Epitope Mapping of Human Alpha-Fetoprotein

Abstract

Thirty monoclonal antibodies (MoAbs) to human α-fetoprotein (AFP) were compared with one another by two methods: Immunoaffinity electrochromatography or additive ELISA. The first method permitted to analyse the epitopes of native AFP in solution [Abelev et al., Immunol Lett 1994;40:133–138] while the other approach also detects the epitopes of conformationally modified (partly denatured) AFP fixed on the plastic [Yazova et al., Immunol Lett 1990;25:325–330]. Competitive analysis of all MoAbs revealed 10 epitopes, 9 expressed on native AFP and 1 only on the partly denatured molecule. The cross-reactions between separate MoAbs allowed to include them into 6 distinct epitope clusters, or immunodominant groups with the characteristic patterns of reactivity. The obtained epitope map of AFP is necessary for the construction of AFP detection kits as well as for the identification of its antigenic and functional subfractions.

Conformational Variants of Human Alpha-Fetoprotein

“…It is necessary to emphasize that epitopes used in this study belong to different non-crossreacting immunodominant clusters [15].…”

“…The MoAbs D 10 , F 5 and F 2 , directed to three noncross-reacting epitopes, were used in that work. These MoAbs belong to different epitope clusters [15]: D 10 to AB (N92), F 2 to F (N118) and F 5 to D (N113). The MoAb to macrophage antigen D 11 [16], an unrelated antibody, was introduced in the experiments as a negative control.…”

“…Three non-cross-reacting MoAbs [15] were chosen for IAE fractionation of AFP: D 10 (cluster AB), F 5 (cluster D) and F 2 (cluster F). The rest of AFP, non-bound by these three antibodies was fixed by polyclonal rabbit anti-AFP.…”

Summary Report: Epitope Analysis of Human Alpha-Fetoprotein

“…Yakimenko et al [16] in Dr. Abelev's laboratory confirmed the presence of 6 major epitope clusters and identified several minor epitopes. These results were almost identical to that found by Dr. Nustad et al [17] and Kamakura [18] found that one of the epitopes did apparently contain carbohydrate in their studies.…”

Analysis of Epitopes of Mouse Monoclonal Antibodies against Human Alpha-Fetoprotein

“…In a recent TD-2 AFP Workshop organized by the International Society for Oncodevelopmental Biology and Medicine (ISOBM), 30 MAbs against AFP were analyzed [8]. Using immunoaffinity electrochromatography and additive ELISA, Abelev's group classified the antibodies into 10 epitopic clusters, I-X, which were divided into 6 antibody groups, A-F [9]. Nustad's group separately classified the panel of MAbs into 5 groups, A-E, by competitive immunoassays [10].…”