Selective Cytotoxicity of Anti-Kappa Serum for B Lymphocytes

MOUSE lymphocytes can be divided into two distinct populations according to the density of immunoglobulin determinants on their surface. Lymphocytes with a high density of immunoglobulin are marrow-derived, nonthymus-processed, B cells, whereas lymphocytes with little or no immunoglobulin are thymus-derived, T cells^1–3. Since more than 95% of mouse immunoglobulin light chains are of the kappa type⁴, treatment of lymphocyte suspensions with an appropriate dilution of rabbit anti-mouse kappa serum and complement should be cytotoxic for only B lymphocytes. This prediction was tested by using lymphocyte populations enriched for either T or B cells or containing the two cell types in a known proportion.