TASK DEFINITION: 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.
PROBLEM: Recent years have seen several advances in our understanding of immunity to virus infection of the lower respiratory tract, including to influenza virus infection. Here, we review the cellular targets of viruses and the features of the host immune response that are unique to the lungs. We describe the interplay between innate and adaptive immune cells in the induction, expression and control of antiviral immunity, and discuss the impact of the infected lung milieu on moulding the response of antiviral effector T cells. Recent findings on the mechanisms that underlie the increased frequency of severe pulmonary bacterial infections following respiratory virus infection are also discussed. Viruses are highly evolved and ubiquitous pathogens. Although infection with many viruses results in a mild, self-limited disease, other viruses can produce severe and frequently fatal infections. The respiratory tract is a major portal through which viruses enter to initiate infection. Whereas some viruses can initiate infection in the respiratory tract and then disseminate to other sites in the body, other viruses typically remain localized to the respiratory tract, where they replicate and induce tissue injury (see Supplementary information S1 (table)). Various defence mechanisms have evolved in the respiratory tract to prevent and control infection by viruses and other pathogens. The respiratory tract can be divided anatomically into the upper respiratory tract (including the nose, mouth and pharynx) and the lower respiratory tract (which consists of the trachea, bronchi and lungs), with the lymphoid tissue of Waldeyer's ring (including the pharyngeal and palatine tonsils) representing the line of demarcation. Because of the crucial role of the lower respiratory tract in respiration, we limit the focus of this Review to recent advances in our understanding of the host immune response to virus infection at this site.

SOLUTION: Regulating the adaptive immune response to respiratory virus infection NIH Public Access

PROBLEM: Ten strains of avian infectious bronchitis virus (IBV) were titrated as plaqueforming units in primary chick embryo fibroblast cells. In the absence of trypsin, plaques were only formed by Beaudette-42 and Iowa-609 strains. When trypsin was incorporated in the overlay medium of cell monolayers, all the IBV strains tested produced plaques within 4days after inoculation. Incorporation of 20--40 ~xg of trypsin per ml of the overlay medium seemed to be suitable for plaque formation of IBV. A preliminary investigation was made of the mode of action of trypsin.

SOLUTION: Archives of Virology Plaque Formation by Avian Infectious Bronehitis Virus in Primary Chick Embryo Fibroblast Cells in the Presence of Trypsin

PROBLEM: RNA-RNA recombination salvages viral RNAs and contributes to their genomic variability. A recombinationally-active subgenomic promoter (sgp) has been mapped in Brome mosaic bromovirus (BMV) RNA3 (Wierzchoslawski et al., 2004. J. Virol.78, 8552-8864) and mRNA-like 5′ sgRNA3a was characterized (Wierzchoslawski et al., 2006. J. Virol. 80, 12357-12366). In this paper we describe sgRNA3a-mediated recombination in both in vitro and in vivo experiments. BMV replicase-directed co-copying of (−) RNA3 with wt sgRNA3a generated RNA3 recombinants in vitro, but it failed to when 3′-truncated sgRNA3a was substituted, demonstrating a role for the 3′ polyA tail. Barley protoplast co-transfections revealed that (i) wt sgRNA3a recombines at the 3′ and the internal sites; (ii) 3′-truncated sgRNA3as recombine more upstream; and (iii) 5′-truncated sgRNA3 recombine at a low rate. In planta co-inoculations confirmed the RNA3-sgRNA3a crossovers. In summary, the non-replicating sgRNA3a recombines with replicating RNA3, most likely via primer extension and/or internal template switching.

SOLUTION:
Recombination of 5′ subgenomic RNA3a with genomic RNA3 of Brome mosaic bromovirus in vitro and in vivo