EFFECTIVENESS OF LIPOSOMES AS ADJUVANTS OF ORALLY AND NASALLY ADMINISTERED TETANUS TOXOID

Tetanus toxoid was incorporated into liposomes composed of equimolar concentrations of distearoyl phosphadylcholine (DSPC) and cholesterol. We investigated the non-parenteral delivery Of free or liposome entrapped tetanus toxoid to guinea pigs and measured the subsequent IgG anti-tetanus-antibody response, using an ELISA. Liposome formulation significantly improved the immune response when compared to the free antigen when delivered via the nasal, oral and i.m. routes. However, 10 x concentration of tetanus toxoid entrapped in DSPC introduced mucosally (nasally and orally) was necessary to produce an IgG antibody titre similar to those obtained via the i.m. delivery. This study suggests that liposomes, administered through the oral and nasal routes, have considerable potential as mucosal adjuvants and warrant further investigation.