Characterization of Anti-Interferon-Gamma Monoclonal Antibodies from Patients with Adult Onset Immunodeficiency

Title: Characterization of anti-Interferon-gamma monoclonal antibodies from patients with adult onset immunodeficiency Anti-Interferon (IFN)-y autoantibodies are an emerge etiology to cause the adult-onset immunodeficiency with mycobacterial or other opportunistic infection in patients from Southeast Asia, including Taiwan. This disease is a severe threatening in Taiwan, and patients suffered from chronical mycobacterial infection despite intensive treatment. Nevertheless, the burden of this disease is highly under-estimated. The clinical manifestation of this disease is well-described by us and other groups; however, the molecular mechanism of the production of anti-IFN-y autoantibodies and the property of these autoantibodies remains mostly unknown. One mission in our laboratory is to understand the molecular mechanism of anti-IFN-y autoantibodies in patients. We found that anti-IFN-y autoantibodies are strongly limited to the individuals with HLA-DRB 1*15:02/16:02 and -DQB1*05:01/05:02 and patients’ plasma only recognized C-terminal region of IFN-y. These finding supported one unique pathogenesis process to produce these autoantibodies among patients. Human B cells cloning is a new method to study the biochemical property and gene structure of human antibodies. To better characterize these autoantibodies, by human B cells cloning, we had isolated 19 monoclonal antibodies (mAbs) to IFN-y from 3 patients. Preliminary data showed that a common V genes usage (IGHV3-21 and IGLV6-57) were found in 12 mAbs from 2 patients and 4 of them showed high neutralizing activity in 1-10 ng/ml concentration. The aim of this proposal is on characterizing anti-IFN-y mAbs to dissect the neutralizing mechanism and antibodies generation. We will, at the first time, to characterize the anti-IFN-y autoantibodies in mAbs and genetic level. There are four major aims to be achieved: Aim 1: Characterize the binding affinity and specificity of anti-IFN-y mAbs. Aim 2: Role of somatic mutation and V(D)J usage in binding affinity of anti-IFN-y mAbs Aim 3: Determine the neutralizing mechanism of anti-IFN-y autoantibodies. Aim 4: Structure determination of full length IFN-y and epitope by X-ray crystallography of IFN-y/mAb complex. The result from this proposal could provide a comprehensive understanding of the property and the neutralizing mechanism of anti-IFN-y autoantibodies from patients. Nevertheless, the result from this studying might also provide the clue of the genesis of anti-IFN-y autoantibodies, which might profoundly affect the future studying, such as identifying the T cells epitope. It is sure that this studying could help to develop the better diagnosis, prevention and treatment to this mysterious disease.

Project ID:PC10701-0296
External Project ID:MOST105-2628-B182-002-MY3