Reduction of Ca2+-transporting systems in memory T cells.
Antigen-specific B and T lymphocytes make up the material grounds of immune memory, their main functional distinction from the so-called "naive" cells is due to the rapid and enhanced response to the antigen-pathogen. An essential distinction between the memory and naive T cells is different sensitivity of these two subpopulations of T lymphocytes to Ca2+-ionophores. Comparative analysis of Ca2+ responses of the immune memory T lymphocytes and naive T cells of mouse CBA/J line to the addition of Ca2+-mobilizing agents concanavalin A, thapsigargin, and ionomycin was carried out. These compounds in concentrations increasing [Ca2+]i in naive cells had no effect on [Ca2+]i in memory cells. Thus, the Ca2+ entrance into memory cells was not activated by exhaustion of intracellular resources. Estimation of intracellular resources of Ca2+, mobilized by ionomycin and thapsigargin in Ca2+ free medium has shown the absence in memory T cells of the intracellular Ca2+ pool, which may be one of factors of their resistance to ionophores. Reduction of the system of Ca2+ influx into memory T cells was shown using the SH-reagent thimerosal. Memory T cells appear to be resistant to "Ca2+ -paradox." Their incubation with 0.5 mM EDTA in the presence or absence of Ca2+ -mobilizing compounds followed by addition of 2 mM CaCl2 did not result in induction of Ca2+ influx into these cells.
Sigova
A A
AA
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region.
Dedkova
E N
EN
Zinchenko
V P
VP
Litvinov
I S
IS
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003208:Concanavalin A / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007156:Immunologic Memory; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D051379:Mice; D008808:Mice, Inbred CBA; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007476:Ionophores; D003208:Concanavalin A; D004533:Egtazic Acid; D015759:Ionomycin; D019284:Thapsigargin; D000252:Calcium-Transporting ATPases; D002118:Calcium