Type I interferons α and β, naturally produced regulators of cell growth and differentiation, have been shown to inhibit IL-7–induced growth and survival of B cell precursors in vitro. After confirming an inhibitory effect on B lymphopoiesis in an ex vivo assay, we treated newborn mice with an active IFN-α2/α1 hybrid molecule to assess its potential for regulating B and T cell development in vivo. Bone marrow and splenic cellularity was greatly reduced in the IFN-α2/α1–treated mice, and B lineage cells were reduced by >80%. The bone marrow progenitor population of CD43+B220+HSA− cells was unaffected, but development of the CD19+ pro–B cells and their B lineage progeny was severely impaired. Correspondingly, IL-7–responsive cells in the bone marrow were virtually eliminated by the interferon treatment. Thymus cellularity was also reduced by >80% in the treated mice. Phenotypic analysis of the residual thymocytes indicated that the inhibitory effect was exerted during the pro–T cell stage in differentiation. In IFN-α/β receptor−/− mice, T and B cell development were unaffected by the IFN-α2/α1 treatment. The data suggest that type I interferons can reversibly inhibit early T and B cell development by opposing the essential IL-7 response.

Type 1 interferons alpha and beta are found to be potent inhibitors of IL-7-induced growth of early B lineage cells, while having no effect on cell growth induced by IL-2, IL-3, IL-4, or autogenous factors. The combination of IL-7 and interferons alpha/beta induces bcl-2 down-regulation and cell death by apoptosis. These conclusions were derived initially from experiments employing exogenous cytokines, but functional type 1 interferons are also shown to be produced by resident bone marrow macrophages. As physiological modulators of IL-7-driven proliferation and cell survival, interferons alpha/beta may cooperate with other homeostatic factors to maintain the balanced production of normal B lineage cells.

The TiO(2) film was coated on poly vinyl chloride (PVC) surface by dip-coating process from TiO(2)-PVC-THF suspension. The morphology and crystal structure of the as-synthesized samples were characterized by SEM and XRD. The photocatalytic properties were measured by the photodegradation reaction of RhB and the anti-adhesion and anti-bacteria for Escherichia coli. The results show that the resultant TiO(2) film is well-conglutinated on PVC surface and has the same crystal structure as the original TiO(2) powder. The TiO(2)/PVC shows excellent photocatalytic activity for the degradation of aqueous RhB and the activity increases with increasing reaction time and tends toward stable after accumulative illumination for 11.5 h. The TiO(2) film shows good bacterial anti-adhesion activity following photo-activation and sterilization property under UV irradiation. The E. coli can be killed completely after UV irradiation for 1.5 h.