Claudia Rasche, Christin Wolfram, Michael Wahls, Margitta Worm
DOI: 10.2340/00015555-0232

Bacterial stimulation plays an important role in modu­lating the allergic immune response. The aim of this study was to investigate the effects of inactivated probiotic Lacto­bacillus acidophilus and non-pathogenic Escherichia coli strain Nissle on the phenotype and function of T- and B-cells. Peripheral blood mononuclear cells from patients with grass-pollen allergy (n = 10) and non-allergic patients (n = 19) were co-stimulated with inactivated bacteria and grass-pollen allergen. Expression of CD23, CD80, CD86 and CD69 were analysed, and the intracellular production of interleukin-4 and interferon-γ was measured by direct ex vivo flow cytometry after stimulation. Both bacteria induced a significant up-regulation of CD69 expression on T-lymphocytes (p = 0.001). CD23 expression was significantly increased following stimulation with allergen (p = 0.008), but reduced after stimulation with Lactobacillus and significantly reduced with E. coli plus allergen (p = 0.029). CD80 expression was reduced after stimulation with Lactobacillus in the allergic group only (p = 0.021). By contrast, CD86 expression was significantly increased after stimulation with Lactobacillus (p = 0.049) and distinctly increased with E. coli in both groups (p = 0.001). The cytokine patterns of CD69-positive T-lymphocytes from allergic patients showed a TH2-dominated response after allergen stimulation (interferon-γ/interleukin-4-ratio 0.2), directed into a T-helper1-like response by stimulation with both types of bacteria (interferon-γ/interleukin-4-ratios 1.5–2.0 in both groups). These data show that both types of bacteria modulate the allergic immune response by the alteration of CD23 and co-stimulatory molecule expression. Regarding cytokine production, the data suggest a differential response to both bacteria depending on the atopic state, but a clear promotion of T-helper1-dominated response in allergic donors.