6–9.8) for 45 min at 4 °C

and washed four times before samples were applied. Sera were applied in serial two-fold or triple-fold dilutions and a mouse control serum sample positive for A/Sidney/5/97 or A/Beijing/262/95 H1N1 was included on each plate. For detection of SIgA, 100 µl of the lavage was used undiluted in the first well and subsequently serial two-fold diluted. The plates were incubated for 1.5 h at 4 °C, washed 3 times and incubated for 1 h at 4 °C with anti-mouse Ig-HRP conjugates (Southern Biotech). After incubation, the plates were washed 3–4 times and incubated for 30 min with BGB324 cell line 100 µl staining solution (1 tablet of OPD (o-Phenylenediamine dihydrochloride) dissolved in 100 ml 0.05 M phosphate-citrate buffer pH 5.0

and 40 µl H2O2). After incubation the reaction was stopped by adding 50 µl 2 M H2SO4 per sample and the absorbance was determined at 492 nm. The IAV-specific IFN-? T-cell and IAV-specific B-cell response in the spleen and local draining cervical lymph nodes (CLN) or inguinal lymph nodes (ILN) after i.n. BLP-SV or i.m. SV vaccination, respectively, was assessed by ELISPOT. For detection of IAV-specific Dabrafenib purchase B-cells, cells were directly cultured in high protein binding filter plates (MultiScreen-IP, Millipore) that were pre-coated with Vaxigrip® suspension for injection: strains 2009/2010, Sanofi Pasteur MSD, lot: E7068 at 1 µg per well dissolved in 50 µl of PBS. For detection of IAV-specific IFN-? T-cells, cells were cultured in the presence of HA antigen or IMDM (Gibco, Invitrogen) medium as a control that was supplemented with heat-inactivated 5% FCS (Bodinco,

The Netherlands), 5 × 10-5 M 2-mercaptoethanol, penicillin (100 units/ml) and streptomycin (100 µg/ml) (Gibco, Germany) for 72 h at 37 °C in high protein binding filter plates (MultiScreen-IP, Millipore) that were pre-coated with a rat anti-mouse IFN-? monoclonal antibody (clone AN-18, purchased at BD Biosciences, Pharmingen) at below 0.1 µg per well dissolved in 50 µl of PBS for 48 h at 37 °C. After incubation, spot forming units of IAV-specific B- and T-cells were detected with goat-anti-mouse IgG-biotin (Sigma) and Avidin-AP (Sigma). Plates were developed with NBT-BCIP (Roche) and analyzed by using the Aelvis spotreader and software. Data are shown as IAV-specific IFN-? T-cell or the IAV-specific B-cell count per 106 cells above background. Single cell suspensions were prepared from spleen and draining lymph nodes and cells were cultured for 72 h in the presence of ConA at 2.5 µg/ml or IMDM (Gibco, Invitrogen) at 37 °C. Analyzing the culture supernatants assessed the amount of cytokine secreted during a 72 h T-cell re-stimulation. Briefly, fluoresceinated microbeads coated with capture antibodies for simultaneous detection of IL-17A (TC11-18H10) and IL-5 (TRFK5) were added to 50 µl of culture supernatant. Cytokines were detected by biotinylated antibodies IL17 (DuoSet ELISA kit, R&D systems Europe Ltd, the U.K.