The current invention concerns the use of PIP or S100A8 for the generation of regulatory T cells. The current invention provides a method of generating regulatory T cells by contacting immature DC with PIP or S100A8 to produce tolerogenic DC and further contacting naïve T cells to the tolerogenic DC to produce regulatory T cells. The invention also concerns PIP protein where immature DC contacted with PIP produce tolerogenic DC that induce conversion of naïve T-cells into regulatory T cells. The invention also concerns S100A8 protein where immature DC contacted with S100A8 produce tolerogenic DC that induce conversion of naïve T-cells into regulatory T cells. The invention also provides methods for identification of factors secreted by iNKT cells that induce conversion of immature DC into tolerogenic DC. The subject invention also concerns using regulatory T cells for treatment and/or management of cancer or the diseases of the immune system.