Hemagglutination of neuraminidase-treated human erythrocytes by Leishmania enriettii infected guinea-pig sera.

Sera from guinea-pigs infected with the protozoan parasite Leishmania enriettii showed higher hemagglutination (HA) titres for neuraminidase treated human erythrocytes than those of normal guinea-pig sera. This HA activity was associated mostly with the 19S fraction of the immune serum and could be absorbed out with an antigenic fraction of the parasite membrane. Antigenic determinants involved in this HA reaction consisted of, at least, beta-D-galactosyl or lactosyl residues.