Studies on adjuvants for human prophylactics. II. Influence of the route of injection on the activity of adjuvants to tetanus toxoid in guinea pigs.

The effects of the route of the injection and adjuvants on the immune response of guinea pigs were investigated at various stages of immune response to tetanus toxoid. Delayed-type hypersensitivity (DH) was observed as the first immune response to the toxoid before initiation of antitoxin production. The DH reaction was weak when plain toxoid was administered subcutaneously. Water-in-oil in water (w/o/w) enhanced greatly the reactivity of the immunized animals; pertussis vaccine, endotoxin and aluminium showed adjuvanticities in this order. The foot pad (fp) injection of plain toxoid promoted remarkably the induction of DH. The reactivity was enhanced considerably by w/o/w and to a less extent by aluminium. However, pertussis vaccine showed an adverse effect on DH by the fp route. Active cutaneous anaphylaxis (ACA) induced by the subcutaneous route was enhanced by w/o/w, endotoxin, pertussis vaccine and, to a less extent, by aluminium. The fp route compared with the sc route enhanced ACA by plain toxoid; w/o/w and aluminium but not endotoxin and the vaccine showed adjuvanticities. The influences of adjuvants and the route of injection on Arthus reactions were inconsistent. The effect of adjuvants on antitoxin production was quite different from that on DH when antitoxin was produced abundantly. Aluminium showed consistently a potent adjuvanticity, but activities of w/o/w, endotoxin and pertussis vaccine were inconsistent 4-6 weeks after the primary stimulus by the subcutaneous route. The adjuvant effect became less significant in the secondary response. The fp route was more favorable for antitoxin production than the subcutaneous route with most adjuvants except pertussis vaccine added to tetanus toxoid. Antitoxin production by plain toxoid was very poor when administered intraperitoneally; aluminium and w/o/w but not endotoxin showed a remarkable adjuvanticity for the antitoxin production.