Na+/H+ antiporter has different properties in human B lymphocytes according to CD5 expression and malignant phenotype

Dario Ghigo, Gianluca Gaidano, Silvia Treves, Federico Bussolino, Gianpiero Pescarmona, Federico Caligaris-Cappio, Amalia Bosia

Research output: Contribution to journalArticlepeer-review

Abstract

In B chronic lymphocytic leukemia (B-CLL) cells, lipopolysaccharide (LPS) and phorbol esters fail to activate the plasma membrane-associated Na+/H+ antiporter and, subsequently, to elicit a rise in cytosolic pH. Since these events are thought to be a prerequisite for LPS-induced proliferation of B normal lymphocytes, we analyzed the kinetic properties of Na+/H+ antiporter in B-CLL cells as compared to both CD5- and CD5+ normal B lymphocytes. In the present work we report that Na+/H+ exchange rate after acid loading is drastically decreased in B-CLL cells, as compared to normal CD5- B lymphocytes, although the antiporter affinity for external Na+ and internal H+ is not significantly different in both cell populations. Kinetic data account for a reduction in the number of operating antiport units in B-CLL. The Na+/H+ antiporter of CD5+ normal B lymphocytes exhibits both an exchange rate and an ion affinity significantly higher than that observed in both CD5+ B-CLL cells and CD5- B normal lymphocytes, thus suggesting a possible explanation for their activated phenotype.

Original languageEnglish
Pages (from-to)583-588
Number of pages6
JournalEuropean Journal of Immunology
Volume21
Issue number3
Publication statusPublished - Mar 1991

ASJC Scopus subject areas

  • Immunology

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