Differential OVA-induced pulmonary inflammation and unspecific reaction in Dark Agouti (DA) rats contingent on CD26/DPPIV deficiency

Abstract

Many disease models have shown that, within the species rat, different strains are differentially susceptible to asthma-induced inflammation depending on the genetic background. Likewise, CD26/DPPIV-deficiency in asthmatic F344 rats has been shown to result in a less pronounced inflammation and in increased Treg cell influx into the lung compared to wild-types. The aim of the present study was to investigate whether the genetic background of the animals interferes with CD26/DPPIV-deficiency in a model of allergic-like inflammation, or whether the deficiency per se is the predominant regulator of the inflammation. Therefore, we hypothesised that CD26/DPPIV-deficient Dark Agouti (DA) rats also exhibit a less pronounced ovalbumin (OVA)-induced inflammation compared to wild-types.After sensitisation with OVA, Al(OH)3 and heat-killed Bordetella pertussis bacilli, animals were challenged three times with 5% aerosolized OVA at intervals of 24h, i.e., on three consecutive days. 24h after the third challenge, animals were sacrificed and examined. In both wild-type and CD26/DPPIV-deficient rat groups, asthma induction led to (1) lung inflammation, (2) significantly increased eosinophil infiltration in the BALF, (3) significantly increased IgE serum levels, (4) a significant increase of inflammatory cytokines, (5) a significant increase of different T cell populations in the lungs and in their draining lymph nodes, as well as to (6) a significantly higher number of all T lymphocyte subtypes in the blood. Thus, the degree of the OVA-induced Th2-driven pulmonary inflammation was similarly pronounced in both wild-type and CD26/DPPIV-deficient DA rats.