Whole-Mount Immunostaining of Human Intestinal Organoids.

Human intestinal organoids (HIOs) recapitulate the architecture and cell diversity of intestinal epithelium, hence providing a system for modeling processes like regeneration and tumorigenesis. Here, we describe a detailed whole-mount immunostaining protocol for HIOs to visualize proliferative cell population. Briefly, this protocol includes preparation of HIOs, fixation and permeabilization of tissue, blocking of non-specific binding, antibody crosslinking, and visualization using a confocal microscope. Additionally, the protocol is broadly adaptable for investigating different antibodies, enabling the exploration of other cell signaling processes in HIO models. By eliminating embedding and sectioning steps, this method is both time-efficient and preserves spatial tissue architecture.