Figure 4.

TLR4 agonist MPL cannot compensate for lack of T-cell help in terms of antibody affinity, IgG isotype induction or protection from spontaneous tumor development. BALB-neuT mice (n = 3–5 per group) were vaccinated with either rED44Her2 or rED44Her2-FrC, in alum or in combination with alum plus MPL. Serum was taken after priming, at week 3, or after boosting, at week 5. (A) Anti-rED44Her2 antibody levels measured by ELISA. (B) IgG antibody affinity from week 3 samples was measured by a chaotropic ELISA, and the affinity index calculated. (C) Levels of IgG isotypes were measured from serum samples taken at week 5. Medians are plotted, with Mann–Whitney statistics shown. Ns = p > 0.05, *p < 0.05, **p < 0.01, ***p < 0.001. (D) Survival of BALB-neuT mice from the spontaneous development of mammary tumors was followed after the above vaccination protocol. Mice were culled when total mean diameter of the tumors reached 15 mm. Log-rank (Mantel–Cox) statistics shown. Ns = p > 0.05, *p < 0.05. Due to the limited number of BALB-neuT mice available, results from two experiments showing the same trends have been combined in (A), (B), (C) and (D).