Rebecca Lencefield (1895-1981) was a renowned American microbiologist at the Rockefeller Institute for Medical Research in New York City. Her career was spent as professor of microbiology at Columbia University.
Lancefield is best known for her system for grouping hemolytic streptococci. The grouping is done using serology (antibody-antigen reactions) based on the carbohydrate antigens on the surfaces of the various streptococcal species.
A partial Lancefield grouping of the hemolytic streptococci is as follows. Please see the reference for a complete list.
Group A: Streptococcus pyogenes
Group B: s. agalactiae
Group C: s. equisimilis, s. equi, and s. dysgalactiae
Group D: enterococci, s. bovis