Virus specific and polyclonal responses following challenge with influenzain immunised mice fed fish oil, linseed oil or beef tallow

Experiments were conducted to determine the effect of diets containing fish oil (providing long chain n-3 fatty acids), linseed oil (providing the sho rter chain n-3 fatty acid, alpha linolenic acid) or beef tallow (control di et) and different doses or routes of immunisation (oral, intra-peritoneal o r sub-cutaneous) on immunity to influenza virus in mice. Between diet group s there was no difference in virus clearance or influenza virus specific an tibody (serum immunoglobulin (Ig) G, lung IgG, lung IgA) for each route of immunisation. Between immunisation routes, intra-peritoneal immunisation wa s associated with the highest lung IgG after challenge while sub-cutaneous immunisation was associated with poorer virus clearance. Immunised mice fed linseed oil cleared more virus than non-immunised controls regardless of i mmunisation route. There was no difference in virus clearance or influenza specific antibody response between fish oil and beef tallow fed mice at eac h oral vaccine dose. Even at the lowest immunisation dose, with little anti body present, virus load was significantly lower than non-immunised control s suggesting a major contribution from cell mediated immunity. Total (polyc lonal) lung IgG was higher in orally immunised and non immunised beef tallo w fed mice and total lung IgA was higher in orally immunised beef tallow fe d mice although these differences were not associated with a difference in virus clearance. Splenocytes from orally immunised and non-immunised mice f ed fish oil had higher proliferative responses to Concanavalin A. The prese nt experiments demonstrate that fish and linseed oil diets do not impair in fluenza virus clearance in mice immunised by mucosal routes. (C) 1999 Elsev ier Science Inc.