Enhanced suppressive function of regulatory T cells from patients with immune-mediated diseases following successful ex vivo expansion.

Recent studies and our current data demonstrated the deficits in the numbers and/or functions of the CD4(+)CD25(+)Foxp3(+) Treg cells in the patients with autoimmune diseases, indicating that restoration of Treg cells in these patients could be a potential therapeutic approach. Here, we demonstrated that CD4(+)CD25(+)Foxp3(+) Treg cells can be purified, activated and expanded from peripheral blood of patients with immune-mediated diseases, to a similar degree to those from healthy donors. Within 3weeks, Treg cells from most patients could be expanded ex vivo 100-2000 fold and maintained their phenotypic characteristics.

Ex vivo expanded human CD4+CD25+Foxp3+ regulatory T cells prevent lethal xenogenic graft versus host disease (GVHD).

Mouse studies demonstrated that infusion of CD4+CD25+ regulatory T cells (Tregs) prevented graft versus host disease (GVHD) lethality after bone marrow transplantation (BMT). But the potential impact of human Tregs on GVHD has not been well demonstrated. In this study, we demonstrated that human Tregs enriched from peripheral blood of healthy donors could be expanded ex vivo to clinically relevant cell numbers in 2-3 weeks while maintaining Foxp3, CD25, CTLA-4, and CD62L expression as well as in vitro suppressive function.

Immunoglobulin A-deficient mice exhibit altered T helper 1-type immune responses but retain mucosal immunity to influenza virus.

We have previously demonstrated that immunoglobulin A (IgA)(-/-) knockout (KO) mice exhibit levels of susceptibility to influenza virus infection that are similar to those of their normal IgA(+/+) littermates. To understand the mechanism of this apparent mucosal immunity without IgA, immunoglobulin isotype and T helper 1 (Th1)-type [interferon-gamma (IFN-gamma)] and Th2-type [interleukin (IL)-4, IL-5)] cytokine responses to influenza vaccine were evaluated. Intranasal immunization with influenza virus subunit vaccine plus cholera toxin/cholera toxin B subunit (CT/CTB) induced significant influenza virus-specific immunoglobulin G (IgG) antibody in the serum and nasal passages of both IgA(-/-) and IgA(+/+) mice, while IgA antibodies were induced only in IgA(+/+) mice.