ULTRASTRUCTURAL-LOCALIZATION OF ACID-PHOSPHATASE IN ROSETTED LYMPHOCYTE-T AND LYMPHOCYTE-B OF NORMAL HUMAN-BLOOD

  • 1 January 1981
    • journal article
    • research article
    • Vol. 102  (1) , 72-83
Abstract
Using EM and cytochemical techniques, the distribution of acid phosphatase (AcPase) within the organelles of lymphocytes from blood rosetted with either neuraminidase-treated sheep erythrocytes (En) or sheep erythrocytes coated with antibody and complement (EAC) was determined. Subsequently, the various reactive organelles of the rosetted lymphocytes were counted, affording a comparison of T and B cells. AcPase was present in .apprx. 80% of T cells and 45% of B cells and was most frequently observed in secondary lysosomes of varying size and content. Although more T cells than B cells were reactive for AcPase, the reaction extent in some B cells clearly precludes the use of AcPase for differentiating the 2 cell lines. While the En rosetting procedure detects T cells in a nonselective manner, the EAC rosette is a marker of a major subpopulation of B lymphocytes, i.e., those bearing complement receptors. The lysosomal enzyme distribution in B and T lymphocytes probably reflects the functional state of individual cells rather than being a reliable cell lineage indicator. A surprising finding (which could be established only by a fine-structural study) was the fact that 20% of circulating resting T cells contained reaction product for AcPase within endoplasmic reticulum, and the perinuclear cisterna, indicating that these cells are actively synthesizing AcPase, probably due to a foregoing inductive event. Such stimulus could be the result of recent surface receptor endocytosis in combination with antigen, antibody, or immune complexes and/or recent mitosis, or possibly some unrelated autophagic incident.