Coordinate regulation of the IL-4, IL-13, and IL-5 cytokine cluster in Th2clones revealed by allelic expression patterns

The cytokines IL-4, IL-13, and IL-5 are markers for the Th2 subset of effec tor T cells and are often expressed together. These cytokine genes are orga nized within 140 kb of orthologous DNA in both mouse and human. Using IL-1- expressing CD4(+) T cell clones derived from F-1 mice, we identified alleli c polymorphisms for each of these cytokines and assessed the parental ident ity of the cytokine mRNAs, Both monoallelic and biallelic expression occurr ed for each gene and for an additional gene, IL-3, that lies with GM-CSF ov er 450 kh telomeric on the same chromosome. When coexpressed in T cell clon es, IL-4 was expressed from the same allele as IL-13 or IL-5 in 81% of inst ances. In contrast, there was only 52% concordance of these three cytokines at the allelic level among clones that expressed IL-3, Independent express ion of the cytokine alleles occurs commonly in T cells, but the clustered l ocus encompassing IL-4, IL-13, and IL-5 is subject to coordinate regulation .