Peak titers induced by immunization at (A) low, and (B) high doses of model antigen (BSA). Peak titers for all microparticle formulations occurred at week 4 while both bolus injection groups peaked at week 10. NS represents not significant when using a Student’s t-test with Holm-Bonferroni correction for multiple comparisons at a significance level of 0.05. Adjusted p values for Formulations C, G, and E are 0.065, 0.054, and 0.078 respectively.