Abstract

Introduction Prolonged exercise significantly reduces both the induction and elicitation of in vivo cell-mediated immune responses (Harper-Smith et al., 2011). The aim of this study was to investigate the effects of bovine colostrum (COL) supplementation on the in vivo cell-mediated responses to Diphenocyclopropenone (DPCP) following prolonged exercise. Methods In a double-blind design, 28 male participants were randomly assigned to either a COL (20 g a day) (n=14) or placebo (PLA) (isoenergetic/isomacronutrient supplement) (n=14) group for 87 days following stratification for age and aerobic fitness only. Exactly 28 days into supplementation, participants took part in 2 h of running at 60% of maximum oxygen uptake. Within 20 min of exercise completion, all participants were sensitised to DPCP using a
single patch applied to the mid-lower back for 48 h. Following the induction of immune-specific memory (sensitisation), participants reported to the laboratory 28 days later for a dose series of DPCP patches to be applied in a randomly allocated order to the volar aspect of their right upper arm for 6 h. Participants returned to the laboratory 24 h and 48 h following the application of patches for skin responses (oedema) to be measured (to the nearest 0.1 mm) at each DPCP patch site using modified skinfold calipers. Results There was no difference in total oedema responses (sum of all skinfold sites) between COL and PLA (p > 0.05). In accordance with Harper-Smith et al.(2011), analysis of the dose response curves allowed for the minimum dose (threshold) for a positive response in each group to be determined
(i.e. sensitivity). The minimum dose for PLA was 2.0 and 2.1 fold greater than COL at 24 h and 48 h respectively (i.e. greater sensitivity in COL). There was a greater response in COL at 24 h for the lowest DPCP dose (p < 0.05), but not at 48 h or with other doses at eithertimepoint (p > 0.05). Discussion There was no apparent effect of COL supplementation on the magnitude of cutaneous immune responses (summed skinfold responses) at recall (4 weeks following initial sensitisation to DPCP). The study does, however, suggest that COL enhances sensitivity of the recall of antigen-specific memory. This may support previous evidence from our laboratory where COL has been shown to act as a nutritional countermeasure to prolonged exercise and decrease susceptibility to illness (Davison and Diment,
2010; Jones et al., 2013). References Davison, G, Diment B. (2010). Br J Nutr, 103, 1425–1432. Jones, AW, Cameron SJS, Thatcher R, Beecroft M, Mur LAJ, Davison G. (2013). Brain Behav Immun, doi.org/10.1016/j.bbi.2013.10.032 Harper-Smith AD, Coakley SL, Ward MD, Macfarlane, AW, Friedmann, PS, Walsh NP. (2011). Brain Behav Immun, 24, 1136-1145.