MODULATION OF SYSTEMIC CYTOKINE LEVELS BY IMPLANTATION OF ALGINATE ENCAPSULATED CELLS

The availability of cell lines that are transfected with IL-4, IL-5 an d IFN-gamma cytokine genes permits the prolonged in vivo delivery of f unctional cytokines in relatively large doses for the modulation of sp ecific immune responses. Often the transfected cells are xenogeneic or allogeneic to the experimental animal and have to be encapsulated in such a way that no cellular response by the host will be induced. Algi nate has proven to be a simple matrix for encapsulating cells under mi ld conditions suitable for in vivo implantation. Encapsulated cells ex press the transfected IL-4 gene for at least 14 days after in vivo imp lantation and were shown to be functional during that period by modula ting ongoing IgE responses. The application of adherent growing transf ected cells permits dose-response titrations and provides an easy meth od for local and systemic cytokine delivery. Alternatively, hybridoma cells can be encapsulated and the secreted antibody monitored in the s erum. It was found that no host immune response was triggered by algin ate encapsulated cells. The efficiency of treatment by encapsulated hy bridoma cells was shown to be equivalent to that of injecting purified antibodies.