The Middle East respiratory syndrome coronavirus (MERS-CoV) causes a highly lethal pneumonia. MERS was recently identified as a candidate for vaccine development, but most efforts focus on antibody responses, which are often transient after CoV infections. CoV-specific T cells are generally long-lived, but the virus-specific T cell response has not been addressed in MERS patients. We obtained peripheral blood mononuclear cells and/or sera from 21 MERS survivors. We detected MERS-CoV–specific CD4⁺ and CD8⁺ T cell responses in all MERS survivors and demonstrated functionality by measuring cytokine expression after peptide stimulation. Neutralizing (PRNT₅₀) antibody titers measured in vitro predicted serum protective ability in infected mice and correlated with CD4⁺ but not CD8⁺ T cell responses; patients with higher PRNT₅₀ and CD4⁺ T cell responses had longer intensive care unit stays and prolonged virus shedding and required ventilation. Survivors with undetectable MERS-CoV–specific antibody responses mounted CD8⁺ T cell responses comparable with those of the whole cohort. There were no correlations between age, disease severity, comorbidities, and virus-specific CD8⁺ T cell responses. In conclusion, measurements of MERS-CoV–specific T cell responses may be useful for predicting prognosis, monitoring vaccine efficacy, and identifying MERS patients with mild disease in epidemiological studies and will complement virus-specific antibody measurements.

The Middle East respiratory syndrome (MERS) is a coronavirus (CoV)-mediated respiratory disease. Virus transmission occurs within health care settings, but cases also appear sporadically in the community. Camels are believed to be the source for community-acquired cases, but most patients do not have camel exposure. Here, we assessed whether camel workers (CWs) with high rates of exposure to camel nasal and oral secretions had evidence of MERS-CoV infection. The results indicate that a high percentage of CWs were positive for virus-specific immune responses but had no history of significant respiratory disease. Thus, a possible explanation for repeated MERS outbreaks is that CWs develop mild or subclinical disease. These CWs then transmit the virus to uninfected individuals, some of whom are highly susceptible, develop severe disease, and are detected as primary MERS cases in the community.

Breast cancer is one of the most common cancer and a leading cause of death in women. Up to date the most commonly used breast cancer cell lines are originating from Caucasians or Afro-Americans but rarely cells are being derived from other ethnic groups. Here we describe for the first time the establishment of a naturally transformed breast cancer cell line, KAIMRC1 from an Arab woman of age 62 suffering from stage IIB breast cancer (T2N1M0). Moreover, we have characterized these cells for the biological and molecular markers, induction of MAPK pathways as well as its response to different commercially available drugs and compounds. Breast cancer tissue sections were minced and cultured in media for several weeks. KAIMRC1 cells were successfully isolated from one of the primary breast tumor tissue cultures without any enzymatic digestion. To study the growth characteristics of the cells, wound healing assay, clonogenic assay, cell proliferation assays and live cell time-lapse microscopy was performed. Karyotyping, Immunophenotyping and molecular pathway specific compound treatment was also performed. A selective breast cancer gene expression panel was used to identify genes involved in the signal transduction dysregulation and malfunction of normal biological processes during breast carcinogenesis. These cells are ER/PR-positive and HER2-negative. The epithelial nature of these cells was confirmed by flow cytometry analysis using epithelial cell markers. They are cuboidal in shape and relatively smaller in size as compared to established cell lines, MCF-7, MDA MB-231 and the normal breast cell line, MCF-10A. In normal cell culture conditions these cells showed the capability of growing both in monolayer as well as in 3-D conformation. They showed a doubling time in vitro of approximately 24 h. They exhibit a modal karyotype of 58–63,X with abnormalities in a couple of chromosomes. KAIMRC1 cells were found to be more responsive to drug treatment in vitro in comparison to the established MDA MB-231 and MCF-7 cell lines. In conclusion we have isolated and characterized a new naturally immortalized breast cell line, KAIMRC1 with a potential to play a key role in opening up novel avenues towards the understanding of breast carcinoma.

In order to revisit the architecture of the catalytic center of the antigenomic hepatitis delta virus (HDV) ribozyme we developed an unbiased in vitro selection procedure that efficiently selected novel variants from a relatively small set of sequences. Using this procedure we examined all possible variants from a pool of HDV ribozymes that had been randomized at 25 positions (4²⁵). The isolated set of sequences shows more variability than do the natural variants. Nucleotide variations were found at all randomized positions, even at positions when the general belief was that the specific base was absolutely required for catalytic activity. Covariation analysis supports the presence of several base pairs, although it failed to propose any new tertiary contacts. HDV ribozyme appears to possess a greater number of constraints, in terms of sequences capable of supporting the catalysed cleavage, than do other catalytic RNAs. This supports the idea that the appearance of this catalytic RNA structure has a low probability (i.e. is a rare event), which may explain why to date it has been found in nature only in the HDV. These contrasts with the hammerhead self-cleaving motif that is proposed to have multiple origins, and that is widespread among different organisms. Thus, just because a self-cleaving RNA motif is small does not imply that it occurs easily.

Genetic deletion of both 4E-BP1 and 4E-BP2 was found to protect cells against viral infections. Here we demonstrate that the individual loss of either 4E-BP1 or 4E-BP2 in mouse embryonic fibroblasts (MEFs) is sufficient to confer viral resistance. shRNA-mediated silencing of 4E-BP1 or 4E-BP2 renders MEFs resistant to viruses, and compared to wild type cells, MEFs knockout for either 4E-BP1 or 4E-BP2 exhibit enhanced translation of Irf-7 and consequently increased innate immune response to viruses. Accordingly, the replication of vesicular stomatitis virus, encephalomyocarditis virus, influenza virus and Sindbis virus is markedly suppressed in these cells. Importantly, expression of either 4E-BP1 or 4E-BP2 in double knockout or respective single knockout cells diminishes their resistance to viral infection. Our data show that loss of 4E-BP1 or 4E-BP2 potentiates innate antiviral immunity. These results provide further evidence for translational control of innate immunity and support targeting translational effectors as an antiviral strategy.