TLR4 and tuberculosis: To test our hypothesis that reducing the particle size of alum would augment its synergy with a TLR4 agonist to promote TH1 immunity, we immunized C57BL/6 mice twice (prime and boost 3 weeks apart) with the recombinant TB vaccine antigen ID93 alone or adjuvanted with Alhydrogel or PAA:nanoalum in presence or absence of the synthetic TLR4 agonist SLA.