Figure 2. Recruitment of basophils to tick-feeding sites during the second, but rarely the first, infestation.

(A) C57BL/6 mice were infested with ticks as in Figure 1. Tick-feeding–site skin lesions were isolated at the indicated time points during the first and second infestations and subjected to semiquantitative RT-PCR analysis (PCR templates were 5-fold serially diluted) for the expression of basophil-specific Mcpt8, mast cell–specific Mcpt4, and housekeeping Hprt1 transcripts. (B) Skin lesions caused by tick feeding were isolated at the indicated time points during the first (black circles) and second (white circles) infestations and subjected to flow cytometric analysis. Changes in the number of basophils during the infestations are shown. Data are shown as mean ± SEM, n = 3 each. (C) Tick-feeding–site skin lesions were isolated 18 hours after the initiation of the first or second infestation and subjected to immunohistochemical examination using anti–mMCP-8 or an isotype-matched control antibody. mMCP-8–expressing basophils were stained in brown. Scale bars: 100 μm. Data shown in A–C are representative of at least 3 repeated experiments.