Cytoplasmic immunofluorescence and light scatter analysis of lamina propria plasma cells by flow cytometry

Cytoplasmic immunoglobulin of lamina propria plasma cells was analyzed by immunofluorescence on the flow cytometer. Lymphoid cells were made permeable to immunofluorescent reagents by treatment with Triton X-100. These cells were then reacted with FITC (green) anti-light chain and with phycoerythrin (red) anti-heavy chain antibodies. Flow cytometric analysis of these cells revealed that plasma cells expressing cytoplasmic immunoglobulin light and heavy chains were specifically stained by the immunofluorescent reagents. These plasma cells were also shown to have membrane Ig as detected by cell surface immunofluorescence. Light scatter analysis indicated that these plasma cells could be distinguished from lymphocytes by 90 degrees light scatter. These studies provide a method by which several parameters of gut plasma cells can be analyzed by flow cytometry.