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Biomedical subjects

G M Shaw

Publications and source records attributed to G M Shaw.

At least 73 records · Page 4Linked to original sources
PubMed1999

Maternal occupational and hobby chemical exposures as risk factors for neural tube defects.

In a case-control study, we investigated whether occupational and nonoccupational (hobbies) chemical exposures to women in the periconceptional period increased their risk for having neural tube defect-affected pregnancies. Women were asked about occupational tasks and hobbies performed during the 3 months before through 3 months after conception. Based on her reported occupational tasks and hobbies, an industrial hygienist assigned a priori defined exposure categories to each task and hobby. The exposure categories included 74 chemical groups, 9 "end-use" chemical groups, and organic solvents. Face-to-face interviews were conducted with mothers of 538 (88% of eligible) infants or fetuses with neural tube defect and mothers of 539 (88%) randomly selected, nonmalformed, live-born infants from a population-based 1989-1991 cohort of California births (N = 703,518). Our results suggested that maternal exposures in the periconceptional period to a variety of chemicals associated with occupational and nonoccupational activities did not contribute substantially to risk of neural tube defects in offspring. We observed no effect estimate greater than 2.0 for maternal exposures to the chemical agent groups studied. We did not observe substantially elevated risks associated with maternal exposures to any of the end-use chemical groups or to organic solvents. Considering occupational exposures only among women who worked did not substantially alter results. Adjustment for maternal vitamin use, race/ethnicity, or education level also did not substantially alter the observed associations.

California↗
PubMed1999

Concordant induction of cyclin E and p21cip1 in differentiated keratinocytes by the human papillomavirus E7 protein inhibits cellular and viral DNA synthesis.

Productive infections by human papillomaviruses (HPVs) occur only in differentiated keratinocytes in squamous epithelia in which the HPV E7 protein reactivates the host DNA replication machinery to support viral DNA replication. In a fraction of the differentiated keratinocytes, E7 also posttranscriptionally induces p21Cip1, which is distributed in a mutually exclusive manner with unscheduled cellular DNA synthesis. In this study, double immunofluorescence labeling unexpectedly revealed that E7 caused a concordant accumulation of both cyclin E and p21Cip1 to high levels in patient papillomas and in organotypic cultures of primary human keratinocytes. The induction of cyclin E is mutually exclusive with unscheduled cellular DNA synthesis or abundant viral DNA. These novel virus-host interactions in differentiated keratinocytes are in contrast to previous observations made in submerged proliferating cultures, in which HPV E7 induces cyclin E and overcomes p21Cip1 inhibition of S-phase entry. We propose that an appropriately timed induction of cyclin E/cyclin-dependent kinase 2 by HPV E7 in postmitotic cells enables S-phase reentry and HPV DNA amplification, whereas prematurely induced cyclin E stabilizes p21Cip1 protein, which then inhibits cyclin E/cyclin-dependent kinase 2. Consequently, cyclin E and p21Cip1 both fail to turn over, and DNA synthesis does not occur.

Basal Ganglia↗
PubMed1999

Periconceptional nutrient intake and risk for neural tube defect-affected pregnancies.

We investigated whether intakes of nutrients, including folate, by women in the periconceptional period were associated with risks of neural tube defect (NTD)-affected pregnancies. Data were part of a case-control study of fetuses and infants with NTDs among 1989-1991 California births. We conducted interviews with mothers of 409 NTD cases and 420 nonmal-formed controls. Nutrient intake for the 3 months before conception was derived from food frequency questionnaires and from questions to mothers about vitamin/mineral supplement use. We computed NTD risk for each nutrient controlling for the influence of all other studied nutrients and for maternal education, race/ethnicity, height, and prepregnancy weight. Most single nutrients reduced NTD risks when intakes were considered in quartiles and unadjusted for other nutrients. Some of the same nutrients, however, did not provide similar interpretations when we adjusted for other nutrients. Adjusted analyses revealed decreased NTD risks with increased intakes of methionine, lutein, magnesium, zinc, and thiamin for women who did not use vitamin supplements periconceptionally. We observed decreased NTD risks associated with increased intakes of linoleic acid, cysteine, calcium, and zinc for women who used supplements. We also observed increased NTD risks with increased intakes of oleic acid. For users as well as nonusers of vitamin supplements, we observed reduced risks with increased intakes of grains and dairy products. Chance was a likely alternative explanation for many of the observed risk patterns.

California↗
PubMed1999

Maternal pesticide exposure from multiple sources and selected congenital anomalies.

We explored the relation between various potential sources of maternal periconceptional pregnancy exposures to pesticides and congenital anomalies in offspring. Data were derived from a case-control study of fetuses and liveborn infants with orofacial clefts, neural tube defects, conotruncal defects, or limb anomalies, among 1987-1989 California births and fetal deaths. We conducted telephone interviews with mothers of 662 (85% of eligible) orofacial cleft cases, 265 (84%) neural tube defect cases, 207 (87%) conotruncal defect cases, 165 (84%) limb cases, and 734 (78%) nonmalformed controls. The odds ratio (OR) estimates did not indicate increased risk for any of the studied anomaly groups among women whose self-reported occupational tasks were considered by an industrial hygienist likely to involve pesticide exposures. Paternal occupational exposure to pesticides, as reported by the mother, revealed elevated ORs for only two of the cleft phenotypes [OR = 1.7 [95% confidence interval (CI) = 0.9-3.4] for multiple cleft lip with/without cleft palate and OR = 1.6 [95% CI = 0.7-3.4] for multiple cleft palate]. Use of pesticide products for household gardening, by mothers or by professional applicators, was associated with ORs > or =1.5 for most of the studied anomalies. Use of pesticide products for the control of pests in or around homes was not associated with elevated risks for most of the studied anomalies, although women who reported that a professional applied pesticides to their homes had increased risks for neural tube defect-affected pregnancies [OR = 1.6 (95% CI = 1.1-2.5)] and limb anomalies [OR = 1.6 (95% CI = 1.0-2.7)]. Having a pet cat or dog and treating its fleas was not associated with increased anomaly risk. Women who reported living within 0.25 miles of an agricultural crop revealed increased risks for offspring with neural tube defects [OR = 1.5 (95%CI = 1.1-2.1)]. For many of the comparisons, data were sparse, resulting in imprecise effect estimation. Despite our investigating multiple sources of potential pesticide exposures, without more specific information on chemical and level of exposure, we could not adequately discriminate whether the observed effects are valid, whether biased exposure reporting contributed to the observed elevated risks, or whether nonspecific measurement of exposure was responsible for many of the observed estimated risks not being elevated.

Adult↗
PubMed1998

Infant C677T mutation in MTHFR, maternal periconceptional vitamin use, and cleft lip.

Studies have reported an association between homozygosity for a variant form of the methylenetetrahydrofolate reductase (MTHFR) gene and risk for neural tube defects. Because of MTHFR's involvement with folate metabolism and evidence that maternal use of a multivitamin with folic acid in early pregnancy reduces risk for cleft lip with or without cleft palate (CLP), we hypothesized that infants homozygous for the C677T genotype would be at increased risk for CLP because of lower MTHFR enzymatic activity. Data were derived from a large population-based, case-control study of fetuses and liveborn infants among a cohort of 1987 to 1989 California births. The analyses involved 310 infants with isolated CLP whose mothers completed a telephone interview and whose DNA was available from newborn screening blood specimens and involved 383 control infants without a congenital anomaly whose mothers completed a telephone interview and whose DNA was available. Cases and controls were genotyped TT if homozygous for the C677T allele, CT if heterozygous for the C677T allele, and CC if homozygous for the C677 (wild-type) allele. Odds ratios for CLP were 0.89 (0.55 to 1.4) and 0.78 (0.56 to 1.1) for infants with TT versus CC and infants with CT versus CC genotypes, respectively. Compared with the CC genotype, the odds ratios for CLP among infants with the TT genotype were 0.74 (0.39 to 1.4) for those infants whose mothers were users and 1.4 (0.54 to 3.6) for those infants whose mothers were not users of multivitamins containing folic acid periconceptionally. The two estimates were not statistically heterogeneous (P = 0.30). Our results did not indicate increased risks for CLP among infants homozygous for the C677T genotype, nor do they indicate an interaction between infant C677T genotype and maternal multivitamin use on the occurrence of CLP.

Case-Control Studies↗
PubMed1998

Localization of HuC (ELAVL3) to chromosome 19p13.2 by fluorescence in situ hybridization utilizing a novel tyramide labeling technique.

HuC is a neural-specific member of the Elav family of RNA-binding proteins. This highly conserved gene family plays a crucial role in neurogenesis, and HuC (HGMW-approved symbol ELAVL3) is expressed at an early stage of neural development. Using a novel tyramide fluorescence in situ hybridization (T-FISH) technique, we localized HuC to chromosome 19p13.2. This localization was confirmed by radiation hybrid mapping and coincides with that of HuR (HGMW-approved symbol ELAVL1), another elav family member. Dual T-FISH analysis with HuC and HuR probes, however, indicated distinct loci, with HuC being centromeric to HuR. This study demonstrates the utility of T-FISH in colocalizing two genes on the same chromosomal preparation using only biotinylated probes.

Antigens, Surface↗
PubMed1998

Racial and ethnic variations in the prevalence of orofacial clefts in California, 1983-1992.

To investigate variations in the prevalence of oral cleft anomalies according to parental race and ethnicity and maternal country of birth, the authors analyzed a cohort of 2,221,755 live births and fetal deaths delivered between 1983 and 1992 to residents of California. A total of 2,329 cleft lip with or without cleft palate (CL +/- P) cases and 1,475 cleft palate alone (CP) cases were identified by the California Birth Defects Monitoring Program, a population-based registry. Compared to Whites, the prevalence of CL +/- P was lower among African Americans (prevalence ratio (PR) = 0.56, 95% confidence interval (CI) = 0.45-0.69), higher among Native Americans (PR = 1.81, CI = 1.20-2.69), and the same among the Japanese (PR = 1.07, CI = 0.62-1.82) and Chinese (PR = 0.96, CI = 0.71-1.29). The risk of CL +/- P was slightly lower among the offspring of foreign-born Chinese women relative to U.S.-born Chinese women (PR = 0.71, CI = 0.33-1.57), and slightly higher among foreign-born Filipinos relative to their U.S.-born counterparts (PR = 1.37, CI = 0.57-3.53), although confidence intervals around these risk estimates were wide owing to sparse data. For CP, lower prevalences were observed among African Americans (PR = 0.72, CI = 0.58-0.91) and Hispanics (PR = 0.77, CI = 0.67-0.87) than among Whites. The risk of CP was higher among foreign-born Filipinos compared to U.S.-born Filipinos (PR = 1.52, CI = 0.58-4.33), although the confidence interval around this estimate included unity. These prevalence variations may reflect differences in both environmental and genetic factors affecting clefting risk.

California↗
PubMed1998

Maternal vitamin use, genetic variation of infant methylenetetrahydrofolate reductase, and risk for spina bifida.

Maternal periconceptional use of vitamin supplements containing folic acid substantially reduces the risk of neural tube defects (NTDs) in the offspring. The mechanism underlying this reduction in risk is unknown. Several recent studies have reported an association between homozygosity for a variant form (the C677T genotype) of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and risk for NTDs in individuals. It has been hypothesized that maternal folic acid supplementation prevents NTDs by partially correcting reduced MTHFR activity associated with the variant form of the enzyme. Using data from two California case-control interview studies (1987-1991 birth cohorts), the authors investigated whether an interaction for spina bifida risk existed between infant MTHFR C677T genotype and maternal use of supplements containing folic acid. The authors genotyped the allelic variants of MTHFR in 214 liveborn case infants with spina bifida and 503 control infants for whom information on maternal periconceptional vitamin use was available. The percentage of all case infants with the C677T MTHFR mutation, for both homozygous (TT) and heterozygous (TC) genotypes, was slightly higher than that of controls. The C677T genotype was substantially more frequent among both case and control Hispanic infants than among non-Hispanic infants. Among all infants whose mothers did not periconceptionally use vitamins containing folic acid, the risk of spina bifida, as measured by the odds ratio, was 1.6 (95% confidence interval (CI) 0.8-3.1) for all infants with the TT genotype and 2.0 (95% CI 0.5-7.4) for non-Hispanic white infants with the TT genotype, as compared with infants with the CC genotype. This result indicates a modestly increased risk associated with the C677T genotype. A lower risk estimate (odds ratio=1.2, 95% CI 0.4-4.0) was observed among infants whose mothers periconceptionally used vitamin supplements containing folic acid. This population-based California study found a modestly increased risk of spina bifida among infants who were homozygous for the C677T genotype, but only minimal evidence of an interaction between the C677T genotype and maternal folic acid intake in the occurrence of spina bifida. If this mutant MTHFR genotype plays a role in the association between maternal vitamin use and NTD risk, it may be a small role, or it may be conditional on maternal genotype.

Case-Control Studies↗
PubMed1998

A novel and ubiquitous system for membrane targeting and secretion of cofactor-containing proteins.

We report the identification of the proteins encoded by the mttABC operon (formerly yigTUW), which mediate a novel Sec-independent membrane targeting and translocation system in Escherichia coli that interacts with cofactor-containing redox proteins having a S/TRRXFLK "twin arginine" leader motif. A pleiotropic-negative mutant in mttA prevents the periplasmic localization of twin arginine redox enzymes, including nitrate reductase (NapA) and trimethylamine N-oxide reductase (TorA). The mutation also prevents the correct localization of the integral membrane molybdoenzyme dimethylsulfoxide reductase (DmsABC). The DmsA subunit has a twin arginine leader. Proteins with a Sec-dependent leader or which assemble spontaneously in the membrane are not affected by this mutation. MttA, B, and C are members of a large family of related sequences extending from archaebacteria to higher eukaryotes.

2S Albumins, Plant↗
PubMed1998

Lack of association between mutations in the folate receptor-alpha gene and spina bifida.

Defects of neural tube closure are among the most common of all human malformations. Epidemiological and genetic studies indicate that most of these defects are multifactorial in origin with genetic and environmental causes. Although periconceptional supplementation of the maternal diet with folic acid has been shown to reduce the recurrence and occurrence of neural tube defects (NTDs) by up to 70%, the underlying mechanism remains unknown. Folic acid enters cells of certain tissues via a receptor-mediated process known as potocytosis. The folate receptor alpha (FR-alpha) gene codes for the protein responsible for binding folate, which is the first, and only, folate-dependent step in folate transport. The FR-alpha exons, which code for mature protein and the intron-exon boundaries, were examined for mutations in three separate studies. Initial screening was performed by single-stranded conformational polymorphism (SSCP) analysis in a subset of 1,688 samples obtained from a population-based case-control study of NTDs in California. In the second study, the DNA sequence of exons 5 and 6 was determined in a group of 50 NTD affected individuals. The final experiment involved using dideoxy fingerprinting (ddF) to screen a population-based case-control sample of 219 individuals who were stratified into four sub-groups on the basis of folate intake and pregnancy outcome. No polymorphism was detected in any of the four exons examined. It is unlikely that the beneficial effects of maternal folate supplementation in preventing NTDs acts through a mechanism involving pharmacological correction of a variant form of folate receptor alpha.

Carrier Proteins↗
PubMed1998

Maternal illness, including fever and medication use as risk factors for neural tube defects.

We investigated if selected maternal illnesses or medications used during the periconceptional period increased risk of having neural tube defect (NTD)-affected pregnancies. We used a population-based case-control study of fetuses and liveborn infants with NTDs among 1989-1991 California births. In-person interviews were conducted with mothers of 538 (88% of eligible) NTD cases and 539 (88%) nonmalformed controls, usually within 5 months of delivery. A maternal fever or febrile illness episode in the first trimester was associated with an increased risk for having a NTD-affected pregnancy, odds ratio (OR) = 1.91 (95% confidence interval, 1.35-2.72) for fever and OR = 2.02 (1.20-3.43) for febrile illness. Risk estimates were not substantially altered after adjustment for maternal age, race/ethnicity, education, vitamin use, and body mass index. Other reported illnesses were generally not associated with risks of 1.5 or greater, or were too infrequent to adequately estimate risk. An OR of 1.5 or greater was observed for maternal use of guaifenesin, OR = 2.04 (0.79-5.28), and an OR of 0.5 or less was observed for maternal use of calcium-containing medicines, OR = 0.38 (0.14-1.03). Our findings are consistent with previous reports that suggested elevated NTD risks from maternal fever. We could not discriminate, however, whether the increased risks observed for maternal fever were indicative of a causal relation or due to reporting bias. Our findings suggest that many of the illnesses common to reproductive-aged women and the medications commonly used to treat them during pregnancy, except, perhaps, for those illnesses that are febrile-related, do not appear to substantially contribute to the occurrence of NTDs in the population.

Adult↗
PubMed1998

Energy and nutrient intakes and health practices of Latinas and white non-Latinas in the 3 months before pregnancy.

OBJECTIVE: To describe the health practices and energy and nutrient intakes from diet and supplements of foreign- and US-born Latinas and white non-Latinas in the 3 months before pregnancy. DESIGN: A descriptive study in which data were obtained retrospectively from 2 questionnaires: an interviewer-administered questionnaire on the subject's medical, reproductive, family, occupational, and lifestyle history and a subject-administered (and interviewer-assisted) 100-item food frequency questionnaire. SUBJECTS/SETTING: A population-based sample of California women (n = 462) who gave birth between 1989 and 1991 to single, live-born infants. One third of women were Latinas, of whom 58.1% were foreign born. STATISTICAL ANALYSES: Means, standard deviations, and percentiles were computed for energy and nutrient intakes of the total population and for white non-Latinas; US-born Latinas; and foreign-born Latinas. One-way analysis of variance was used to compare group means. RESULTS: Mean and median energy intake in all ethnic groups exceeded 2,000 kcal/day, although less than half of the population consumed 5 servings of fruit and vegetables per day. For iron, half of the women were below the Recommended Dietary Allowance. In contrast to the dietary intake of white non-Latinas and US-born Latinas, foreign-born Latinas had the lowest contribution of fat to total energy intake and the highest dietary intake of carbohydrate, cholesterol, fiber, grain products, protein foods, folate, vitamin C, iron, and zinc. CONCLUSIONS: A woman's ethnicity, as well as whether her place of birth was within or outside of the United States, may be predictors of her dietary and health practices before pregnancy. Vitamin, mineral, and food supplementation and consumption of cold breakfast cereal may be avenues for improving perinatal micronutrient intake.

Adolescent↗
PubMed1998

Potent suppression of HIV-1 replication in humans by T-20, a peptide inhibitor of gp41-mediated virus entry.

T-20, a synthetic peptide corresponding to a region of the transmembrane subunit of the HIV-1 envelope protein, blocks cell fusion and viral entry at concentrations of less than 2 ng/ml in vitro. We administered intravenous T-20 (monotherapy) for 14 days to sixteen HIV-infected adults in four dose groups (3, 10, 30 and 100 mg twice daily). There were significant, dose-related declines in plasma HIV RNA in all subjects who received higher dose levels. All four subjects receiving 100 mg twice daily had a decline in plasma HIV RNA to less than 500 copies/ml, by bDNA assay. A sensitive RT-PCR assay (detection threshold 40 copies/ml) demonstrated that, although undetectable levels were not achieved in the 14-day dosing period, there was a 1.96 log10 median decline in plasma HIV RNA in these subjects. This study provides proof-of-concept that viral entry can be successfully blocked in vivo. Short-term administration of T-20 seems safe and provides potent inhibition of HIV replication comparable to anti-retroviral regimens approved at present.

Adult↗
PubMed1998

Cytotoxic T-lymphocyte escape viral variants: how important are they in viral evasion of immune clearance in vivo?

Although viral variants which are not recognized by epitope-specific cytotoxic T lymphocytes (CTL) have been shown to arise during a number of persistent virus infections, in many cases their significance remains controversial: it has been argued that the immune response is sufficiently plastic to contain their replication. In this review, we describe the mechanisms by which amino acid changes in viral proteins may affect epitope recognition by virus-specific CTL, and discuss the viral and immunological basis for the emergence of viral variants bearing such amino acid changes during infection. We then consider the impact that viral variation may have on the host CTL response and its ability to contain virus replication. We argue that the emergence of a viral variant demonstrates that it must have an in vivo replicative advantage, and that as such, the variant must tip the balance between virus replication and immune control somewhat in favor of the virus. Further, we suggest that although the immune response can evolve to recognize new viral epitopes, the CTL generated following such evolution frequently have a reduced ability to contain virus replication. We conclude that this escape mechanism likely does make a significant contribution to persistence/pathogenesis during a number of different virus infections.

Amino Acid Sequence↗
PubMed1998

Common themes of antibody maturation to simian immunodeficiency virus, simian-human immunodeficiency virus, and human immunodeficiency virus type 1 infections.

Characterization of virus-specific immune responses to human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) is important to understanding the early virus-host interactions that may determine the course of virus infection and disease. Using a comprehensive panel of serological assays, we have previously demonstrated a complex and lengthy maturation of virus-specific antibody responses elicited by attenuated strains of SIV that was closely associated with the development of protective immunity. In the present study, we expand these analyses to address several questions regarding the nature of the virus-specific antibody responses to pathogenic SIV, SIV/HIV-1 (SHIV), and HIV-1 infections. The results demonstrate for the first time a common theme of antibody maturation to SIV, SHIV, and HIV-1 infections that is characterized by ongoing changes in antibody titer, conformational dependence, and antibody avidity during the first 6 to 10 months following virus infection. We demonstrate that this gradual evolution of virus-specific antibody responses is independent of the levels of virus replication and the pathogenicity of the infection viral strain. While the serological assays used in these studies were useful in discriminating between protective and nonprotective antibody responses during evaluation of vaccine efficacy with attenuated SIV, these same assays do not distinguish the clinical outcome of infection in pathogenic SIV, SHIV, or HIV-1 infections. These results likely reflect differences in the immune mechanisms involved in mediating protection from virus challenge compared to those that control an established viral infection, and they suggest that additional characteristics of both humoral and cellular responses evolve during this early immune maturation.

Animals↗
PubMed1998

An isolate of human immunodeficiency virus type 1 originally classified as subtype I represents a complex mosaic comprising three different group M subtypes (A, G, and I).

Full-length reference clones and sequences are currently available for eight human immunodeficiency virus type 1 (HIV-1) group M subtypes (A through H), but none have been reported for subtypes I and J, which have only been identified in a few individuals. Phylogenetic information for subtype I, in particular, is limited since only about 400 bp of env gene sequences have been determined for just two epidemiologically linked viruses infecting a couple who were heterosexual intravenous drug users from Cyprus. To characterize subtype I in greater detail, we employed long-range PCR to clone a full-length provirus (94CY032.3) from an isolate obtained from one of the individuals originally reported to be infected with this subtype. Phylogenetic analysis of C2-V3 env gene sequences confirmed that 94CY032.3 was closely related to sequences previously classified as subtype I. However, analysis of the remainder of its genome revealed various regions in which 94CY032.3 was significantly clustered with either subtype A or subtype G. Only sequences located in vpr and nef, as well as the middle portions of pol and env, formed independent lineages roughly equidistant from all other known subtypes. Since these latter regions most likely have a common origin, we classify them all as subtype I. These results thus indicate that the originally reported prototypic subtype I isolate 94CY032 represents a triple recombinant (A/G/I) with at least 11 points of recombination crossover. We also screened HIV-1 recombinants with regions of uncertain subtype assignment for the presence of subtype I sequences. This analysis revealed that two of the earliest mosaics from Africa, Z321B (A/G/?) and MAL (A/D/?), contain short segments of sequence which clustered closely with the subtype I domains of 94CY032.3. Since Z321 was isolated in 1976, subtype I as well as subtypes A and G must have existed in Central Africa prior to that date. The discovery of subtype I in HIV-1 hybrids from widely distant geographic locations also suggests a more widespread distribution of this virus subtype, or at least segments of it, than previously recognized.

Base Sequence↗
PubMed1998

A comprehensive panel of near-full-length clones and reference sequences for non-subtype B isolates of human immunodeficiency virus type 1.

Non-subtype B viruses cause the vast majority of new human immunodeficiency virus type 1 (HIV-1) infections worldwide and are thus the major focus of international vaccine efforts. Although their geographic dissemination is carefully monitored, their immunogenic and biological properties remain largely unknown, in part because well-characterized virological reference reagents are lacking. In particular, full-length clones and sequences are rare, since subtype classification is frequently based on small PCR-derived viral fragments. There are only five proviral clones available for viruses other than subtype B, and these represent only 3 of the 10 proposed (group M) sequence subtypes. This lack of reference sequences also confounds the identification and analysis of mosaic (recombinant) genomes, which appear to be arising with increasing frequency in areas where multiple sequence subtypes cocirculate. To generate a more representative panel of non-subtype B reference reagents, we have cloned (by long PCR or lambda phage techniques) and sequenced 10 near-full-length HIV-1 genomes (lacking less than 80 bp of long terminal repeat sequences) from primary isolates collected at major epicenters of the global AIDS pandemic. Detailed phylogenetic analyses identified six that represented nonrecombinant members of HIV-1 subtypes A (92UG037.1), C (92BR025. 8), D (84ZR085.1 and 94UG114.1), F (93BR020.1), and H (90CF056.1), the last two comprising the first full-length examples of these subtypes. Four others were found to be complex mosaics of subtypes A and C (92RW009.6), A and G (92NG083.2 and 92NG003.1), and B and F (93BR029.4), again emphasizing the impact of intersubtype recombination on global HIV-1 diversification. Although a number of clones had frameshift mutations or translational stop codons in major open reading frames, all the genomes contained a complete set of genes and three had intact genomic organizations without inactivating mutations. Reconstruction of one of these (94UG114.1) yielded replication-competent virus that grew to high titers in normal donor peripheral blood mononuclear cell cultures. This panel of non-subtype B reference genomes should prove valuable for structure-function studies of genetically diverse viral gene products, the generation of subtype-specific immunological reagents, and the production of DNA- and protein-based subunit vaccines directed against a broader spectrum of viruses.

Adolescent↗