CCL28 is a recently identified chemokine ligand for CCR10 and CCR3 that has been identified in mucosal epithelial surfaces in diverse tissues. CCL28-mediated eosinophil chemotaxis and peroxidase release were inhibited by preincubation of cells with anti-CCR3. CCL28 was constitutively expressed in lung tissue collected from nonsensitized control mice but increased levels were found in mice sensitized and rechallenged with cockroach antigen (CRA). CCL28 levels peaked in the lungs 24 hours after intratracheal challenge with CRA, whereas eotaxin expression peaked at 8 hours. Increased expression of CCR3 but not CCR10 could be detected during the induction of the CRA-induced pulmonary inflammation. To investigate the role of CCL28 in allergic airway responses, mice were treated with CCL28 antiserum 1 hour before receiving the final CRA challenge. The level of airway hyperresponsiveness in mice treated with anti-CCL28 was significantly reduced at 24 hours, but not 8 hours, compared to mice receiving control serum. This reduction was not related to decreased Th2 cytokine, chemokine, or leukotriene levels at 24 hours although peribronchial eosinophilia was significantly reduced. Thus, CCL28 appears to play a role in regulating eosinophil recruitment to peribronchial regions of the lung possibly by coordinated temporal production with eotaxin.