Fig. 2.

Cell surface Cat-315 immunoreactivity is associated with neurons and not with non-neuronal cells. Double label immunofluorescence experiments with Cat-315 and cell type-specific markers demonstrate that Cat-315 labels a subset of cortical neurons in culture. A, B, An E16 plus 3 CD culture double labeled with Cat-315 (A) and Rat-401 (B) demonstrates that the cells labeled by Cat-315 are not labeled by Rat-401, and vice versa. There is no overlap in the cells stained with these two antibodies. C,D, An E16 plus 7 CD culture double labeled with Cat-315 (C) and GFAP (D) demonstrates that the cells labeled by Cat-315 are negative for GFAP. Again, there is no overlap in the cells stained with these two antibodies. E, F, An E16 plus 7 CD culture double labeled with Cat-315 (E) and an antibody to the neuron-specific TuJ1 (F) demonstrates that all cells labeled by Cat-315 are also labeled by TuJ1; Cat-315 therefore labels neurons. Although all Cat-315-positive cells are TuJ1-positive (arrows), not all TuJ1-positive cells are Cat-315-positive (asterisks). This shows that Cat-315 labels only a subset of neurons. Scale bars:A–D, 50 μm; E–F, 25 μm.