Evaluation of the effects of skin ultraviolet light exposure on BCG vaccination effectiveness.

CAMPO, V; FRIEDRICH, A; MANUELLI, P; PAZ, M; LEONI, J; GONZÁLEZ MAGLIO, D

Congreso; IV LASID Meeting; LXIII Argentinean Immunology Society Meeting; II French-Argentinean Immunology Meeting; 2015

It is well known that ultraviolet radiation (UVr) leadsto immunosuppression, inhibiting contact hypersensitivity (CHS) reactions. However, the way UVr modulates immune responsesagainst microorganisms and vaccines has been poorly explored. Previously, wehave found that a single high UV dose (shUVd - 400 mJ/cm2) promotesskin inflammation while it decreases CHS, in contrast to repetitive low UVdoses (rlUVD - 4 consecutive days, 20 mJ/cm2) which does not induceinflammation and increases CHS.Our aim was to evaluate the effect of both types ofirradiation on BCG vaccination effectiveness in vivo.SKH:1 hairless mice were irradiated and 24h later immunizedwith intradermal BCG (1x106 CFU). Non-irradiated mice andnon-vaccinated mice were used as control. Four weeks after vaccination, delayed-typehipersensitivity (DTH) reactions were evaluated and mice were bled andsacrificed. Cell proliferation and cytokine production were determined in vitro stimulating spleen cells with 40µg/ml of BCG lysate. DTH reaction and specificIgG antibodies were slightly, but not significantly, increased in shUVd exposedanimals compared with rlUVd ones (1.6 vs 1.1 mm and 0.92 vs 0.67 units of OD492nm). In vitro T cellproliferation had no differences between groups, but IL-4 production wasincreased in rlUVd exposed animals compared with shUVd ones (19.2 vs 6.3 pg/ml;p<0.05).These results show that UVr is able to modulate immuneresponses to vaccination, while the impact in the response may depend on the vaccinepotency. Further studies should be done in order to elucidate effects on othertypes of vaccines.