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]: Coronavirus reverse genetic systems have become valuable tools for studying the molecular biology of coronavirus infections. They have been applied to the generation of recombinant coronaviruses, selectable replicon RNAs, and coronavirus-based vectors for heterologous gene expression. Here we provide a collection of protocols for the generation, cloning, and modification of full-length coronavirus cDNA using vaccinia virus as a cloning vector. Based on cloned coronaviral cDNA, we describe the generation of recombinant coronaviruses and stable cell lines containing coronaviral replicon RNAs. Initially, the vaccinia virus-based reverse genetic system was established for the generation of recombinant human coronavirus 229E. However, it is also applicable to the generation of other coronaviruses, such as the avian infectious bronchitis virus, mouse hepatitis virus, and SARS coronavirus.
[EX A]: Generation of Recombinant Coronaviruses Using Vaccinia Virus as the Cloning Vector and Stable Cell Lines Containing Coronaviral Replicon RNAs

[EX Q]: Porcine epidemic diarrhoea (PED) is a contagious enteric disease of pigs caused by a coronavirus. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) based on the use of monoclonal antibodies was developed for the detection of porcine epidemic diarrhoea virus (PEDV). The DAS-ELISA was compared with RT-PCR in the examination of 506 specimens collected during 2006-2007 from pigs originating from different farms located in the Po valley. Both faecal samples obtained directly from the rectum of live animals showing clinical signs and intestinal samples collected from the caecum of deceased pigs were included in the study. The correlation between the two methods was higher when testing faecal samples (K = 0.97, 95% CI: 0.94-1.00) than testing intestinal samples (K = 0.62, 95% CI: 0.35-0.89). The use of ELISA technology provided an efficient and effective mean of evaluating the presence of coronavirus PED antigen in field samples and indicates that this procedure is a very useful tool in epidemiological studies.
[EX A]: Comparison of enzyme-linked immunosorbent assay and RT-PCR for the detection of porcine epidemic diarrhoea virus

[EX Q]: Despite the clinical relevance, dengue virus (DENV) research has been hampered by the absence of robust reverse genetic systems to manipulate the viral serotypes for propagation and generation of mutant viruses. In this article, we describe application of an infectious clone system for DENV serotype 1 (DENV1). Similar to previous clones in both flaviviruses and coronaviruses, the approach constructs a panel of contiguous cDNAs that span the DENV genome and can be systematically and directionally assembled to produce viable, full-length viruses. Comparison of the virus derived from the infectious clone with the original viral isolate reveals identical sequence, comparable endpoint titers, and similar focus staining. Both focus-forming assays and percent infection by flow cytometry revealed overlapping replication levels in two different cell types. Moreover, serotype-specific monoclonal antibodies (MAbs) bound similarly to infectious clone and the natural isolate. Using the clone, we were able to insert a DENV4 type-specific epitope recognized by primate MAb 5H2 into envelope (E) protein domain I (EDI) of DENV1 and recover a viable chimeric recombinant virus. The recombinant DENV1 virus was recognized and neutralized by the DENV4 type-specific 5H2 MAb. The introduction of the 5H2 epitope ablated two epitopes on DENV1 EDI recognized by human MAbs (1F4 and 14C10) that strongly neutralize DENV1. Together, the work demonstrates the utility of the infectious clone and provides a resource to rapidly manipulate the DENV1 serotype for generation of recombinant and mutant viruses.
[EX A]:
Epitope Addition and Ablation via Manipulation of a Dengue Virus Serotype 1 Infectious Clone