APOB and infection: To validate this hypothesis, A/J and C57BL/6 mice were treated with 4-aminopyrazolopyrimidine (4-APP), a drug that impairs low-density lipoprotein secretion44, and subsequently infected intravenously with S. aureus. Whereas inhibition of ApoB rendered C57BL/6 mice more susceptible to S. aureus, demonstrated by the significantly higher bacterial loads in kidneys at 48 h infection (P-value<0.05, t-test), (Fig. 5d), it did not affect the level of susceptibility of A/J mice (Fig. 5d).