Suppression of the lymphoproliferative response by positively charged liposomes.

The efficiency of positively-charged liposomes as immunomodulators was investigated in vitro using a lymphoproliferative response assay on cultured human lymphocytes challenged either with different polyclonal activators or with actin, a cytoskeletal protein of poor immunogenicity. Our results indicate that these liposomes suppress the [3H]thymidine incorporation in lymphocyte cultures and inhibit the mitogen-induced proliferation without, however, exhibiting significant cytotoxicity.