Oral adjuvants for viral vaccines in humans.

The availability of various viral vaccines prompted extensive studies on oral adjuvants. In this study, parotid protein (parotin), taurine and lithium were chosen as safe and potent oral adjuvants for rubella and influenza virus vaccines. The anti-rubella virus antibody titres in persons administered orally with parotin were significantly higher than those of persons with the non-adjuvanted vaccines. The combinations of oral adjuvants were used for vaccination with trivalent influenza vaccines. Each group, receiving taurine, taurine + lithium, taurine + parotin or taurine + parotin + lithium, was higher in the magnitude of increased influenza virus antibody titres than the non-adjuvant control group. Although taurine was shown to be an effective adjuvant in taurine responders but not in taurine non-responders, the combination of taurine, lithium and/or parotin gave higher increased rate of influenza antibody titres than with taurine alone. These results have shown to be a valuable approach to the clinical use of oral adjuvants.