Incorporation of the reovirus M cell attachment protein into small unilamellar vesicles: incorporation efficiency and binding capability to L929 cells in vitro.

Neutral phosphatidylcholine/cholesterol (10 : 3) liposomes with the reovirus M cell attachment protein sigma 1 were made by means of detergent dialysis method. An immunological evaluation method revealed an incorporation efficiency (pg protein/microgram lipid) of 314. Binding studies with mouse fibroblasts (L929 cells) yielded a 10 fold improvement of uptake of coated liposomes compared to uncoated liposomes. Competition studies with reovirus serotype 3 demonstrated that coated liposomes were capable of binding to the reovirus receptor. In vitro incubation of rat Peyer's patches with either coated or uncoated liposomes resulted in a 10-20 fold higher uptake of the coated liposomes. These results suggest that selective adherence of a carrier system to M cells may facilitate delivery of carrier contents to mucosal underlying lymphoid tissue, thereby enhancing immune response.