The effects of transforming growth factor-beta and interleukins 2, 5 and 6 on immunoglobulin production in cultured rat salivary gland tissues.

The effects of transforming growth factor-beta, alone, and in combination with selected interleukins on immunoglobulin production were investigated using an in vitro rat tissue fragment culture system with either parotid, submandibular or sublingual gland tissue. In the majority of culture groups, TGF-beta alone, or in combination with either interleukin 2 (IL-2), IL-5, IL-6 or IL-5 and IL-6 together, significantly increased immunoglobulin A (IgA) levels over those obtained in untreated cultures. The levels of IgG and IgM were generally not affected, with the exception of one sublingual and two submandibular groups(s), where cytokine administration up-regulated either IgG or IgM production. These data indicate that transforming growth factor-beta in combination with IL-2, IL-5, IL-6 or IL-5 and IL-6 can exert a stimulatory effect on IgA production in vitro, supporting a potential regulatory role for these cytokines in salivary gland IgA responses.