Unexpected action of histamine on dendritic cells under acidosis

AMARAL MARÍA M; DAVIO CARLOS; MARTÍNEZ DIEGO; GEFFNER JORGE; VERMEULEN MÓNICA

DELPHI. GRECIA

Congreso; EHRS 2006 XXXVth ANNUAL MEETING; 2006

THE EUROPEAN HISTAMINE RESEARCH SOCIETY

We have shown that acidosis improves uptake of antigens and MCH class-I restricted presentation by dendritic cells (DC). Here we analyzed whether acidosis may be able to modulate the regulatory action exerted by histamine (H) on DC. DC were obtained from C57BL/6 bone marrow progenitors cultured with GM-CSF. They were cultured at pH 7.3 or 6.5 during 1 h, washed and suspended at pH 7.3, and treated with H (1 mM) for 30 min at 37oC. Then, we evaluated the uptake of OVA-FITC and the production of IL-12 by flow cytometry. H increased endocytosis by DC and this effect was improved in pH 6.5-treated DCs: pH 7.3, 27±2,3; pH 7.3 + H, 53±4,8; pH 6.5, 64±5,9; pH 6.5 + H, 126±11,2 (mean fluorescence intensity ±SE, n=7, p