Romurtide, a synthetic muramyl dipeptide derivative, promotes megakaryocytopoiesis through stimulation of cytokine production in nonhuman primates with myelosuppression

Immune defence mechanisms and immunoenhancement strategies in oropharyngeal candidiasis

The prevalence of oropharyngeal candidiasis continues to be high, mainly because of an increasing population of immunocompromised patients. Traditional treatment of oropharyngeal candidiasis has relied on the use of antimicrobial drugs. However, unsatisfactory results with drug monotherapy and the emergence of resistant strains have prompted investigations into the potential use of adjunctive immunoenhancing therapies for the treatment of these infections. Here we review the host-recognition systems of Candida albicans, the immune and inflammatory response to infection, and antifungal effector mechanisms. The potential of immune modulation as a therapeutic strategy in oropharyngeal candidiasis is also discussed.

Cancer relapse under chemotherapy: why TLR2/4 receptor agonists can help

Liver or lung metastases usually relapse under chemotherapy. Such life-threatening condition urgently needs new, systemic anticancer compounds, with original and efficient mechanisms of action. In B16 melanoma mice treated with cyclophosphamide, D'Agostini et al. [D'Agostini, C., Pica, F., Febbraro, G., Grelli, S., Chiavaroli, C., Garaci, E., 2005. Antitumour effect of OM-174 and Cyclophosphamide on murine B16 melanoma in different experimental conditions. Int. Immunopharmacol. 5, 1205-1212.] recently found that OM-174, a chemically defined Toll-like receptor(TLR)2/4 agonist, reduces tumor progression and prolongs survival. Here we review 149 articles concerning molecular mechanisms of TLR2/4 agonists, alone or in combination with chemotherapy. It appears that TLR2/4 agonists induce a well controlled tumor necrosis factor-alpha (TNF-alpha) secretion, at plasma levels known to permeabilize neoangiogenic tumor vessels to the passage of cytotoxic drugs. Moreover, TLR2/4 agonists induce inducible nitric oxide synthase (iNOS) expression, and nitric oxide is able to induce apoptosis of chemotherapy-resistant tumor cell clones. Finally, TLR2/4-stimulation activates dendritic cell traffic and its associated tumor-specific, cytotoxic T-cell responses. Therefore, parenteral TLR2/4 agonists seem promising molecules to prolong survival in cancer patients who relapse under chemotherapy.

Development of immunoadjuvants for immunotherapy of cancer

Previously, we have reported that cell-wall skeleton (CWS) fraction was the major adjuvant-active principle of mycobacterial cells which were used in Freund's complete adjuvant (FCA). We have described the biochemical and immunological properties of CWS of mycobacteria and related bacteria, especially the CWS of Mycobacterium bovis BCG strain (BCG-CWS) in detail. The effectiveness of BCG-CWS for the cancer immunotherapy in patients was shown in several clinical trials. On the action mechanism of BCG-CWS on host immune cells, we have suggested that dendritic cells and macrophages express two sorts of receptors, Toll-like receptors, TLR-2 and TLR-4, and a putative binding receptor for BCG-CWS, whose signaling pathways lead to a sufficient antigen-presenting state in the activation of the innate immune system. We have also reported the usefulness of synthetic immunoadjuvants such as muramyldipeptide (MDP) derivatives, trehalose-dimycolates (TDM) and DNA fraction for the application for the cancer and infectious diseases in experimental systems and cancer patients.

The cloning of a rat peptidoglycan recognition protein (PGRP) and its induction in brain by sleep deprivation

Peptidoglycan recognition protein (PGRP) binds to peptidoglycan (PG) or live bacteria and is upregulated by PG. PGRP is a ubiquitous protein involved in innate immunity. Tag7, a novel cytokine, is also induced by bacterial products; tag7 is apoptotic to murine L929 cells in a NF-kappaB-independent manner. Both of these genes are expressed in brain, lymphatic and haematopoietic tissues. We provide evidence that murine PGRP and tag7 encode identical transcripts and have structural relationships to lysozymes. Further, we have cloned the cDNA of rat PGRP and analyzed its expression in brains of sleep-deprived and control rats. The mRNA levels of PGRP/tag7 were measured by RT-PCR and compared to the housekeeping gene porphobilinogen deaminase (PBD). PGRP was constitutively expressed in rat brain. PGRP mRNA was increased by 43% and 17% in the brainstem and hypothalamus, respectively, in sleep-deprived rats compared to controls. The upregulation of PGRP expression by sleep deprivation suggests a role for PGRP in a homeostatic regulation of sleep.