Analysis of the subcellular localization of the various B-cell receptor (BCR) components by immunofluorescence microscopy. Fixed and permeabilized chronic lymphocytic leukemia (CLL) B cells were incubated with various combinations of mAbs as follows: anti-anticalnexin and anti-m (A), anti-C79a and anticalnexin (B), and anti-CD79b and anti-TGN46 (C). Red and green images were collected and merged, with yellow coloration indicating co-localization. It is shown that there is co-localization of m and CD79a molecules with calnexin, indicating a retention of these molecules in the reticulum endosplasmic (RE) compartment. In contrast, CD79b co-localization with TGN46, which indicates that CD79b has not been retained in the RE compartment and attained the Golgi compartment.