Rabbits immunized with whole streptococci of group B, type II, produce two immunologically distinct type-specific antibodies which are essentially equal by weight in protecting mice against infection with homologous type strains.The capsular antigen with which these antibodies react is a polysaccharide containing galactose, glucose, glucosamine, and a labile component which has not been chemically identified. Extraction of the bacteria with TCA yields this ‘complete’ antigen, whereas extraction with HCl yields a partial antigen without the labile component. This degraded antigen can also be derived from the TCA antigen by treating the latter with hot HCl, and is indistinguishable from that extracted directly from the bacteria with HCl.One of the antibodies produced, the TCA antibody, is directed against the labile component of the polysaccharide. The other, the HCl antibody, is directed against a β-d-galactoside determinant; and the precipitin reaction with this antibody is not masked in the ‘complete’ TCA antigen by the presence of the labile component.The group-specific polysaccharide, which is located in the cell-wall, is also extracted with either TCA or HCl but can be eliminated from the preparations by fractional precipitation with ethanol. Although it is known that the type-specific polysaccharide is located in the streptococcal capsule, it is not at present clear in what form this substance occurs in the living streptococcal cell. It may be present partially as the degraded HCl form, or possibly wholly as the intact TCA form. Further immunological and chemical studies of these type-specific polysaccharides are in progress, and will be presented in another communication.

Although the available evidence dearly indicates that the Group A streptococcus represents the probable etiological agent of acute rheumatic fever, its role in the pathogenesis of this disease remains obscure. One of the widely considered theories suggests that some individuals become sensitized to one or more streptococcal antigens during an infection with this microorganism, aad that the acute rheumatic process stems from the interaction between these antigens and antibodies within the tissues of the host. This concept of hypersensitivity has led to many studies of the antigens of Group A streptococci. However, in spite of the accumulation of a large body of information about these antigens, the pathogenesis of rheumatic fever remains an eni~na. No specific antigen has been identified, and the manner by which the inflammatory reaction is invoked and sustained is unknown at this time.In an attempt to determine whether**~treptococcal antigens or antigen-antibody complexes are present in the lesions of acute rheumatic fever, Coons reasoned that a visibly tagged antibody might be of aid in the localization of streptococcal antigens at the sites of histological damage in rheumatic fever (1). Although Coons turned from his original objective, the immunofluorescent technique which he developed has served as a spring board for many other investigations into the role of antigen-antibody reactions in rheumatic fever.In the early immunofluorescent studies, investigators examined the involvement of host gamma globulin in the pathological process. In a small series of patients, Vazquez and Dixon noted that gamma globulin was preferentially concentrated in the myocardial lesions of rheumatic fever (2). In a more extensive study by Kaplan, bound gamma globulin was detected in widely scattered sites throughout the myocardium in 20 % of a series of surgical specimens obtained from rheumatic hearts (3). In another detailed study, Wagner did not find any relationship between the bound gamma globulin which he demonstrated in the Aschoff bodies of rheumatic hearts and fluorescein-tagged streptococcal antigens. In addition, by using fluorescein-tagged Group A

Cefazolin, a new cephalosporin derivative, was studied in the treatment of 105 hospitalized patients with a variety of infections including endocarditis, pneumonia, and urinary and soft tissue infections, and was found to be effective in 104 patients. Cefazolin was also tested in vitro and shown to be effective against staphylococci, pneumococci, Escherichia coli, Klebsiella sp., and Proteus mirabilis by agar dilution method. It was shown to produce high serum levels when administered in a 250-to 1,000-mg intramuscular dose and was well tolerated and free from renal toxicity. Comparison of the results of this study with those from our prior studies on cephaloridine revealed equivalent antibiotic potency, good tolerance to both the agents when given intramuscularly, superior, average blood levels with cefazolin, equal clinical efficacy, and absence of renal toxicity with cefazolin (unlike cephaloridine). Similarly, the results of treatment of pneumococcal pneumonia with intramuscular cefazolin were found to be superior to those for oral cephalexin.Cefazolin is a new (available for study in the United States in 1972) parenteral cephalosporin derivative of 7-aminocephalosporanic acid shown in Japanese studies to be well tolerated and free from renal toxicity (19,20

The term ' % form" has been applied to certain morphological variants of bacteria which grow in special media as minute colonies composed of pleomorphic globules that do not take the Gram stain (1, 2). These bacterial variants show a high degree of mechanical and osmotic fragility, and their properties suggest that they may lack a rigid bacterial cell wall.The first direct evidence for the absence of a cell wall was obtained by Sharp a al.(3) who demonstrated by chemical and serological techniques that L forms of Group A streptococci lack the group-specific carbohydrate, a major component of the streptococcal cell wail. Chemical analysis of L forms of other species also indicates that important constituents of the cell wail are not present (4).Enzymatic removal of the ceil wall from living bacteria without disruption of the cell was described by Weibuil (5). His initial studies involved the action of lysozyme on B. megatherium in a hypertonic environment provided by sucrose, and the spherical structures remaining after removal of the ceil wail were termed protoplasts. Protoplasts have now been prepared by similar techniques from many bacterial species, and they share the property of requiring a hypertonic environment which can be supplied either by sucrose or salts (6). Dilution of a suspension of protoplasts with water results in their disruption (5). The protoplast membrane, which remains as a well defined structure after osmotic rupture, has been shown by morphological and chemical studies to be distinct from the bacterial ceil wall (7-9). The viability of protoplasts is indicated by their metabolic activity and by the observation of "budding" and "dumbbell" forms (10, 11). However, reproduction of protoplasts in a nutrient medium has not been described.Group A streptococci offer certain advantages for a study of the relationship of L forms and protoplasts to each other and to the parent bacterial forms,