Promotion of Replication in Lymphoid Cells by Specific Thiols and Disulfides in Vitro

Abstract

Lymphocyte division has been the subject of many studies from the point of view of cellular immunology and antibody synthesis. Blast cell transformation and mitosis occur both in vitro and in vivo under stimulus from a number of agents which act on the cell surface, particularly in experimental situations by lectins (1).Although the sequence of events which connect the mitogenic stimulus to DNA synthesis is still incompletely known and several different cell types may be involved, a nmnber of preliminary changes have been recognized. Thus, for example, the cyclic AMP level in lymphocyte cultures rises within 2 rain of stimulation (2), membrane biosynthesis increases within 1/4 h of stimulation (3), nuclear template activity increases within 2 h (4). I t is of considerable importance to an understanding of the neoplastic change in lymphoid cells to know the extent to which such processes and factors controlling them are retained in replicating lymphoma cells, and the extent to which they are altered.We here report a comparison, between the effects of certain thiols and disulfides which we have found to be necessary for the growth of mouse lymphoma cells in vitro, and their effects in enhancing the action of mitogens on splenic lymphocytes.Our observations stem from the finding that mouse lymphoma cells of the line L1210 (V) which had previously been established in culture only with great difficulty (5), proliferate in a medium formulated by Balk (6). The specific growth promoting component of this medium was found to be its high concentration of added L-cysteine (1.5 mM) (7). As will be described, a number of thiols and disulfides can substitute for L-cysteine, some at very low concentration (to < 1 #M). Precise structure activity relationships exist. Furthermore, 13 of 23 other mouse leukemic and neoplastic lymphoid cell lines were also thiol-disulfide dependent in vitro.

Thiol compounds inhibit mercury-induced immunological and immunopathological alterations in susceptible mice

“…Previous studies [6][7][8] and also this study showed that the addition of thiol compounds, including meso-DMSA and DMPS, enhanced the proliferative response to Con A and LPS. It is believed that effects of thiol compounds on the activities of lymphocytes are due to the low redox potential of thiol compounds to either maintain monothiols completely in a reduced state on cell surface proteins or to interrupt disulfide bonds between cell membrane proteins [6,28,29].…”

“…Previous studies [6][7][8] and also this study showed that the addition of thiol compounds, including meso-DMSA and DMPS, enhanced the proliferative response to Con A and LPS. It is believed that effects of thiol compounds on the activities of lymphocytes are due to the low redox potential of thiol compounds to either maintain monothiols completely in a reduced state on cell surface proteins or to interrupt disulfide bonds between cell membrane proteins [6,28,29]. Such modulation on lymphocyte activities has been found to be related to chemical structure of thiol compounds [6], in which the substitution of non-thiol group on thiol compounds with other functional groups may alter the activity of the molecule [6,29].…”

“…To analyse further whether the other thiol compounds also have similar effects, we tested the four thiol compounds with a chemical structure close to 2-ME, i.e. DTT, L-cysteine [6], meso-DMSA and DMPS [11][12][13] at various concentrations from 0 . 01 mM to 100 mM.…”

“…We compared the different thiol compounds with regard to their ability to enhance the proliferative response of lymphocytes to mitogens [6][7][8]. As shown in Fig.…”

Flow cytometric analysis of RNA content in different cell populations using pyronin Y and methyl green

“…However, a considerable proportion of the cells were observed to have less RNA than 0-time cells. Since murine spleen cells characteristically do poorly in cell culture (4,12), these cells were probably either dead or dying at the time of fixation. Few cells with greater than 0-time RNA contents were observed.…”