Figure 6. IgFc receptors on basophils are essential for antibody-mediated, protective immunity against ticks.

(A) The CD49b⁺ basophil–enriched fraction of splenocytes from C57BL/6 mice infested only once (sensitized) or never (naive) was adoptively transferred into naive, uninfested C57BL/6 mice, and 2 hours later, the recipient mice were infested with ticks. The relative tick repletion for each group is shown. The value for the control, vehicle-treated mice was defined as 100%. Data are shown as mean ± SEM, n = 3 each. (B) The basophil-enriched fraction of splenocytes from DT- or PBS-treated Mcpt8^DTR mice that had been infested once was adoptively transferred into naive, uninfested littermate control mice. The recipient mice were then infested, and the relative tick repletion is shown as in A. Data are shown as mean ± SEM, n = 3 each. (C) The basophil-enriched fraction of splenocytes from wild-type or Fcer1g^–/– mice that had been infested once was adoptively transferred into naive, uninfested C57BL/6 mice, which were then infested. The relative tick repletion is shown as in A. Data are shown as mean ± SEM, n = 3 each. Data shown in A–C are representative of at least 3 repeated experiments. **P < 0.01.