Inositol 1,4,5-trisphosphate- and arachidonic acid-induced calcium mobilization in T and B lymphocytes.
Inositol triphosphate (IP3) formation and increase in intracytoplasmic calcium are mediators of signal transduction in lymphocytes. It has been proposed that IP3 induces Ca2+ release from intracellular stores. It is in order to study the relationship between these two events that we have analyzed the effect of IP3 addition on Ca2+ mobilization in permeabilized resting T and B lymphocytes, EBV-B lymphocytes, and HTLV1-T lymphocytes. IP3 induces a rapid and significant release of Ca2+ from the endoplasmic reticulum in a dose-dependent manner. Ca2+ release is more sensitive to IP3 addition in cycling cells (EBV-B lymphocytes and HTLV1-T lymphocytes) than in resting T and B lymphocytes. Arachidonic acid (AA) induces Ca2+ release from the endoplasmic reticulum (ER) in a manner similar to that of IP3. Neither component has an effect on Ca2+ accumulated in mitochondria, and they have no additive effects suggesting that they act on a similar Ca2+ pool. These results directly demonstrate that in T and B human lymphocytes IP3 mobilizes Ca2+ from ER as in other cellular systems and that other potential second messengers, namely AA, could play a significant role in the internal mobilization of calcium during T and B lymphocyte activation.
Corado
J
J
INSERM U 132, Hôpital Necker-Enfants Malades, Paris, France.
Le Deist
F
F
Griscelli
C
C
Fischer
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000378:metabolism*
D001095:Arachidonic Acids; D016718:Arachidonic Acid; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D002118:Calcium