[Normal antistreptolysin titres and demonstration of rheumatoid factors in rhesus monkeys (Macaca mulatta) (author's transl)].

Rhesus monkeys are often used as experimental animals. Many clinical and biochemical parameters are known but there are only few papers dealing with the normal values of antistreptolysin O (ASL). Informations about antistreptococcal antibodies are necessary in order to follow the course of immunization and infection experiments. When non-absorbed sera were used, the mean value of antistreptolysin O in clinically healthy rhesus monkeys (Macacus rhesus) amounted to 178 +/- 52 ASU. After absorption with dextran sulphate, the mean value was 90 +/- 20 ASU. Absorption with dextransulphate is a necessary prerequisite to exact determinations of antistreptolysin titres because it removes unspecific inhibitors of streptolysin O. In the sera of rhesus monkey more inhibitors were present than in human sera. On an average, in monkeys 55% of the material reacting with streptolysin O was an inhibitor, compared with about 40% in human sera. As a result of common infections with streptolysin O-producing streptococcal groups C and G antistreptolysin titres can frequently be seen to increase above the average normal value. Using non-absorbed and dextran sulphate absorbed sera, respectively 350 and 200 ASU must be regarded as the normal upper limits for serum antistreptolysin-titres.