Cell Biology of Cytotoxic and Helper T Cell Functions: Immunofluorescence Microscopic Studies of Single Cells and Cell Couples

This review deals with certain important features of the cell biology of natural killer (NK) cells, cytotoxic T lymphocytes (CTL), and helper T (Th) cells. These features appeared originally in studies of the cell biology of cells other than immunological cells, and their relevance to immune cell interactions was then appreciated and explored. This brief review is therefore meant to be selective rather than exhaustive, and it focuses primarily on problems that have been intensively studied in our laboratory over the past decade. At the outset, it should be emphasized that we concentrate on investigations of single (generally cloned) T cells and cell couples, rather than of cell populations. Recent reviews have appeared that deal with other aspects of the cell biology of T cells and their interactions (1-7). The entree to this work stemmed from our investigations of eukaryotic cell motility; these have been separately reviewed (8). These studies are considered briefly first, since they not only introduce the ideas that have played a prominent part in our immunological work, but they also demon-