Biallelic expression of the IL-2 locus under optimal stimulation conditions.
Recent experiments have suggested that the IL-2 locus is monoallelically expressed. We tested this hypothesis using TCR-transgenic mice carrying one inactivated IL-2 allele. The frequency in single-cell assays of IL-2-producing cells following optimal stimulation by antigen and antigen-presenting cells was equivalent to that from wild-type mice, but the amount of IL-2 produced per cell was twofold less. Similar observations were made by intracellular staining for IL-2, although stimulation in bulk culture was less optimal, showing only a 1.7-fold difference. Importantly, the frequency of responding cells from the heterozygotes was less than from the wild-type mice if the IL-2 assay was performed after only 24 - 30 h of activation, suggesting that the targeted allele could compete with the normal allele early after stimulation and give the misimpression that the heterozygotes had fewer IL-2-producing cells. These data strongly argue that the IL-2 locus can be expressed biallelically under optimum stimulation conditions.
Chiodetti
L
L
National Institutes of Health, National Institute of Allergy and Infectious Diseases, Laboratory of Cellular and Molecular Immunology, Bethesda 20892-0420, USA. lchiodetti@niaid.nih.gov
Barber
D L
DL
Schwartz
R H
RH
D000483:Alleles; D000818:Animals; D002874:Chromosome Mapping; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics*; D008198:Lymph Nodes / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D013601:T-Lymphocytes / Q000378:metabolism*
D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell