Aerobic Exercise and Environmental Heat Stress as Adjuvants to Seasonal Influenza Vaccine

Abstract

Influenza strain diversity and variability and individual immune health contribute to reduced vaccine efficacy. Among adjuvants that enhance vaccine effectiveness, several studies have examined the relationship between acute exercise stress and influenza vaccination immune responses in humans. It is proposed that acute bouts of stress enhance immune response, but optimal intervention, timing of intervention, and mechanisms have yet to be identified. As Toll‐like receptor (TLR) agonists enhance innate immune responses and support development of chronic humoral responses, exercise induced release of the TLR4 ligand lipopolysaccharide (LPS) into circulation may be a mechanism for benefit of pre‐vaccine exercise. This study aimed to assess the effects of exercise and exercise‐heat stress completed before seasonal influenza vaccination (IV) on short‐ and long‐term immune responses. Thirty‐four males (body mass, 77.41±12.48kg; age, 21.5±4.4y; maximal aerobic capacity (VO2max), 43.53±8.24mL/kg/min) were randomized into 1 of 3 groups: no exercise (NE, n=12) or 60 minutes of 60%VO2max exercise with (MEH, n=11) or without (ME, n=11) environmental heat stress. Exercise and baseline blood samples were completed 25.11±5.92h before IV, and subsequent blood samples were collected 23.45±6.13h, 13.06±2.96d, and 29.54±3.73d following IV. Exercise environmental conditions were different between ME and MEH, respectively (average wet bulb globe temperature, 32.91±2.67°C, 41.21±2.88°C; p<0.001), but physiological stress was similar (average rectal temperature, 37.30±0.48°C, 27.61±1.36°C, p=0.513; heart rate, 114±105bpm, 118±105bpm, p=0.103) due to controlled exercise intensity. On‐going research will utilize hemagglutinin inhibition, cortisol, and LPS assays to quantify virus‐specific antibody responses, stress, and TLR4 activation respectively. Understanding innate and humoral responses will elucidate the potential of exercise and exercise‐heat stressors as adjuvants for IV.Support or Funding InformationNew investigator start‐up, InCHIP Interdisciplinary Seed GrantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.