5. IVIG can be used for treatment of ITP, because IVIG provide large number of (lgG, IgM) antibodies, which can bind to (FcRn, FcyRII-B) expressed on (B, T) cells to inhibit the production of pathogenic antibodies. 6. When TNFR are coupled with IgG Fc region, the half- lives of TNFR will be prolonged. It's due to receptor of (FcRn, FcyRII-B) which is expressed on endothelium. 7. (IgM, IgG, IgA) antibodies has the strongest ability to activate the complement. 8. The first antibodies produced in primary humoral response are ( lgG,lgM) 9. The highest levels of antibodies in the serum are ( lgG,lgM,lgE IgA)..