Experimental immunology

Reactivity of human serum transferrin with two mannose-binding lectins: LCA and ConA

Abstract


Acute phase response is a systemic response to mechanical injuries, traumas or bacterial inflammations. Acute phase proteins (apps) play an important role in this non-specific immune reaction. These serum N-glycoproteins physiologically occur in few variants what is called a microheterogeneity. During acute phase response both concentrations and percentage contents of individual variants are changed.
In this report we tried to analyse transferrin microheterogeneity using two lectins: ConcanavalinA (ConA), a lectin from Canavalia ensiformis and for the very first time Lens culinaris agglutinin (LCA). Both lectins have the same specificity for D-glucosyl and D-mannosyl residues. We compared Tf microheterogeneity in three groups of sera: healthy controls and of patients with acute and chronic conditions.
To estimate the microheterogeneity of the transferrin the affinity immunoelectrophoresis according to Bfg-Hansen was used. To measure the total transferrin concentration the rocket immunoelectrophoresis acc. to Laurell was used.
In a crossed affinoimmunoelectrophoresis with ConA, Tf in healthy sera and sera of patients with traumas and chronic inflammations create four variants: T1, T2, T3, T4 (from the fastest to the most retarded one). The percentage contents in reaction with controls was T1=4%, T2=9%, T3=82%, T4=4%. In a crossed affinoimmunoelectrophoresis with LCA, Tf in healthy sera and sera of patients with traumas create three glycoforms: LCA1, LCA2 and LCA3 (the fastest, retarded and the most retarded variant respectively). The percentage contents in reaction with controls was: LCA1=4%, LCA2=78%, LCA3=17%. The percentage amounts of the main variant LCA2 and T3 decrease especially in the first stages of acute phase reaction, while the amounts of the others glycoforms increase. Those changes are significantly stronger in traumas, thus can serve as a marker of severity of the reaction.
LCA and ConA can well be used as a diagnostic tools of the acute phase reactions, although variants produced in reaction with LCA are much more apparent and there is no T4-like form that disturbs the electrophoretical images. Therefore LCA lectin is better to apply in affinoimmunoelectrophoresis used for Tf glycosylation analysis.