Acquired immunological tolerance of foreign cells is impaired by recombinant interleukin 2 or vitamin A acetate.

Abstract

The susceptibility of newborn mice to the inception of tolerance after exposure to antigen is associated with their deficiency in the production of endogenous interleukin 2 (IL-2). As further evidence of the complicity of IL-2 in the inception and maintenance of tolerance, it is shown here that a solid and long-lasting state of tolerance induced by the intravenous injection into newborn CBA mice of lymphoid cells from (CBA x C57BL/1OScSn)Fj hybrids can be brought to an end by the administration of exogenous IL-2 or by supplementing an otherwise normal diet with vitamin A acetate, the effect of which is to increase the proportion of the moiety of the T-cell population that produces IL-2. These results indicate that certain nonspecific stimuli can influence whether immunological tolerance is maintained.

The purification of eukaryotic polypeptides synthesized in Escherichia coli

“…Examples include immunoglobulins (Boss et al, 1984;Cabilly et al, 1984), IL-2 (Liang et al, 1985;Malkovsky et al, 1985), bovine, chicken and salmon growth hormones (George et al, 1985;Gill et al, 1985;Sekine et al, 1985), prochymosin (Green et al, 1985) and urokinase (Winkler et al, 1985). However, with few exceptions (Boss et al, 1984;Cabilly et al, 1984;Marston et al, 1984), quantification of the efficiency with which the proteins are refolded is not provided.…”

Vitamin A Deficiency and Immunity.

“…They observed that vitamin A [139] and betacarotene [140] stimulated NK cell activity. An enhancement in both in vitro and in vivo killer T-lymphocyte function and cell-mediated cytotoxicity has been shown as a result of retinoid treatment [46,84,141]. Recently, interleukin 2-induced LAK cell activity was demonstrated to be enhanced by retinoic acid [142].…”

Inhibition of human immunodeficiency virus replication by nonimmunosuppressive analogs of cyclosporin A.

“…Supernatants from the PBMC cultures stimulated with PHA in the presence or absence of drugs were tested for IL-2 content by assay on CTLL-2 cells (23,24). Human recombinant IL-2 (25) 10 p,g/ml for 4 hr, washed twice with phosphate-buffered saline and then incubated at 106 cells per ml in complete medium in the presence of CsA or CsA analog at 10 ,ug/ml, respectively. After 48 hr, cell-free supernatants were collected to determine HIV p24 levels by ELISA.…”