This work aimed at the development of targeted drug delivery systems using nanoparticles fused with antibodies. The antibody anti-human CD8 was coupled onto PLGA nanoparticles, and the ability of these particles to specifically target cells expressing CD8 was studied. The obtained particles were found to be of spherical shape exhibiting a size between 350 and 600 nm. In vitro experiments with different cellular cultures (TE671, CHO and HEK293) using unmodified nanoparticles containing rhodamine have shown that particles were present on their surface within 48 h of incubation. In vitro tests using anti-CD8 conjugated nanoparticles in CHO cell cultures indicated that all transfected cells which express CD8 show these particles on their surface within 1 h of incubation. These results demonstrated that, in a shorter time, the produced particles can target cells expressing CD8 on their surface which offers the ability to reduce drug side effects. The antibody-coupled nanoparticles represent a promising approach to improve the efficacy of active targeting for lymphoblastic leukaemia therapy. (C) 2010 Elsevier B.V. All rights reserved.