ANCHORAGE AND LYMPHOCYTE FUNCTION .2. CONTACT WITH NON-CELLULAR SURFACES, CELL-DENSITY AND T-CELL ACTIVATION

  • 1 January 1981
    • journal article
    • research article
    • Vol. 43  (3) , 573-580
Abstract
Varying numbers of human blood lymphocytes were stimulated by concanavalin A (Con-A) in a constant medium volume. At low cell densities DNA synthesis was proportional to the number of cells in the cultures whereas at high densities DNA synthesis was considerably lower than expected. In the presence of non-mitogenic microcarrier beads, to which the cells attached, DNA synthesis was proportional or nearly proportional to the cell number in the cultures also at high cell densities. The potentiating effect of beads on lymphocyte stimulation was particularly noteworthy in individuals showing a weak mitogen response. Another approach that yielded proportionality between DNA synthesis and cell number both at low and high cell densities was the use of culture vessels with a larger bottom area. Under such conditions the presence of beads did not augment DNA synthesis. The availability of a non-cellular adhesive surface is probably a major limiting factor. Cell density may be a major regulating factor in the control of lymphocyte activation. Anchorage of the cells to a surface may modulate the density dependent growth control mechanism indirectly via an influence on cell-cell interaction. An alternative less-likely interpretation is that the contact with non-cellular surfaces directly gives rise to regulatory responses in lymphocytes or accessory cells.