The differences in BAL neutrophils are not explained by differences in B6 and lpr neutrophil chemotaxis An impairment in lpr neutrophil chemotaxis towards KC could explain the attenuation of BAL neutrophils seen in the lpr mice exposed to MV + LPS. Therefore, we compared the chemotactic ability of neutrophils isolated from B6 and lpr mice to KC in vitro. However, we noticed no impairment of chemotaxis in the lpr neutrophils; if anything, chemotaxis was slightly increased in the lpr neutrophils as compared with the B6 neutrophils ( Figure 6 ).