Interestingly, the expressions of Gal-9 receptors (Tim-3, CD44, CD137, and PDI) were all significantly increased in both the lung and MLNs after infection; however, significantly increased expressions of CD137 and PDI in the lungs and CD44 and PDI in the MLNs were detected on day 5 and/or day 7 after α-lactose treatment (Fig. 6b). Here, CD44 is linked to infection.