Abstract: The present invention relates generally to the field of tissue modification, and in particular, but not exclusively, to methods of modifying cells of ocular and particularly corneal tissue to produce immunoglobulins or immunoglobulin fragments. The invention also relates to modified ocular cells and tissues, to expression vectors utilised in such methods, to methods of xeno- and allo-transplantion using the modified tissue and to methods of therapy of ocular diseases and disorders. In a preferred embodiment of the invention there is provided a method of modifying cells of ocular tissue to produce an immunoglobulin or immunoglobulin fragment of interest, which comprises exposing ocular tissue to an effective concentration for transfection of an expression vector comprising a nucleotide sequence encoding for the immunoglobulin or immunoglobulin fragment, for a period sufficient to allow transfection, such that cells of said ocular tissue produce the immunoglobulin or immunoglobulin fragment.