Background: The biological effects of TNFα on targeted cells largely depend on the expression level of membrane-bound receptors type 1 and type 2. Although TNFR2 are predominantly involved in the implementation of proliferative processes, its overexpression may indirectly trigger signaling pathways throughTNFR1 with activation of pro-apoptotic pathways. Thus, the expression level of TNFR2 may influence on cell response to the mediator. The aim was to study the differences in the response of immunocompetent cells to TNFα, depending on the expression of TNFR2 on them.
Methods: Flow cytometry sorting was used to allocate cells with different expression level of TNFR2 among T-lymphocytes and monocytes. Cultivation of sorted fractions over 72 hours with presence of rhTNF-alpha in different concentrations to assess dosedependent changes in cells functional status. Analysis of cell cycle was performed after cultivation.
Results: After 72h cultivation sorted T cells retained TNFR2 expression. TNFR2+ cells had higher percentage of actively dividing cells in G2/M compared to TNFR-negative cells for both T cells and monocytes. Among CD14+TNFR2- cells, greater number of apoptotic cells was observed compared to CD14+TNFR2+ cells. For TNFR2- fractions there was a tendency to increase the number of actively proliferating cells with an increase in the dose of rhTNFα. Also among TNFR2- monocytes the highest level of apoptosis (more than 30% of cells) was observed in the absence of rhTNFα.
Conclusion: T cells and monocytes were shown to differ in functional status depending on the presence of membrane-bound TNFR2. The fractions of cells expressing TNFR2 were characterized by increasing proliferation activity, in contrast to the TNFR2-negative cell fractions. Regulation of the functional status of cells through the influence on receptor expression has potential for use in anti-cytokine therapy strategies.
Acknowledgements
The work was supported by Grant of I.M. Sechenov First Moscow State Medical University №71/1/2017.