SUMMARYAlthough it is known that dendritic cells (DC) migrate in response to inflammatory stimuli, there is little information about the expression of receptors for chemotactic factors on DC. The present study has demonstrated by double immunostaining and flow cytometry of Langerhan's cell (LC)-enriched epidermal cell suspensions that a small subpopulation (5-6%) of epidermal resident LC (rLC) expresses receptors for C5a (C5aR). Epidermal rLC positive for C5aR show a round-shape morphology, were located next to the basement membrane, and express HLA-DR molecules higher than C5aR negative rLC. These observations suggest that rLC would express C5aR as part of their process of maturation during tissue trafficking. To investigate whether epidermal LC up-regulate C5aR along their differentiation pathway, LC were differentiated in vitro after culture in epidermal cell suspensions supplemented with granulocyte-macrophage colony-stimulating factor (GM-CSF). As a result, in vitro differentiated LC increased the expression of C5aR up to 69% of the DC population. In accordance with this observation, interdigitating DC of secondary lymphoid organs (lymph node and tonsil) also expressed C5aR. Migratory CD1a positive DC that spontaneously migrated out of dermal or split-skin organ explants were also positive for C5aR and were used for chemotaxis and chemokinesis assays in response to human recombinant C5a (rC5a). Optimum migration to rC5a was observed at 10 ÿ 8 M with a sigmoidal dose-response curve. Checkboard analysis demonstrated that locomotion in response to rC5a was chemotaxis and not chemokinesis.

DBA/2J mated‐CBA/J female mice are prone to a high incidence of fetal abortions. This fetal wastage can be dramatically reduced by immunizing the female mice with BALB/c, but not DBA/2J spleen cells during early gestation, whereas underlying mechanisms remain to be elucidated. Recently, DCs have been described at the feto‐maternal interface in human uterus. The aim of this study was to analyse the role of DCs in the maintenance of pregnancy in the CBA/J × DBA/2J model. Bone marrow derived DCs were generated from virgin female CBA/J mice (6–8 weeks old) by using a modified version of Inaba's et al. technique, some of the DCs were pulsed with paternal DBA/2 J antigens lisate ex vivo. Immunization with DCs of the CBA/J females took place twice before matings. Four different experimental groups were included: (1) no treatment control, (2) mice injected with conditionated medium (GM‐CSF), (3) immunized with DCs and (4) immunized with Ag‐pulsed DCs, n = 5, respectively. Therapy with paternal antigen lisate pulsed DCs as well as the therapy with DCs alone significantly reduced the abortion rate from 23.8% in the controls (1 + 2) to 2.2% in Group 3 and 5% in Group 4. Our results indicate a protective role of DCs at the feto‐maternal interface during pregnancy. Putative pathways are the induction of an immunological response necessary in the prevention of abortion, i.e. a Th2 milieu or the production of asymmetric antibodies. These preliminary results may foster additional experiments on DCs in reproductive biology, which may soon be translated into clinically relevant health applications in a novel area of DCs research.

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Mycobacterium tuberculosis increases IFNγ secretion which plays an important role in granuloma formation and clearance of it. Also, the exposure of macrophages to M. tuberculosis increases secretory leukocyte protease inhibitor (SLPI), a serine protease inhibitor with antimycobacterial activity. Therefore, the aim of the present study was to determine the role of a putative interaction between IFNγ and SLPI in PBMC derived from healthy donors (HD) and tuberculosis patients (TB). Peripheral blood mononuclear cells (PBMC) from TB and HD were treated with Mtb antigen and IFNγ and SLPI was determined by ELISA. Our results showed that the stimulation with Mtb of PBMC from HD, it decreased SLPI (p<0.01) while increased IFNγ secretion. Furthermore, the blockage of IFNγ reversed the effect of the Mtb antigen on SLPI secretion in PBMC-derived HD. Surprisingly Mtb antigen did not modify the SLPI secretion in PBMC-derived from TB, although it increased IFNγ. Furthermore, the mAb against IFNγ did not affect the SLPI secretion. When plasma levels of SLPI and IFNγ were measured, we found a positive correlation between them in TB but not in HD. Moreover, tuberculosis patients showed more SLPI in plasma, being the levels higher with the severity of the disease. Overall, these results suggest that there is a negative cross talk between IFNγ and SLPI in HD that it is not present in TB patients. Therefore, the higher concentration of IFNγ and SLPI might contribute to control the infection.