Host cell responses of Salmonella typhimurium infected human dendritic cells

Live attenuated Salmonella are attractive vaccine candidates for mucosal application because they induce both mucosal immune responses and systematic immune responses. After breaking the epithelium barrier, Salmonella typhimurium is found within dendritic cells (DC) in the Peyer's patches. Although there are abundant data on the interaction of S. typhimurium with murine epithelial cells, macrophages and DC, little is known about its interaction with human DC. Live attenuated S. typhimurium have recently been shown to efficiently infect human DC in vitro and induce production of cytokines. In this study, we have analysed the morphological consequences of infection of human DC by the attenuated S. typhimurium mutant strains designated PhoPc, AroA and SipB and the wild-type strains of the American Type Culture Collection (Manassas, VA, USA), ATCC 14028 and ATCC C53, by electron microscopy at 30 min, 3 h and 24 h after exposure. Our results show that genetic background of the strains profoundly influence DC morphology following infection. The changes included (i) membrane ruffling; (ii) formation of tight or spacious phagosomes; (iii) apoptosis; and (iv) spherical, pedunculated membrane-bound microvesicles that project from the plasma membrane. Despite the fact that membrane ruffling was much more pronounced with the two virulent strains, all mutants were taken up by the DC. The microvesicles were induced by all the attenuated strains, including SipB, which did not induce apoptosis in the host cell. These results suggest that Salmonella is internalized by human DC, inducing morphological changes in the DC that could explain immunogenicity of the attenuated strains.

Female Imitatio Christi in early modernity – the search for strong virgins like St Wilgefortis

At first glance you think that this is Christ crucified. At a second glance, you recognize a woman hanging on a cross. This is not an invention of the 20th century but reaches back to history where we we can find women cross-dressed or even bearded as men. St Wilgefortis or St Uncumber was a bearded and crucified woman who was venerated widely in northern Europe during the fifteeneth and sixteenth centuries. Wilgefortis is a corruption of the term „virgo fortis“ („strong virgin“). She and other female saints were considered as „imitations of Christ“. The paper deals with the reasons why this saint became so popular and how even today ideas about such strong virgins which mirror androgynous symbolism live on in popular culture.