Jornal de Alergia e Terapia

Abstrato

Exposure to Human Herpes Virus Type 6 Protects Against Allergic Asthma in Mice

Alexandra Svensson*, Nina Almqvist, Annie George Chandy, Inger Nordström and Kristina Eriksson

We have previously shown that infection with Human Herpes Virus (HHV)-6 during the first 18 months in life protects against IgE sensitization and Th2 driven immunity. The aim of this study was to investigate if exposure to HHV-6 affects the allergic response and the adaptive immunity in vivo. For this purpose, a well known mouse model of ovalbumin (OVA)-induced allergic asthma was used. BALB/c mice were OVA sensitized and exposed to HHV-6 intraperitoneal on two occasions, followed by intranasal challenge with OVA on five consecutive days one week after the second sensitization. 24 hours after the final OVA exposure, serum, bronchoalveolar lavage (BAL) and lung-tissue were collected. We show that mice exposed to HHV-6 have significantly lower frequency of OVA-specific IgE compared to control mice. This was associated with significantly reduced numbers of inflammatory cells and eosinophils in the BAL fluid of HHV-6 exposed mice. HHV-6 exposure also significantly inhibited the production of IL-4, IL-5 and IL-13 in the BAL fluid and in the lung tissue of the virus exposed mice. In conclusion, we suggest that exposure to HHV-6 protect against allergic asthma in mice, by limiting the Th2-driven inflammation.