Cytokines Mediating Inflammation in a Model of Secondary Immunodeficiency in Wistar Rats: Immunomodulation Triggered by Thymomodulin

We have previously demonstrated in a rat model of immunodeficiency, an increase in the number of γδ T cells in the gut lamina propria and in the number of CD8αα+, CD25+, γδ+ subpopulations of intestinal intraepithelial lymphocytes (iIEL). The increased percentage of CD8αα+ iIEL that express CD25 indicates inflammation. The present study confirms the existence of an inflammatory process in the immunodeficient animals (R21) that is not detectable at the histological level but is characterized by an increase of the pro-inflammatory cytokines TNF-α and IFN-γ. We have shown a direct relationship between TNF receptor II (TNF-RII) expression and the higher levels of the γδ+ iIEL expressing TNF-α (TCRγδ+/TNF-α+ cells) that could be indicating a differential T cell reactivity. The effects of the increased expression of inflammatory cytokines such as TNF-α and INF-γ seem to be down regulated by the high levels of antigen specific TGF-β expression, which, we believe, is antigen specific and appears to maintain oral tolerance. Finally, in malnourished animals NF-κB remains principally in the cytosol and is unable to translocate to the nucleus, indicating the existence of alterations in the metabolic pathways leading to nuclear factor κB translocation from the cytoplasm to the nucleus. The therapeutic action of the immunomodulator TmB was demonstrated by its capacity to return all the cytokines studied to control levels. Moreover, its effects allowed the transcription factor NF-κB to translocate to the nucleus from the cytosol.

Stress increases VCAM-1 expression at the fetomaternal interface in an abortion-prone mouse model

Sound stress exposure increases fetal loss via inflammatory pathways. Inflammation is known to up-regulate cell adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1), which mediates the adhesion of leukocytes to the vascular endothelium. In this work, we studied the frequency of VCAM-1(+) vessels at the fetomaternal interface in stressed and non-stressed pregnant CBA/J female mice mated with DBA/2J (high fetal loss model) or BALB/c (low fetal loss model) males. The high fetal loss model had fewer large vessels on gestation day 6.5, and stress reduced the frequency of large vessels to a similar number in both high and low fetal loss models. In the high fetal loss model, however, the frequency of VCAM-1+ vessels was dramatically increased. This study shows that VCAM-1 expression is modulated by stress at the fetomaternal interface in abortion-prone cross-breeding.

Subclinical depressive symptoms affect responses to acute psychosocial stress in healthy premenopausal women

Subclinical depressive symptoms constitute a primary risk factor for major depression as well as for cardiovascular conditions, which may be mediated by endocrine or immune alterations. The aim of this study was to assess the association between the extent of subclinical depressive symptoms and neuroendocrine and immune cell responses to acute psychosocial stress in healthy females. In N = 33 healthy premenopausal women, state anxiety, plasma adrenocorticotropic hormone and serum cortisol, and interleukin-6 (IL-6) concentration responses to public speaking stress were assessed. Beck depression inventory (BDI) scores were entered as a covariate in the analyses. The IL-6 response was significantly associated with BDI scores (p < 0.05). Secondary analyses revealed that women with more subclinical depressive symptoms demonstrated a reduced stress-induced increase in circulating IL-6 level (p < 0.05). By contrast, stress-induced neuroendocrine activation was not associated with depressive symptoms. Hence, subclinical depressive symptoms were associated with IL-6 responses to stress in young, healthy women. Unexpectedly, there was a reduced increase of serum IL-6 level in response to stress. Effects of depressive symptoms on the IL-6 response to stress may differ between subclinical and major depression.

Analysis of Macrophage Presence in Murine Placenta: Influence of Age and Parity Status

PROBLEM

Beneficial effects of multiparity status have been previously reported by different authors. However, this fact has not been fully explained. Taking into consideration the influence of the parity status on the in vitro asymmetric/protective antibodies and the fact that interleukin-6 (IL-6) is involved in the production and immune-regulatory functions of placental macrophages, the aim of this work was to compare the placental IL-6 production and tissue macrophage presence in mice with different age and parity status.

METHOD OF STUDY

Three groups of mice (CBA/J x CBA/J) were analyzed: primiparous young (PY: 3.0 +/- 0.5 months old), primiparous old (PO: 8.5 +/- 0.5 months old), and multiparous old (MO: 8.5 +/- 0.5 months old, with three to four previous pregnancies). Macrophage and IL-6 were identified in placental tissue by immunohistochemistry employing anti-F4/80 or anti-IL-6 antibodies. IL-6 secretion was analyzed in the placental culture supernatants by enzyme-linked immunosorbent assay.

RESULTS

The results obtained indicate that, despite the level of macrophages observed in the PO placentae was higher than in PY ones, their expression in MO placentae was very much increased, appearing like a thick layer between decidua and trophoblast. However, no significant difference was found among the groups in the tissue expression of IL-6 and in IL-6 secreted in vitro.

CONCLUSIONS

Our data indicate that parity status influences the number of local macrophages and might provide evidence that could explain the known beneficial effect of multipaternity. We suggest that the number of previous pregnancies favor the production of a 'protective' population of macrophages.

Interleukin regulation of asymmetric antibody synthesized by isolated placental B cells

PROBLEM

Protecting antibodies against trophoblast surface molecules were previously described. Here we analysed the synthesis of asymmetric IgG by placental B-lymphocytes.

METHOD OF STUDY

B cells were isolated from human term placenta and cord blood, stimulated with anti-CD40 IgG and cocultured with transfected Fcgamma R-expressing mice Ltk-fibroblast. Interleukin-4, IL-6, IL-10, IL-11 and IL-13 were added to cultures for 14 days. Asymmetric IgG were assessed in culture supernatants by concanavalin A (Con A) fixation and enzyme-linked immunosorbent assay.

RESULTS

When IL-6 was added to the cultures, the percentages of asymmetric IgG synthesized by placental B cells were: IL-6: 29 +/- 10; IL-6 + IL-10: 24 +/- 7; IL-4 + IL-10 + IL-6: 38 +/- 9. The last combination induced the highest increase in the asymmetric IgG synthesis as compared with control (19 +/- 10%, P < 0.05). Additionally, placental B cells synthesized more asymmetric IgG than umbilical cord blood B-lymphocytes (P = 0.0015).

CONCLUSIONS

Isolated placental B-lymphocytes synthesized asymmetric IgG in response to Th2 interleukins, more notably IL-6 in combination with IL-4 and IL-10. The in vitro increase of protective asymmetric IgG synthesis in response to Th2-cytokines support the hypothesis that a local Th2-switch is beneficial for pregnancy outcome.