Lymphocyte associated beta 2-microglobulin studied by crossed radioimmunoelectrophoresis

A sensitive radioimmunoelectrophoretic assay was employed in the study of beta 2-microglobulin (beta2m) from human blood lymphocytes, allowing the detection of 2.5 pmol of beta2m corresponding to 3 x 10(6) lymphocytes. The intrinsic (amphiphilic) membrane proteins were solubilized and examined in crossed immunoelectrophoresis against rabbit antisera in the presence of non-ionic detergent. The beta2m associated precipitate was traced by post-electrophoretic incubation with 125I-labelled antibodies to beta2m and autoradiography. A polyspecific rabbit antiserum to human lymphoid cells retained its capacity to precipitate lymphocyte beta2m after absorption with isolated beta2m (on an immunosorbent column), showing that lymphocyte beta2m is complexed to other molecules. No free beta2m was found on lymphocytes when examined against the absorbed antiserum to human lymphoid cells in an intermediate gel and anti-beta2m in a reference gel.