Evaluation of the immune responses after the administration of recombinant <i>L. casei</i> in Balb/c mice.

<p>Mice were immunized orally or intranasally with PBS, pgsA/<i>L. casei</i>, pgsA-sM2/<i>L. casei</i> or pgsA-CTA1-sM2/<i>L. casei</i> at 0 to 3, 7 to 9 and 21 to 23 days orally or 0 to 3, 7 to 9 and 21 days intranasally. Sera were collected on days 0, 14, and 28. Mouse lungs and intestines were collected at day 28. (A and B) The absorbance of the IgG antibodies specific to the sM2 (left) and CTA1 (right) proteins in the intranasal (top) and oral (bottom) groups. (C and D) The absorbance of the IgA antibody specific to the sM2 protein in the lungs (left) and intestines (right) in the intranasal (top) and oral (bottom) groups. Serum IgG, lung IgA and intestinal IgA were investigated by ELISA and measured at an absorbance of 450_nm. Bars denote mean ± S.D. The asterisk indicates a significant difference between pgsA-CTA1-sM2/<i>L. casei</i> and other groups (*<i>P</i><0.05).