In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

[EX Q]: The respiratory syncytial virus (RSV) fusion (F) glycoprotein is a major target of neutralizing antibodies arising from natural infection, and antibodies that specifically bind to the prefusion conformation of RSV F generally demonstrate the greatest neutralization potency. Prefusion-stabilized RSV F variants have been engineered as vaccine antigens, but crystal structures of these variants have revealed conformational differences in a key antigenic site located at the apex of the trimer, referred to as antigenic site . Currently, it is unclear if flexibility in this region is an inherent property of prefusion RSV F or if it is related to inadequate stabilization of site in the engineered variants. Therefore, we set out to investigate the conformational flexibility of antigenic site , as well as the ability of the human immune system to recognize alternative conformations of this site, by determining crystal structures of prefusion RSV F bound to neutralizing human-derived antibodies AM22 and RSD5. Both antibodies bound with high affinity and were specific for the prefusion conformation of RSV F. Crystal structures of the complexes revealed that the antibodies recognized distinct conformations of antigenic site , each diverging at a conserved proline residue located in the middle of an -helix. These data suggest that antigenic site exists as an ensemble of conformations, with individual antibodies recognizing discrete states. Collectively, these results have implications for the refolding of pneumovirus and paramyxovirus fusion proteins and should inform development of prefusion-stabilized RSV F vaccine candidates. Respiratory syncytial virus (RSV) is a pervasive pathogen that causes severe lower respiratory tract infections, leading to~100,000 deaths globally each year and hundreds of millions of dollars in healthcare costs. However, despite its prevalence, there is no vaccine for RSV and the only available therapy is limited to high-risk infants, leaving the vast majority of people with no effective means of prevention or treatment. The RSV fusion (F) protein is a major target of neutralizing antibodies, including extremely potent antibodies that PLOS Pathogens | https://doi.recognize prefusion-specific epitopes. In this study, we determined the crystal structures of two neutralizing human antibodies bound to prefusion RSV F. Our results reveal that each antibody recognizes a different conformation of a neutralization-sensitive epitope, suggesting that this region is inherently flexible and may be important for RSV F function. These results should guide future vaccine-design efforts and help elucidate the mechanisms of RSV F triggering and fusion. Conformational flexibility of antigenic site PLOS Pathogens | https://doi.
[EX A]: Alternative conformations of a major antigenic site on RSV F

[EX Q]: The immunostimulatory effects of oligodeoxyribonucleotides (ODN) containing unmethylated CpG dinucleotides (CpG-ODN) in certain base contexts have been extensively studied in man and mice. One major action is their ability to trigger production of massive amounts of interferon-a (IFN-a) by plasmacytoid dendritic cells (PDC), also referred to as natural IFN-a/b producing cells (NIPC). The present study using porcine PBMC activated by CpG-ODN or plasmid DNA revealed a considerable variation in the IFN-a production in response to various CpG-ODN constructs. Several phosphodiester ODNs, such as 5 0 TTTTCAATTCGAAGATGAAT 3 0 (ODN H), and the plasmid pcDNA3 all required pre-incubation with lipofectin in order to induce IFN-a. Intact unmethylated CpGs were also important, because methylation or substitution of the cytosines and CpG-inversion strongly reduced the IFN-a induction by single-or double-stranded forms of ODN H. Certain CpG-ODNs that contained flanking phosphorothioate or phosphodiester poly-G sequences were potent inducers of IFN-a without pre-incubation with lipofectin, for instance the ODN 2216 (5 0 GGGGGACGATCGTCGGGGGG 3 0 ). While poly-G sequences have been suggested to increase uptake of ODNs by cells, they did not obviate the need for lipofectin when added to the ODN H. However, they resulted in up to five-fold increases of the IFN-a levels caused by ODN H upon lipofection, indicating other enhancing effects of poly-G sequences on the induction of IFN-a. The identity of the IFN-a producing cells (IPC) stimulated by CpG-ODN or plasmid DNA was studied by means of flow cytometry using combined staining for intracellular IFN-a and surface markers. Approximately 1-3 IPC/10 3 PBMC were detected, compared to only 3 IPC/10 4 PBMC stimulated by Aujeszky's disease virus. The IPC frequencies were confirmed by detection of IFN-a mRNA positive cells by in situ hybridisation. The IPC induced by CpG-ODN or plasmid DNA had a similar phenotype, expressing CD2 and CD4 and intermediate levels of MHC class II and the myeloid marker SWC3, but not the markers of T and B cells or
[EX A]: Characteristics of oligodeoxyribonucleotides that induce interferon (IFN)-a in the pig and the phenotype of the IFN-a producing cells monocytes (CD3, CD21 and CD14)

[EX Q]: Previous reports suggest that type I and type II Interferon can co-operatively inhibit some virus replication, e.g. HCV, SARS-CoV, HSV-1. To find out the molecular mechanism underlying this phenomenon, we analyzed the transcription profile stimulated by IFN- and IFN- in Huh-7 cells and found that the transcription of a subset of IFN stimulated genes (ISGs) including BclG, XAF1, TRAIL and TAP1 was enhanced when IFN- and were both present. Promoter analysis of BclG revealed that IRF-1 and STAT1 were both required in this process. Enhanced IRF-1/DNA complex formation was observed in interferon co-treatment group by gel shift analysis. Furthermore, IRF-1 activation was found to be generally required in this cluster of ISGs. STAT1 tyrosine phosphorylation was elevated by IFN combination treatment, however, only the hyper-transactivation of GAS but not ISRE was observed. In conclusion, hyper-activation of IRF-1 and elevated STAT1 dimer formation may be two general switches which contribute to a much more robust antiviral symphony against virus replication when type I and type II IFNs are co-administered.
[EX A]:
Hyper-activated IRF-1 and STAT1 contribute to enhanced Interferon stimulated gene (ISG) expression by Interferon and co-treatment in human hepatoma cells