Indeed, with Cry1Ac the response recorded in NALT is higher than those reported after immunization with CT B-subunit [18], with the surface protein of Streptococcus AgI/II [19], with

the antigen rBCG-V3J1 [20]; or using inactivated influenza vaccine coadministered with CTB [21], or with a vaccine containing fimbrial protein of Porphyromonas gingivalis NVP-LDE225 datasheet and CT [22]. Likewise, in NP the specific IgA antibody-producing cell responses elicited by Cry1Ac were superior to the responses generated using other antigens, such as OVA with CT [23], the antigen rBCG-V3J1 [20] and a vaccine with fimbrial protein of P. gingivalis and CT [22]. However, there is also evidence that other antigens induce a greater antibody-producing cell response than

the one induced with Cry1Ac in NP, such as NTHi a mucosal vaccine against Haemophilus FK866 solubility dmso influenzae coadministered with CT [24]. According to the majority of studies showing that intranasal immunization primarily triggers IgA antibody-producing cell responses [6, 25–28], we also found that with Cry1Ac or CT immunization, the IgA responses were the highest we recorded in both NP and NALT. However, it is important to mention that the IgG responses induced with these proteins at these nasal tissues also were significant. These observations coincide with other studies [18, 22, 29] that also have demonstrated that besides IgA, considerable IgG cell responses are locally produced in the nasal mucosa. In contrast, following intranasal immunization with rBCG-V3J1 vaccine [20], much higher V3-specific IgG than IgA-producing cell responses were found in several mucosa-associated tissues, including NALT, NP, PP and i-LP. Although the role of IgA in mucosal protection is well established, mucosal-associated IgG has also been shown to contribute to host defence [30–33]. So probably the responses of this isotype induced in click here NALT and NP might participate in mucosal protection as well. Furthermore, to our knowledge we have described here, for the first time, the effect of intranasal immunization on the expression

of the activation markers CD25 and CD69 in NALT and NP lymphocytes. Our data indicate that Cry1Ac is effective in inducing activation of B and T cells in both NALT and NP. However, the activation markers were differentially induced. Whereas the expression of CD25 was increased in B cells, as well as in CD4+ and CD8+ T cells from NALT and NP, CD69 was increased in B cells from both compartments but only in CD4+ T cells from NP. The expression of CD25 and CD69 is characteristic of highly activated T cells. Certainly, in lung airways, it has been shown that substantial numbers of virus-specific CD4 and CD8 T cells expressing these activation markers can be recovered more than 1 year after resolution of either an influenza or Sendai virus infection [34–36].