The effect of 2-acetyl-4-tetrahydroxybutylimidazole on lymphocyte subsets in peripheral blood of the rat.

A constituent of Ammonia Caramel, 2-acetyl-4-tetrahydroxybutylimidazole (THI), is known to cause a reduction in the number of circulating lymphocytes when fed to rats. In the present study the effect of giving THI 1 mg/kg by gavage daily for 7 days on the numbers of lymphocytes in subsets has been monitored in peripheral blood. Both immunoglobulin light chain-bearing B-cells (MARK-1+) and CD5 marker-bearing T-cells (OX-19+) were reduced in number within 1 day of treatment. Within the pan-T-cell population, Class II MHC reactive helper T-lymphocytes (W3/25-) were more reduced than the Class I MHC reactive cytotoxic/suppressor T cells (OX-8+). The number of null cells (MARK-1-, OX-19-) was not affected; the majority of these cells appeared to be large granular lymphocytes.