Human Lymphocytes Bearing “Ia-Like” Antigens; Absence in Patients with Infantile Agammaglobulinemia

Open Access
Publisher Website
Google Scholar
Abstract
The new Ia-like antigens, which are primarily expressed on B cells, were studied in detail along with other lymphocyte markers in the peripheral blood of normal individuals and patients with immune deficiency. Rabbit antisera to purified Ia antigens proved of special value in this work although alloantisera gave similar results. The Ia antigens were found on most monocytes and all lymphocytes expressing membrane Ig and in addition on a normal population of cells lacking Ig. Both of these lymphocyte populations were completely absent in patients with infantile agammaglobulinemia with a selective B cell defect. Different findings were obtained for Fc-positive cells. In addition to T cells with Fc receptors, a non-T population was apparent that lacked both surface Ig and Ia determinants; these two cell types were not reduced in patients with infantile agammaglobulinemia. These findings suggest that all the Ia-positive lymphocytes, both those with and without clearly detectable Ig, belong to the B cell lineage. The special value of the Ia antigens as markers for distinguishing lymphocyte subpopulations was apparent in this study.