[Functional state of peripheral blood neutrophils in children with rheumatism and borderline conditions]

The authors discuss the effect of exotoxin of beta-hemolytic streptococcus (streptolysin-O) on the chemotactic activity of the peripheral blood leukocytes. 107 children with various forms of rheumatic fever and acute diseases of Streptococcal etiology and 18 healthy children were examined. The absence of the phenomenon of a specific chemotactic deactivation of polymorphonuclear leukocytes in response to streptolysin-O in healthy persons and in those suffering from rheumatic fever has been revealed. Sharply marked sensitization of polymorphonuclear leukocytes to streptolysin-O in patients with rheumatism increasing in the course of the disease and remaining in the inactive phase has been noted. The functional activity of polymorphonuclear leukocytes is characterized by chemotactic deactivation in response to streptolysin O that probably provides a favorable outcome of the disease.

[The significance of determination of streptococcal deoxyribonuclease B antibody titers]

Results obtained by testing 266 sera using antistreptolysin O (ASTO) and antideoxyribonuclease B (ADNB) tests were compared. Upper limit of the normal ADNB titer was determined for population by analysing titer levels in 258 samples taken from healthy subjects (blood donors) and it was 225 IU/ml. Increased titer of one or both antibodies was found in 76 (29%) sera-ASTO and (or ADNB-positive sera being the much larger number than the positive sera number obtained by ASTO test) 40-15% 7. This confirms necessity of the ADNS test application in all patients with normal ASTO titer.

Colorimetric liposome lysis for assay of anti-streptolysin O antibody

We developed an automated colorimetric assay based on liposome lysis for measurement of the titer of anti-streptolysin O antibodies (ASO) in human sera by using liposomes in which alkaline phosphatase (EC 3.1.3.1) was entrapped. The assay involved the inhibition by ASO of liposome lysis caused by streptolysin O. The procedure was fully automated for use with a routine clinical automated analyzer. The inter- and intra-assay precision showed that results were reproducible. Potential interfering substances such as bilirubin, hemoglobin, and triglycerides did not affect the results. With this assay, results correlated well with those by the Rantz-Randall method and the latex agglutination method (r = 0.900 and 0.890, respectively). This automated colorimetric assay for ASO should be of use for diagnosing streptococcal infections.

The effect of Streptococcus pneumoniae pneumolysin on human respiratory epithelium in vitro

Streptococcus pneumoniae culture filtrates and pneumolysin both slow human ciliary beating and damage respiratory epithelium in vitro. A polyclonal pneumolysin antibody bound to sepharose beads removed pneumolysin from culture filtrates and showed that pneumolysin alone was responsible for the effects on epithelium. In a 48-h organ culture pneumolysin caused ciliary slowing and epithelial disruption in a dose-dependent manner down to 5 ng/ml. Comparison of the ciliary slowing activity and pneumolysin concentration in filtrates in a continuous broth culture showed a maximal effect at 16 h (pneumolysin 7.5 micrograms/ml). Later the activity decreased while the pneumolysin concentration increased (8.8 micrograms/ml). This loss of activity was prevented by neutralisation of the acid pH of the culture medium. Eight different culture filtrates produced significant (P less than 0.05) ciliary slowing which correlated (r = 0.95) with simultaneously measured haemolytic (pneumolysin) activity. Substitution of tryptophan (position 433) by phenylalanine reduced the haemolytic and ciliary slowing activity of pneumolysin, but did not affect its ability to activate complement. There was no correlation between the ciliary slowing produced by the culture filtrate and that produced by the autolysate of a particular strain, nor between ciliary slowing and the extent of autolysis or the serotype of the strain.

Regulation of antigen-induced blastogenesis and interleukin-2 expression by adherent mononuclear cells in humans infected with Schistosoma mansoni

The immune response and its regulation by adherent mononuclear cells were investigated in 39 Egyptians aged 13-30 (mean +/- SD, 16.2 +/- 3.6) with chronic Schistosoma mansoni infection (fecal egg excretion, 40-2480 eggs/g; mean, 709 +/- 612). Blastogenesis and production of interleukin-2 (IL-2) by peripheral blood mononuclear cells showed a significant correlation when streptolysin O but not when soluble worm antigenic preparation (SWAP) was used as stimulus. This suggested independent regulation of these responses to SWAP. Thirteen subjects showed SWAP-restricted suppression of blastogenesis but not IL-2 production by adherent cells. Compared with 24 other S. mansoni-infected subjects, they had depressed blastogenic responses to SWAP but comparable SWAP-induced IL-2 production and responsiveness to exogenous IL-2. This study indicates that IL-2 production is not the site of action of parasite antigen-restricted suppressor adherent cells in chronic S. mansoni infection.

Evaluation of a new latex agglutination test for detection of streptolysin O antibodies

Acute- and convalescent-phase serum specimens were collected from 50 patients with group A streptococcal pharyngitis. The anti-streptolysin O (ASO) titer for each serum specimen was determined by using both the standard neutralization assay and the latex agglutination (LA) test (Rheumagen ASO; Biokit Inc., New Britain, Conn.). When the ASO titers derived by the two methods were compared, the correlation coefficient was 0.93. When the ability of the LA test to demonstrate a significant ASO titer rise (greater than or equal to 2 dilutions) was compared with that of the standard neutralization assay, the LA test had a sensitivity of 91%, a specificity of 86%, a positive predictive value of 83%, and a negative predictive value of 92%. Triplicate LA test determinations were performed on a subset of 31 serum specimens, and for 29 (94%), the repeated ASO titers were all within 1 dilution of each other; the width of the 95% confidence interval for the triplicate measurements of each serum specimen was +/- 32.8 IU. We found the Rheumagen ASO to be a simple, rapid LA procedure for measuring ASO titers that produces results that are highly reproducible, show little lot-to-lot variability, and are comparable to the ASO titers obtained with the standard neutralization assay.

An ELISA method for the quantification of anti-streptolysin-O antibodies

This paper describes a new assay, based on the ELISA technique, for the quantification of antibodies to streptolysin-O (ASLO). We have compared its performances with that of a standard method (inhibition of hemolysis). Using a panel of 137 sera covering the whole range of ASLO titers, the results showed a good correlation between both methods but the ELISA method was more reproducible than the standard technique, thus represents a convenient alternative for the quantification of ASLO.

Measurement of antibody responses to pneumolysin--a promising method for the presumptive aetiological diagnosis of pneumococcal pneumonia

An enzymeimmunoassay (EIA) for measuring antibodies to pneumococcal pneumolysin has been developed. The method was used to study the possible pneumococcal aetiology of pneumonia in 159 mostly elderly patients admitted to hospital because of a positive chest X-ray. The results obtained with the assay were compared to those obtained by other diagnostic methods, namely blood culture, detection of pneumococcal antigen in urine and demonstration of an antibody response to pneumococcal C-polysaccharide and capsular polysaccharides. Antibody response to pneumolysin was found in 32 of 39 (82%) patients with pneumococcal pneumonia aetiologically diagnosed presumptively by other methods. In addition, the EIA for pneumolysin antibodies was positive in 31 patients without evidence of pneumococcal aetiology by other methods. The clinical and laboratory investigations of these patients supported the presumption of bacterial infection. We conclude that the EIA we have developed for measuring pneumolysin antibodies is a promising, sensitive method for the presumptive aetiological diagnosis of pneumococcal pneumonia. The assay is simple to perform because only one antigen is needed and measurement of IgG antibodies alone seems to be enough for aetiological diagnosis.

Age-related variations in anti-streptococcal antibody levels

The present study was undertaken to determine the upper 95% confidence limits (CL) for titres of antibodies to streptolysin O (ASO) and streptococcal DNase B (ADNB) using 741 sera from a general population. The ASO titres in sera from children increased abruptly with increasing age, from a mean of 21 (CL 67) in infants of 3 years or less to 211 (CL 462) in children 7 to 8 years old. In children 9 to 12 years of age titres exhibited a plateau with mean values of 168-258 (CL 436-611). In individuals over 20 years the mean ASO titre diminished with increasing age, individuals of 70 years or more showing a mean titre of 83 (CL 169). A similar variation was seen for ADNB. Infants 3 years of age or younger exhibited no detectable ADNB whereas individuals 70 years or more had a mean titre of 11 (CL 91). A maximal mean ADNB titre of 184 (CL 706) was detected in 9-year-old-children. It was concluded that age-related reference values for anti-streptococcal antibodies increase the clinical relevance of the tests.

Expression of the pneumolysin gene in Escherichia coli: rapid purification and biological properties

The gene for pneumolysin, the thiol-activated toxin from Streptococcus pneumoniae, has been expressed in Escherichia coli. The recombinant protein has been purified using a rapid, high yield, purification procedure and has been shown to be identical with respect to N-terminal amino-acid sequence, specific activity, effect on human polymorphonuclear phagocytes and effect on human complement to the native toxin purified from the pneumococcus. This provides a large enough source of material to begin investigation of pneumolysin as a candidate for inclusion in a pneumococcal vaccine.

Comparison of latex and haemolysin tests for determination of anti-streptolysin O (ASO) antibodies

A latex agglutination test was compared with the micro-titration haemolysin inhibition method for the detection of anti-streptolysin O (ASO) antibodies in 428 serum samples. After slight modification of the latex method to produce maximal agglutination good agreement was shown between the results obtained by the two methods. The latex test had a sensitivity of 83.6%, a specificity of 93.3%, a predictive positive value of 86.5% and a predictive negative value of 91.6%. It was convenient, required less labour than the haemolysin test, and permitted economic testing of small numbers of sera.

Comparative efficacy of pneumococcal neuraminidase and pneumolysin as immunogens protective against Streptococcus pneumoniae

Neuraminidase and pneumolysin were purified from cultures of Streptococcus pneumoniae and used, either singly or in combination, to immunize juvenile mice which were subsequently challenged intranasally with virulent S. pneumoniae. In each of two independent trials, a small but significant (P less than 0.05) increase in survival time (compared with that of non-immunized mice) was observed in groups which had been immunized with neuraminidase, but only if the enzyme had been pre-treated with 3.4% (v/v) formaldehyde. The median extension in survival time was significantly less (P less than 0.01) than that of mice which had been immunized with pneumolysin alone. The median survival time for mice which had received both formaldehyde-treated neuraminidase and pneumolysin was not significantly different from that of mice which had received pneumolysin alone. While these findings provide direct evidence that neuraminidase contributes to the pathogenicity of the pneumococcus in mice, they suggest that this protein may be of less value than pneumolysin as a vaccine component in the present experimental model.

Comparison of three rapid methods for detection of antibodies to streptolysin O and DNase B

Three commercial systems were compared for ability to detect antibodies to streptolysin O (ASO) and DNase B (ADB). Streptozyme (Wampole Laboratories, Cranbury, N.J.) exhibited high sensitivity (100%) for detecting ASO but low sensitivity for ADB (22.2%). The LeapStrep (Organon Teknika, Malvern, Pa.) and Check-Spectra (Diagnostic Technology, Hauppauge, N.Y.) tests had low sensitivities for detecting ASO (35.3 and 21.4%, respectively) and ADB (22.2 and 33.3%, respectively).

Sera from patients with high titers of antibody to streptolysin O react with listeriolysin

Sera of patients with suspected rheumatic fever and elevated titers of antibody to streptolysin O were examined by an immunoblotting technique. All but two serum samples, which yielded relatively low titers, bound to a 60-kilodalton protein in the supernatant from a culture of Listeria monocytogenes, which presumably represents the listeriolysin.

[Age-dependent characteristics of immune cytolysis of mouse cells with cytogenetic changes induced by streptolysin O]

It has been determined that streptolysin-O induces cytogenetic alterations in the cell culture of murine kidneys in all the mice examined, the most pronounced alterations being noted in the cells of newborn and, especially, old mice. The injection of syngeneic lymphocytes from newborn and sexually mature mice of the middle age group has led to a considerable decrease in the number of cells with altered chromosome number in cultures. The lymphocytes from old mice have no antimutagenic activity.

Homogeneous liposome lysis assay for determination of anti-streptolysin O antibody titer in serum

We developed a liposome lysis assay for determining anti-streptolysin O antibodies (ASO) in human sera involving the use of carboxyfluorescein-entrapped multilamellar liposomes. This assay system was based on the inhibition of streptolysin O-induced liposome lysis by ASO. Briefly, after incubation of a given amount of streptolysin O with ASO for 30 min at 37 degrees C, carboxyfluorescein-entrapped liposomes composed of egg yolk phosphatidylcholine and cholesterol in a molar ratio of 1:1 were added to the mixture to determine the residual streptolysin O activity. Liposome lysis, detected as carboxyfluorescein release from the liposomes, was inversely proportional to the ASO titer. The results of within-run and between-run precision studies indicated that the liposome lysis assay is accurate and gives reproducible data. Bilirubin, hemoglobin, and triglycerides did not interfere with the liposome lysis assay. The ASO titers of 100 patient sera, evaluated by our new method and the Rantz-Randall method, showed good correlation.

Bacteriological and serological aspects of group A streptococcal pharyngotonsillitis caused by group A streptococci

Several bacteriological and serological variables were studied in connection with a clinical treatment trial in 212 patients with group A streptococcal pharyngotonsillitis. Anaerobic incubation was not superior to incubation in 5% CO2 in air for the detection of group A streptococci. Saliva cultures were inferior to conventional throat cultures in detecting group A streptococci. No strains from patients with recurrences were found to be tolerant to penicillin. In several patients (all asymptomatic), group C and G streptococci were found in follow-up cultures. Group A streptococci serology was more often positive after two months than after one month, also in patients without recurrence.

Streptococcal antibody: as an indicator of tonsillectomy

The significance of antibody for streptolysin-O concerning tonsillectomy was studied. The results obtained were as follows. 1. The upper limit of ASO titer in 5,121 school children was 250 u and a value of more than 333 u was considered abnormal. But the level of the normal limit was different from year to year. 2. Among 143 cases with a high ASO titer of more than 833 u, only 12 cases had recurrent tonsillitis. There was no correlation between the tonsillar hypertrophy and the height of streptococcal antibodies. 3. There was a correlation between the titers determined by ELISA IgG-ASO and ASO in Todd units (r = 0.69), but there was no agreement between the titers determined by ELISA IgM-ASO and ASO in Todd units. 4. IgM-ASO determined by ELISA showed high levels in cases with early stages of streptococcal infection, focal infection and streptococcal carriers. Cases with high ASO, both IgG- and IgM-subclasses, were considered to have an indicative factor for tonsillectomy.

Serum antibodies to pneumolysin in patients with pneumonia

Serum antibodies to purified pneumolysin were determined by enzyme-linked immunosorbent assay (ELISA) in paired samples from 406 adult patients with community-acquired pneumonia and in samples from 184 healthy controls. A high sensitivity (83%) was obtained in patients with blood culture-confirmed pneumococcal pneumonia. In patients with a tentative pneumococcal diagnosis based on culture of samples from the sputum or the nasopharynx, 45% were positive by ELISA. The difference likely reflected the different relevance of cultural findings for the diagnosis of pneumococcal pneumonia. A significant rise in ELISA titer was found in 17% of the patients. When the diagnosis was also based on high titers, 25% were positive. Pneumococcal pneumonia diagnosed by the pneumolysin ELISA was significantly more common in the patients with a more severe disease and who required hospitalization (21 versus 5% for outpatients). Younger patients were more often positive for pneumococci as determined by high titers, while older patients showed titer rises. Mixed infections with other infectious agents were not uncommon. The finding of low titers in acute-phase samples from positive patients and in the youngest and oldest age groups of healthy controls were unexpected, indicating that further studies on the role of pneumolysin in pneumococcal disease are warranted.

Study of antibody response to 4 streptococcal antigens in rheumatic fever and Kawasaki disease with or without cardiovascular lesions

Patients with rheumatic fever (RF) and Kawasaki disease (MCLS) were divided into two groups, one with and the other without cardiovascular lesions, and their sera were examined for antibodies to 4 streptococcal antigens: anti-streptococcal polysaccharide (ASP), anti-deoxyribonuclease B (ADN-B), anti-streptolysin O (ASO) and anti-streptokinase (ASK) in order to clarify the relationship between group A streptococci and these two diseases. In RF the frequency of positive levels of ASP at its early stage was lower than those of the other 3 antibodies, but the ASP titer tended to persist at elevated levels. The frequency of ADN-B in patients with rheumatic heart disease (RHD) was higher than that in those without RHD, but with regard to the other antibodies no difference was found between the two. Of the 4 antibodies the frequency of at least one positive level was 100% in all the sera of RF patients within 3 months from onset. The differences in the frequencies of positive levels of all 4 antibodies in both MCLS and the controls did not prove to be significant. The frequencies of ASP, ADN-B and ASO in the sera of patients without cardiovascular lesions tended to be slightly higher than those in patients with cardiovascular lesions.

Anti-streptopolysaccharide antibody in children with rheumatic fever and scarlet fever

As the serological test of streptococcal infection, the measurement of anti-exotoxin antibodies such as ASO is widely practiced. M protein of the cell wall of group A streptococcus has type specificity. To detect the anti M protein antibody is very significant, but it is not easy to apply this to clinical practice because there are many types and because of the difficulty of purifying M protein. C polypeptide has group specificity, so the measurement of the antibody to C polypeptide is very important as the serological test of group A streptococcus.

Modulation of granulocyte functions by bacterial exotoxin and endotoxins

The modulation of granulocyte functions by bacterial exotoxins (Streptolysin O, alveolysin, theta toxin) and endotoxins from salmonella and lipid A is described here. Incubation of polymorphonuclear granulocytes with thiol-activated toxins resulted in an increased leukotriene generation. Toxin-pretreated PMNs revealed an increased omega oxidation of LTB4, which may explain why toxin-stimulated cells release more LTC4 than LTB4. Furthermore, toxin-pretreated PMNs showed a decreased leukotriene generation on subsequent stimulation with the Ca-ionophore A 23187 or opsonized zymosan.