Studies on Streptolysin O and Antistreptolysin O Iii. A Practical Method for the Antistreptolysin O Titration of Human Sera

Abstract

In the previous reports (Kusama et al., 1958 a, b), the spectrophotometric determination of the hemolytic activity of streptolysin O (SL) and some fundamental aspects of the streptolysin O -antistreptolysin O reaction were presented. The qualitative difference of antistreptolysin O (ASL) in human sera, as manifested by different slopes of reaction curves and different combining velocities, was con sidered probably to be due to the avidity difference. A spectrophotometric method for the ASL titration which could minimize this qualitative difference by using a larger amount of SL than employed by other workers was described, and a standard ASL was prepared from a human serum with reference to the Danish standard ASL.Since the spectrophotometric method is rather laborious and time-consuming, a simple method which could be suited for the routine diagnostic work is consi dered in this report.The principle of the method is to compare visually the degree of hemolysis in a number of tubes containing known, varying amounts of the standard ASL with that in a dilution series of the unknown serum, using a constant dose of SL. A dilution of the unknown serum and a known amount of the standard ASL (expressed in units per cc), which would each cause 50% hemolysis, will be estimated by direct comparison or interpolation.Multiplying the former (the degree of dilution) by the latter (the number of units) will give the units of ASL per cc of the unknown serum. MATERIALS

Immunological Significance of Antistreptolysin O (Asl) in Streptococcal Infections Iv. The Antibody Decline in Scarlet Fever Convalescents

“…The method reported by one of the present authors (Kusama, 1958) was the same process of the antibody decline is envisioned in both groups. The titer at the 4th week in the intially negative group was definitely lower than that in the initially positive group, and it influenced the antibody levels in later periods.…”

Immunological Significance of Antistreptolysin O (Asl) in Streptococcal Infections Ii. A Two-Year Study of Streptococcal Infections in Primary School Children

“…2. Serological examinations: Sera from some of the children were assayed for the ASL titer by the method previously reported by one of the authors (Kusama , 1958)…”