RECEPTORS FOR IGG (FC RECEPTORS) ON HUMAN LYMPHOCYTES - RE-EVALUATION BY MULTIPLE TECHNIQUES

  • 1 January 1978
    • journal article
    • research article
    • Vol. 34  (2) , 281-287
Abstract
Whether receptors for Ig[immunoglobulin]G (Fc receptors), as identified by different methods, are found on identical human lymphocyte subpopulations, and the relationship of Fc receptors to surface Ig (SIg) and receptor for complement (C'') were examined. Fc receptors were identified by 2 rosetting techniques (antibody-sensitized human erythrocytes, HuEA, or sheep erythrocytes, ShEA) and 2 immunofluorescent techniques (heat-aggregated IgG of human origin, HuAgg, or of guinea-pig origin, GPAgg). When lymphocytes depleted of cells rosetting with ShEA were compared to HuEA-depleted lymphocytes, the 2 subpopulations appeared to be significantly different. When lymphocytes were depleted of cells rosetting with ShEA which were sensitized with lower concentrations of antibody, the subpopulation so depleted appeared to be virtually identical to HuEA-depleted lymphocytes. Apparently more than 1 lymphocyte subpopulation has Fc receptors and each subpopulation can, in part, be identified and distinguished from the other by the capacity to bind IgG at differing concentrations. These experiments may serve to resolve the controversy concerning the presence of Fc receptors on lymphocytes bearing SIg. Depletion of lymphocytes rosetting with ShEA removed most of the SIg-bearing lymphocytes; depletion of cells rosetting with ShEA which were sensitized with lower concentrations of IgG antibody failed to deplete SIg-bearing lymphocytes even though other Fc-bearing populations were completely depleted. SIg-bearing lymphocytes (B [bone marrow-derived] lymphocytes) have Fc receptors but high concentrations of IgG are needed to demonstrate them.