Effects Of Acute Eccentric Exercise On Primary Antibody Responses To Ovalbumin Vaccination In Aged Mice.

Abstract

Several studies have suggested that acute eccentric exercise can enhance vaccination responses in humans. However, the underlying mechanisms have remained understudied. We have shown that acute eccentric exercise does not improve the antibody responses to ovalbumin (OVA) vaccination in young mice. Thus, we replicated the study in an immunosenescence animal model, where there is reduced vaccine efficacy. PURPOSE: To determine the effects of acute eccentric exercise on the primary antibody response to vaccination in aged mice. METHODS: C57BL/6 male mice, aged 27 months (n=16) were randomized into either eccentric exercise (ECC, n=8) or sedentary (SED, n=8) groups. For the ECC group, mice were exercised at 17m/min at -20% grade for 45 min on a treadmill. SED mice remained in their home cages. All mice were inoculated in the gastrocnemius with 25 μg of OVA and 200 μg aluminum hydroxide (a suboptimal dosage based on titration experiments) in 50 μl sterile saline immediately after the exercise. Blood was collected prior to, and one, two and four weeks after vaccination. ELISA was performed to analyze anti-OVA IgG. At three weeks post exercise, all mice were injected with 100 μg OVA dissolved in 10 μl PBS into the dorsal side of the right ear to determine the delayed-type hypersensitivity (DTH) response. The left ear received 10 μl PBS alone as a control. Ear thickness was measured immediately before, 24 h and 48 h after intradermal injection. The measurements were performed in triplicate, where researchers were blinded to treatment. Maximum ear swelling occurred at 24 hours post injection. Results were expressed as the difference between the right and left ear thickness. RESULTS: We found a significant time main effect (p<0.001) indicating a significant increase in anti-OVA IgG at one, two and four weeks relative to pre-immunization. However, there were no significant time x treatment (p=0.652) nor treatment main effects (p=0.764). There was a significant difference between ECC and SED groups in ear DTH at 24 h post injection (p = 0.028), indicating eccentric exercise increased the DTH response. CONCLUSION: Acute eccentric exercise immediately before vaccination improved the DTH (i.e. cell-mediated immune), but not the antibody, response to vaccination in aged mice.