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: Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. However, resistant strains may impose substantial challenges. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4-binding site (CD4bs). Site-directed mutagenesis revealed that several key epitope mutations facilitate resistance and are located in the inner domain, loop D, and β23/loop V5/β24 of HIV-1 gp120. The resistance is largely correlated with binding affinity of antibodies to the envelope trimers expressed on the cell surface. Our results therefore demonstrate the existence of broadly resistant HIV-1 strains against CD4bs neutralizing antibodies. Treatment strategies based on the CD4bs bnAbs must overcome such resistance to achieve optimal clinical outcomes. Recently identified broadly neutralizing antibodies (bnAbs) show great potential for clinical interventions against HIV-1 infection. Among the bnAbs isolated to date, those targeting the CD4bs are the most abundant and thoroughly studied as they disrupt the crucial step of viral interaction with the cellular receptor molecule CD4. Despite the superior potency and breadth of these CD4bs bnAbs, each fails to neutralize a small but significant portion of pseudotyped virus panels. Here, we report on the identification and characterization of a panel of HIV-1 strains with broad and potent resistance against a large number of bnAbs, particularly those targeting the CD4bs. Resistance is largely attributed to mutated residues within the epitopes or steric hindrance imposed by the bulky side-chain or glycan shield of the mutated residues, and is largely correlated with reduced binding avidity of the antibody to the quaternary trimeric envelope protein expressed on the PLOS Pathogens | https://doi.surface of the transfected cells. Treatment strategies based on the CD4bs bnAbs therefore must overcome such resistance to achieve optimal clinical outcomes. Recent scientific advances have identified a growing number of broadly neutralizing antibodies (bnAbs) against human immunodeficiency virus type I (HIV-1), providing promising candidates for HIV-1 prevention and treatment [1] [2] [3] [4] [5] . Compared with bnAbs isolated in earlier studies, these bnAbs demonstrated broader and more potent activity against global HIV-1 panels and displayed impressive safety and efficacy profiles for therapeutic applications in a number of animal models and human clinical trials [1, [6] [7] [8] [9] [10] [11] . These results also offer the opportunity to tailor these antibodies and maximize their prevention and treatment potential. Broadly speaking, these bnAbs recognize six major "vulnerable sites" on the HIV-1 envelope glycoprotein gp160 (gp120 and gp41), which are (1) the CD4-binding site (CD4bs), (2) the V1V2 apex, (3) the V3 glycan, (4) the fusion peptide (FP), (5) subunit interface and (6) membrane proximal external region (MPER) of gp41[1-5]. These bnAbs neutralize HIV-1 by blocking viral entry into the target cells, although additional effector functions are likely at play, particularly in the context of in vivo infection and clinical application[1, 12-16]. Among the bnAbs isolated to date, those targeting the CD4bs are the most abundant and thoroughly studied as they disrupt the first and crucial step of viral interaction with the cellular receptor CD4 [3, 4, 17, 18] . In this step, the trimeric envelope glycoprotein, composed of gp120 and gp41, binds with the target cell through the receptor CD4, with either CCR5 or CXCR4 as co-receptor [19] [20] [21] . This triggers a cascade of conformational changes that fuses the viral envelope with the target membrane and releases the viral genome into the cell [22, 23] .More than two dozen CD4bs bnAbs have been isolated to date. This number is likely to grow with the advent of more specific and high-throughput techniques for isolating antibodies.For instance, the prototype VRC01 and its close relative VRC03, which effectively neutralize a panel of diverse pseudotyped viruses,were isolated from a clade-B infected individual [24] [25] [26] . The more recently isolated CD4bs bnAbs, such as 3BNC117, N6, N49P7, 3BNC60, VRC-PG04, VRC-PG20, NIH45-46, VRC-CH31, 12A12, CH103, 8ANC131, VRC13, and VRC16, have shown similar or even enhanced potency and breadth compared with VRC01 [1-5, 27, 28].The CD4bs bnAbs are classified into two groups based on their mode of recognition and heavy chain characteristics, such as the VRC01 class(3BNC117, N6, N49P7, 3BNC60, VRC-PG04, VRC-PG20, NIH45-46, VRC-CH31 and 12A12) and non-VRC01 classes (CH103, 8ANC131, VRC13 and VRC16) [17, 18] . Structurally, these bnAbs recognize residues within the inner domain, the Loop D, the CD4 binding loop, and the β23/loop V5/β24 region [17, 18, [29] [30] [31] .The V1V2 and V3 loop also impact recognition,particularly in the context of the quaternary trimeric envelope protein [32] [33] [34] [35] [36] .The primary mechanism of neutralization mimics and competes with the CD4 receptorto bind HIV-1 gp120, thereby preventing bound trimers from transitioning to the subsequent steps required for membrane fusion, although evidence indicates that there are differences in the fine details of this process [17, 18, 35, 36] . Despite the superior potency and breadth of these CD4bs bnAbs, each fails to neutralize a small but significant portion of pseudotyped virus panels [17, 25, 27, 28, 37, 38].For instance, VRC01 is unable to neutralize about 10% of tested viruses [25] , and resistant strains have been isolated from patients infected with subtype B, subtype C, CRF07_BC, and CRF08_BC[29, [39] [40] [41] [42] . Furthermore, reports show thatVRC01-, 3BNC117-and N6-resistant strains have emerged in both animal models and human clinical trials [11, 15, [43] [44] [45] [46] [47] , indicating that resistant virus Broadly resistant HIV-1 against CD4bs antibodies PLOS Pathogens | https://doi.org/10.

SOLUTION: Broadly resistant HIV-1 against CD4-binding site neutralizing antibodies

PROBLEM: Autophagy is a key innate immune response to intracellular parasites that promotes their delivery to degradative lysosomes following detection in the cytosol or within damaged vacuoles. Like Listeria and Shigella, which use specific mechanisms to avoid autophagic detection and capture, the bacterial pathogen Francisella tularensis proliferates within the cytosol of macrophages without demonstrable control by autophagy. To examine how Francisella evades autophagy, we screened a library of F. tularensis subsp. tularensis Schu S4 HimarFT transposon mutants in GFP-LC3-expressing murine macrophages by microscopy for clones localised within autophagic vacuoles after phagosomal escape. Eleven clones showed autophagic capture at six hours postinfection, whose HimarFT insertions clustered to four genetic loci involved in lipopolysaccharidic and capsular O-antigen biosynthesis. Consistent with the HimarFT mutants, in-frame deletion mutants of two representative loci, FTT1236 and FTT1448c (manC), lacking both LPS and capsular O-antigen, underwent phagosomal escape but were cleared from the host cytosol. Unlike wild type Francisella, the O-antigen deletion mutants were ubiquitinated, and recruited the autophagy adaptor p62/SQSTM1 and LC3 prior to cytosolic clearance. Autophagy-deficient macrophages partially supported replication of both mutants, indicating that O-antigen-lacking Francisella are controlled by autophagy. These data demonstrate the intracellular protective role of this bacterial surface polysaccharide against autophagy.

SOLUTION: The Francisella O-antigen mediates survival in the macrophage cytosol via autophagy avoidance NIH Public Access

PROBLEM: Over the last three decades, virus-like particles (VLPs) have evolved to become a widely accepted technology, especially in the field of vaccinology. In fact, some VLP-based vaccines are currently used as commercial medical products, and other VLP-based products are at different stages of clinical study. Several remarkable advantages have been achieved in the development of VLPs as gene therapy tools and new nanomaterials. The analysis of published data reveals that at least 110 VLPs have been constructed from viruses belonging to 35 different families. This review therefore discusses the main principles in the cloning of viral structural genes, the relevant host systems and the purification procedures that have been developed. In addition, the methods that are used to characterize the structural integrity, stability, and components, including the encapsidated nucleic acids, of newly synthesized VLPs are analyzed. Moreover, some of the modifications that are required to construct VLP-based carriers of viral origin with defined properties are discussed, and examples are provided.

SOLUTION:
Construction and Characterization of Virus-Like Particles: A Review