Suppression of Murine Lupus by CD4+and CD8+Treg Cells Induced by T Cell-Targeted Nanoparticles Loaded With Interleukin-2 and Transforming Growth Factor β

Objective. To develop a nanoparticle (NP) platform that can expand both CD4+ and CD8+ Treg cells in vivo for the suppression of autoimmune responses in systemic lupus erythematosus (SLE). Methods. Poly(lactic-co-glycolic acid) (PLGA) NPs encapsulating interleukin-2 (IL-2) and transforming growth factor beta (TGF beta) were coated with anti-CD2/CD4 antibodies and administered to mice with lupus-like disease induced by the transfer of DBA/2 T cells into (C57BL/6 x DBA/2)F-1 (BDF1) mice. The peripheral frequency of Treg cells was monitored ex vivo by flow cytometry. Disease progression was assessed by measuring serum anti-double-stranded DNA antibody levels by enzyme-linked immunosorbent assay. Kidney disease was defined as the presence of proteinuria or renal histopathologic features. Results. Anti-CD2/CD4 antibody-coated, but not noncoated, NPs encapsulating IL-2 and TGF beta induced CD4+ and CD8+ FoxP3+ Treg cells in vitro. The optimal dosing regimen of NPs for expansion of CD4+ and CD8+ Treg cells was determined in in vivo studies in mice without lupus and then tested in BDF1 mice with lupus. The administration of anti-CD2/CD4 antibody-coated NPs encapsulating IL-2 and TGF beta resulted in the expansion of CD4+ and CD8+ Treg cells, a marked suppression of anti-DNA antibody production, and reduced renal disease. Conclusion. This study shows for the first time that T cell-targeted PLGA NPs encapsulating IL-2 and TGF beta can expand both CD4+ and CD8+ Treg cells in vivo and suppress murine lupus. This approach, which enables the expansion of Treg cells in vivo and inhibits pathogenic immune responses in SLE, could represent a potential new therapeutic modality in autoimmune conditions characterized by impaired Treg cell function associated with IL-2 deficiency.