LANCEFIELD EXTRACT OF GROUP A STREPTOCOCCI TYPE 15 ACTS LIKE AN ANTI-HUMAN IgG WITH RESTRICTED SPECIFICITY

Lancefield extract of streptococci group A type 15 precipitates certain human sera and agglutinates red cells coated with some IgG anti-Rh antibodies. The frequency of precipitation varies between populations. The serum component in the precipitate is IgG. The results indicate that an iso-allotypic marker is detected by the extract.