SL immunization with DelNS1 vaccine activates mucosal and extramucosal CD4+ T cells.

<p>CFSE-labeled CD4⁺ T cells from HA-TCR transgenic mice were adoptively transferred into naïve mice. One day later, recipients were given SL 2×10⁷ pfu of Delta H1N1, 2×10⁵ pfu of mouse-adapted wt live or 40 µg of formalin-inactivated A/PR8. Three days after the immunization, proliferating (CFSE stained) HA-TCR CD4⁺ T cells were detected in cervical lymph nodes (CLN), lungs, mediastinal lymph nodes (MdLN) and spleens by FACS analysis. The data are representative of two experiments showing similar results.</p

Induction of homotypic and HSI upon immunization with Delta H1N1.

<p>BALB/c mice were immunized IN or SL with different doses of Delta H1N1 (▴H1N1), given once (1x) or twice (2x) at 2-week intervals. Four weeks later, animals were intranasally challenged with 5×LD₅₀ of homologous mouse-adapted A/PR8 (Fig. 3A) or heterosubtypic mouse-adapted A/Philippines (A/P) H3N2 (Fig. 3B) virus. Morbidity and mortality were monitored daily. Data are expressed as mean (body weight or % survival) determined on groups of 5–10 mice.</p

Induction of HI Abs upon immunization with Delta H1N1.

<p>On the day before challenge as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039921#pone-0039921-g003" target="_blank">Figure 3</a>, the sera were collected and the titers of HI Abs were determined against A/PR8 virus. The values represent the mean + SEM antibody titers of sera from 5 mice per group.</p

Levels of virus-specific IgA induced in mucosal and systemic compartments upon immunization with DeltaNS1 IAV.

<p>BALB/c mice were immunized as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039921#pone-0039921-g006" target="_blank">Figure 6</a>. Four weeks later, titers of H1N1 (A/PR8) virus-specific IgA in sera and secretions were determined by ELISA. The values represent mean + SEM ELISA titers determined on groups of 5 mice.</p

Levels of virus-specific IgG induced in mucosal and systemic compartments upon immunization with DeltaNS1 IAV.

<p>BALB/c mice were immunized with different doses of Delta H1N1 (▴ H1N1) or wt live virus A/PR8/34 (PR8) H1N1 (WT) via the sublingual (SL) or intranasal (IN) route. Four weeks later, titers of H1N1 (A/PR8) virus-specific IgG in sera and secretions were determined by ELISA. The values represent mean + SEM ELISA titers determined on groups of 5 mice.</p

Induction of virus-specific IgG and IgA upon immunization with Delta H5N1.

<p>BALB/c mice were immunized with different doses of Delta H5N1 (▴ H5N1) or wt live virus A/PR8/34 (PR8) H1N1 via the sublingual (SL), nasal (N) or intranasal (IN) route. Four weeks later sera were collected and the levels of H5N1 virus-specific IgG and IgA were determined by Delta H5N1 virus-coated ELISA plates. The values represent the mean + SEM (vertical bars) end point ELISA antibody titers determined on 5 mice per group.</p

Induction of virus-specific Abs upon immunization with Delta H1N1.

<p>On the day before challenge as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039921#pone-0039921-g003" target="_blank">Figure 3</a>, the sera were collected and the titers of virus-specific Abs were determined by A/PR8 virus-coated ELISA plates. The values represent the mean + SEM antibody titers of sera from 5 mice per group.</p