FUNCTIONAL AND BIOCHEMICAL CHARACTERISTICS OF HUMAN “NULL” LYMPHOID CELLS

Publisher Website
Google Scholar
Abstract
Human peripheral null cells (non-T and non-B lymphocytes) were isolated by removing B lymphocytes and monocytes on nylon-wool columns and by E [erythrocyte] rosette-forming cells depletion. The null cell population contained less than 1% of S[surface]Ig-bearing cells, cells with complement receptors (EAC+ [E, antibody, complement-positive]) and E mouse rosette-forming cells, but was contaminated by about 5% of T lymphocytes and 10% of monocytes. High affinity Fc receptors were present on 12% of the null cells. No intracytoplasmic (C) Ig were detected by immunofluorescence. Culture of these null cells for 2-6 days did not modify their surface receptors. Null cells were not stimulated to undergo blastogenesis by the following mitogenic agents: concanavalin (Con) A, phytohemagglutinin-L (PHA-L), lentil lectin, wheat germ agglutinin, pokeweed mitogen (PWM), peanut agglutinin and neuraminidase-galactose oxidase. PWM did not induce the transformation of null cells into B lymphocytes; no SIg, CIg and production of Ig were detected by immunofluorescence and by measuring the incorporation of 3H-leucine. The antibody-dependent cellular cytotoxicity of these null cells was very active compared to unpurified lymphocytes. Analysis of the lectin-binding surface glycoproteins, after labeling of the cells by polyacrylamide gel electrophoresis, showed that the 27,000-33,000 dalton component (Ia-like antigen) present in large amounts on B lymphocytes and monocytes was absent in null cells. These results are in agreement with the hypothesis that null cells consist of 1 or several populations different from the other lymphocytes and that they are not direct precursors or immature T and B lymphocytes.

This publication has 25 references indexed in Scilit: