Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, epitopes of HIV envelope proteins that are involved in ADCC were identified. Peripheral blood mononuclear cells (PBMC) were obtained from adults with asymptomatic HIV infection or early symptoms of AIDS. These PBMC, which were reported to be "armed" in vivo with HIV-specific antibodies, were used as effector cells in 51Cr release assays. Target cells consisted of CD4 lymphocytes from healthy seronegative donors, coated with the IIIB strain of HIV-1 or with one of seven synthetic peptides. Cytotoxicity was detected against CD4 lymphocytes coated with HIV-1 IIIB or with the peptides env aa 507-518, corresponding to the carboxy-terminus of gp120, and env aa 597-611, corresponding to the region of the cysteine loop of gp41. The magnitude of target cell lysis was directly related to the quantity of peptide used. In contrast, target cells coated with the peptide gag aa 129-135, corresponding to the p17/p24 cleavage region of the gag precursor, were not killed. The same immunodominant regions which were involved in ADCC were recognized in enzyme-linked immunoabsorbent assays (ELISA) by the majority of 107 sera from HIV-infected adults. We conclude that the immunodominant epitopes located at the carboxy-terminus of gp120 and the cysteine loop of gp41 serve as recognition structure for antibodies, capable of mediating ADCC against HIV-infected cells.
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PMID:Antibody-dependent cellular cytotoxicity (ADCC) is directed against immunodominant epitopes of the envelope proteins of human immunodeficiency virus 1 (HIV-1). 128 12

Ten monoclonal antibodies prepared against a soluble, recombinant form of gp160, derived from the IIIB isolate of HIV-1, were characterized. Four of the antibodies neutralized HIV-1IIIB infectivity in vitro, three blocked the binding of recombinant gp120 to CD4, three were reactive with gp41, and one preferentially reacted with an epitope on gp120 within the gp160 precursor. All three CD4 blocking antibodies bound to distinct epitopes, with one mapping to the C1 domain, one mapping to the C4 domain, and one reactive with a conformation-dependent, discontinuous epitope. Of these, the antibody reactive with the discontinuous epitope exhibited neutralizing activity against homologous and heterologous strains of HIV-1. The binding of these monoclonal antibodies to a panel of seven recombinant gp120s prepared from diverse isolates of HIV-1 was measured, and monoclonal antibodies with broad cross reactivity were identified. The epitopes recognized by 7 of the 10 monoclonal antibodies studied were localized by their reactivity with synthetic peptides and with fragments of gp120 expressed as fusion proteins in a lambda gt-11 gp160 epitope library.
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PMID:Monoclonal antibodies to the extracellular domain of HIV-1IIIB gp160 that neutralize infectivity, block binding to CD4, and react with diverse isolates. 128 8

The clinical manifestations and some immunological parameters (CD4 lymphocytes, CD4/CD8 ratio, IgM, IgA, IgG levels, skin test) were examined in 226 adult patients (148 males and 78 females) infected with HIV. These included 58 (26%) asymptomatic patients with seropositive test, 109 (48%) with the only clinical manifestation generalized lymphadenopathy; 54 (24%) with AIDS-related infections, 5 (2%) with AIDS. A subsequent follow-up of 3 months to 3 years demonstrated that AIDS developed in 7 patients, 9 died. The period of infection with HIV and death ranged from 1.5 to 9 years. The signs of cell immunodeficiency were found in 70% of the examinees. Recommendations are given on the classification of HIV infection.
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PMID:[Clinical manifestations and the problems of classification of HIV infection]. 128 10

The human immunodeficiency virus (HIV) proteins gp120 and gp41 are the principal immune target in HIV infection. One of the most important trends in the study of AIDS is linked to the mapping of sites involving in the binding to the cell receptor CD4 and in the induction of virus-neutralizing antibodies (VNA). Recent studies have revealed that gp120 as the major domain contains inducing type-specific BNA (PND) and a binding region with CD4 (CD4-BR). PND is located in the hypervariable loop of gp120 (residues 301-336 for a BRU strain), and CD4-BR is in the conservation area (residues 410-450). By using the synthetic fragments from these areas (BRU and MN strains) and HIV-infected persons' sera, the authors established that the immune response to PND and CD4-BR is somewhat interrelated: there is a synchronized response of HIV antibodies to peptides from the two regions in ELISA (r = 0.82). For analysis of this phenomenon, experiments with cross-linked immunoreactivity of rabbit antisera to peptides from PND and CD4-BR with homologous and heterologous peptides were performed by applying three control peptides from HIV and hepatitis B virus. It has been found that there is a cross reactivity between rabbit anti-PND (MN, BRU) and anti-CD4-BR abs. Peptide homological analysis revealed common structural elements for PND and CD4-BR despite significant differences in their proposed functions. There is a large amount of positively charged aa within both PND and CD4-BR which may be involved in gp120-CD4 interaction. Acetylation of Lys residues resulted in complete loss of peptide reactivity.
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PMID:[Peptides from the principal neutralizing and CD4-binding domain: similar immunoreactive properties and structure pattern]. 128 21

The major neutralizing epitope on the external glycoprotein of HIV-1 was studied with an envelope-specific monoclonal antibody and with a human serum positive for antibodies to HIV-1 proteins, both of which were able to neutralize virus infectivity. The monoclonal antibody reacted specifically with gp120 from HIV-1IIIB, and was shown to neutralize infection of CEM cells by cell-free virions, and inhibited the formation of syncytia normally observed when uninfected cells are cocultured with HIV-1-infected cells. Similar neutralization of viral infection and inhibition of syncytia formation was also demonstrated by the HIV-1-antibody-positive human serum. By examining a number of overlapping peptides from a region of HIV-1 gp120 known to contain a neutralizing epitope, this epitope was localized between amino acids 307 and 320 (V3 loop) in the external glycoprotein molecule. The monoclonal antibody did not interfere with the binding of gp120 to CD4, or with the subsequent step of CD4-induced shedding of gp120 from the viral envelope. However, it blocked the proteolytic cleavage of the V3 loop by thrombin, suggesting that the antibody may be inhibiting the interaction of the loop with other membrane-bound proteins.
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PMID:Characterization of a neutralizing monoclonal antibody to the external glycoprotein of HIV-1. 128 59

The authors studied the immune status of 14 HIV-infected patients, 6 of whom had lymphadenopathy, 4 were diagnosed as having AIDS-related complex and 4, a full-blown AIDS. Analysis of laboratory findings showed that of predictive value are serum levels of immunoglobulin B, a CD4 cell count less than 200, reduced populations of CD20 and CD16 lymphocytes, and a depressed response to pokeweed mitogen. Based on the clinical manifestations and laboratory results, three stages characterizing the immune system in HIV infection have been identified.
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PMID:[The possibilities of using immunological indices as criteria for determining the stage of HIV infection and the disease prognosis]. 128 13

An increasing number of antiviral agents are presently in various stages of development and testing, and an increasing number have recently been licensed for use in humans. These drugs have been used extensively to treat viral infections in immunocompromised individuals, and these studies indicate that for many antiviral agents the response to therapy is highly dependent on the integrity of the underlying host immune response. In particular, the response to zidovudine, acyclovir and ganciclovir in persons with HIV-1 infection is highly dependent upon CD4 number, which can be considered a surrogate marker for the state of host immune function in these subjects. Responses to interferons likewise can be shown to depend on the host immune response, with responses due to both direct antiviral effects of this agent as well as immunomodulatory effects mediated through interferon-induced upregulation of HLA molecule expression. The interdependence of host immunity with antiviral efficacy is underscored by the increased antiviral drug resistance in persons with advanced degrees of chronic immunosuppression, related to the higher level of viral replication and viraemia which occurs in the absence of an effective host immune response. Further definition of the precise mechanisms of these interactions should facilitate the rational design of antiviral agents and immunomodulatory therapies to improve treatment of viral infections.
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PMID:Viruses, chemotherapy and immunity. 128 13

We have previously demonstrated that acidic medium inhibits the replication of HIV-1. The present study was designed to examine the effects of other growth conditions and infection of fibroblasts by coculture with HIV infected lymphoid cells. Several lymphoblastoid cell lines normally grown in RPMI-1640 were grown in Eagle's MEM. These cells supported virus replication to higher titres than did RPMI-1640. Peak viral titres were achieved within 24-48 h after newly infected or chronically infected cells were placed in fresh medium. When virus was stored in liquid medium either frozen or at higher temperatures, virus titres were retained for several months while frozen but decreased upon storage at 4 degrees C or higher. If cells were passaged after trypsinization in Ca(++)-depleted medium, then a decreased susceptibility of cells for HIV-1 by 2 log10 at 24 h post infection was observed. Infectivity of cell-free and cell-associated HIV-1 was measured using syncytium formation, reverse transcriptase activity and p24 antigen. No fusion between HIV-1 infected CD4+ lymphoblasts and CD4- fibroblasts was observed but HIV-1 infected lymphoid cells, even in the absence of syncytium formation, exerted a strong toxic effect on fibroblasts. This study extends previous findings that medium acidity was inhibitory to virus replication and survival. Thus, conditions for study of HIV must be well controlled in buffered medium so that misleading results are not obtained regarding virus multiplication and possibly regarding transmission to and pathogenesis in CD4- cells.
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PMID:The influence of cell culture and storage conditions on HIV-1 infectivity and fusogenic activity. 128 37

In order to study the epidemiological, clinical, and progressive characteristics of TB in HIV-infected individuals, a retrospective study was conducted in nine infectious disease centres of university hospitals located in the southern half of France. Among the 5730 HIV-seropositive in- and out-patients, 123 (2.1 per cent) had TB (121 infections caused by M. tuberculosis, 2 by M. bovis). Tuberculosis was pulmonary in 53 patients (43.1 per cent), extrapulmonary in 36 patients (29.3 per cent), and combined in 34 patients (27.6 per cent). There was no statistically significant difference among these three locations as to the mean CD4 count/mm3 (160 +/- 17), the type of antituberculosis therapy, the length of treatment (10.8 +/- 0.6 months) and the outcome. Fifty-two (45.2 per cent) patients received an initial antituberculosis therapeutic regimen of four drugs: isoniazid, rifampicin, ethambutol, pyrazinamide; 54 (46.9 per cent) were started on three drugs: isoniazid, rifampicin, ethambutol; and nine (7.8 per cent) received a two-drug combination: isoniazid, rifampicin. Fourteen of 75 patients subsequently received secondary preventive therapy. The mean follow-up time was 252 +/- 290 days. Clinical healing was obtained in 57.7 per cent of patients. Forty-six patients died, 33 during treatment: 23 from AIDS and eight from TB (in the first 3 weeks of treatment). Five patients suffered from relapses due to poor treatment compliance. Patients had a good prognosis if tuberculosis was diagnosed early.
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PMID:Tuberculosis in patients infected with human immunodeficiency virus 1. A retrospective multicentre study of 123 cases in France. The Groupe des Infectiologues du Sud de la France. 128 4

A follow-up study was done in Bissau on 113 HIV-2 seropositive patients and 97 HIV-2 seronegative patients 3-15 months after hospitalization. Follow-up totalled 63.5 person years for seropositive patients and 62 for seronegative patients. The mortality during the follow-up period was 43.3% among the seropositive patients (rate 72/100 person years; p.y.) and 25.8% among the seronegative patients (40/100 p. y.). Among 25 HIV-2 associated AIDS cases the mortality was 80% (rate 117/100 p. y.). The median survival time for the AIDS patients was 8 months. Among 48 HIV-2 seropositive patients who lacked signs or symptoms included in the WHO case definition for AIDS at the time of hospitalization 6 patients (12.5%) developed AIDS related symptoms (ARS) during altogether 31.5 person years of follow-up (rate 19/100 p. y.). Tuberculin anergy was demonstrated in 83.3% (15/18) of HIV-2 seropositive patients with AIDS or ARS, in 14.3% (6/42) of seropositive patients without HIV-related symptoms and in 6.9% (5/72) of seronegative patients. A low CD4 T-lymphocyte count in combination with a low CD4/CD8 T-cell ratio was found significantly more often in HIV-2 seropositive patients with AIDS or ARS (62.5%, 10/16) than in HIV-2 seropositive patients without HIV associated symptoms (6.9%, 2/29) or in seronegative patients (2.7%, 1/37). Thus the mortality among recently hospitalized HIV-2 seropositive patients was high and a high proportion of seropositive patients with HIV-related symptoms had evidence of immunodeficiency.
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PMID:Clinical and immunological follow-up of previously hospitalized HIV-2 seropositive patients in Bissau, Guinea-Bissau. 128 6


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