The possible biochemical factors able to affect the in vitro expression of the high-risk human papillomavirus type 16 (HPV16) E7 oncoprotein have been analyzed. Evidence is provided that E7 mRNA stability is increased and, conversely, transcript translation is inhibited by binding to a 32-kDa protein from rabbit reticulocyte lysate; sequence analysis identified the 32-kDa binding protein as rabbit α₁-globin protein; and interaction between rabbit α₁-globin and E7 mRNA occurs through the 6-mer peptide SEQIKA present in human cytokeratin 7 protein. The in vitro data were confirmed by the occurrence of HPV16 E7 mRNA-cytokeratin 7 binding in squamous cervical cancer SiHa cells.

Broad T cell and B cell responses to multiple HCV antigens are observed early in individuals who control or clear HCV infection. The prevailing hypothesis has been that similar immune responses induced by prophylactic immunization would reduce acute virus replication and protect exposed individuals from chronic infection. Here, we demonstrate that immunization of naïve chimpanzees with a multicomponent HCV vaccine induced robust HCV-specific immune responses, and that all vaccinees exposed to heterologous chimpanzee-adapted HCV 1b J4 significantly reduced viral RNA in serum by 84%, and in liver by 99% as compared to controls ( P = 0.024 and 0.028, respectively). However, despite control of HCV in plasma and liver in the acute period, in the chronic phase, 3 of 4 vaccinated animals developed persistent infection. Analysis of expression levels of proinflammatory cytokines in serial hepatic biopsies failed to reveal an association with vaccine outcome. However, expression of IDO, CTLA-4 (1) and PD-1 levels in liver correlated with clearance or chronicity. Conclusion: Despite early control of virus load, a virus-associated tolerogenic-like state can develop in certain individuals independent of vaccination history. (Hepatology 2007;45:602–613.)

BackgroundPreventive and therapeutic vaccine strategies aimed at controlling hepatitis C virus (HCV) infection should mimic the immune responses observed in patients who control or clear HCV, specifically T helper (Th) type 1 and CD8⁺ cell responses to multiple antigens, including nonstructural protein (NS) 3. Given the experience with human immunodeficiency virus, the best candidates for this are based on DNA prime, pox, or adenovirus boost regimens MethodsIn rhesus macaques, we compared NS3-expressing DNA prime and adenovirus boost strategy with 2 alternative priming approaches aimed at modifying Th1 and CD8⁺ responses: DNA adjuvanted with interleukin (IL)–2– and –12–encoding plasmids or Semliki Forest virus (SFV) ResultsAll prime-boost regimens elicited NS3-specific B and T cell responses in rhesus macaques, including CD8⁺ responses. SFV priming induced higher lymphoproliferation and longer Th1 memory responses. The use of IL-2– and IL-12–expressing vectors resulted in reduced Th2 and antibody responses, which led to increased Th1 skewing but not to an increase in the magnitude of the IFN-γ and CD8⁺ responses ConclusionsAll strategies induced Th1 cellular responses to HCV NS3, with fine modulations depending on the different priming approaches. When they are developed for more HCV antigens, these strategies could be beneficial in therapeutic vaccine approaches

To evaluate the reactivity of the recombinant proteins expressed in Escherichia coli strain BL21(DE3), a Western blot assay was performed by using a panel of 78 serum samples obtained, respectively, from convalescent-phase patients infected with severe acute respiratory syndrome-associated coronavirus (SARS-CoV) (30 samples) and from healthy donors (48 samples). As antigen for detection of SARS-CoV, the nucleocapsid protein (N) showed high sensitivity and strong reactivity with all samples from SARS-CoV patients and cross-reacted with all serum samples from healthy subjects, with either those obtained from China (10 samples) or those obtained from France (38 serum samples), giving then a significant rate of false positives. Specifically, our data indicated that the two subunits, S1 (residues 14 to 760) and S2 (residues 761 to 1190), resulted from the divided spike reacted with all samples from SARS-CoV patients and without any cross-reactivity with any of the healthy serum samples. Consequently, these data revealed the nonspecific nature of N protein in serodiagnosis of SARS-CoV compared with the S1 and S2, where the specificity is of 100%. Moreover, the reported results indicated that the use of one single protein as a detection antigen of SARS-CoV infection may lead to false-positive diagnosis. These may be rectified by using more than one protein for the serodiagnosis of SARS-CoV.

Each year, during winter months, human Metapneumovirus (hMPV) is associated with epidemics of bronchiolitis resulting in the hospitalization of many infants. Bronchiolitis is an acute illness of the lower respiratory tract with a consequent inflammation of the bronchioles. The rapid onset of inflammation suggests the innate immune response may have a role to play in the pathogenesis of this hMPV infection. Since, the matrix protein is one of the most abundant proteins in the Paramyxoviridae family virion, we hypothesized that the inflammatory modulation observed in hMPV infected patients may be partly associated with the matrix protein (M-hMPV) response. By western blot analysis, we detected a soluble form of M-hMPV released from hMPV infected cell as well as from M-hMPV transfected HEK 293T cells suggesting that M-hMPV may be directly in contact with antigen presenting cells (APCs) during the course of infection. Moreover, flow cytometry and confocal microscopy allowed determining that M-hMPV was taken up by dendritic cells (moDCs) and macrophages inducing their activation. Furthermore, these moDCs enter into a maturation process inducing the secretion of a broad range of inflammatory cytokines when exposed to M-hMPV. Additionally, M-hMPV activated DCs were shown to stimulate IL-2 and IFN-γ production by allogeneic T lymphocytes. This M-hMPV-mediated activation and antigen presentation of APCs may in part explain the marked inflammatory immune response observed in pathology induced by hMPV in patients.