Isotype

Isotype can refer to different concepts in biology and information design. In immunology, an isotype is a class of antibody defined by the constant region of its heavy chain. The major heavy-chain isotypes are IgM, IgD, IgG, IgA, and IgE, while the light chains have two isotypes, kappa and lambda. The antibody isotype determines its effector functions and tissue distribution. Naive B cells typically express IgM and IgD; through class switching, B cells can produce other isotypes such as IgG, IgA, or IgE without changing antigen specificity. This switching changes how the antibody engages with the immune system—for example, IgG can mediate opsonization and placental transfer, IgA provides mucosal protection, and IgE is involved in allergic responses.

In information design, Isotype refers to the International System of Typographic Picture Education (ISOTYPE), a method of visual statistics developed in the early 20th century by Otto Neurath and colleagues. ISOTYPE uses standardized pictograms to represent quantities and data, aiming to make statistics accessible to non-literate audiences. The approach emphasizes consistent symbol design, size, and composition to enable quick cross-field comparisons of populations, resources, or social indicators. ISOTYPE influenced the development of modern information graphics and data visualization, contributing to how complex data can be communicated clearly across language and cultural barriers.