CCR2 and infection: Other studies used a relatively low dose of 2 x 102 LVS administered intranasally (IN), which apparently was not lethal for CCR2 KO mice [19]; morbidity was not explicitly discussed, but the IN LD50 of LVS in C57BL/6J mice is typically about 103–5 x 103 CFU, and therefore those data imply that the susceptibility of CCR2 KO mice to IN LVS infection is not different from wild type mice.