Link to Pubmed [PMID] – 16872860
Microbes Infect. 2006 Aug;8(9-10):2341-51
BCG rectal administration to newborn and adult mice induced protective immune responses against tuberculosis. BCG reaches the sub-epithelial site and the draining mesenteric lymph nodes (MLNs), and dendritic cells (DC) could be recruited to these sites. Using polarized Caco-2 epithelial cells, we showed that BCG translocates epithelial cells to basolateral compartment. Delayed in newborn BALB/c mice, an important recruitment of CD11c+ DCs, was documented in the rectal lamina propria and the MLNs during the first two weeks after rectal BCG delivery. In MLNs, two major DC subtypes were observed: conventional DCs (cDCs) (B220-) and plasmacytoid DCs (pDCs) (B220+). CIRE, mouse DC-specific intracellular adhesion molecule 3 grabbing non-integrin (DC-SIGN) is predominantly expressed on pDCs and at a higher level on pDCs from the adult compared to newborn MLNs. cDCs with a higher capacity to induce the proliferation of naïve CD4+ T cells than pDCs, triggered CD4+ T cells to produce interferon-gamma whereas pDCs triggered them to release interleukin-10. Both DC subtypes equilibrates T cells as a source of microbicidal/microbiostatic signals and those acting as source of counter-inflammatory signals, preventing tissue damage and/or accelerating tissue repair. Thus, rectal delivery of BCG could be a safe and efficient route of vaccination against tuberculosis.