Hereby we report the transfection performance of a new family of synthetic vehicles having spherical dendritic structures readily made and utilized in direct delivery of genes into cells and model animals. Besides their ease of preparation and storage they enjoy some unique advantages, eg they are inexpensive, inert, highly stable and easy to handle and apply compared with other existing synthetic vehicles for gene delivery (cationic lipids, dendrimers and liposomes). Data obtained thus far on cell cultures and animal models have irrevocabIy demonstrated their inertness as well as their impressive performance in easy, quick and direct transfections, which include: (1) Direct delivery of plasmid, pEcoRI-E (origin of replication of VZV) and pNN2 (containing HSV1 polymerase gene) into human kidney (G293, Vero) and hepatocyte (Huh7) cell cultures, by simply mixing each of these plasmids with the dendrosome for a very short period and exposing it to the target cell in culture. (2) Direct intramuscular (IM) or intradermal (ID) injection of mixture of a dendrosome with CMV containing the gene for hepatitis B surface antigen into BalbC mice. Here it is found that as a high a ratio of plasmid/dendrosome as 150 (or even higher in second and third injections) can be easily achieved, which elicits a quick and intense immune (antibody) response compared with common methods (eg 20% sucrose) or recombinant antigen vaccines.