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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Envelope glycoproteins, gp 120 and gp41, of the human immunodeficiency virus type 1 (HIV-1) elicit immune responses, including virus-neutralizing antibodies, which are expected to play a role in the defence against HIV-1 infection. Subregions of the gp120/gp41 sequence have immunosuppressive effects or may be implicated in autoimmune responses. Some of the immunodominant epitopes of gp120/gp41 do not contribute to protective immunity and act as immunological decoys. These circumstances emphasize the need to select from gp120/gp41 regions inducing protective responses. Towards this goal, 30 peptides covering approximately 87% of the HIV-1 strain BH10 gp120/gp41 sequence were synthesized. Antibodies in rabbit and human anti-HIV-1 sera recognized 28 and nine of the peptides, respectively, indicating that most of the gp120/gp41 sequence is immunogenic and secondly, that the antibody response to HIV-1 is restricted in infected humans. Most of the peptides, without conjugation to carriers, elicited high levels of anti-peptide (endpoints 1: greater than 10(4] and anti-gp120/gp41 (endpoints 1: greater than or equal to 10(3] antibodies. The highest levels of virus-neutralizing antibodies were elicited by peptide 306 to 338 from a hypervariable loop of gp120. Additional peptides from the full-length hypervariable loop (303 to 338) of HIV-1 BH10 and from 20 additional HIV-1 isolates were recognized differentially by human anti-HIV, suggesting that success of passive immunization may depend on a match between administered antibodies and the challenging HIV-1 strain, and also that active immunization with selected peptides from a hypervariable region of distinct HIV-1 isolates should be explored further as a method for prophylaxis against infection.
J Gen Virol 1990 Jan
PMID:B cell epitope mapping of human immunodeficiency virus envelope glycoproteins with long (19- to 36-residue) synthetic peptides. 168 72

Antibody-binding sites were mapped on all overlapping nonapeptides of the major core protein p24 of human immunodeficiency virus type 1 (HIV-1) using murine monoclonal antibodies (MAbs) and sheep and rabbit polyclonal antibodies raised against HIV-1/H9 (strain IIIB) viral lysate and antibodies obtained from humans infected with HIV-1. The binding sites were mapped to various distinct regions of this protein. After superimposition of the antibody-binding sites on a proposed model of p24 of HIV-1, these sites appeared to be located on the surface of the protein on loops, turns and coils of p24 but, unexpectedly, not on the major part of the predicted 'puff'. Little reaction was found with the inaccessible anti-parallel beta-barrel. These results are the first experimental evidence for the validity of the structure proposed for p24 of HIV-1.
J Gen Virol 1990 Nov
PMID:Location of epitopes on the major core protein p24 of human immunodeficiency virus. 170 76

Antibodies raised to an overlapping series of peptides following the amino acid sequence of the external envelope glycoprotein (gp 120) of human immunodeficiency virus type 1 (HIV-1) recognize eight regions in recombinant gp 120 molecules. If the recombinant molecules are glycosylated, three of these regions show a reduced capacity to bind antibody. Of the other five regions, two are strain-specific and carbohydrate restricts antibody binding to their N-terminal flanks, and three can be recognized by antibodies in recombinant gp 120 from an unrelated strain of HIV-1. Antibodies in sera from HIV-1-infected patients bind at high levels to peptides from five regions of gp 120. Of these regions, two coincide with those recognized by antibodies raised to peptides. Four of the five epitopes recognized by the rat antipeptide sera whose ability to bind antibody is influenced most by glycosylation, and three of the five regions which induce high levels of antibodies in patients' sera, contain putative glycosylation sites which are variable between strains of HIV-1. Such sites flank the putative neutralization and CD4-binding regions of gp 120. It is suggested that changes in the number and position of carbohydrate moieties following mutation can alternately mask and reveal epitopes. Masking an epitope can render a virus resistant to neutralization, whereas virus which binds antibody without being neutralized is able to gain entry to cells bearing antibody and complement receptors. Changes in the glycosylation pattern of gp 120 may therefore contribute to the control of HIV-1 spread within its host.
J Gen Virol 1990 Dec
PMID:Glycosylation governs the binding of antipeptide antibodies to regions of hypervariable amino acid sequence within recombinant gp120 of human immunodeficiency virus type 1. 170 12

Murine monoclonal antibodies (MAbs) gp41-1 (IgG2a) and gp41-2 (IgG1), directed against the envelope glycoprotein of human immunodeficiency virus type 1 (HIV-1), were produced and characterized. These MAbs recognized both gp160 and gp41 and reacted with divergent HIV-1 isolates. Surface binding assays using viable HIV-infected cells indicated that these MAbs were directed against surface-exposed epitopes. Both MAbs caused a reduction in reverse transcriptase activity. Syngeneic monoclonal antiidiotypic antibodies (anti-ids) against gp41-1 were also generated. Six anti-ids (agp41-11 to agp41-16) were selected by ELISA using F(ab')2 fragments of gp41-1; no reaction was observed when fragments from an irrelevant IgG2a MAb were used. Anti-ids were recognized by both gp41-1 and gp41-2 biotinylated MAbs. Competitive ELISA studies suggested that anti-ids were directed against at least three distinct idiotopes on gp41-1. All anti-ids reacted with idiotopes associated with both heavy and light chains and not with separated chains. The binding of MAbs gp41-1 and gp41-2 to HIV-infected cells was inhibited by each anti-id, except for the binding of gp41-2 which was not affected by the presence of agp41-12. Immunization of rabbits with agp41-11 and agp41-13 resulted in an antibody response against recombinant gp160. These studies indicated that these two anti-ids contain a surrogate image of the antigen recognized by gp41-1.
J Gen Virol 1991 Jan
PMID:Monoclonal idiotypic and anti-idiotypic antibodies to human immunodeficiency virus type 1 envelope glycoprotein. 170 62

Antibody-reactive peptide scanning (Pepscan) using overlapping nonapeptides and human sera as probes allows the identification of amino acids contributing significantly to antigen-antibody interaction. Five-hundred and two overlapping nonapeptides derived from the human immunodeficiency virus type 2 strain Rod (HIV-2Rod) external envelope glycoprotein gp125 were synthesized to serve as probes for reactivity with eight sera of HIV-2-infected individuals. Fifteen antibody-binding regions were identified, among which two amino-terminal regions [E3, amino acids (aa) 118 to 132; E4, aa 125 to 141] and four carboxy-terminal regions (E11, aa 303 to 324; E12, aa 340 to 358; E14, aa 436 to 452; E15, aa 486 to 507) were the most antigenic. The amino acids in binding sites E3 and E4 were highly variable among simian immunodeficiency virus (SIV), HIV-2 and HIV-1. The antibody-binding domains E14 and E15 were highly conserved among HIV-2 strains (94% and 86% identity of HIV-2Rod to HIV-2Isy and HIV-2NIHZ, respectively). Both domains had more amino acids in common with SIV (88% for E14, 64% for E15) than with HIV-1 (41% for E14, 45% for E15). Epidemiological studies revealed that the sera of African HIV-2-infected individuals bound the E11 and E15 peptides best (31%, 8/26). The sera of African HIV-1-infected individuals showed significant levels of cross-reactivity to the HIV-2 peptides, especially to the E15 peptide, whereas the sera of European HIV-1-infected individuals showed only moderate levels of cross-reactivity. If peptides covering the E15 epitope were used, African HIV-2-positive sera showed only a low level of cross-reactivity (4%) to E15 of HIV-1 and SIV. African HIV-1-positive sera bound the HIV-1 E15 peptide best (81%, 52/64), but showed high levels of cross-reactivity to SIV E15 (17%, 11/64) and HIV-2 E15 (25%, 16/64). European HIV-1-positive sera showed a high level of reactivity of HIV-1 E15 (91%, 50/55) and a low level of cross-reactivity to the HIV-2 (2%, 1/55), and none to the SIV E15 (0/55) peptide. These results indicate that the immunodominant regions of the HIV-2 external envelope (E11 and E15) align with the most immunodominant regions of HIV-1.
J Gen Virol 1991 Jun
PMID:Characterization of human antibody-binding sites on the external envelope of human immunodeficiency virus type 2. 171 Jun 45

The recombinant reverse transcriptase of HIV-1 virus has been isolated from Escherichia coli cells transformed by the plasmid pRT40 DNA. The 103 Kd protein produced by these cells is shown to be processed to proteins with lower molecular masses by the reverse transcriptases own protease activity as well as Escherichia coli proteases. The resulting 103-66 Kd proteins possess the polymerase activity while 51 Kd and smaller proteins are lacking the activity. The 66 and 51 Kd reverse transcriptase fragments demonstrate the positive immunological reaction with the human blood serum from the people possessing antibodies to HIV-1 virus. The recombinant reverse transcriptase of HIV-1 produced by Escherichia coli cells is shown to be useful in AIDS diagnosis in humans.
Mol Gen Mikrobiol Virusol 1991 Mar
PMID:[Polymerase and immunologic activity of reverse transcriptase of the HIV-1 virus, isolated from Escherichia coli]. 171 97

Of 101 new admissions to an urban outpatient psychiatric clinic, 17 (16.8%) were known to be at high risk and 11 (10.9%) at suspected high risk for developing or transmitting HIV infection, but apparently few were appropriately counseled. This suggests a need for implementing specific policies and procedures for HIV assessment and counseling.
Gen Hosp Psychiatry 1992 Jan
PMID:Assessing HIV risk in the general hospital psychiatric clinic. 173 Mar 95

Under conditions in which a clonal cell line (M10) isolated from a human T cell lymphotrophic virus type I-transformed MT-4 cell line was completely killed by infection with wild-type human immunodeficiency virus type 1 (HIV-1), equivalent M10 cells survived infection with HIV-1 vif, vpr or vpu mutant virus after transient cytopathic effects. Several cell clones, which were isolated from the proliferating M10 cells after infection with vif and vpu mutant viruses (M10/vif- and M10/vpu-), had heterogeneous HIV-1 phenotypes in terms of HIV-1 antigen expression, their syncytium forming capacity, reverse transcriptase activity and the infectivity of HIV-1 particles produced. When the replication kinetics of the HIV-1 particles produced were assayed in M10 cells, the clones could be classified into three types, i.e. type I producing non-infectious HIV-1, type II producing infectious HIV-1 with low replicative ability and type III producing infectious HIV-1 with a replicative ability similar to that of wild-type HIV-1. HIV-1 major viral cell proteins and virus particle fractions were almost typical in types II and III but not in type I. Electron microscopic examination of particles released by I, II and III clones revealed rare defective, predominantly defective and essentially normal virions, respectively. Northern and Southern blot analyses revealed no apparent deletion in the proviral DNA and mRNA prepared from these clones, except in the case of type I and II clones isolated from M10/vpu- which contained large deletions in the mRNAs for gag and gag-pol proteins. Thus, M10 cells surviving infection with HIV-1 vif or vpu mutants are heterogeneous, persistently expressing HIV-1 antigens and producing non-infectious or less cytopathic virus.
J Gen Virol 1992 Jan
PMID:Cells surviving infection by human immunodeficiency virus type 1: vif or vpu mutants produce non-infectious or markedly less cytopathic viruses. 173 Sep 43

In order to assess the adequacy of learning about the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS) in vocational training for general practice, a postal questionnaire survey was carried out among trainers and their trainees in seven health regions of England and Scotland. A total of 616 trainers (62%) and 538 trainees (58%) responded to the questionnaire asking about their knowledge, skills and attitudes regarding HIV and AIDS. Trainees' principal difficulties with HIV and AIDS resembled those of general practitioners currently in practice. More than 60% of trainees lacked knowledge about HIV and AIDS in babies, 50% would not accept intravenous drug misusers onto their list, only 12% found it easy to discuss sex with homosexual male patients, and only 37% felt able to offer counselling about HIV and AIDS. Trainees who had had a tutorial on HIV and AIDS as part of vocational training were significantly more knowledgeable than the remainder (P less than 0.01). In addition, trainees who found workshops on HIV and AIDS useful were more willing than others to take on drug misusers (P less than 0.05) and more confident in their ability to counsel patients with HIV infection (P less than 0.01). No significant associations were found between the trainers' own knowledge, attitudes and skills regarding HIV and AIDS and those of their trainees. It is concluded that there is a need to improve teaching about HIV and AIDS in vocational training for general practice. All general practitioner trainees should receive a tutorial to update their knowledge about HIV and AIDS, and attend a suitable workshop to challenge unfavourable attitudes and improve confidence in counselling.
Br J Gen Pract 1991 Oct
PMID:AIDS: knowledge, skills and attitudes among vocational trainees and their trainers. 158 62

Neuropsychiatric problems have assumed an increasingly prominent role in HIV-infected individuals. Disease occurs at all levels of the central and peripheral nervous systems by a variety of mechanisms. The AIDS dementia complex is the prototypical example of "direct" effects of HIV on the neuraxis, while infections such as toxoplasmosis and cryptococcal meningitis are complications of HIV-induced immunosuppression. Neurologic manifestations vary in frequency depending upon the overall stage of HIV disease; diagnostic difficulties may be encountered because of HIV's effect on cerebrospinal fluid parameters. The uncertainties of management of neurosyphilis in this setting provide and example of these problems. As is the case with other organ systems, the main goal of neurodiagnostic efforts is to find the increasing number of treatable components of neuropsychiatric dysfunction.
J Gen Intern Med
PMID:Neurologic and psychiatric manifestations of HIV disease. 184 9


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