Electrophoretic mobility of peripheral non-B human Fc gamma-receptors bearing lymphocytes.

The electrophoretic mobilities of separated "null" lymphocytes and of null and T cells bearing receptors for the fragment of immunoglobulins (Fc) portion of IgG have been studied in normal human blood. The data have been compared with those of other circulating subsets and with more conventional marker techniques. A large proportion of B cells was removed by nylon wool adherence. Further purification of the effluent cells separated 3 non-B populations using the property of sheep's red blood cells to form 2 types of rosettes with T cells on the basis of their relative affinity: "active" rosettes, and low affinity E-rosettes. A population of "null" cells was obtained which was effluent of the nylon wool column and non rosette-forming cells with SRBC (E-RFC). The average purity of this population was 85%; it was found to contain an increased proportion of rosette-forming cells with IgG coated erythrocytes (EA-IgG RFC) (41.3 +/- 10.4% vs. 11.9 +/- 3.8% in the total population) and exhibited high spontaneous incorporation of thymidine but low response to mitogens. The "null" cell population and its erythrocyte-antibody complex-rosette forming cells (EA-RFC) exhibited a defined electrophoretic mobility, centered between 1.05 and 1.15 micrometer. sec-1. v-1. cm in NaCl 0.145 M. The T populations, defined as ERFC, possessed different electrophoretic mobilities, and contained different proportions of Fc gamma receptor-bearing cells. Possessing an e. m. generally greater than 1.15 micrometer. sec-1. v-1. cm., high affinity "active" rosettes did not appear to contain EA-RFC, while the low affinity ERFC contained 18% (8 to 33) EA (IgG) RFC, and had an e.m. comprised between 1.00 and 1.15 micrometer. sec-1. v-1. cm. The presence of antibody-dependent cellular cytotoxicity was found to correlate with EA-RFC: mainly in EA-RFC of the "null" cells, but also to a lesser extent in EA-RFC of the low affinity ERFC. In normal human blood, these non-B Fc gamma receptor bearing cells appeared to possess a comparable electrophoretic mobility centered between 1.05 and 1.15 micrometer. sec-1. v-1. cm. in the "null" and low affinity ERFC subsets.