Method for producing a human antibody or binding fragment thereof with desired specificity characterized by the isolation of B cells from short-term oligoclonal cultures of activated B cells that secrete IgG isotype antibodies comprising the following steps in the sequence: (a) selecting memory B cells that express antibodies against a protein of interest from one or more biological samples based on the expression of at least one cell surface membrane marker and / or antigen-binding, in which said biological sample derives of a patient suffering from autoimmune polyecrinopathy syndrome type 1 (APS-1) / autoimmune polyocrinopathy-candidiasis-ectodermal dystrophy (APECED), and in which the cells are depleted of the IgM and IgD isotypes； (b) stimulate the selected cells with a first polyclonal B cell activator that is Epstein-Barr virus (EBV) under cell culture conditions for three to five hours； (c) separating the cells from said activator, wherein the activator is removed by dilution or washing； (d) activating the stimulated cells with a second polyclonal B cell activator which is a CpG-based oligonucleotide under cell culture conditions that do not comprise a cytokine； (e) screen activated cells that express IgG isotype antibodies of interest and preferably； (e ') collect individual cells from the oligoclonal cultures that produce the antibody of interest； (f) sequencing and / or cloning the cDNA of at least the light and heavy chain variable regions and optionally the constant region of the antibody of interest, in which the method does not comprise cell cloning of the B cells.Procedimiento para producir un anticuerpo humano o fragmento de unión del mismo con especificidad deseada caracterizado por el aislamiento de células B de cultivos oligoclonales a corto plazo de células B activadas que secretan anticuerpos de isotipo IgG que comprende las siguientes etapas en la secuencia: (a) seleccionar células B de memoria que expresan anticuerpos contra una proteína de in
