Flow cytometric analysis of Ig light chain surface expression with fluorescent liposomes. Cells were stained with anti-Igκ– and anti-Igλ–streptavidin antibodies and then incubated with biotin-coupled, Cy5-filled liposomes. (A-D) Shown are examples of a sIgλ⁺ cell line (A; CB-LCL 6-1), a sIgκ⁺ cell line (B; CB-LCL 5-B40), and a sIg-negative cell line (C-D; CB-LCL 5-7-1).