CCR5 mediates pro-osteoclastic and osteoclastogenic leukocyte chemoattraction.

Periodontal disease (PD) progression involves the selective leukocyte infiltration into periodontium, supposedly mediated by the chemokine/chemokine receptor system. In this study, we investigated the role of chemokine receptor CCR5 in the immunoregulation of experimental PD in C57BL/6 (WT) and CCR5KO mice. Aggregatibacter actinomycetem comitans infection triggered the chemoattraction of distinct CCR5+ leukocyte subpopulations (determined by flow cytometry): CCR5+F4/80+ leukocytes, which co-express CD14 , CCR2, TNF-α, and IL-1ß, indicative of activated macrophages; and CCR5+CD4+ cells, which co-express CXCR3, IFN-γ, and RANKL, indicative of Th1 lymphocytes, therefore comprising pro-osteoclastic and osteoclastogenic cell subsets, respectively. CCR5KO mice presented a lower PD severity (lower inflammation and alveolar bone loss) when compared with the WT strain, since the migration of F4/80+, TNF-α+, CD4+, and RANKL+ cells specifically decreased due to the lack of CCR5. Also, ELISA analysis demonstrated that the production of TNF-α, IL-1ß, IL-6, IFN-γ, and RANKL in periodontal tissues was significantly decreased in the CCR5KO strain. The periodontal bacterial load and antimicrobial patterns were unaltered in CCR5KO mice. Our results demonstrate that the chemokine receptor is involved in the migration of distinct leukocyte subpopulations throughout experimental PD, being a potential target for therapeutic intervention in PD.

NK cell activity in the presence of IL-12 is a prognostic assay to neoadjuvant chemotherapy in cervical cancer.

OBJECTIVE: Little is known about the impact of neoadjuvant chemotherapy on cell-mediated immunity in patients with advanced cervical cancers. PATIENTS AND METHODS: We have studied 24 patients with advanced cervical cancer submitted to neoadjuvant chemotherapy (CT) using cis-platinum (100 mg/m(2)/cycle) and bleomycin (30 mg/cycle). The cell-mediated immunity parameters available before and after CT were NK cells, CD4(+)/CD28 and CD8(+)/CD28 T-lymphocyte numbers, PBMC cytotoxicity, and modification of this parameter with "in vitro" addition of IL-12. RESULTS: The number of NK cells was higher before CT (P < 0.008) in 13 patients who presented a good clinical response to treatment, compared to 11 patients with a poor clinical response. In addition, PBMC cytotoxicity (P < 0.001), CD4(+) and CD8(+) T-lymphocyte values (P < 0.0047), and CD8(+)/CD28(+) cells were also higher in the group with a good response compared with the group with a poor response. Addition of IL-12 to the medium increased the lytic capacity of PBMC after CT only in the group with a good clinical response (P < 0.05). CONCLUSIONS: NK cell numbers, CD8(+) T-cell levels, and CD8(+)/CD28(+) cell levels can be used as prognostic factors before CT. Our results suggest that patients with a poor response have lower lytic activity per NK cell and are refractory to IL-12 stimulation, probably as a result of the reduced expression of IL-12 receptors or of an intracellular defect in the mechanism of transduction. These observations also provide support for human clinical trials of IL-12 and neoadjuvant CT in patients with cervical cancer.

Transforming growth factor beta and immunosuppression in experimental visceral leishmaniasis.

Hamsters infected with Leishmania donovani develop a disease similar to human kala-azar. They present hypergammaglobulinemia, and their T cells do not respond to parasite antigens. This unresponsiveness has been primarily ascribed to defects in antigen-presenting cells (APCs), because these cells are unable to stimulate proliferation of parasite-specific T cells from immunized animals. In this study, we show that APCs (adherent spleen cells) from L. donovani-infected hamsters produce high levels of the inhibitory cytokine transforming growth factor beta (TGF-beta). Immunohistochemical studies with an anti-TGF-beta monoclonal antibody (MAb) showed that this cytokine is abundantly produced in vivo by the spleen cells of infected animals. In addition, high levels of TGF-beta are produced in vitro by infected hamster cells, either spontaneously or after stimulation with parasite antigen or lipopolysaccharide. Furthermore, in vivo-infected adherent cells obtained from spleens of L. donovani-infected hamsters caused profound inhibition of the in vitro antigen-induced proliferative response of lymph node cells from hamsters immunized with leishmanial antigens. Moreover, this inhibition was totally abrogated by the anti-TGF-beta MAb. These results suggest that the immunosuppression observed in visceral leishmaniasis is, at least in part, due to the abundant production of TGF-beta during the course of the infection.

Antibody-dependent cellular cytotoxicity in chronic human Chagas disease.

Antibody-dependent cellular cytotoxicity mediated by granulocytes (ADGC) or lymphocytes (ADLC) was assessed in 23 patients with chronic Chagas disease. The results of ADGC against T. cruzi were normal. ADLC against chicken erythrocytes was significantly reduced in patients as compared with normal controls. Possible causes of this abnormality were investigated.