Concanavalin A-induced agglutination of Naegleria

Concanavalin A (Con A) agglutinated all Naegleria gruberi strains tested but did not agglutinate any N. fowleri strains tested. Agglutination was time and temperature dependent and Con A concentration and ameba concentration dependent over certain ranges. Agglutination increased to maximum up to 1 h incubation with Con A. At least 1 X 10(6) amebae/ml were needed for maximum agglutination, and Con A concentrations higher than 100 microgram/ml did not appreciably increase agglutination. Incubation of 4 degrees C or with 10 mM alpha-methyl-D-mannoside inhibited agglutination of N. gruberi. These data indicate a difference in polysaccharide structure of cell membranes of N. fowleri and N. gruberi.