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1.
Br J Surg ; 108(6): 613-621, 2021 06 22.
Article in English | MEDLINE | ID: mdl-34157080

ABSTRACT

INTRODUCTION: Operating room recording, via video, audio and sensor-based recordings, is increasingly common. Yet, surgical data science is a new field without clear guidelines. The purpose of this study is to examine existing published studies of surgical recording modalities to determine which are available for use in the operating room, as a first step towards developing unified standards for this field. METHODS: Medline, EMBASE, CENTRAL and PubMed databases were systematically searched for articles describing modalities of data collection in the operating room. Search terms included 'video-audio media', 'bio-sensing techniques', 'sound', 'movement', 'operating rooms' and others. Title, abstract and full-text screening were completed to identify relevant articles. Descriptive statistical analysis was performed for included studies. RESULTS: From 3756 citations, 91 studies met inclusion criteria. These studies described 10 unique data-collection modalities for 17 different purposes in the operating room. Data modalities included video, audio, kinematic and eye-tracking among others. Data-collection purposes described included surgical trainee assessment, surgical error, surgical team communication and operating room efficiency. CONCLUSION: Effective data collection and utilization in the operating room are imperative for the provision of superior surgical care. The future operating room landscape undoubtedly includes multiple modalities of data collection for a plethora of purposes. This review acts as a foundation for employing operating room data in a way that leads to meaningful benefit for patient care.


Subject(s)
Data Collection/methods , Operating Rooms/statistics & numerical data , Surgical Procedures, Operative/statistics & numerical data , Data Collection/instrumentation , Humans , Surgical Procedures, Operative/methods , Tape Recording , Video Recording
2.
J Cancer Surviv ; 15(5): 767-775, 2021 10.
Article in English | MEDLINE | ID: mdl-33226568

ABSTRACT

PURPOSE: Area deprivation index (ADI), a measure of neighborhood socioeconomic disadvantage, has been linked to metabolic outcomes in the general population but has received limited attention in survivors of childhood acute lymphoblastic leukemia (ALL), a population with high rates of overweight and obesity. METHODS: We retrospectively reviewed heights and weights of ≥ 5 year survivors of pediatric ALL (diagnosed 1990-2013). Residential addresses were geocoded using ArcGIS to assign quartiles of ADI, a composite of 17 measures of poverty, housing, employment, and education, with higher quartiles reflecting greater deprivation. Odds ratios (OR) and 95% confidence intervals (CI) for the association between ADI quartiles and overweight/obesity or obesity alone were calculated with logistic regression. RESULTS: On average, participants (n = 454, 50.4% male, 45.2% Hispanic) were age 5.5 years at diagnosis and 17.4 years at follow-up. At follow-up, 26.4% were overweight and 24.4% obese. Compared to the lowest ADI quartile, survivors in the highest quartile were more likely to be overweight/obese at follow-up (OR = 2.33, 95% CI: 1.23-4.44) after adjusting for race/ethnicity, sex, age at diagnosis, and age at follow-up. The highest ADI quartile remained significantly associated with obesity (OR = 5.28, 95% CI: 1.79-15.54) after accounting for weight status at diagnosis. CONCLUSIONS: This study provides novel insights into possible social determinants of health inequalities among survivors of childhood ALL by reporting a significant association between neighborhood deprivation and overweight/obesity. IMPLICATIONS FOR CANCER SURVIVORS: Survivors of childhood ALL residing in neighborhood with greater socioeconomic disadvantage may be at increased risk of overweight and obesity and candidates for targeted interventions.


Subject(s)
Overweight , Precursor Cell Lymphoblastic Leukemia-Lymphoma , Child , Child, Preschool , Female , Humans , Male , Overweight/epidemiology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/epidemiology , Residence Characteristics , Retrospective Studies , Survivors
3.
AIDS Res Hum Retroviruses ; 17(9): 837-49, 2001 Jun 10.
Article in English | MEDLINE | ID: mdl-11429125

ABSTRACT

The conserved, immunogenic CD4 binding site on the viral envelope is an attractive HIV or SIV vaccine candidate. Polymerization of an 18 amino acid segment derived from the C4 domain of SIV gp120 produced a peptide polymer or "peptomer," having an alpha-helical conformation possibly mimicking a proposed structure of the C4 domain in the unbound native protein. The SIV peptomer and native gp120 were compared as subunit boosts following two adenovirus type 5 host range (Ad5hr)-SIVenv recombinant priming immunizations. Both vaccine regimens successfully elicited SIV-specific CTL responses in five of six immunized macaques. Peptomer-boosted macaques exhibited significantly higher envelope-specific T cell proliferative responses than either the gp120-boosted macaques or controls. Peptomer immunization also elicited peptomer and SIV gp120-specific binding antibodies, but only native gp120 boosting elicited SIV neutralizing antibodies. Upon intrarectal challenge with SIVmac32H, all nine macaques became infected. The solely envelope-based vaccine conferred no protection. However, changing the boosting immunogen to the C4 peptomer did not improve protective efficacy in spite of its elicitation of humoral and cellular immune responses, including robust T-helper activity. In spite of the peptomer's strong immunogenicity and potential for induction of broadly protective immune responses, it was not effective as a subunit vaccine.


Subject(s)
Epitopes, T-Lymphocyte/immunology , Peptides/immunology , SAIDS Vaccines/immunology , Simian Immunodeficiency Virus/immunology , Vaccines, Synthetic/immunology , Adenoviridae/immunology , Amino Acid Sequence , Animals , Antibodies, Viral/analysis , Cells, Cultured , Epitopes, T-Lymphocyte/genetics , Female , Genetic Vectors/immunology , Humans , Leukocytes, Mononuclear/cytology , Leukocytes, Mononuclear/immunology , Macaca mulatta , Male , Molecular Sequence Data , Neutralization Tests , Peptides/genetics , Polymers , Protein Conformation , SAIDS Vaccines/genetics , Simian Acquired Immunodeficiency Syndrome/prevention & control , Vaccines, Attenuated/immunology , Vaccines, Synthetic/genetics , Virus Shedding
4.
J Therm Biol ; 26(3): 179-182, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11240223

ABSTRACT

1. Comparison of erythrocyte osmotic fragility (EOF) between various ectotherms and endotherms was investigated at 5, 25, and 38 degrees C. 2. We hypothesized that ectotherms might possess erythrocytes whose osmotic fragility would be less affected by temperature than those of endotherms. 3. Ectotherm erythrocytes were much more osmotically resistant than those of endotherms. 4. The EOF of ectotherms and endotherms showed similar responses to temperature. 5. It does not appear that the osmotic fragility of erythrocytes from ectotherms in this study are adapted to be less affected by temperature than those of endotherms. The highly osmotic resistant erythrocytes of ectotherms may alleviate the need for further adaptation for osmotic resistance.

5.
J Bacteriol ; 182(7): 1802-11, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10714983

ABSTRACT

The cell wall provides an attractive target for antibiotics against Mycobacterium tuberculosis. Agents such as isoniazid and ethambutol that work by inhibiting cell wall biosynthesis are among the most highly effective antibiotics against this pathogen. Although considerable progress has been made identifying the targets for cell wall active antibiotics, little is known about the intracellular mechanisms that are activated as a consequence of cell wall injury. These mechanisms are likely to have an important role in growth regulation and in the induction of cell death by antibiotics. We previously discovered three isoniazid-induced genes (iniB, iniA, and iniC) organized in tandem on the M. tuberculosis genome. Here, we investigate the unique features of the putative iniBAC promoter. This promoter was specifically induced by a broad range of inhibitors of cell wall biosynthesis but was not inducible by other conditions that are toxic to mycobacteria via other mechanisms. Induction required inhibitory concentrations of antibiotics and could be detected only in actively growing cells. Analysis of the iniBAC promoter sequence revealed both a regulatory element upstream and a potential repressor binding region downstream of the transcriptional start site. The induction phenotype and structure of the iniBAC promoter suggest that a complex intracellular response occurs when cell wall biosynthesis is inhibited in M. tuberculosis and other mycobacteria.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cell Wall/drug effects , Gene Expression Regulation, Bacterial/drug effects , Genes, Bacterial/genetics , Mycobacterium tuberculosis/genetics , Promoter Regions, Genetic/genetics , Amino Acid Sequence , Antitubercular Agents/pharmacology , Base Sequence , Binding Sites , Cell Wall/metabolism , Isoniazid/pharmacology , Kinetics , Molecular Sequence Data , Mycobacterium tuberculosis/cytology , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/growth & development , Operon/genetics , RNA, Messenger/analysis , RNA, Messenger/genetics , Response Elements/genetics , Sequence Deletion/genetics , Species Specificity , Transcription, Genetic/drug effects , Transcription, Genetic/genetics , Transcriptional Activation/drug effects
6.
AIDS ; 14(16): 2445-55, 2000 Nov 10.
Article in English | MEDLINE | ID: mdl-11101054

ABSTRACT

OBJECTIVES: Immunization with attenuated poxvirus-HIV-1 recombinants followed by protein boosting had protected four of eight rhesus macaques from HIV-2SBL6669 challenge. The present study was designed to confirm this result and to conduct the reciprocal cross-protection experiment. METHODS: Twenty-four macaques were primed with NYVAC (a genetically attenuated Copenhagen vaccinia strain) recombinants with HIV-1 and HIV-2 env and gag-pol or NYVAC vector alone and boosted with homologous, oligomeric gp160 proteins or adjuvant only. Binding and neutralizing antibodies, cytotoxic T-lymphocytes (CTL) and CD8 T cell antiviral activity (CD8AA) were evaluated. One half of each immunization and control group were intravenously challenged with SHIV(HXB2) the other half was challenged with HIV-2SBL6669,. Protective outcome was assessed by monitoring virus isolation, proviral DNA and plasma viral RNA. RESULTS: Both immunization groups developed homologous binding antibodies; however, homologous neutralizing antibodies were only observed in NYVAC-HIV-2-immunized macaques. While no cross-reactive neutralizing antibodies were detected, both immunization groups displayed cross-reactive CTL. Significant CD8AA was observed for only one NYVAC-HIV-2-immunized macaque. Virological assessments verified that both NYVAC-HIV-1 and NYVAC-HIV-2 immunization significantly reduced viral burdens and partially protected against HIV-2 challenge, although cross-protection was not at the level that had been previously reported. Humoral antibody and/or CTL and CD8AA were associated with protection against homologous HIV-2 challenge, while cellular immune responses seemed more important for cross-protection. No significant protection was observed in the SHIV-challenged macaques, although NYVAC-HIV-1 immunization resulted in significantly lower viral burdens compared with controls. CONCLUSIONS: Further delineation of cross-reactive mechanisms may aid in the development of a broadly protective vaccine.


Subject(s)
AIDS Vaccines , HIV Infections/prevention & control , HIV-1/immunology , HIV-2/pathogenicity , Poxviridae/genetics , Animals , Cross Reactions , Female , Genetic Vectors , HIV Antibodies/blood , HIV Infections/immunology , HIV Infections/virology , HIV-1/genetics , Immunization , Macaca mulatta , Male , RNA, Viral/blood , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Acquired Immunodeficiency Syndrome/prevention & control , Simian Immunodeficiency Virus/pathogenicity , T-Lymphocytes, Cytotoxic/immunology
7.
J Virol ; 73(9): 7430-40, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10438833

ABSTRACT

Rhesus macaques were immunized with a combination vaccine regimen consisting of adenovirus type 5 host range mutant-simian immunodeficiency virus envelope (Ad5hr-SIVenv) recombinant priming and boosting with native SIV gp120. Upon intravaginal challenge with SIVmac251, both persistently and transiently viremic animals were observed (S. L. Buge, E. Richardson, S. Alipanah, P. Markham, S. Cheng, N. Kalyan, C. J. Miller, M. Lubeck, S. Udem, J. Eldridge, and M. Robert-Guroff, J. Virol. 71:8531-8541, 1997). Long-term follow-up of the persistently viremic immunized macaques, which displayed significantly reduced viral burdens during the first 18 weeks postchallenge compared to controls, has now shown that one of four became a slow progressor, clearing virus from plasma and remaining asymptomatic with stable CD4 counts for 134 weeks postchallenge. Reboosting of the transiently viremic macaques did not reactivate latent virus. Rechallenge with two sequential SIVmac251 intravaginal exposures again resulted in partial protection of one of two immunized macaques, manifested by viral clearance and stable CD4 counts. No single immune parameter was associated with partial protection. Development of a strong antibody response capable of neutralizing a primary SIVmac251 isolate together with SIV-specific cytotoxic T lymphocytes were implicated, while CD8(+) T-cell antiviral activity and mucosal immune responses were not associated with delayed disease progression. Our data show that even a third immunization with the same Ad5hr-SIVenv recombinant can elicit significant immune responses to the inserted gene product, suggesting that preexisting Ad antibodies may not preclude effective immunization. Further, the partial protection against a virulent, pathogenic SIV challenge observed in two of six macaques immunized with a vaccine regimen based solely on the viral envelope indicates that this vectored-vaccine approach has promise and that multicomponent vaccines based in the same system merit further investigation.


Subject(s)
Adenoviruses, Human , Genetic Vectors , HIV Envelope Protein gp120/immunology , Membrane Glycoproteins , SAIDS Vaccines/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Vaccines, DNA/immunology , Viral Envelope Proteins , Adenoviruses, Human/immunology , Animals , Antibodies, Viral/immunology , Cell Line, Transformed , Disease Progression , Female , Follow-Up Studies , Genetic Vectors/immunology , Humans , Immunity, Mucosal/immunology , Macaca mulatta , Recombinant Fusion Proteins/immunology , Simian Acquired Immunodeficiency Syndrome/prevention & control , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/growth & development , T-Lymphocytes, Cytotoxic/immunology , Vaccination , Vagina/immunology , Vagina/virology , Viremia
8.
J Virol ; 72(12): 10275-80, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9811775

ABSTRACT

Vaccine-induced protection of chimpanzees against laboratory-adapted and syncytium-inducing, multiply passaged primary human immunodeficiency virus type 1 (HIV-1) isolates, but not against non-syncytium-inducing, minimally passaged ones, has been demonstrated. Following challenge with such an isolate, HIV-15016, we obtained complete protection in one of three chimpanzees previously protected against low- and high-dose HIV-1SF2 exposures after immunization with an adenovirus-HIV-1MN gp160 priming-HIV-1SF2 gp120 boosting regimen. At challenge, the protected chimpanzee exhibited broad humoral immunity, including neutralizing antibody activity. These results demonstrate the potential of this combination vaccine strategy and suggest that vaccine protection against an HIV isolate relevant to infection of people is feasible.


Subject(s)
AIDS Vaccines/pharmacology , HIV-1/immunology , HIV-1/pathogenicity , AIDS Vaccines/administration & dosage , Adenoviridae/genetics , Adenoviridae/immunology , Amino Acid Sequence , Animals , DNA Primers/genetics , HIV Antibodies/blood , HIV Envelope Protein gp120/administration & dosage , HIV Envelope Protein gp120/genetics , HIV Envelope Protein gp120/immunology , HIV Envelope Protein gp160/administration & dosage , HIV Envelope Protein gp160/genetics , HIV Envelope Protein gp160/immunology , HIV Infections/immunology , HIV Infections/prevention & control , HIV Infections/virology , HIV-1/genetics , Humans , Immunization, Secondary , Molecular Sequence Data , Neutralization Tests , Pan troglodytes , Peptide Fragments/administration & dosage , Peptide Fragments/genetics , Peptide Fragments/immunology , RNA, Viral/genetics , RNA, Viral/isolation & purification , Virus Cultivation
9.
Nat Med ; 3(6): 651-8, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9176492

ABSTRACT

A combination AIDS vaccine approach consisting of priming with adenovirus-HIV-1MN gp160 recombinants followed by boosting with HIV-1SF2 gp120 was evaluated in chimpanzees. Long-lasting protection, requiring only three immunizations, was achieved against a low-dose challenge with the SF2 strain of HIV-1 and a subsequent high-dose SF2 challenge administered 1 year later without an intervening boost. Notably, neutralizing antibody responses against both clinical and laboratory isolates developed in three chimpanzees and persisted until the time of high-dose challenge. The possibility that cytotoxic T-lymphocytes contribute to low-dose protection of a chimpanzee lacking neutralizing antibodies is suggested. Our results validate the live vector priming/subunit booster approach and should stimulate interest in assessing this combination vaccine approach in humans.


Subject(s)
Adenoviridae/immunology , HIV Envelope Protein gp120/immunology , HIV Envelope Protein gp160/immunology , HIV-1/pathogenicity , Recombinant Fusion Proteins/immunology , Vaccination/methods , Animals , Female , HIV Infections/immunology , HIV Infections/prevention & control , Pan troglodytes , Recombinant Fusion Proteins/administration & dosage , T-Lymphocytes, Cytotoxic/physiology , Vaccines/administration & dosage
10.
J Virol ; 70(12): 8431-7, 1996 Dec.
Article in English | MEDLINE | ID: mdl-8970964

ABSTRACT

The ability of human immunodeficiency virus type 1 (HIV-1) to replicate in the presence of strong immune responses to the virus may be due to its high mutation rate, which provides envelope gene variability for selection of neutralization-resistant variants. Understanding neutralization escape mechanisms is therefore important for the design of HIV-1 vaccines and our understanding of the disease process. In this report, we analyze mutations at amino acid positions 281 and 582 in the HIV-1 envelope, where substitutions confer resistance to broadly reactive neutralizing antisera from seropositive individuals. Neither of these mutations lies within an antibody-binding site, and therefore the mechanism of immune escape in both cases is by alteration of the shape of the envelope proteins. The conformation of the CD4-binding site is shown to be critical with regard to presentation of other discontinuous epitopes. From our analysis of the neutralization of these variants, we conclude that escape from polyclonal sera occurs through alterations at several different epitopes, generally resulting from single amino acid substitutions which influence envelope conformation. Experiments on a double mutant showed that the combination of both mutations is not additive, suggesting that these variants utilized alternate pathways to elicit similar alterations of the HIV-1 envelope structure.


Subject(s)
Epitopes/immunology , HIV Antibodies/immunology , HIV Antigens/immunology , HIV Envelope Protein gp120/immunology , HIV Envelope Protein gp41/immunology , HIV Infections/immunology , HIV-1/immunology , Animals , Binding Sites, Antibody , CD4 Antigens/immunology , COS Cells , Epitopes/genetics , Genetic Variation , HIV Antigens/genetics , HIV Envelope Protein gp120/genetics , HIV Envelope Protein gp41/genetics , HIV Infections/blood , HIV-1/genetics , HIV-1/isolation & purification , Humans , Neutralization Tests , Point Mutation , Tumor Cells, Cultured
11.
Nat Med ; 1(4): 321-9, 1995 Apr.
Article in English | MEDLINE | ID: mdl-7585061

ABSTRACT

Rhesus macaques were immunized with attenuated vaccinia or canarypox human immunodeficiency virus type 1 (HIV-1) recombinants and boosted with HIV-1 protein subunits formulated in alum. Following challenge with HIV-2SBL6669, three out of eight immunized macaques resisted infection for six months and another exhibited significantly delayed infection, whereas all three naive controls became infected. Immunizations elicited both humoral and cellular immune responses; however, no clear correlates of protection were discerned. Although more extensive studies are now called for, this first demonstration of cross-protection between HIV-1 and -2 suggests that viral variability may not be an insurmountable problem in the design of a global AIDS vaccine.


Subject(s)
AIDS Vaccines , HIV Infections/prevention & control , HIV-1/immunology , HIV-2/immunology , Vaccines, Synthetic , AIDS Vaccines/administration & dosage , AIDS Vaccines/immunology , Amino Acid Sequence , Animals , Avipoxvirus , Enzyme-Linked Immunosorbent Assay , Gene Products, env/chemistry , Gene Products, env/immunology , HIV Antibodies/analysis , HIV Core Protein p24/immunology , HIV Envelope Protein gp120/chemistry , HIV Envelope Protein gp120/immunology , HIV Envelope Protein gp160 , HIV Infections/immunology , Immunization, Secondary , Macaca mulatta , Molecular Sequence Data , Peptide Fragments , Pilot Projects , Protein Precursors/chemistry , Protein Precursors/immunology , Vaccination , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunology , Vaccinia virus
12.
AIDS Res Hum Retroviruses ; 11(3): 383-93, 1995 Mar.
Article in English | MEDLINE | ID: mdl-7786583

ABSTRACT

Eighteen rhesus macaques were inoculated with either an infectious molecularly cloned human immunodeficiency virus type 2 (HIV-2)SBL/ISY, or with one of eight mutants defective in one or more accessory genes. The immune responses generated by the macaques were monitored for up to 2 years postinfection. All the macaques except those that received mutants lacking the vpr or vif genes demonstrated low to moderate antibody titers. Macaques inoculated with vpx- mutants exhibited a persistent serological response, suggesting continuous virus expression even in the absence of detectable virus in the peripheral blood mononuclear cells (PBMCs). Neutralizing antibodies developed in only four macaques. In general, low-level cytotoxic T lymphocyte (CTL) activity, not clearly HIV-2 specific, was detected in PBMCs. However, one virus-negative macaque exhibited significant HIV-2-specific CTL activity in an enriched CD8+ cell population from PBMCs, suggesting clearance of the viral infection. In addition, CTL activity against the Env and Gag/Pol epitopes of HIV-2 by CD8+ lymphocytes from the spleens and lymph nodes of two infected macaques, in one case requiring CD8+ T cell enrichment and in the other clearly evident in unfractionated tissue lymphocytes, was demonstrated for the first time. This sequestration of tissue CTLs occurred in the absence of significant levels of circulating CTLs in the blood. Our results suggest that routine monitoring of PBMCs may sometimes be inadequate for detecting cell-mediated immune responses. Elucidation of immune correlates of vaccine protection may therefore require sampling of lymphoid tissues and assessment of enriched CD8+ populations.


Subject(s)
Acquired Immunodeficiency Syndrome/immunology , Defective Viruses/immunology , Gene Deletion , Genes, Viral , HIV-2/immunology , Acquired Immunodeficiency Syndrome/blood , Animals , Antibody Formation , Cytotoxicity, Immunologic , Enzyme-Linked Immunosorbent Assay , Genes, nef , Genes, vif , Genes, vpr , HIV Antibodies/blood , HIV-2/genetics , Immunity, Cellular , Lymphocyte Activation , Lymphocytes/immunology , Lymphocytes/virology , Macaca mulatta , Mutagenesis , Neutralization Tests , Time Factors
13.
J Virol ; 67(12): 7493-500, 1993 Dec.
Article in English | MEDLINE | ID: mdl-7693973

ABSTRACT

Sera from many HIV-1-infected individuals contain broadly reactive, specific neutralizing antibodies. Despite their broad reactivity, variant viruses, resistant to neutralization, can be selected in vitro in the presence of such antisera. We have previously shown that neutralization resistance of an escape mutant with an amino acid substitution in the transmembrane protein (A582T) occurs because of alteration of a conformational epitope that is recognized by neutralizing antibodies directed against the CD4 binding site. In this report we demonstrate that immune escape via a single-amino-acid substitution (A281V) within a conserved region of the envelope glycoprotein gp120 confers neutralization resistance against a broadly reactive neutralizing antiserum from a seropositive individual. We show this alteration affects V3 and additional regions unrelated to V3 or the CD4 binding site. Together with previous studies on escape mutants selected in vitro, our findings suggest that immune-selective pressure can arise by multiple pathways.


Subject(s)
Antibodies, Viral/immunology , HIV Envelope Protein gp120/immunology , HIV Seropositivity/blood , HIV-1/immunology , Mutation/immunology , Amino Acid Sequence , Animals , Antibodies, Viral/blood , CD4 Antigens/immunology , Cells, Cultured , Epitopes/genetics , Epitopes/immunology , HIV Envelope Protein gp120/genetics , HIV Seropositivity/genetics , HIV-1/genetics , Humans , Molecular Sequence Data , Neutralization Tests , Protein Conformation , Selection, Genetic
14.
J Virol ; 66(6): 3602-8, 1992 Jun.
Article in English | MEDLINE | ID: mdl-1374810

ABSTRACT

In contrast to infrequent and low-titer cross-neutralization of human immunodeficiency virus type 1 (HIV-1) isolates by HIV-2- and simian immunodeficiency virus (SIV)-positive sera, extensive cross-neutralization of HIV-2NIH-Z, SIVMAC251, and SIVAGM208K occurs with high titer, suggesting conservation of epitopes and mechanism(s) of neutralization. The V3 regions of HIV-2 and SIV isolates, minimally related to the HIV-1 homolog, share significant sequence homology and are immunogenic in monkeys as well as in humans. Whereas the crown of the V3 loop is cross-reactive among HIV-1 isolates and elicits neutralizing antibodies of broad specificity, the SIV and especially HIV-2 crown peptides were not well recognized by cross-neutralizing antisera. V3 loop peptides of HIV-2 isolates did not elicit neutralizing antibodies in mice, guinea pigs, or a goat and together with SIV V3 peptides did not inhibit serum neutralization of HIV-2 and SIV. Thus, the V3 loops of HIV-2 and SIV do not appear to constitute simple linear neutralizing epitopes. In view of the immunogenicity of V3 peptides, the failure of conserved crown peptides to react with natural sera implies a significant role of loop conformation in antibody recognition. Our studies suggest that in addition to their grouping by envelope genetic relatedness, HIV-2 and SIV are neutralized similarly to each other but differently from HIV-1. The use of linear peptides of HIV-2 and SIV as immunogens may require greater attention to microconformation, and alternate subunit approaches may be needed in exploiting these viruses as vaccine models. Such approaches may also be applicable to the HIV-1 system in which conformational epitopes, in addition to the V3 loop, participate in virus neutralization.


Subject(s)
Acquired Immunodeficiency Syndrome/immunology , HIV Envelope Protein gp120/immunology , HIV/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Amino Acid Sequence , Animals , Antibodies, Viral/immunology , Cross Reactions , Epitopes/immunology , HIV Seropositivity/immunology , HIV-1/immunology , HIV-2/immunology , Humans , Macaca , Molecular Sequence Data , Peptide Fragments/immunology , Peptides/immunology , Sequence Homology, Nucleic Acid
15.
J Virol ; 64(7): 3240-8, 1990 Jul.
Article in English | MEDLINE | ID: mdl-2352323

ABSTRACT

We previously reported the in vitro generation of a neutralization-resistant variant of the molecularly cloned isolate of human immunodeficiency virus type 1 (HIV-1), HXB2D. The molecular basis for the resistance was shown to be a point mutation in the env gene, causing the substitution of threonine for alanine at position 582 of gp41. Here, we show the variant to be resistant to syncytium inhibition as well as to neutralization by the immune-selecting serum. Moreover, 30% of HIV-positive human sera able to neutralize the parental virus have significantly decreased ability to neutralize the variant. As the A-to-T substitution thus has general relevance to the interaction of HIV-1 with the host immune system, we investigated further the biologic and immunologic bases for the altered properties. Synthetic peptides corresponding to the 582 region failed to compete in infectivity, neutralization, or syncytium inhibition assays and did not elicit neutralizing antibodies. Furthermore, human antibodies, affinity purified on synthetic peptide resins, bound to gp41 and peptides from the 582 region but did not possess neutralizing antibody activity. Some viral constructs in which the AVERY sequence in the 582 region was altered by site-directed mutagenesis were not infectious, indicating that the primary structure in this region is crucial for viral infectivity. Constructs predicted to possess a local secondary structure similar to that of the variant nevertheless behaved like the parental virus and remained neutralization sensitive. These results suggest that the requirements for neutralization resistance in this region are very precise. Our results with synthetic peptides show that the 582 region does not by itself constitute a neutralization epitope. Moreover, the degree of flexibility in amino acid substitution which allows maintenance of neutralization sensitivity suggests that position 582 does not form part of a noncontiguous neutralization epitope. The basis for neutralization resistance of the immune-selected variant is more likely a conformational change altering a neutralization epitope at a distant site.


Subject(s)
Antigens, Viral/genetics , HIV Envelope Protein gp41/immunology , HIV-1/immunology , Amino Acid Sequence , Base Sequence , Cloning, Molecular , DNA Mutational Analysis , HIV Antibodies/immunology , HIV Envelope Protein gp41/genetics , HIV-1/genetics , Humans , In Vitro Techniques , Molecular Sequence Data , Mutation , Neutralization Tests , Oligopeptides/immunology , Protein Conformation
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