Comparative analysis of the antibodies against capsular polysaccharides of Escherichia coli K-92 and K-235: an immunochemical method for the identification of polysialic acids.
1. The antibodies produced against the capsular poly-N-acetylneuraminic acid (poly-Neu5Ac) of E. coli K-92 (alpha 2-8-, alpha 2-9-linked) were 100-fold less sensitive than those obtained against E. coli K-235 capsular polysaccharide (CP) (alpha 2-8-linked) and recognized both kinds of polymers to a similar extent. 2. The partial hydrolysis of each purified polysaccharide revealed that E. coli K-92 CP is more labile at acidic pH than the polymer alpha 2-8-linked of E. coli K-235. 3. The antisera against CP from E. coli K-92 bound its own oligomers in which the number of Neu5Ac units was higher than three, whereas they only cross-reacted with the oligomers derived from E. coli K-235 containing a number of residues higher than 12. 4. The antisera against E. coli K-235 CP that recognized alpha 2-8 oligomers with a number of Neu5Ac residues higher than 5, also reacted, although very weakly, with those containing alpha 2-8 and alpha 2-9 linkages in which the carbon length was higher than (Neu5Ac)3. 5. Both types of antibodies were also able to recognize the native antigens in living bacteria and could be employed for the recognition of the type of linkage presents in different sialylpolymers.
Rodríguez-Aparicio
L B
LB
Departamento de Bioquímica y Biología Molecular, Universidad de León, Spain.
Luengo
J M
JM
Ferrero
M A
MA
Reglero
A
A
D000907:Antibodies, Bacterial / Q000276:immunology*; D000918:Antibody Specificity; D016667:Bacterial Capsules / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D004926:Escherichia coli / Q000276:immunology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007118:Immunoassay; D012794:Sialic Acids / Q000032:analysis / Q000276:immunology*
D000907:Antibodies, Bacterial; D012794:Sialic Acids; C021319:polysialic acid