Assessment of immunogenic linear epitopes on human Immunoglobulin G by immunoinformatic approach

Immunoglobulin G (IgG) is the most abundant antibody in serum and extracellular fluids. The amount of serum IgG is associated to severity of some diseases like immunodeficiency, infections and autoimmunity. Therefore IgG has a high diagnostic value. Immunoinformatic is a branch of immunology which helps in solving of immunologic problems, well understanding of immune responses and precise diagnosis of diseases using the computational biology. The aim of this study is epitope mapping of human IgG by immunoinformatic approaches.
Methods of study : The amino acid sequence and third structure of reference human IgG was found in PDB database. The second IgG structure was determined by Phyre 2 software. IgG linear epitopes were determined by Ellipro and IEDB softwares.
Linear epitopes are located in 160 - 175 and in 350 – 360 amino acid sequence of light and heavy chains respectively as was determined by IEDB software. 11 linear epitopes in constant domains of human IgG, one in fragment of antigen binding (Fab) and others in fragment of crystalizable (Fc) region (equally distributed in the second and third domains of IgG heavy chain constant region (CH2 and CH3) were determined by Ellipro. 5 main epitope are located in CH3 domain.
In this study a lot of linear epitopes located on human IgG were determined by two softwares and the results of previous experimental studies confirm our results. These epitopes are useful tools for producing specific monoclonal anti IgG antibodies, epitope mapping of human IgG and phylogenic studies.