Humoral and cellular immune responses in different rat strains on oral exposure to ovalbumin

No adequate enteral sensitization models are available to study food allerg y and allergenicity of food proteins. Using a previously described oral sen sitization protocol to sensitize Brown Norway rats (BN) to food proteins, t he influence of genetically-based strain-specific characteristics of the im mune system on the outcome of oral sensitization studies was investigated. BN, Hooded Lister (HL), Piebald Virol Glare (PVG) and Wistar rats were dail y administered 1 mg of ovalbumin (OVA) by gavage dosing for 42 days without the use of an adjuvants. The highest OVA-specific IgG responses were detec ted in the BN rats followed by Wistar, HL and PVG rats. OVA-specific IgE re sponses were only detectable in the BN rats. The cellular immune response w as examined by determination of delayed-type hypersensitivity (DTH) reactio ns in the animals. The response was most pronounced in the HL and Wistar ra ts. PVG and BN rats showed comparable DTH responses but the responses were significantly weaker than those observed in HL and Wistar rats. It was conc luded that the genetic make-up of different rat strains influences the outc ome of oral sensitization studies. In addition, using the described oral se nsitization protocol, the BN rat seems to be the most suitable strain for i nducing oral sensitization. (C) 1999 Elsevier Science Ltd. All rights reser ved.