Methods: To investigate the role of the IgE immunoreactive antigen 5(Ag 5) in the sero-positive patients with CE, we determined N-terminal of 57 kDa subunit of Ag5 responsible for IgE and C-terminal of this active antigen related to induction of IgG specifically.
Results: Immunoblotting analysis showed that specific IgE to 57 kDa subunit related to inter-chain disulphide band of two 22 kDa and 38 kDa components of Ag5 and conformational epitope on these subunits. In addition, since the 57kDa component arise from the removal of the C-termainal portion of 22kDa subunit of Ag 5, thus IgE specifically recognized N-terminal of 22 kDa subunit which remain bounded to the other component, whereas IgG reacted with C-terminal of 38 kDa component of Ag5.
Conclusion: Recognition of the specific binding site on the 57kDa subunit of Ag5 can lead to understanding the regulating mechanism of IgE/IgG production in some immune circumstances that IgE tends to be dominated, whereas in other IgG is predominated.