Effects And Mechanisms Of Gp350 On The Production Of Immunoglubulin By Cultured CD5～+B Cells

Natural immunity has been becoming a very important topic in recentstudies, meanwhile, researchers has also been paying close attention to nature autoantibodies(NAA) which is an important part of human natural immunity. Anti-keratin auto antibody(AK auto Ab) is accepted generally as a significant component of natural auto antibody which is found in human as well as vertebrate, and is of characteristic of polyreactivity, low avidity, extensive connectivity and shorting of specificity to the species. Extensive studies have been performed to investigate the immunological characteristic of AK auto Ab and it's significant position in physiological or pathological situation. It has been demonstrated directly or indirectly that AK auto Ab is an important element in the immune network and plays a important role in maintaining physiological functions, clearing aged cells and metabolic products, regulatingimmune responses and protecting against infection. In some pathological states such as psoriasis and contact dermatitis, a certain serum level of the antibody could inhibit the progression of the diseases, and is beneficial to the recovery from the diseases. CD5+B cells have been identified as a special population is prominent in early life and produce low avidity and polyreactive IgM antibodies. These cells also play an important role in maintenance maturation and self-stablation of immune system such as clonal selection of thymocyte, idiotypic immunity, antigen presenting and induction immunologic tolerance. Complement receptor 2 (CD21/CR2) located primarily on B cells and follicular dendritic cells, most evidence points toward there being a shared binding site in complement receptor type 2 for the complement ligand C3dg and Epstein-Barr virus(EBV) outer envelop glycoprotein gp350/gp220, HIV-1. IL-6, IFN-a ,CD23/Fc RII and play wide range roles in immunoloregulation. It has been demonstrated that complement activating and CR2 cross-linking on B lymphocytes set up a bridge between innate and acquired immunity. The interaction of C3 and CD21 on B lymphocytes will benefit initiating immune response and regulating primary antibody response. CD21/CD35 is important in the process of antibody avidity maturing, this is critical to B lymphocyte activation especially in the state of low antigenconcentration. On the other hand , mIgM-CD21 cross-linking will contribute to response of B lymphocyte with low avidity to T dependent or T independent antigens. A certain aspect of complement investigation is involved in the field of NAA. Complement system may have an effect on the positive selection of CD5+TJ lymphocytes. Cr2-/-mice,deficent in CR1/CR2, may present a reduction of CD5+B lymphocyte population in peritoneal cavity.The major neutralizing epitope for the Epstein-Barr virus is present on its envelope glycoprotein gp350/220 (hereafter referred to as gp350), it's antigenic determinant play the role of Antibody-dependent cellular cytotoxicity. Antibody to gp350 posses neutralization and immunoprotecive. gp350 is the special ligand to CR2 which can mediated EBV adsorption to CR2 site of host cells. There have been a great deal of reports about gp350 binding to human B cells complement receptor 2 such as Epstein-Barr Virus and its glycoprotein-350 upregulate IL-6 in human B-lymphocytes via CD21; some researchers coupled a monoclonal anti-human IgD to the gp350 gylcoprotein of Epstein-Barr virus, which has been shown to bind to the complement receptor 2 (CR2), and compared its B cell stimulatory ability to that of anti-Ig and to a multivalent anti-Ig-dextran conjugate, The anti-Ig-gp350 conjugate stimulated higher levels of human B cell proliferationin vitro than did anti-Ig or anti-Ig conjugated to control viral protein, comparable to the proliferation stimulated by the multivalent anti-Ig-dextran. This enhanced proliferation was dependent on binding of the conjugate to CR2, in as much as an anti-CD2 antibody blocked the enhanced proliferative response. This enhanced proliferative response was associated with prolonged...