Th2 Profile of Stimulated PBMC from Atopic Patients is Enhanced by C. Pneumoniae and is Switched to Th1 by Lactobacillus GG

Abstract

Chlamydophila pneumoniae (Cpn) is a respiratory obligate intracellular pathogen and a common cause of asthma exacerbations. Lactobacillus (L) is a beneficial normal gut flora containing a peptidoglycan cell wall which is structurally different from Cpn and can decrease allergic responses in patients with atopic dermatitis. We previously demonstrated Cpn increased Th2 cytokine and IgE production from PBMC of allergic asthmatics. We determined if a similar Th2 response is elicited with Lactobacillus stimulated PBMC from allergic asthmatics. PBMC samples (1x10^6) from allergic asthmatic patients (serum IgE+) were cultured for 1hr +/- Cpn TW-183 at a MOI=1, +/- anti-Toll Like Receptor (TLR) 2/4 or cultured for 24hr +/- Lactobacillus GG (1x10^6). The levels of cytokines (IL-2, IL-4, IL-6, IL-10, IL-12 and IFN gamma) and IgE in supernatants were determined (ELISA). Cpn stimulated PBMC from allergic asthmatic patients significantly increased IL-4 and IgE levels (p= 0.043, p<0.05 respectively) and levels of IL-10, IL-12, and IFN-gamma resembled those of controls (p= ns). Lactobacillus GG stimulated PBMC from allergic asthmatic patients significantly increased IL-10 and IFN gamma levels (p=0.003 and p= 0.043, respectively) and levels of IL-4 and IL-12 resembled those of controls (non-detectable and p=ns, respectively). Increased Th1 responses elicited by Lactobacillus may result, in part, from morphologic properties like the presence of peptidoglycan, absent in Chlamydia, which stimulates an innate immune response by binding to their allocated Toll-like receptors.