Dl. Mueller et al., SUBSET OF CD4-CELL CLONES EXPRESSING IL-3 RECEPTOR ALPHA-CHAINS USES IL-3 AS A COFACTOR IN AUTOCRINE GROWTH( T), The Journal of immunology, 153(7), 1994, pp. 3014-3027
In this paper we demonstrate that IL-3 can act as a cofactor for the g
rowth of some CD4(+) T cells. This lymphokine synergized with IL-4 to
induce both a unique set of protein tyrosine phosphorylations and the
vigorous proliferation of the keyhole limpet hemocyanin-specific and I
-A(b)-restricted CD4(+) Th0 cell clone, E6. In addition, neutralizing
anti-IL-3 Abs specifically inhibited the growth of E6 T cells to Ag or
anti-CD3 mAb stimulation. Finally, this T cell clone was shown to exp
ress both the IL-3R alpha-chain and an IL-3R beta-chain (AlC2A). An ex
amination of other CD4(+) T cell clones determined that one Th1 clone
(A.E7), two Th0 clones (16B.2 and L9A.1), and one Th2 clone (D10.G4.1)
were not influenced by the addition of rIL-3. However, proliferation
of the Th2 clones CDC25 and CDC35 to CD3-stimulation was significantly
enhanced by IL-3. The sensitivity of these latter two clones to IL-3
was also found to be associated with expression of IL-3R alpha-chains.
Because E6 T cells are highly dependent on IL-4 for autocrine growth
similar to Th2 cells, these results suggest that IL-3 may synergize wi
th IL-4 to enhance the proliferation of a subset of IL-4-dependent CD4
(+) T cells, and the study indicates that IL-3R alpha-chain expression
may be a specific marker of this CD4(+) T cell subset.