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]: Bacille Calmette-Guérin (BCG) is an attenuated strain of Mycobacterium bovis currently used as a vaccine against tuberculosis. Global distribution and propagation of BCG has contributed to the in vitro evolution of the vaccine strain and is thought to partially account for the different outcomes of BCG vaccine trials. Previous efforts by several molecular techniques effectively identified large sequence polymorphisms among BCG daughter strains, but lacked the resolution to identify smaller changes. In this study, we have used a NimbleGen tiling array for whole genome comparison of 13 BCG strains. Using this approach, in tandem with DNA resequencing, we have identified six novel large sequence polymorphisms including four deletions and two duplications in specific BCG strains. Moreover, we have uncovered various polymorphisms in the phoP-phoR locus. Importantly, these polymorphisms affect genes encoding established virulence factors including cell wall complex lipids, ESX secretion systems, and the PhoP-PhoR two-component system. Our study demonstrates that major virulence factors are different among BCG strains, which provide molecular mechanisms for important vaccine phenotypes including adverse effect profile, tuberculin reactivity and protective efficacy. These findings have important implications for the development of a new generation of vaccines.
[EX A]: BMC Genomics Novel genome polymorphisms in BCG vaccine strains and impact on efficacy

[EX Q]: Four Massachusetts-type (Mass-type) strains of infectious bronchitis coronavirus (IBV) were compared genetically with the pathogenic M41 and H120 vaccine strains using the complete genomic sequences. The results revealed that strains ck/CH/LNM/091017 and ck/CH/LDL/101212 were closely related to the H120 vaccine, which suggests that they might represent re-isolations of vaccine strains or variants of vaccine strains that have resulted from the accumulated point mutations after several passages in chickens. In contrast, strains ck/CH/LHLJ/07VII and ck/CH/LHLJ/100902 had a close genetic relationship with the pathogenic M41 strain. In addition, molecular markers have been identified that distinguish between field and vaccine (or vaccine-like) Mass-type viruses, which may be able to differentiate between field and vaccine strains for diagnostic purposes. Phylogenetic analysis, and pairwise comparison of full-length genomes and the nine genes, identified the occurrence of recombination events in the genome of strain CK/VH/LHLJ/07VII, which suggests that this virus originated from recombination events between M41-and H120-like strains at the switch site located at the 3 0 end of the nucleocapsid (N) genes. To our knowledge, this is the first time that evidence for the evolution and natural recombination under field conditions between Mass-type pathogenic and vaccinal IBV strains has been documented. These findings provide insights into the emergence and evolution of the Mass-type IB coronaviruses and may help to explain the emergence of Mass-type IBV in chicken flocks all over the world.
[EX A]: Comparative analysis of four Massachusetts type infectious bronchitis coronavirus genomes reveals a novel Massachusetts type strain and evidence of natural recombination in the genome

[EX Q]: Background: Nonspecific interstitial pneumonia (NSIP) is characterized by interstitial infiltration of T lymphocytes, and subpopulations of these cells may be associated with the progression of fibrosis. However, few studies evaluate the correlation of prognosis with this characteristic. Therefore, we performed morphological and quantitative analyses of T lymphocytes in patients with NSIP and evaluated the relationship between T lymphocytes and prognosis. Methods: Immunohistochemistry was used to detect the presence of CD4+ and CD8+ T lymphocytes in 55 biopsies of patients with NSIP to determine the numbers of these T cell subpopulations in lymphoid follicles as well as in perivascular, interstitial, and peribronchial anatomical compartments. The relationship between CD4+ and CD8+ T lymphocyte populations and prognosis was analyzed. Results: The mean age of 55 patients was 48.9 ± 10.5 years, and 36 (65 %) of patients were women. All patients were followed for a mean duration of 46 ± 25 months. Thirteen (23.6 %) patients died during follow-up. Perivascular CD4+ lymphocyte infiltration (HR, 0.939; 95 % CI, 0.883-0.999; p = 0.048) was an independent risk factor for survival. Perivascular infiltrates of CD4+ T lymphocytes correlated with survival time (r = 0.270, p = 0.046). Patients with improved forced vital capacity survived longer and had higher numbers of CD4+ T lymphocytes that infiltrated perivascular tissue. The densities of CD4+ and CD8+ T lymphocytes infiltrating other tissues were not significantly associated with survival time. Conclusions: Perivascular infiltration of CD4+ T lymphocytes in patients with NSIP correlated with prognosis. The underlying mechanisms are unknown and require further studies.
[EX A]:
Prognosis of nonspecific interstitial pneumonia correlates with perivascular CD4+ T lymphocyte infiltration of the lung