The word "isotype" refers to a symbol or picture that represents and conveys information or ideas. It can be used as a visual representation that helps people understand concepts or data quickly and easily. Full definition
Flow cytometric analysis (A) of MCF7, MCF7 / HER2, and BT474 cells labeled with F3 - IgG, trastuzumab, or a human IgG isotype control antibody. (journals.plos.org)
A polyclonal antibody contains a mixture of several isotypes of immunoglobulin G (e.g., IgG1, IgG2a). (ptglab.com)
aureus IgG isotypes influences surface protein A mediated immune subversion. (euvaccine.eu)