Distribution of Antibodies to Streptococcal Esterases in Patients with Scarlet Fever

Repetitive counterelectrophoresis (RCE), which has been described (Hayano and Tanaka, 1977), was used to assay the contents of antibodies to streptococcal esterases (STE) in sera from patients with scarlet fever. The levels of antibodies to STE were expressed semiquantitatively by reading the intensity of the colored spot developed by RCE with a densitometer. The present study deals with the determination of anti-STE in sera drawn at intervals from 54 patients diagnosed as suffering from scarlet fever. The STE used in this study were prepared from the streptococcal strains as follows. STE-AI was prepared from SS379 (group A, type 40), STE-AII from strain 69882 (group A, type 49), STE-B from strain H36B (group B, lb), and STE-C from strain Austin (group C). Of the 54 cases studied, 32 (59.3%) showed anti-STE-AI, 24 (44.4%) showed anti-STE-AII, 5 (9.3%) showed anti-STE-B, and 23 (42.6%) showed anti-STE-C. Comparison of the titer of anti-streptolysin O (ASLO) with the type of specific reaction of anti-STE-AI and -AII, determined in the same specimen, showed a marked correlation. Of 20 cases giving ASLO titers of 12 or less, 18 showed no sign of anti-STE-AI and -AII and two showed signs of anti-STE-AI. Of 34 cases giving ASLO titers of more than 12, 33 showed signs of anti-STE-AI and/or -AII, 22 showed signs of anti-STE-AI and -AII, 7 showed signs of anti-STE-AI, and 4 showed signs of anti-STE-AII. Of all the cases, 26 showed coincident rises in titers of ASLO and levels of anti-STE-AI and/or -AII during the course of the disease. One case showed the presence of only anti-STE-B. All of the 23 cases that showed the presence of anti-STE-C showed signs of anti-STE-AI. Some of these cases showed a marked increase in levels of anti-STE-C during the course of the disease.     

Reaction of Thymus Epithelial Cells with Antibodies to Group A Streptococcal Polysaccharide

Immunofluorescence studies show that thymus epithelial cells react with antibodies to group A streptococcal polysaccharide.     

Multivalent Group A Streptococcal Vaccine Elicits Bactericidal Antibodies against Variant M Subtypes

Group A streptococci cause a wide spectrum of clinical illness. One of several strategies for vaccine prevention of these infections is based on the type-specific M protein epitopes. A multivalent M protein-based vaccine containing type-specific determinants from 26 different M serotypes is now in clinical trials. Recent epidemiologic studies have shown that, within some serotypes, the amino-terminal M protein sequence may show natural variation, giving rise to subtypes. This raises the possibility that vaccine-induced antibodies against the parent type may not be as effective in promoting bactericidal killing of variant subtypes. In the present study we used rabbit antisera against the 26-valent M protein-based vaccine in bactericidal tests against M1, M3, and M5 streptococci, which were represented by multiple subtypes. We show that the vaccine antibodies effectively promoted in vitro bactericidal activity despite the fact that the M proteins contained naturally occurring variant sequences in the regions corresponding to the vaccine sequence. Our results show that the variant M proteins generally do not result in significant differences in opsonization promoted by rabbit antisera raised against the 26-valent vaccine, suggesting that a multivalent M protein vaccine may not permit variant subtypes of group A streptococci to escape in a highly immunized population.     

A Study of HL-A Antigen Phenotype in Rheumatic Fever and Rheumatic Heart Disease Patients

The distribution of the HL–A antigens was studied in 76 patients who have had rheumatic fever or have rheumatic heart disease and in 177 disease-free Caucasian individuals. There was a decreased incidence of A–3 in the disease group as compared to the control. No significant increase in the frequency of any HL–A antigen was detectable in the disease group as compared to normal controls. The results were not affected by the exclusion of non Caucasians from the disease group. The parents of patients with rheumatic fever and heart disease showed a significant increase in shared antigens as compared with the parents of disease-free individuals. The total number of HL–A antigens detected on lymphocytes from rheumatic patients was significantly less than on those from normal individuals.     

Fatal Group A Streptococcal meningitis in an adult

Despite the recent resurgence in reports of invasive Group A Streptococcal (GAS) infections worldwide, it remains a rare cause of pyogenic meningitis both in children and adults. We report a case of fatal GAS meningitis in a healthy adult emphasizing the need for clinicians to be aware of its fulminant course, prompting early diagnosis and treatment. There is also a need to consider postexposure chemoprophylaxis in close contacts of such cases.     

Group A Streptococcal Meningitis in the Antibiotic Era

 A case of group A streptococcal meningitis is reported and the 51 cases reported in the literature since 1966 reviewed. A total of 24 men and 24 women were included in the study; the mean age (±SD) was 20.9±25.5 years. Fifty-eight percent of the patients had comorbid conditions, 80% had a distant focus of infection, and 65.8% had blood cultures positive for group A streptococci. Seventy-five per cent of the patients were treated with penicillin. The overall case-fatality rate was 12% (6 patients). Sequelae were more prevalent among children (44%) than among adults (7.7%) (OR=9.43; 95% CI, 1.02–438.95;P=0.03). Group A streptococcus is a rare cause of pyogenic meningitis, affecting mainly children or adults with co-morbidity. Although the case-fatality rate is relatively low, neurological sequelae are frequent among survivors, especially children.     

Role of Streptococcal Pyrogenic Exotoxin B in the Mouse Model of Group A Streptococcal Infection

Streptococcal pyrogenic exotoxin B (SPE B) is a cysteine protease produced by Streptococcus pyogenes. In this study, the differences in virulence between protease-positive clinical isolates and their protease-negative mutants were examined in a mouse model. Isogenic protease-negative mutants were constructed by homologous recombination, using integrational plasmids to disrupt the speB gene. These mutants caused less mortality and tissue damage than protease-positive strains when inoculated into BALB/c mice via air pouch, suggesting that SPE B cysteine protease plays an important role in the pathogenesis of S. pyogenes infection. Reconstitution of SPE B in the air pouches increased the mortality of mice receiving the speB mutant strain. Infiltrated cell numbers in the exudates from the air pouches of mice infected with SPE B-producing S. pyogenes were higher than those from mice infected with protease-negative mutants at 12 h. However, despite pretreatment with vinblastine to deplete neutrophils, injection of protease-positive bacteria still resulted in severe tissue injury, indicating that neutrophil infiltration may not be the major factor involved in SPE B-enhanced tissue damage. The role of SPE B was further confirmed by demonstrating that SPE B immunization of mice conferred protection from challenge with a lethal dose of protease-positive bacteria.     

Preferential Binding of Cross-Reactive Group a Streptococcal Anti-DNA Monoclonal Antibodies to Decondensed Human Sperm DNA

Four murine anti-streptococcal monoclonal antibodies (mAbs) that cross-react with human DNA were evaluated by immunofluorescence flow cytometry for their reactivity with condensed and decondensed human sperm nuclei. All 4 anti-DNA mAbs reacted with condensed sperm nuclei. The reactivity of 3 of these mAbs with decondensed sperm nuclei was 13 to 177 times higher than that found with condensed nuclei. Under identical conditions, mAbs to cytoskeletal/cytocontractile proteins lacked reactivity with decondensed sperm nuclei. Binding of monoclonal anti-DNA antibodies to decondensed sperm nuclei was abolished by preincubation with double-stranded DNA. The preferential binding of anti-DNA antibodies to decondensed sperm DNA suggests the utility of decondensed sperm nuclei as the antigenic substrate for screening anti-DNA antibodies by flow cytometry.     

Preferential Binding of Cross-Reactive Group a Streptococcal Anti-DNA Monoclonal Antibodies to Decondensed Human Sperm DNA

Four murine anti-streptococcal monoclonal antibodies (mAbs) that cross-react with human DNA were evaluated by immunofluorescence flow cytometry for their reactivity with condensed and decondensed human sperm nuclei. All 4 anti-DNA mAbs reacted with condensed sperm nuclei. The reactivity of 3 of these mAbs with decondensed sperm nuclei was 13 to 177 times higher than that found with condensed nuclei. Under identical conditions, mAbs to cytoskeletal/cytocontractile proteins lacked reactivity with decondensed sperm nuclei. Binding of monoclonal anti-DNA antibodies to decondensed sperm nuclei was abolished by preincubation with double-stranded DNA. The preferential binding of anti-DNA antibodies to decondensed sperm DNA suggests the utility of decondensed sperm nuclei as the antigenic substrate for screening anti-DNA antibodies by flow cytometry.     

Taxonomic Relationships among Spotted Fever Group Rickettsiae as Revealed by Antigenic Analysis with Monoclonal Antibodies

The spotted fever group (SFG) is made up of more than 20 different rickettsial species and strains. Study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. In this study, we determined taxonomic relationships among the SFG rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. A total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodominant proteins or on the lipopolysaccharide-like antigens of strains of Rickettsia africae, Rickettsia conorii, Rickettsia massiliae, Rickettsia akari, Rickettsia sibirica, and Rickettsia slovaca, were used in the study. The distribution and expression of the epitopes among 29 SFG rickettsiae and Rickettsia bellii were assessed by determination of reaction titers in a microimmunofluorescence assay. The results were scored as numerical taxonomic data, and cluster analysis was used to construct a dendrogram. The architecture of this dendrogram was consistent with previous taxonomic studies, and the implications of this and other findings are discussed.     

Studies in Rheumatic Fever: VI. Ultrastructure of Chronic Rheumatic Heart Disease

The fine structure alterations in the atrium and atrial appendage, mitral valve and papillary muscle are described in 11 matched patients with chronic rheumatic heart disease. The muscle changes consisted of loss of myofilaments and accumulation of lipid and osmiophilic dense bodies. The connective tissue stroma of the atrium and the mitral valve showed extensive deposition of collagen and elastic fibers. There were numerous foci of collagen degeneration, characterized by fraying of the collagen fibers and accumulation of homogeneous granular material at these sites. Although the muscle changes were more striking, the connective tissue alterations appear important in the evolution of the chronic disease. The extent of collagen degeneration appeared to parallel the degree of collagen formation. The muscle fiber degeneration and connective tissue alterations did not correlate with the clinical findings. At the resolution of the electron microscope, the continuing process in the rheumatic heart appears to be primarily collagen formation and degradation rather than primary degeneration of the muscle fibers. It is the balance of these processes which determine the clinical state of the patient. Acute muscle damage along with evidence of inflammation do not seem to be associated with progressive, chronic rheumatic heart disease.     

Immune Response of Rats to Group A Streptococcal Vaccine

Adult female Sprague-Dawley rats were hyperimmunized with group A streptococcal vaccine in an attempt to evaluate this species for its immunological responsiveness to the group A streptococcal carbohydrate. Pronounced hyperproteinemia, generally attributable to hypergammaglobulinemia was produced in 30 to 40% of the animals. The immune response of the rats was extremely variable, yielding precipitating antibody concentrations ranging from <0.1 mg per ml to >26 mg per ml. Antibody levels also varied considerably in the same rat at different times during the immunization routine. The highest concentration of precipitating antibody was 26.3 mg per ml. Evidence is presented to suggest the production of antibodies of restricted heterogeneity and the production of non-streptococcal antibodies during the immune response.     

Antibody Responses to Group A Streptococcal Infections in the Hamster

The immune response after streptococcal infections of the skin and of the joints was studied in an experimental animal model. Hamsters were challenged intradermally or intra-articularly with different streptococcal serotypes, and antibodies for streptolysin O (ASO), deoxyribonuclease B (anti-deoxyribonuclease B), and group A carbohydrate (anti-group A CHO) were determined. After a single injection at either site, 7 of 48 animals (14%) developed group A-CHO antibodies; however, none of the animals developed detectable levels of ASO or anti-deoxyribonuclease B. After repeated infections of the skin or joint, anti-deoxyribonuclease B antibodies were detectable in 13% (4 of 30) and 30% (5 of 17) of the animals, respectively. Elevations of ASO occurred after repeated joint infections in 4 of 16 animals (25%), whereas none of 30 hamsters repeatedly infected intradermally developed antibodies against streptolysin O. For all three antibodies tested, elevated levels were more frequently noted after repeated joint infections than after repeated skin infections with the same streptococcal serotype. These data, similar to ones previously noted in human impetigo, indicate that ASO responses are feeble after streptococcal skin infections and that the site of infection per se, rather than the infecting strain, appears to be responsible for this poor response.     

Comparison of illumigene Group A Streptococcus Assay with Culture of Throat Swabs from Children with Sore Throats in the New Zealand School-Based Rheumatic Fever Prevention Program

Group A streptococcal (GAS) pharyngitis is a particularly important condition in areas of New Zealand where the incidence of acute rheumatic fever remains unacceptably high. Prompt diagnosis and treatment of GAS pharyngitis are cornerstones of the Rheumatic Fever Prevention Programme, but these are hindered by the turnaround time of culture. Tests with excellent performance and rapid turnaround times are needed. For this study, throat swabs (Copan ESwabs) were collected from schoolchildren self-identifying with a sore throat. Samples were tested by routine culture and the illumigene GAS assay using loop-mediated isothermal amplification. Discrepant results were resolved by retesting of the same specimen by an alternative molecular assay. Seven hundred fifty-seven throat swab specimens were tested by both methods. The performance characteristics of the illumigene assay using culture on blood agar as the “gold standard” and following discrepancy analysis were as follows: sensitivity, 82% and 87%, respectively; specificity, 93% and 98%, respectively; positive predictive value, 61% and 88%, respectively; and negative predictive value, 97% and 97%, respectively. In our unique setting of a school-based throat swabbing program, the illumigene assay did not perform quite as well as described in previous reports. Despite this, its improved sensitivity and rapid turnaround time compared with those of culture are appealing.