Clearance of Pneumococcal Colonization in Infants Is Delayed through Altered Macrophage Trafficking
Fig 4
CCL2 overexpression increases macrophage recruitment and pneumococcal clearance.
(A-C) Mice were inoculated with a control (GFP-expressing) or a CCL2-expressing AAV5 vector at 4d of age, followed by pneumococcal colonization at 7d old. Seven and 21 days later, mice were sacrificed and nasal lavages were obtained with RLT lysis buffer. (A) RNA was isolated and cDNA reverse-transcribed, followed by qRT-PCR to measure the relative expression of Ccl2 in the upper respiratory tract, using primers Ccl2ORF-F and Ccl2ORF-R. ELISA was used to measure CCL2 protein levels in nasal lavage (B) and serum (C) at 7 and 21 dpi. (D) Mice were inoculated with a control (GFP-expressing) or a CCL2-expressing AAV5 vector at 4d of age, followed by pneumococcal colonization at 7d of age. Seven days later, mice were sacrificed, nasal lavages obtained and flow cytometry used to measure macrophage recruitment. (E) At 21d post-inoculation, nasal lavages were obtained and plated to measure the pneumococcal load in the nasopharynx. Data are represented as mean +/- SEM. n.s., not significant. * = p < 0.05, *** = p < 0.001. Dotted line, limit of detection.