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.

Example Input: We previously identified unusual variants of Moloney and Friend ecotropic mouse gammaretroviruses that have altered host range and are cytopathic in cells of the wild mouse species Mus dunni. Cytopathicity was attributed to different amino acid substitutions at the same critical env residue involved in receptor interaction: S82F in the Moloney variant Spl574, and S84A in the Friend mouse leukemia virus F-S MLV. Because M. dunni cells carry a variant CAT-1 cell surface virus receptor (dCAT-1), we examined the role of this receptor variant in cytopathicity and host range. We expressed dCAT-1 or mCAT-1 of NIH 3T3 origin in cells that are not normally infectible with ecotropic MLVs and evaluated the transfectants for susceptibility to virus infection and to virus-induced syncytium formation. The dCAT-1 transfectants, but not the mCAT-1 transfectants, were susceptible to virus-induced cytopathicity, and this cytopathic response was accompanied by the accumulation of unintegrated viral DNA. The dCAT-1 transfectants, however, did not also reproduce the relative resistance of M. dunni cells to Moloney MLV, and the mCAT-1 transfectants did not show the relative resistance of NIH 3T3 cells to Spl574. Western analysis, use of glycosylation inhibitors and mutagenesis to remove receptor glycosylation sites identified a possible role for cell-specific glycosylation in the modulation of virus entry. Virus entry and virus-induced syncytium formation using the CAT-1 receptor are mediated by a small number of critical amino acid residues in receptor and virus Env. Virus entry is modulated by glycosylation of cellular proteins, and this effect is cell and virus-specific.
Example Output: Role of receptor polymorphism and glycosylation in syncytium induction and host range variation of ecotropic mouse gammaretroviruses

Example Input: The presentation of viral peptide epitopes to host cytotoxic T lymphocytes (CTLs) is crucial for adaptive cellular immunity to clear the virus infection, especially for some chronic viral infections. Indeed, hosts have developed effective strategies to achieve this goal. The ideal scenario would be that the peptide epitopes stimulate a broad spectrum of CTL responses with diversified T-cell receptor (TCR) usage (the TCR repertoire). It is believed that a diversified TCR repertoire requires a "featured" peptide to be presented by the host major histocompatibility complex (MHC). A featured peptide can be processed and presented in a number of ways. Here, using the X-ray diffraction method, the crystal structures of an antigenic peptide derived from rinderpest virus presented by bovine MHC class I N*01801 (BoLA-A11) have been solved, and two distinct conformations of the presented peptide are clearly displayed. A detailed analysis of the structure and comparative sequences revealed that the polymorphic amino acid isoleucine 73 (Ile73) is extremely flexible, allowing the MHC groove to adopt different conformations to accommodate the rinderpest virus peptide. This makes the peptide more featured by exposing different amino acids for T-cell recognition. The crystal structures also demonstrated that the N*01801 molecule has an unusually large A pocket, resulting in the special conformation of the P1 residue at the N terminus of the peptide. We propose that this strategy of host peptide presentation might be beneficial for creating a diversified TCR repertoire, which is important for a moreeffective CTL response. Viral diseases and other infections caused by intracellular pathogens of cattle result in large global economic losses every year. In the past several decades, rinderpest virus (RPV) (23, 40), foot-and-mouth disease virus (FMDV) (7), and bovine tuberculosis infection (62) have brought disastrous consequences, including social panic and even a threat to human health. Nearly 6 decades ago, most countries were committed to developing more-effective vaccines (46), and remarkable achievements were made in controlling threatening bovine viral infectious diseases and other zoonoses (23, 46). In the 1960s, British virologist Walter Plowright developed a live attenuated vaccine against rinderpest virus, which was widely used in rinderpest eradication efforts (40). However, it still remains extremely challenging for humans to completely eradicate a virus. The questions of how the bovine attenuated vaccine induces immune responses and how the viral peptides are presented and recognized by host immune molecules are still largely unanswered. Therefore, studies on bovine immunity against the rinderpest virus may provide clues for our battle against other viral infections. Generally speaking, effective vaccines have common characteristics: they are rich in T-cell and B-cell epitopes and can induce the immune system to generate protective immune responses (3, 36, 54) . During this process, major histocompatibility complex (MHC) molecules play a pivotal role in the host. MHC class I (MHC I) molecules form a heterotrimer complex composed of the heavy chain of MHC, the antigenic peptide, and ␤ 2 -microglobulin (␤ 2 m). Generally, MHC I loads endogenous peptides, including the virus-derived peptides. Briefly, at the initial stage of virus infection, antigenic proteins are processed in a proteasome-dependent or -independent manner. The resultant short peptides are then transported to the endoplasmic reticulum and are loaded onto the peptidebinding grooves of MHC I molecules. Consequently, the peptide-loading MHC I complexes are translocated to the cell surface and are recognized by cytotoxic T lymphocytes (CTLs) with specific T-cell receptors (TCRs) (49, 63). This immune recognition induces an MHC-restricted CD8 ϩ T-cell response that is characterized by the killing and elimination of the infected cells by effector T cells. The majority of virus-derived peptides are processed and presented through this pathway
Example Output: Two Distinct Conformations of a Rinderpest Virus Epitope Presented by Bovine Major Histocompatibility Complex Class I N*01801: a Host Strategy To Present Featured Peptides ᰔ †

Example Input: COVID-19 has spread from China to the rest of the world in a span of just over three months, escalating into a pandemic that poses several humanitarian as well as scientific challenges. We here investigated the geographical expansion of the infection and correlate it with the annual indexes of air quality observed from the Sentinel-5 satellite orbiting around China, Italy and the U.S.A. Controlling for population size, we find more viral infections in those areas afflicted by Carbon Monoxide (CO) and Nitrogen Dioxide (NO2). Higher mortality was also correlated with poor air quality, namely with high PM2.5, CO and NO2 values. In Italy, the correspondence between poor air quality and SARS-CoV-2 appearance and induced mortality was the starkest. Similar to smoking, people living in polluted areas are more vulnerable to SARS-CoV-2 infections and induced mortality. This further suggests the detrimental impact of climate change on the prevention of epidemics.
Example Output:
Initial evidence of higher morbidity and mortality due to SARS-CoV-2 in regions with lower air quality