Histamine inhibits immunoglobulin production via histamine H2 receptors without affecting cell growth in human B cells.

The effect of histamine upon immunoglobulin (Ig) production and proliferation in human B cells was studied. Histamine inhibited Ig production by the human B cell lines IM-9 and CBL in a dose-dependent fashion during 4 days of culture. As little as 10(-5) M was inhibitory. In contrast, proliferation was not affected. Inhibition by histamine was blocked by histamine H2 antagonist, cimetidine, but not by histamine H1 antagonist, diphenhydramine. Moreover, histamine H2 agonist dimaprit inhibited Ig production from B cell lines in a dose-dependent manner, and as little as 10(-8) M was inhibitory. Histamine also inhibited IgM and IgG production by peripheral and tonsillar B cells stimulated with Staphylococcus aureus Cowan strain I and IL-2 without affecting proliferation. This inhibition was also blocked by cimetidine. These results indicate that histamine has a direct inhibitory effect on B cells via histamine H2 receptors, and acts as an immunoregulatory factor.