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Basophils produce interleukins (IL)-4 in response to various stimuli and may contribute to type 2 immune responses to various infections and allergens. We found that resting basophils freshly isolated from mice produce IL-4 in response to IL-3 but not to high-affinity Fc receptor (FcεRI) cross-linking (CL), yet both required the immunoreceptor tyrosine-based activation motif (ITAM) containing adaptor Fc receptor γ-chain (FcRγ), while basophils activated in vitro by IL-3 become responsive to FcεRI CL. Acquisition of responsiveness to FcεRI CL occurred upon infection with Trichinella spiralis or administration of superantigen. Because cultured basophils return to a quiescent state upon starvation with IL-3 with surface FcεRI levels unchanged, this acquisition is reversible and probably reflects intracellular events requiring protein synthesis. Interestingly, similar activation-associated acquisition was observed for responsiveness to other stimuli, including CD200R3 CL, which is known to signal via DAP-12, and the allergen protease papain. This acquisition of responsiveness to FcεRI CL was inhibited by Jak inhibitor. Thus, the IL-3 signal bifurcates downstream of Jak, into two distinct pathway, one leading to IL-4 production and the other to render basophils competent to respond to stimuli dependent on ITAM-containing adaptors DAP12 and FcRγ for IL-4 production.

Quantum size effect of CdTe quantum dots (QDs) has been one of the targets of extensive research of the optical spectroscopy of semiconductors, but little is known about their effects on electrochemiluminescence (ECL) behavior, especially in the anodic potential range. In this present study, water-soluble CdTe QDs with different sizes are synthesized with a microwave assisted hydrothermal method. Upon electrochemical oxidation of the CdTe QD in the presence of tri-n-propylamine (TPrA) as coreactant, two ECL signals called ECL1 and ECL2 are observed at the potentials corresponding to the oxidation of TPrA (at +0.8 V) and CdTe QDs (at +1.2 V), respectively. The relative intensity of ECL1 has significantly increased with increasing the particle size of CdTe QDs, and disappeared when particle size is less than 2.4 nm. Upon an anodic potential of +0.8 V, TPrA is oxidized at the electrode surface, where the intermediate radical species like TPrA • + radical cation and CdTe QDs • − radical anion are supposed to be formed to give the excited chemical species of CdTe QDs*. The possible ECL mechanisms are proposed from a view point of thermodynamics.

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