IMMUNOLOGY AND THE CONFOCAL MICROSCOPE

The techniques of classical epifluorescence microscopy are already wid ely used by the immunological community to detect antigens at the cell ular level. Coupled with the use of specific inhibitors that affect di verse intracellular events these techniques have provided valuable inf ormation on the mechanisms involved in antigen presentation. The same biological samples can now be examined by confocal microscopy, which h as a higher resolution than conventional microscopy and allows one to analyse quantitatively single cross-sections of the sample. The confoc al microscope is therefore especially well-suited for studies on intra cellular membrane traffic, cell-to-cell interactions. and the distribu tion of particular antigens and their co-localization with other intra cellular markers. This review describes the technique of confocal micr oscopy and the goals of sample preparation, along with several detaile d protocols for fixing and permeabilizing cells and mounting them on m icroscope slides. Representative examples are cited from studies on th e endocytosis of surface receptors, the distribution of adhesion and m ajor histocompatibility complex (MHC) molecules, and the interaction o f an intracellular parasite with MHC molecules of the host cell.