[Isoform 1]: Cytokine that induces the release of T-cell- attracting chemokines from monocytes and, in particular, enhances the maturation of CD11c(+) dendritic cells. Can induce allergic inflammation by directly activating mast cells. {ECO:0000269|PubMed:11418668, ECO:0000269|PubMed:11480573, ECO:0000269|PubMed:17242164}. [Isoform 2]: May act as an antimicrobial peptide in the oral cavity and on the skin. . This is the function of Ensembl gene identifier ENSG00000145777 (TSLP, thymic stromal lymphopoietin).