The production of two Th2 cytokines, interleukin-4 and interleukin-10, is controlled independently by locus Cypr1 and by loci Cypr2 and Cypr3, respectively

 The strains BALB/cHeA (BALB/c) and STS/A (STS) differ in production of IL-4 and IL-10, two Th2 cytokines, after stimulation of spleen cells with Concanavalin A, STS being a low and BALB/c a high producer. We analyzed the genetic basis of this strain difference using the recombinant congenic (RC) strains of the BALB/c-c-STS/Dem (CcS/Dem) series. This series comprises 20 homozygous strains. Each CcS/Dem strain contains a different, random set of approximately 12.5% genes of the "donor" strain STS and approximately 87.5% of the "background" strain BALB/c. We selected for further analysis the RC strain production intermediate between BALB/c and STS. In (CcS-20×BALB/c)F₂ hybrids we found that different loci control expression of IL-4 and IL-10. Cypr1 (cytokine production 1) on chromosome 16 near D16Mit15 controls IL-4 production, whereas the production of IL-10 is influenced by loci Cypr2 near D1Mit14 and D1Mit227 on chromosome 1 and Cypr3 marked by D5Mit20 on chromosome 5. In addition, the relationship between the level of these two cytokines depends on the genotype of the F₂ hybrids at a locus cora1 (correlation 1) on chromosome 5. This differential genetic regulation may be relevant for the understanding of biological effects of T-helper cells in mice of different genotypes. Received: 2 March 1998 / Revised: 8 June 1998