Ig titres in sera of tumour-free BALB/c mice inoculated with empty NBPs (at doses equating to 0.2 mg kg -1 HerDox) twice per week for 4 weeks. Statistical significances determined using two-way multiple-comparisons ANOVA (95% CI) and Tukey post hoc test ( n = 3 mice per treatment group). Data are presented as mean ± s.d.
