Problems with the use of liposome- and retrovirus-mediated gene transfer methods in the primary lymphoid cells of the Oka organs of the greasyback shrimp, Metapenaeus ensis (De Haan, 1844)

In this study, both liposome- and retrovirus-mediated gene transfer methods were examined for their potential to transfer and express two retroviral vectors containing the mouse c-Myc or the green fluorescent protein ( GFP ) gene into the primary lymphoid cell cultures (OKA) derived from “Oka” organs (= organs of the lymphoid system) of the greasyback shrimp Metapenaeus ensis (De Haan, 1844). It was found that the c-Myc gene could be delivered into OKA cells by the liposome-mediated method, but the introduced c-Myc gene could not be effectively transcribed into mRNA. In contrast, the pantropic retrovirus-mediated method failed to introduce the c-Myc gene into OKA cells, and GFP was not detected in the transformed cells, either. This work inferred two problems for the use of the two above-mentioned gene transfer methods in the non-dividing OKA cells: (1) the viral promoter of long terminal repeats (LTRs) had low activity in shrimp cells; (2) the pantropic retrovirus-mediated gene transfer system had a low tropism to shrimp lymphoid cells.