Advances in vaccine delivery: transcutaneous immunisation

Needle-free delivery of vaccines has become a global priority. Transcutaneous immunisation (TCI), topical application of vaccine antigens to the skin, can elicit systemic antibody and T-cell responses, suggesting that this new technique may provide a means for vaccination without needles. TCI requires the use of an adjuvant such as cholera toxin added to a vaccine antigen, such as diphtheria toxoid, to induce antibodies to diphtheria toxoid. The adjuvant and antigen are thought to target Langerhans cells, potent antigen-presenting cells found in the superficial layers of the skin. TCI appears to be a highly practical technique for delivery of vaccines that provides unique access to the immune system.