Aggregates, Crystals, Gels, and Amyloids: Intracellular and Extracellular Phenotypes at the Crossroads of Immunoglobulin Physicochemical Property and Cell Physiology
Immunofluorescent micrographs of HEK 293 cells expressing recombinant human IgGs. First three rows: cells were costained with anti-CD147 (green) and anti-human IgG (red). Fourth row: cells were costained with anti-human IgG (green) and anti-transferrin receptor (TfR) (red). Bottom row: Cells were co-stained with anti-human IgG (green) and anti-calnexin (red). Top row: the cells were transfected to express a high-secreting IgG clone. Recombinant human IgGs populated cytoplasmic reticular structures in transfected cells at steady state. Second row: cells express a low-secreting IgG clone. IgGs aggregated into Russell bodies in transfected cells. Russell bodies are pointed by arrows. Third through fifth rows: Russell body-housing cells are shown in a higher magnification. RB formation was typically accompanied by cell rounding in HEK 293 cells.