The in vitro development of immunoglobulin producing cells from the human bone marrow null lymphocyte

The distribution of human bone marrow lymphocyte population was studied on twenty normal adults. The distribution of bone marrow lymphocytes were as follows: null lymphocytes 79.4%, E-RFC 8.9%, Thy+ lymphocytes 0.4%, Tgamma 0.9%, Tmi 1.4%, SmIg+ cells 7.8%, EAC-RFC 11.7%, EA-RFC 6.2%, and K cells 2.7%. Bone marrow null lymphocytes were intermediate in their size between small lymphocytes and lymphoblasts. The presence of a lot of short microvilli on null lymphocytes was demonstrated by scanning electron microscopic examinations. The bone marrow null lymphocytes had no cytoplasmic Ig. When the bone marrow null lymphocytes were mixed-lymphocytes-cultured with allogeneic T lymphocytes and then stimulated with PWM, there developed Ig producing cells. Differences between pre-B cells and bone marrow null lymphocytes were discussed.