CUBN and breast cancer: To examine the possibility that aggregated IgG or IgY multimers can release active antibodies and restore biological activity, samples of self-assembled (24 and 72 h preparation time) and native Igs were diluted 1:100 in PBS and tested for their binding capacity over 3 days in a binding assay to HER2-positive SKBR3 human breast cancer cells or to Newcastle disease virus (NDV) antigen, respectively.