Ar. Saha et al., ZINC INDUCES THYMULIN SECRETION FROM HUMAN THYMIC EPITHELIAL-CELLS IN-VITRO AND AUGMENTS SPLENOCYTE AND THYMOCYTE RESPONSES IN-VIVO, International journal of immunopharmacology, 17(9), 1995, pp. 729-733
Zinc is incorporated into zinc-thymulin by the thymus and in this form
is a critical hormonal regulator of cellular immunity. In the absence
of serum, zinc induces human thymic epithelial cells (TEC) to secrete
a factor which promotes the expansion of interleukin-2 (IL-2) recepto
r positive human peripheral blood lymphocytes in response to a low dos
e of phytohemagglutinin (PHA). This factor is removed by antithymulin
antisera plus filtration and is thus presumed to be zinc-thymulin. Int
raperitoneal treatment of hydrocortisone treated aged mice with zinc-t
hymulin (100 ng/day x5) resulted in mild augmentation of splenocyte bu
t not thymocyte responses in vitro to IL-1, IL-2, and natural cytokine
mixture (NCM) and to PHA and concanavalin A (Con A) (average increase
40%). Like zinc-thymulin treatment, oral ingestion of zinc (72 mu g/d
ay x 5) resulted in augmentation of splenocyte IL responses; in contra
st, it augmented thymocyte responses to all stimuli (average increase
100%). These preliminary experiments indicate that treatment with zinc
may have immunotherapeutic relevance, particularly in the aged and st
ressed organism.