The goal of this project is to identify and characterize B lymphocyte receptors for lymphokines via the production of monoclonal antibodies. A secondary goal is development of monoclonal antibodies which distinguish functionally distinct subpopulations of B lymphocytes. Monoclonal antibody F1-10 detects a determinants preferentially expressed on activated B lymphocytes. Expression peaks 60 hours after activation using LPS. The F1-10 determinant is also expressed on splenic B lymphocytes and a subpopulation of bone marrow cells but at much lower levels and is absent from thymocytes, splenic T lymphocytes, and activated T lymphocytes. Mapping studies using BXD recombinant inbred mice indicate a gene controlling expression of the F1-10 determinant is located on chromosome 17 between hbap-4 and acry-1. These results together with a unique strain distribution pattern suggest that F1-10 is detecting a previously undescribed determinant selectively expressed on activated B lymphocytes which may be a receptor for lymphokines. A new hybridoma screening method has been developed using particle concentration fluorescence which is capable of detecting antibodies binding to molecules which are expressed at very low levels (500-1000 molecules per cell).
