CD8A and viral infectious disease: These data together with our previous findings [23,24,80] suggest that when pre-poised in the respiratory tract as in the allergic setting, eosinophils may directly neutralize virus (perhaps by piecemeal degranulation), become activated in response to virus infection permitting their retrograde migration out of the lungs into the draining lymphoid organs where they can interact with CD8+ T cells in an antigen-specific manner (Figure 7).