The subject invention is directed to a mixed cell composition to generate
a therapeutic protein at a target site by providing a first population of
mammalian cells transfected or transduced with a gene that is sought to
be expressed, and a second population of mammalian cells that have not
been transfected or transduced with the gene, wherein endogenously
existing forms of the second population of mammalian cells are decreased
at the target site, and wherein generation of the therapeutic protein by
the first population of mammalian cells at the target site stimulates the
second population cells to induce a therapeutic effect.