Precipitating Antibodies in Human Sera from Different Age Groups and in Colostrum as Determined by Streptococcal Antigens with Diffusion‐in‐Gel Methods

Summary The development of the immune globulins was studied by means of the determination of precipitating antibodies against β‐hemolytic streptococci in sera from different age groups—fetal, newborn, child and adult. The analyses were performed with diffusion‐in‐gel methods. In fetal sera after 18–20 weeks of gestation precipitating antibodies were found, but in a lower number than in the sera from the corresponding mothers. The same number of antibodies were found in the maternal and umbilical cord sera after 21–40 weeks of gestation as well as at parturition. The antistreptolysin O titer was also the same in the sera from the mothers and newborn. From birth till the age of 9–17 months a decreasing number of antibodies was seen. From this age a slow increase was noted and the level which was found i the adult material was approached in the age group of 13–16 years. The same immune electrophoretic characteristics was demonstrated for the antibodies in the different groups of sera as in colostrum. Finally a positive correlation was found between the number of precipitating antibodies and the antistreptolysin O titers.