Distinct association of transferrin receptor with HLA class I molecules on HUT-102B and JY cells.

The topological relationship of transferrin receptor (TfR) has been studied relative to the heavy and light chains of the HLA class I molecules, class II molecules, interleukin-2 receptor alpha-chain and ICAM-1 molecule in the plasma membrane of HUT-102B2 T and JY B lymphoblastoid cell lines using the flow cytometric fluorescence energy transfer technique (FCET). The effect of different growing conditions (logarithmic and plateau phases) on the relative surface density of the receptors and the lateral organization of the TfR was also studied. The TfR showed a high degree of self-association on the surface of both cell lines regardless of the growing phase. TfR was in close vicinity to HLA class I heavy and light chains on HUT-102B cells in both plateau and logarithmic phases, while it was not associated with HLA class I on the surface of JY cells. HLA class II molecules form a cluster with TfR on HUT-102B cells, while only a modest association was found on JY cells, and only in the logarithmic phase. The possible explanation of this distinct association and a two dimensional model of the antigen and receptor distributions are presented in this paper.