

Antibodies↗
PubMed1960

Factors affecting the chain length of group A streptococci. II. Quantative M-anti-M relationships in the long chain test.

Minute amounts of M protein were detected in culture supernates of virulent Group A streptococci by type-specific inhibition of the long chain and the bactericidal tests for anti-M antibody. The amount of M protein that was detected by the inhibition of these biological systems was less than could be demonstrated by precipitation tests. All strains of streptococci rich in M protein which were studied formed long chains when grown in sufficient concentrations of anti-M antibody. Very low concentrations of anti-M antibody escaped detection by the long chain test when strains of excessive M protein content were employed. Under such conditions the bactericidal test detected anti-M antibody more sensitively than the long chain test owing to the smaller inoculum employed in the former method. The scission of streptococcal chains may be inhibited by union of antibodies with surface antigens other than M protein. Long chains were formed when M-negative, R-positive strains were grown in sera containing anti-R antibody.

Anti-Bacterial Agents↗
PubMed1961

The occurrence of two M antigens in certain group A streptococci related to type 14.

A strain of Group A streptococcus previously considered to belong to Type 14 was shown to have two immunologically distinct M antigens, designated Type 14 and Type 51. Most strains having the Type 14 M antigen were found to have also the Type 51 M antigen, and are considered to belong to Type 14-51. Four strains had the Type 51 M antigen without the Type 14 M antigen and one strain had the Type 14 M antigen without the Type 51 M antigen. The failure of a variant to produce the known M antigen of the parent strain does not necessarily mean that the strain is M(-), because a second M antigen may be present as was the case in several strains described here.

Antigens↗