Cell adhesion-related proteins as specific markers of sponge cell types involved in allogeneic recognition

Sponge immunocyte identification is of interest to comparative immunologists since characterizing these cells will allow investigations into the mechanisms of non-self recognition in the oldest animal phylum. Here, we report that polyclonal antibodies raised against the core protein of a proteoglycan involved in cell adhesion in the marine sponge Microciona prolifera are specific markers for archaeocytes, the totipotent sponge cells. Archaeocytes are mobilized upon allogeneic contact and they accumulate in the contact zone. A second type of cell, the gray cells, are specifically recognized by monoclonal antibodies raised against CD44, a hyaluronan receptor. Gray cells do also accumulate in the contact area. Specific staining of a third sponge cell type, the rhabdiferous cells, shows that these do not accumulate upon allografting. These specific cell markers allow tracking of archaeocytes and gray cells, and show that they play an active role in sponge allogeneic reactions.     

Dendritic cells and natural killer cells in the pathogenesis of HIV infection

Dendritic cells (DC) and natural killer (NK) cells, the main cellular components of the innate immune system, participate in the most ancient first line of defense against infections. Both types of cells patrol peripheral tissues, whereas their rapid recruitment and activation at mucosal surfaces [the major entry point for the human immunodeficiency virus (HIV)] is a hallmark of acute inflammatory response. The ability of HIV to survive and replicate in the human host relies upon several molecular mechanisms eluding the immune surveillance of both adaptive immunity and of DC and NK cells beginning with the acute phase of primary HIV infection. DC and NK cells, unlike CD4⁺ T cells, are impaired more functionally rather than being depleted by HIV infection. In this article we will review some of the aspects of DC/NK cells interaction with HIV infection both in vitro and in vivo, and we will also speculate on the potential consequence for HIV pathogenesis and for the capacity of the virus to escape the surveillance of the innate immune system.     

Saccharomyces cerevisiae as an eukaryotic cell model to assess cytotoxicity and genotoxicity of three anticancer anthraquinones

The toxicity of most drugs is associated with their enzymatic conversion to toxic metabolites. Bioactivation reactions occur in a range of cellular organs and organelles, including mitochondria. We have investigated different effects (i.e. growth inhibition, mortality and genotoxicity) of doxorubicin, epirubicin and mitoxantrone on the D7 strain of Saccharomyces cerevisiae and on its petite (rho degrees ) respiratory-deficient mutant at various cellular concentrations of cytochrome P450 and glutathione (GSH). The data confirmed the importance of oxygen production for doxorubicin toxicity. The complete absence, or a very low level, of cytochrome oxidase subunit IV conferred some resistance to doxorubicin. Low GSH levels decreased resistance to doxorubicin in both strains, suggesting that thiol depletion could potentiate membrane lipid peroxidation. Doxorubicin induction of petite colonies suggests that the drug is able to select rather than induce respiratory-deficient mutants. Epirubicin induced levels of cytotoxicity similar to those of doxorubicin. The effects did not appear to be significantly dependent on mitochondrial function or GSH levels, whereas cells were strongly protected by cytochrome P450. GSH did not induce an evident alteration. Neither were genotoxic effects induced. Mitoxantrone had reduced levels of both growth inhibition and cytotoxicity in comparison to anthracyclines and induced convertants, revertants and aberrants. All the effects considered were amplified at high cytochrome P450 cellular concentrations, although the drug was also shown to act without previous metabolism via cytochrome P450. Anthracenedione effectiveness was increased by metabolism via cytochrome P450 and partially reduced by GSH. However, further mechanisms were suggested, which might implicate mitochondrial function and/or production of electrophilic cytotoxic and/or genotoxic intermediates by means of GSH conjugation. The biological effectiveness of doxorubicin, epirubicin and mitoxantrone on S.cerevisiae was shown to be strictly dependent on cell-specific physiological/biochemical conditions, such as a functional respiratory chain and levels of cytochrome P450 and GSH.     

Metastatic pleural mesothelioma presenting with solitary involvement of the tongue: report of a new case and review of the literature

We report a new case of mesothelioma that presented with an isolated lingual metastasis 14 months after initial diagnosis. The patient was a 71-year-old man with a history of pleural decortication and chemotherapy for epithelioid mesothelioma who recently complained of chronic bleeding from a nodular consolidation of tongue. There was no clinical or instrumental evidence of extrathoracic tumor spread. Microscopic examination of a lingual biopsy specimen revealed nests of atypical polygonal cells with moderate cytoplasm, immunopositive for keratins, epithelial membrane antigen, vimentin, thrombomodulin, and calretinin. This case provides additional evidence that mesothelioma could rarely, but not exceptionally, metastatize, to unusual sites such as the tongue. In that location it can mimic primary poorly differentiated squamous carcinoma or adenocarcinoma as well as a number of other metastatic malignancies. In addition to obvious medicolegal implication, metastatic mesothelioma should be correctly recognized so as to avoid useless radical treatment.     

Antigenic characterisation of influenza B virus with a new microneutralisation assay: comparison to haemagglutination and sequence analysis

Although the haemagglutination inhibition assay is considered the "gold standard" for antigenic characterisation of influenza viruses, some limitations of this technique are well known. A new microneutralisation assay, as a tool for antigenic characterisation of influenza B viruses, has been standardised and its performance evaluated in comparison with the haemagglutination inhibition test in the light of molecular characterisation of the haemagglutinin. Twelve B viruses belonging to the two lineages and the four sub-lineages discriminated by phylogenetic analysis of HA were tested. The microneutralisation assay clearly distinguishes viruses belonging to different lineages and, in addition, discriminates strains belonging to different sub-lineages that are poorly or not discriminated using the haemagglutination inhibition test. This new microneutralisation assay could provide a useful tool for antigenic characterisation of circulating influenza viruses and contribute, together with the haemagglutination inhibition test and sequence analysis of the haemagglutinin and neuraminidase, in the choice of the strain for use in vaccine composition.