counterimmunoelectrophoresis coun·ter·im·mu·no·e·lec·tro·pho·re·sis (koun'tər-ĭm'yə-nō-ĭ-lěk'trə-fə-rē'sĭs, -ĭ-my&oomacr;'-)
n.
A modification of immunoelectrophoresis in which antigen and antibody move in opposite directions and form precipitates in the area between the cells where they meet in concentrations of optimal proportions.