Human papillomaviruses (HPVs) are involved in the pathogenesis of cancer of the cervix (CaCx). MicroRNA (miRNA) expression analysis using Ambion (Austin, TX, USA) arrays showed that three miRNAs were overexpressed and 24 underexpressed in cervical cell lines containing integrated HPV-16 DNA compared to the normal cervix. Furthermore, nine miRNAs were overexpressed and one underexpressed in integrated HPV-16 cell lines compared to the HPV-negative CaCx cell line C-33A. Based on microarray and/or quantitative realtime PCR and northern blot analyses, microRNA-218 (miR-218) was specifically underexpressed in HPVpositive cell lines, cervical lesions and cancer tissues containing HPV-16 DNA compared to both C-33A and the normal cervix. Expression of the E6 oncogene of highrisk HPV-16, but not that of low-risk HPV-6, reduced miR-218 expression, and conversely, RNA interference of E6/E7 oncogenes in an HPV-16-positive cell line increased miR-218 expression. We also demonstrate that the epithelial cell-specific marker LAMB3 is a target of miR-218. We also show that LAMB3 expression is increased in the presence of the HPV-16 E6 oncogene and this effect is mediated through miR-218. These findings may contribute to a better understanding of the molecular mechanisms involved in cervical carcinogenesis.

To establish experimental Pneumocystis carinii infection in simian immunodeficiency virus (SIV)-infected macaques as a model of acquired immunodeficiency syndrome (AIDS)-associated P. carinii pneumonia (PCP), SIV-infected macaques were inoculated intrabronchially with macaque-derived P. carinii, and P. carinii-specific polymerase chain reaction (PCR) and flow cytometric analysis of bronchoalveolar lavage fluid were done biweekly for up to 44 weeks after inoculation. All inoculated animals had a P. carinii-specific PCR product after infection. CD8(+) T cells in lung lavage samples from SIV- and P. carinii-coinfected animals increased to >90% of total CD3(+) cells, a pattern associated with naturally acquired P. carinii infection. Progression of disease also was correlated with increased neutrophil infiltration to the lungs. The animals had a protracted period of asymptomatic colonization with P. carinii before progression to PCP. The development of a model of PCP in SIV-infected rhesus macaques provides the means to study AIDS-associated PCP.

The goal of this study was to examine SIV- and Pneumocystis carinii-coinfected rhesus macaques as a model of P. carinii infection in HIV-seropositive humans. The influence of P. carinii infection on the cellular composition of bronchoalveolar lavage (BAL) fluid from SIV-infected and normal rhesus macaques was examined by flow cytometric analysis and polymerase chain reaction (PCR). BAL fluid from SIV- and P. carinii coinfected macaques showed a substantial T lymphocyte influx composed of more than 90% CD8+ T cells. These results are in contrast to BAL fluid from SIV-infected macaques with no detectable P. carinii-specific PCR product, where CD4+ T cells were present in significant numbers and the CD8+ T cell population was less than 70% of total CD3+ lymphocytes. We observed no significant differences in peripheral blood CD4+ or CD8+ T cell levels in the SIV-infected animals, regardless of P. carinii status, indicating that the CD8+ T cell infiltration in the lungs of the P. carinii-positive animals was likely the result of P. carinii infection. These results demonstrate that although peripheral blood CD4+ T cell levels are predictive of susceptibility to P. carinii infection in this model, the levels are not reflective of the T cell profile in the lung during SIV and P. carinii coinfection. The SIV- and P. carinii-coinfected macaques showed a spectrum of lung disease severity that was histologically similar to human P. carinii pneumonia (PCP). Interestingly, even mild P. carinii infection was sufficient to alter the normal CD4+/CD8+ T cell profiles in the lungs of SIV-infected rhesus macaques. These results are similar to immunologic findings in human AIDS-associated PCP and support the usefulness of this model in the study of immune responses to P. carinii.

The nucleotide sequences of a segment of the Pneumocystis mitochondrial large-subunit (mt LSU) rRNA gene from rhesus macaques coinfected with simian immunodeficiency virus (SIV) and Pneumocystis carinii were examined. Of 12 isolates examined, 3 were found to be identical and the others showed substantial sequence variation, with up to 13% divergence among variants. We identified two general sequence types that differed at several sites, including a conserved 26-nucleotide insertion. Four monkeys had evidence of two Pneumocystis variants present simultaneously, indicative of a mixed infection. There was a high degree of variance between the rhesus macaque-derived Pneumocystis mt LSU rRNA gene sequence and the cognate sequences in Pneumocystis organisms derived from other hosts. Analysis of the mt LSU rRNA genes of Pneumocystis organisms derived from rhesus macaques and several other mammalian hosts supports the observation that rhesus macaque-derived Pneumocystis is most closely related to human-derived Pneumocystis. In addition, the data identify the mt LSU rRNA gene as an informative locus for transmission and epidemiological studies of the SIV-rhesus macaque model of Pneumocystis infection.