Immune cells fight pathogens, destroy infected/malignant cells, and contribute to the healing of traumatic tissue damage. To be fully competent for these diverse tasks, immune cells must be activated and induced to differentiate into effector cells in the immune niche. Immune niches are provided not only by secondary lymphoid organs, but they also include sites of inflammation as well as tumor microenvironments. Microenvironments in the immune niche play an important role in the immune cell activation and are critical for the occurrence and dissolution of the immune response. In turn, immune cells interplay with local stromal cells and shape the immune niches, by the cell-cell interaction or the cell-matrix interaction. Therefore, the effect of inflammation is usually tissue-specific and in many cases related to the immune status. In order to better understand the interplay between immune cells and their microenvironments, more comprehensive investigations are required, which would extend our knowledge in tissue environment homeostasis and improve therapeutic strategies in infectious diseases, inflammatory diseases, malignant diseases, and wound healing.

This special issue invites original research and review articles which further the understanding and clarify the related fundamental knowledge and underlying mechanism of the interplay between immune cells and their microenvironments, in order to explore new therapeutic strategies and improve clinical efficacy.

Potential topics include but are not limited to the following:

• Current perspectives in tissue-specific immune niches
• Tissue-specific infiltration of immune cells
• Immune cell-stromal cell interaction or immune cell-matrix interaction
• Immune response in the maintenance of tissue homeostasis
• Immune response in tissue repair and regeneration
• Therapeutic strategies that modulate the immune niche and the immune response