[The expression of an antigen interacting with monoclonal antibody IB4 on the surface membranes of normal human leukocytes and in lymphoproliferative diseases].

Monoclonal antibody (MAb) 1B4 of IgG3 isotype reacting with 55 +/- 10% peripheral blood lymphocytes was obtained. MAb 1B4 is bound with 100% of B and NK cells and 50-70% of T cells in blood. The most part of CD8+ cells (60-100%) and approximately 50% of CD4+ cells belong to 1B4+ population. T-ALL cells do not express 1B4 antigen. Analysis of reactivity of MAb 1B4 with transformed malignant cells has shown that 1B4 antigen appeared in the process of differentiation of B lymphocytes at the state of pre-B cells and disappeared with activation of B lymphocytes and transition to plasma cells.