Phenotypical and functional analysis of intraepithelial lymphocytes from small intestine of mice in oral tolerance.

In this work, we evaluated the effects of administration of OVA on phenotype and function of intraepithelial lymphocytes (IELs) from small intestine of transgenic (TGN) DO11.10 and wild-type BALB/c mice. While the small intestines from BALB/c presented a well preserved structure, those from TGN showed an inflamed aspect. The ingestion of OVA induced a reduction in the number of IELs in small intestines of TGN, but it did not change the frequencies of CD8(+) and CD4(+) T-cell subsets. Administration of OVA via oral + ip increased the frequency of CD103(+) cells in CD4(+) T-cell subset in IELs of both BALB/c and TGN mice and elevated its expression in CD8ß(+) T-cell subset in IELs of TGN. The frequency of Foxp3(+) cells increased in all subsets in IELs of BALB/c treated with OVA; in IELs of TGN, it increased only in CD25(+) subset. IELs from BALB/c tolerant mice had lower expression of all cytokines studied, whereas those from TGN showed high expression of inflammatory cytokines, especially of IFN-γ, TGF-ß, and TNF-α. Overall, our results suggest that the inability of TGN to become tolerant may be related to disorganization and altered proportions of inflammatory/regulatory T cells in its intestinal mucosa.

Prime-boost vaccination based on DNA and protein-loaded microspheres for tuberculosis prevention.

We evaluated the use of a vaccine formulation based on a mixture of two different PLGA microspheres, composed by faster and slower release profiles, containing DNA encoding hsp65 and the recombinant hsp65 protein, respectively, aiming to DNA priming and protein boost after a single dose vaccination. The combination of PLGA50:50 microspheres containing DNA-hsp65 and trehalose dimycolate (TDM) with PLGA75:25 microspheres containing recombinant hsp65 (prime-boost Me) was able to induce high levels of anti-hsp65 specific antibodies. The serum levels of these specific antibodies remained high during 90 days after vaccination, whereas the DNA Me formulation based only in DNA-hsp65 plus TDM-loaded microspheres was not able to sustain the high antibody levels during the same period. Production of IFN-gamma was significant in animals vaccinated with both formulations, while the prime-boost Me vaccinated mice sustained higher levels of this cytokine during all the evaluation period. Thus, prime-boost strategy by using biodegradable microspheres seems to be a promising strategy to stimulate long-lasting immune response.