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HIV-1 genetic diversity and genotypic drug susceptibility in the Republic of Georgia.

The genetic diversity and genotypic drug susceptibility of HIV-1 strains circulating in the Republic of Georgia, formerly part of the Soviet Union, were investigated for first time. Forty-eight HIV-positive drug-naive Georgian individuals contributed PBMC DNA between 1998 and 2003. On the basis of phylogenetic analyses of partial pol sequences, the predominant HIV-1 genetic forms were subtype A (70%), followed by subtype B (26%); both genetic forms were carried by injecting drug users and heterosexuals. There was also one subtype C (2%) and one CRF18_cpx (2%). The Georgian subtype A strains clustered with subtype A from Russia, designated A(FSU). Twelve of the subtype A strains (25%) contained the secondary protease inhibitor mutation V77I and 9 also had two other silent mutations. This "V77I haplotype" marks one particular genetic lineage of the epidemic in the former Soviet Union. Two strains (4%) carried antiretroviral (ARV) drug resistance mutations. Nearly full-length genome sequences of five Georgian strains were also completed. Two, 98GEMZ011 (subtype A) and 98GEMZ003 (subtype B), closely resembled the parental strains that recombined to create CRF03_AB. The use of these parental strains in the analysis revealed an additional segment of subtype A in CRF03_AB. Thus, the HIV-1 epidemic in Georgia was composed of a mixture of subtype A(FSU) and subtype B.

Adult↗

Evaluation of a reverse hybridization assay for genotyping of hepatitis C virus.

BACKGROUND/AIMS: Several strains of the hepatitis C virus exist; distinct genotypes and subtypes can be identified by sequence comparison of the viral genomes. Recent evidence that the genotype/subtype of hepatitis C virus may influence the clinical course of chronic hepatitis C and the response to interferon-alpha therapy for this disease suggests that methods to identify the genotype may become clinically useful. In the present study we evaluated a recently introduced reverse hybridization assay. METHODS: HCV-RNA was isolated from serum samples from 61 consecutive patients attending our out-patient clinic and subsequently sequenced in the 5'-noncoding and the nonstructural-5 region by the dideoxynucleotide chain termination method. HCV-genotyping was performed by phylogenetic analysis of nonstructural-5 sequences. The amplification product for the reverse hybridization assay was obtained by "nested" polymerase chain reaction using biotinylated primers corresponding to the 5'-noncoding region. The assay is based on hybridization of the resulting polymerase chain reaction product with oligonucleotide probes immobilized as parallel lines on membrane strips. RESULTS: According to the phylogenetic analysis of the nonstructural-5 region the prevalence of hepatitis C virus subtypes was as follows: 1a 18%, 1b 51%, 2a 3%, 2b 3%, 2c 7% and 3a 18%. The reverse hybridization assay correctly identified each hepatitis C virus genotype (1, 2, and 3). However, differentiation of hepatitis C virus subtypes was insufficient. 1/11 HCV-1a isolates was incorrectly classified by the reverse hybridization assay as HCV-1b and vice versa 3/31 HCV-1b isolates as HCV-1a. Classification of hepatitis C virus subtypes 2a, 2b and 3a was correct, but 4/4 HCV-2c isolates were misinterpreted by the assay as HCV-2a. CONCLUSIONS: The reverse hybridization assay can differentiate between hepatitis C virus genotypes 1, 2, and 3, but is not completely reliable for hepatitis C virus subtyping.

Base Sequence↗

AIDS in an HIV-seronegative Ghanaian woman with intersubtype A/G recombinant HIV-1 infection.

A 29-year-old Ghanaian woman who developed AIDS while being HIV-antibody seronegative was investigated during a collaborative study aimed at the identification of viral causes of a HIV-seronegative AIDS syndrome in West Africa. Plasma was screened with a panel of EIA tests for antibodies to HIV and HIV-1 p24 antigen. Retroviral infection was investigated by detection of reverse transcriptase (RT) activity in plasma, viral RNA amplification and quantification, and virus isolation. Positive amplification products were sequenced and phylogenetic analyses were carried out. Most EIA tests were unable to demonstrate the presence of anti-HIV anti-bodies, whereas confirmatory assays yielded inconclusive results. Retroviral infection was documented by detection of RT activity, HIV-1-specific genomic amplification and virus isolation. This virus was HIV-1 subtype A with an unusual six amino acid insertion in the gp120 V4 loop and with the nef gene of subtype G. The patient's plasma did not react with either autologous or heterologous viral lysates or HIV-1 peptides, whereas antibodies to other viral antigens were present. In conclusion, the Ghanaian patient exhibited a rare subtype A/G recombinant HIV-1 infection with a near absence of a HIV-specific humoral response. The lack of detectable antibody response might be due to either a highly pathogenic, rapidly fatal, HIV-1 infection preventing the development of the typical humoral immune response or to a host-related dysfunction of the immune system. Direct antigenemia or genomic detection of the virus should be undertaken when clinical or biological data suggests an HIV infection in the absence of serological evidence.

Acquired Immunodeficiency Syndrome↗

The Taiwanese hepatitis C virus genome: sequence determination and mapping the 5' termini of viral genomic and antigenomic RNA.

The complete nucleotide sequence of hepatitis C virus (HCV) cloned from the liver tissue of a Taiwanese patient with post-transfusion type C hepatitis was determined. The 5' end of HCV genomic RNA was located 341 nucleotides upstream from the initiation codon for the viral polyprotein open reading frame. The 5' end of the viral antigenomic RNA was shown to have 13 consecutive As. Thus the 3' terminus of the viral genome is a stretch of U which ends about 50 nucleotides downstream from the stop codon of the large open reading frame. The nucleotide sequence homology between this HCV strain and two Japanese isolates was 90.5 and 90.7%, respectively. Homology with the United States strain, however, was only 77.8%. Accordingly, the indigenous Taiwanese HCV strain is of the same subtype as the Japanese isolates. Novel features of the viral genome termini are possibly relevant to HCV genome replication.

Amino Acid Sequence↗

Involvement of closely related strains of a new clonal group of Listeria monocytogenes in the 1998-99 and 2002 multistate outbreaks of foodborne listeriosis in the United States.

In 1998-99, a multistate outbreak of listeriosis in the United States was associated with contaminated hot dogs and was caused by a strain of Listeria monocytogenes serotype 4b that had been only rarely encountered before in the national PulseNet database. Upon further characterization, the strains from this outbreak were designated as Epidemic Clone II (ECII). ECII isolates exhibited diversification in a genomic region ("region 18") that was otherwise conserved among L. monocytogenes of serotype 4b. Additional unique genetic markers were identified through genome sequencing of one of the isolates from the 1998-99 outbreak. In 2002, another multistate outbreak of listeriosis also involved bacteria of serotype 4b and was attributed to contaminated turkey deli meats. Molecular subtyping data revealed that the macrorestriction patterns of the isolates from the 1998-99 and 2002 outbreaks were closely related. In addition, the 2002 outbreak isolates harbored chromosomal genetic markers found to be unique to, and typical of, the 1998-99 outbreak isolates, including diversification in genomic region 18. Macroarray- based subtyping using chromosomal sequences confirmed the close genetic relatedness between the isolates from the two outbreaks. Genomic content was highly conserved among isolates from each outbreak, with differences detected only in prophage and internalin-like gene sequences. However, since these differences were observed among isolates from each of the outbreaks, they did not differentiate the 1998-99 isolates as a group from those of the 2002 outbreak. Two of 15 randomly chosen serotype 4b clinical isolates from a non-outbreak period (calendar year 2003) appeared to be closely related to the 1998-99 and 2002 outbreak isolates. These findings suggest that both multistate outbreaks of listeriosis in the United States involved closely related members of a single clonal group (ECII) that had not been identified in outbreaks prior to 1998. Since the outbreaks involved different food vehicles and processing plants, the findings suggest establishment of ECII in a still unidentified reservoir in the United States, from which the organisms were introduced to different processing plants.

Animals↗

Identification of a novel clade of human immunodeficiency virus type 1 in Democratic Republic of Congo.

The high genetic heterogeneity of HIV-1 in the Democratic Republic of Congo (DRC) constitutes a real challenge for the development of vaccines to counter the spread of the HIV-1 epidemic. It is important to continue to monitor the epidemic by studying the circulating strains and their impact on the overall spread. As part of the ongoing effort to study the global distribution of HIV-1 subtypes and circulating recombinant forms (CRFs), here we describe a new phylogenetic clade of HIV-1 by the analysis of two full-length sequences (83CD003 and 90CD121E12) collected from two individuals at a 7-year interval (1983 and 1990, respectively). One of the two sequences (90CD121E12) was obtained from a vertically infected, 12-month-old baby in Kimpese, rural DRC, an area with low and stable seroprevalence of HIV-1 in women attending antenatal clinics. The two sequences are genetically similar by 95% of their full genome and topologically form a distinct cluster that is equidistant from the existing subtypes (A through K) by the analysis of both the full genome and subgenomic regions. Furthermore, they share several other genetic features, including an additional pair of cysteine residues, predictive of an extra disulfide bridge, in the V4 loop of gp120. This new clade is currently rare, spreading at a slower pace than the other subtypes found in the DRC region. Pending the identification of at least one partial length sequence of the same lineage from another patient who is epidemiologically unlinked to those described here, this clade is not yet named as a subtype as per the recommendation of the nomenclature committee.

Amino Acid Sequence↗

A Multi-omics Regulated Cell Death Framework Defines Immune Phenotypes and Guides Precision Therapy in Colorectal Cancer.

Colorectal cancer (CRC) is molecularly and immunologically heterogeneous, contributing to variable treatment response. Because regulated cell death (RCD) intersects with tumor metabolism, immune regulation, and therapeutic susceptibility, we built an RCD-centered framework for CRC stratification. Multi-cohort transcriptomic data were used to infer RCD subtypes with non-negative matrix factorization (NMF) and non-negative least squares (NNLS). Genomic, bulk RNA-seq, single-cell RNA-seq, and spatial transcriptomic datasets were integrated to characterize subtype-associated biology. Machine-learning models were developed for immunotherapy response and survival-risk estimation. Candidate compounds were screened by GDSC2-based drug-sensitivity modeling and molecular docking, and FSTL3 was functionally assessed in vitro. The framework separated CRC samples into two RCD-related phenotypes resembling immune-hot and immune-cold states. RCD1 showed immune activation and higher mutational burden, whereas RCD2 showed immune-suppressed features, intratumoral heterogeneity, and aggressive biology. RCD-associated signatures showed potential for predicting immunotherapy response and survival risk. Dasatinib was prioritized for immune-cold, high-risk tumors, with preliminary evidence supporting its activity in CRC cells, while functional assays suggested a role for FSTL3 in growth, invasion, epithelial-mesenchymal transition, and apoptosis regulation. These findings suggest that RCD-based multi-omics analysis may refine CRC stratification and help generate therapeutic hypotheses.

Colorectal cancer↗

Distinguishing molecular forms of HIV-1 in Asia with a high-throughput, fluorescent genotyping assay, MHAbce v.2.

High-resolution HIV-1 genotyping of large sample sets is crucial to define the evolving and dynamic epidemics in Asia. Here we present MHAbce v.2, a multi-region hybridization assay that individually discriminates subtypes B, C, CRF01_AE, and virtually all of their described recombinants, based on real-time PCR using subtype-specific TaqMan probes in 8 regions throughout the viral genome. In a validation panel (n=70), the assay performed with a sensitivity of 95.7% and specificity of 99.8%. The assay was field-tested on samples from a retrospective MTCT cohort (n=180; Lampang Province, Northern Thailand; 1996-1998). 177/180 of the samples were typeable, and 94.4% were typed as CRF01_AE. The remaining strains represented even proportions of subtype B and B/CRF01_AE recombinants and were confirmed by sequencing, revealing early links between the heterosexual and IDU HIV-1 epidemics in Thailand. MHAbce v.2, with an area of application including China, India, Southeast Asia, and the Pacific Rim, can be used to develop a comprehensive and detailed picture of this important component of the HIV/AIDS pandemic.

Adult↗

Myeloid-Mediated Immunoregulation and Resistance to Immune Checkpoint Inhibitor Therapy Across Squamous Cell Carcinomas: Mechanisms and Reprogramming Strategies.

Immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 have improved outcomes across squamous cell carcinomas (SCCs) of the head and neck, lung, esophagus, and skin, yet durable responses remain confined to a subset of patients in every subtype. Objective response rates vary substantially across SCCs despite overlapping genomic alterations, comparable tumor mutational burden, and high PD-L1 expression, indicating that tumor-intrinsic biomarkers alone do not explain this variability. Growing evidence points to the tumor immune microenvironment, and in particular the myeloid compartment, as a critical determinant of immunotherapy responsiveness. In this review, we synthesize current evidence on myeloid-mediated immune regulation across SCC subtypes, focusing on tumor-associated macrophages, myeloid-derived suppressor cells/tumor-associated neutrophils, and dendritic cells, and the mechanisms by which these populations impair antigen presentation, restrict T cell infiltration, and sustain immunologically "cold" tumor states. We further examine therapeutic strategies aimed at reprogramming rather than simply depleting suppressive myeloid populations, including radiation therapy, STING agonism, and myeloid-targeted agents (CSF1R, PI3Kγ, and CXCR2 inhibition), each of which has shown encouraging preclinical and early clinical activity in combination with ICI. Collectively, this evidence supports a model in which the myeloid compartment functions as an actionable, convergent determinant of ICI resistance across SCC subtypes, rather than merely a passive biomarker. We propose that through the integration of spatial and single-cell profiling of myeloid states with clinical history it will be possible to predict response to immune checkpoint therapy and personalize myeloid-directed combination strategies, though the specific biomarkers needed to match individual patients to a given myeloid-targeted approach remain to be defined. We further discuss the toxicity considerations associated with both immune checkpoint blockade and radiation-based combination approaches, the early-phase status of most myeloid-targeted agents currently in clinical development, and the extent to which mechanistic insight, derived predominantly from HNSCC, generalizes to squamous cell carcinomas arising at other anatomic sites.

dendritic cells↗

Characterization of novel recombinant HIV-1 genomes using the branching index.

We have characterized six novel genomes of human immunodeficiency virus type 1 (HIV-1) sampled from individuals infected in Uganda and former Zaire. Four isolates (SE6954, SE8603, UG035, and UG266) had clear recombination patterns that included subtypes A1, D and C. The two remaining strains (SE8646 and SE9010) also appeared to be recombinant but had a more complex pattern. To facilitate the classification of these two genomes we developed a metric, the branching index, for characterization of "problematic" sequence fragments that associate to a subtype cluster with a high bootstrap value but are only distantly related to the reference sequences. The branching index is able to signal when parental representatives may be missing and a subtype classification thus is not meaningful. Several fragments of SE8646 and SE9010 had a branching index below the subtype defining cutoff value (0.55) and, therefore, these genomes could not be unequivocally classified. The branching index, with a cutoff value defined from analyses of HIV-1 reference sequences, may be a useful approach not only for more conservative classifications of HIV-1 subtypes but also for analyzing relationships among other types of sequences.

Evolution, Molecular↗

Deregulation of FOXF1/FENDRR from t(14;16)(q32;q24) defines a subtype of high-risk lineage ambiguous leukemia.

Despite great progress in understanding the genomic basis of immature T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma (T-ALL) and acute leukemias of ambiguous lineage, there are still cases that lack defining genetic markers, complicating risk stratification, and limiting targeted therapeutic options. Recent studies have shown that enhancer hijacking drives oncogene activation in approximately half of T-ALL cases, with the BCL11B (BCL11 transcription factor B) enhancer frequently involved. Here, we describe a subtype of leukemia with a distinct gene-expression signature, and immunophenotype characterized by positivity for immature (CD38), myeloid (CD13), T-lymphoid (cytoplasmic [c]CD3, CD7), and B-lymphoid markers (CD19, CD79a, CD10). This subtype is defined by the t(14;16)(q32;q24) translocation, which places the FOXF1 gene and its antisense long noncoding RNA gene FENDRR under the regulatory control of the BCL11B enhancer, leading to their ectopic transcriptional activation. Common concomitant genetic lesions are loss-of-function alterations of GATA3, CDKN2A/CDKN2B deletion and activating JAK/STAT and NOTCH1 pathway mutations. Patients were predominantly children and adolescents/young adults and experienced poor treatment outcome. High-throughput drug screening of 176 compounds demonstrated efficacy of combined BCL2 apoptosis regulator family proteins and JAK/STAT signaling inhibitors. Additionally, the clinical use of tyrosine kinase inhibitors in some of these patients showed therapeutic efficacy. Collectively, these findings identify BCL11B-enhancer-mediated deregulation of FOXF1/FENDRR as a hallmark of a subtype of high-risk lineage ambiguous leukemia that is potentially amenable to targeted therapeutic intervention.

Humans↗

Mega-Enhancer Bodies Organize Neuronal Long Genes in the Cerebellum.

Dynamic regulation of gene expression plays a key role in establishing the diverse neuronal cell types in the brain. Recent findings in genome biology suggest that three-dimensional (3D) genome organization has important, but mechanistically poorly understood functions in gene transcription. Beyond local genomic interactions between promoters and enhancers, we find that cerebellar granule neurons undergoing differentiation in vivo exhibit striking increases in long-distance genomic interactions between transcriptionally active genomic loci, which are separated by tens of megabases within a chromosome or located on different chromosomes. Among these interactions, we identify a nuclear subcompartment enriched for near-megabase long enhancers and their associated neuronal long genes encoding synaptic or signaling proteins. Neuronal long genes are differentially recruited to this enhancer-dense subcompartment to help shape the transcriptional identities of granule neuron subtypes in the cerebellum. SPRITE analyses of higher-order genomic interactions, together with IGM-based 3D genome modeling and imaging approaches, reveal that the enhancer-dense subcompartment forms prominent nuclear structures, which we term mega-enhancer bodies. These novel nuclear bodies reside in the nuclear periphery, away from other transcriptionally active structures, including nuclear speckles located in the nuclear interior. Together, our findings define additional layers of higher-order 3D genome organization closely linked to neuronal maturation and identity in the brain.

Journal Article↗

Genomic diversity of human immunodeficiency virus type-1 in India.

Surveillance of HIV-1 subtypes has important implications for the development of candidate vaccine and understanding the possible differences in the transmission and natural history of different subtypes. In this study, HIV-1 subtypes were determined for homologies in the C2-V3-V5 region by heteroduplex mobility assay (HMA) in HIV-1 seropositive patients referred to the National HIV/AIDS Reference Centre, All India Institute of Medical Sciences in New Delhi, India. Of the 125 samples analysed, 98 (78.4%) were HIV-1 subtype C, 11 (8.8%) were subtype B', 3 (2.4%) were subtype A and 2 (1.6%) were subtype E. In 11 samples, subtype determination was not clear-cut. It is possible that these individuals may be infected with recombinant strains of HIV-1. These findings may have significant implications for the designing and testing of effective HIV-1 vaccine candidate in India.

Female↗

Genetic variability of gag and env regions of HIV type 1 strains circulating in Slovenia.

The aim of this study was to investigate the genetic diversity of HIV-1 strains circulating in Slovenia. Proviral DNA isolated from peripheral blood mononuclear cells (PBMCs) of 20 randomly selected HIV-1-infected individuals was classified into subtypes by sequence-based phylogenetic analysis of the env (C2V3) and gag (p24) regions of the viral genome. The phylogenetic tree based on env C2V3 sequences showed that 15 of the 20 samples were subtype B, two A1, one F1, one CRF01_AE, and one CRF02_AG. The phylogenetic analysis of the gag gene yielded identical results expect for one sample that had a discordant subtype; it was identified as subtype A1 in the env and AE in the gag region. Our study confirmed that although subtype B predominates, other subtypes and circulating recombinant forms (CRFs) are also present in Slovenia. The high intrasubtype genetic diversity of subtype B sequences suggests a multiple introduction of subtype B strains into Slovenia.

Amino Acid Sequence↗

Integrated Genomic and Immune Profiling of Early Onset Lung Cancer in East Asians Reveals a Distinct Molecular Architecture.

BACKGROUND: The age cut-off for early-onset lung cancer (EOLC) varies across studies (40-50 years). Here, we define EOLC as diagnosis at &#x2264; 40 years, a threshold identifying a subgroup with distinct clinical characteristics. However, whether EOLC differs fundamentally from late-onset lung cancer (LOLC) at the molecular level and represents a distinct subtype requiring different management remains unclear. METHODS: This integrated analysis included genomic and immune profiling data from 8,021 lung cancer patients, comprising 302 EOLC and 7,719 LOLC cases. Using targeted sequencing, we assessed somatic and germline alterations, mutational signatures, and immune biomarkers including tumor mutational burden (TMB), MSI status, and PD-L1 expression. RESULTS: EOLC patients were more often female, had adenocarcinoma, and earlier-stage disease. Molecular profiling revealed significant enrichment of ERBB2 mutations in EOLC, while KRAS, TP53, and MET mutations were more common in LOLC. Mutational signature analysis indicated tobacco-related signatures predominated in LOLC, whereas endogenous processes contributed more substantially in EOLC. Germline analysis showed a higher burden of pathogenic variants in EOLC (14.57% vs. 8.93%, P < .01), with TP53 and BRCA1 being particularly prominent. Immunologically, LOLC tumors exhibited higher TMB and PD-L1 positivity. CONCLUSION: Integrated profiling establishes EOLC as a distinct molecular subtype, defined by a unique triad: an ERBB2-driven somatic profile, germline susceptibility in DNA damage response pathways, and an endogenous mutagenic process within a low-TMB microenvironment. The findings are specific to the selected threshold and should be interpreted accordingly, while elucidating EOLC pathogenesis and supporting age-specific management strategies.

Humans↗

[Genetic characterization of the entire genome of an H9N2 avian influenza virus A/Chicken/Shanghai/F/98].

Eight full-length genes of an H9N2 subtype avian influenza virus A/Chicken/Shanghai/F/ 98(H9N2), were amplified by RT-PCR and rapid amplification of cDNA ends (RACE) and sequenced. The results of phylogenetic analysis showed that A/Chicken/Shanghai/F/98 was entirely different from Quail/Hong Kong/G1/97 which was directly related to human infection with avian influenza virus in Hong Kong, whereas its HA, NA, M and NS genes belonged to A/Chicken/Beijing/ 1/94-like sublineage with the nucleotide homology of 96.7%, 96.4%, 97.5% and 98.0% respectively. The homology of NA gene between A/Chicken/Shanghai/F/98 and A/Duck/Hong Kong/Y280/ 97 was 97.4% and they both lost 9 nucleotides between nt 205 to 206. However, the PB2, PB1, PA, NP genes did not show any close relationship with those of the three known sublineages and the later three didn't share immediate ancestors with available isolates whose sequences had been reported. Therefore, A/Chicken/Shanghai/F/98 is a product of natural reassortment between H9N2 avian influenza viruses from different sublineages.

Animals↗

A specific subtype C of human immunodeficiency virus type 1 circulates in Brazil.

OBJECTIVE: To characterize the subtype C strains of HIV type 1 that circulate in Brazil, especially those originated from the southern part of the country. DESIGN AND METHODS: One hundred and twelve HIV-1-positive subjects had their plasma viral RNA extracted. Protease (PR) and reverse transcriptase (RT) genomic regions were polymerase chain reaction-amplified and sequenced for subtype determination. Subtype C strains were selected and compared to other strains of this subtype from the database, and specific amino acid signature patterns were searched. RESULTS: Brazilian subtype C viruses form a very strong monophyletic group when compared to subtype C viruses from other countries and presented specific signature amino acids. Recombinants between subtype C and B viruses have been documented in areas of co-circulation. The incidence of primary PR and RT inhibitor resistance mutations in drug-naïve subjects was observed. An increasing number of secondary resistance mutations was also seen, some of which are characteristic of subtype C-related sequences. CONCLUSIONS: Introduction of subtype C of HIV-1 in Brazil was likely a single event of one or a mixture of similarly related strains. Recombination between subtype C and B viruses is an ongoing process in the country. Primary and secondary drug resistance mutations were observed, although some of the secondary mutations could be associated with subtype C molecular signatures. Subtype-specific polymorphisms of PR and RT sequences found in this subtype C Brazilian variant might influence this emergence and have an impact on HIV treatment and on vaccine development in the country.

Adolescent↗