Adoptive immunotherapy of experimental autoimmune encephalomyelitis via T cell delivery of the IL-12 p40 subunit.

CD4+ T cells are believed to play a central role in the initiation and perpetuation of autoimmune diseases such as multiple sclerosis. In the murine model for multiple sclerosis, experimental autoimmune encephalomyelitis, pathogenic T cells exhibit a Th1-like phenotype characterized by heightened expression of proinflammatory cytokines. Systemic administration of "regulatory" cytokines, which serve to counter Th1 effects, has been shown to ameliorate autoimmune responses. However, the inherent problems of nonspecific toxicity limit the usefulness of systemic cytokine delivery as a potential therapy. Therefore, we used the site-specific trafficking properties of autoantigen-reactive CD4+ T cells to develop an adoptive immunotherapy protocol that provided local delivery of a Th1 cytokine antagonist, the p40 subunit of IL-12. In vitro analysis demonstrated that IL-12 p40 suppressed IFN-gamma production in developing and effector Th1 populations, indicating its potential to modulate Th1-promoted inflammation. We have previously demonstrated that transduction of myelin basic protein-specific CD4+ T cells with pGC retroviral vectors can result in efficient and stable transgene expression. Therefore, we adoptively transferred myelin basic protein-specific CD4+ T cells transduced to express IL-12 p40 into mice immunized to develop experimental autoimmune encephalomyelitis and demonstrated a significant reduction in clinical disease. In vivo tracking of bioluminescent lymphocytes, transduced to express luciferase, using low-light imaging cameras demonstrated that transduced CD4+ T cells trafficked to the central nervous system, where histological analysis confirmed long-term transgene expression. These studies have demonstrated that retrovirally transduced autoantigen-specific CD4+ T cells inhibited inflammation and promoted immunotherapy of autoimmune disorders.

Antigen-specific T cell-mediated gene therapy in collagen-induced arthritis.

Autoantigen-specific T cells have tissue-specific homing properties, suggesting that these cells may be ideal vehicles for the local delivery of immunoregulatory molecules. We tested this hypothesis by using type II collagen-specific (CII-specific) CD4(+) T hybridomas or primary CD4(+) T cells after gene transfer, as vehicles to deliver an immunoregulatory protein for the treatment of collagen-induced arthritis (CIA), a mouse model of rheumatoid arthritis (RA). CII-specific T cells or hybridomas were transduced using retroviral vectors to constitutively express the IL-12 antagonist, IL-12 p40. Transfer of engineered CD4(+) T cells after immunization significantly inhibited the development of CIA, while cells transduced with vector control had no effect. The beneficial effect on CIA of IL-12 p40-transduced T cells required TCR specificity against CII, since transfer of T cells specific for another antigen producing equivalent amounts of IL-12 p40 had no effect. In vivo cell detection using bioluminescent labels and RT-PCR showed that transferred CII-reactive T-cell hybridomas accumulated in inflamed joints in mice with CIA. These results indicate that the local delivery of IL-12 p40 by T cells inhibited CIA by suppressing autoimmune responses at the site of inflammation. Modifying antigen-specific T cells by retroviral transduction for local expression of immunoregulatory proteins thus offers a promising strategy for treating RA.