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

The ability of HIV-1 envelope glycoprotein gp120 to induce transmembrane signaling processes in human T cells and tumor T-cell lines was investigated. Differently glycosylated gp120 preparations were characterized with respect to their purity, the fraction of native gp120, and the affinity of the gp120-CD4 interaction. These data were used to establish experimental conditions that allow a substantial fraction of the CD4 receptor to be complexed with gp120 in the course of the experiments. The results are in contrast to several previous studies since no effect of gp120 on the intracellular Ca2+ concentration, the metabolism of inositol phosphates and arachidonic acid, protein kinase C translocation, and tyrosine phosphorylation was found. Cross-linking of the gp120:CD4 complex by anti-gp120 antibodies did not elicit additional effects.
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PMID:The HIV-1 surface protein gp120 has no effect on transmembrane signal transduction in T cells. 132 56

Pneumocystis carinii was recovered from the lungs of a 20-year-old woman in apparent good health who had volunteered to undergo bronchoalveolar lavage (BAL) as a normal control subject. Total and differential cell counts in the BAL fluid revealed a significantly increased number and proportion of T lymphocytes, although the CD4:CD8 ratio was in the normal range. Despite the lack of specific antibiotic therapy, in a subsequent lavage no P. carinii were recovered, and the total and differential cell counts returned to normal, suggesting that the infection had resolved. Serologic evaluation revealed no evidence of human immunodeficiency virus infection, although elevated titers of antibodies to Epstein-Barr virus were demonstrated, suggesting ongoing or resolving viral infection. These findings suggest that P. carinii may cause subclinical pneumonitis even in the absence of a clinically evident immune deficient state. Furthermore, an increase in cell count and in the proportion of lymphocytes in an otherwise unremarkable BAL may indicate the presence of P. carinii in the airways and may be the only sign of subclinical infection of the respiratory tract by this organism.
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PMID:Subclinical pneumonitis due to Pneumocystis carinii in a young adult with elevated antibody titers to Epstein-Barr virus. 132 86

In HIV-infected men, human papillomavirus (HPV) infection is strongly linked with the development of anogenital lesions but is not a sufficient factor to explain the neoplastic transformation of such lesions. We investigated the association between HPV and herpesvirus infections in penile and anal lesions from 54 HIV-seronegative and 54 HIV-seropositive men by means of colposcopy, histopathology and in situ hybridization. Our patients showed condyloma acuminata (39%), papular warts (35%) and macular warts (26%). High-grade lesions were predominant in the HIV+ men, whereas low-grade lesions were more frequent in the HIV- men. In the HIV+ group, potential oncogenic HPV were the most frequently detected (83.4%) whereas the "low-risk" HPV were found chiefly in HIV- men (62.1%). The CD4 number was lower in patients showing "high-risk" HPV than in men showing lesions without HPV or with non-oncogenic HPV. HPV types 6/11 were found mainly associated with koilocytosis or with AIN(PIN)I. Oncogenic HPV were more often detected in AIN(PIN)II-III. The herpesviruses DNA detection revealed a higher prevalence of HSVI and -2 than CMV and EBV in the studied biopsies. The frequency of HSV and CMV detection was higher in the HIV+ than in the HIV- men. A link was found between the "high-risk" HPV and the CMV detection whatever the population considered. The detection in HPV lesions of other sexually transmitted viral agents could therefore represent an important means of preventing progression of the anogenital disease, especially in immunosuppressed patients.
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PMID:Viral co-infections in human papillomavirus-associated anogenital lesions according to the serostatus for the human immunodeficiency virus. 133 Sep 31

Disseminated toxoplasmosis, one of the most severe acquired immune deficiency syndrome (AIDS)-associated infections in humans, is believed to develop from a latent infection after the cellular immune system is suppressed by human immunodeficiency virus type 1 (HIV-1). However, Toxoplasma gondii may serve as a cofactor in enhancing the immunodeficiency induced by HIV-1. This hypothesis is supported by the facts that: 1) co-infection with other pathogens in humans infected with HIV-1 may enhance the progression of the disease to AIDS; and 2) concomitant infection with T. gondii enhances feline immunodeficiency virus-induced immune dysfunction and is likely to cause a more rapid disease onset than an infection with HIV alone. It is possible that T. gondii infection induces tumor necrosis factor (TNF) production. TNF then stimulates the induction of T-cell proteins that bind to the long terminal repeat of HIV-1. This binding at the repeat site then leads to increased HIV-1 activation which causes the dysfunction of CD4 cells and a resulting immunodeficiency that allows even greater amounts of T. gondii replication.
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PMID:Toxoplasma gondii: an AIDS enhancing cofactor. 133 11

Two immature T cell lines (FT1 and FT4) were established after in vitro cloning of peripheral blood lymphocytes (PBLs) from an asymptomatic human immunodeficiency virus type 1 (HIV-1) seropositive, human T cell-lymphotropic virus type 1 seronegative homosexual subject. Although derived from a limiting dilution cell cloning assay, these cell lines were not recloned for this study. Their growth was independent of exogenous interleukin-2. Both cell lines were able to form colonies when cloned in agar, but failed to form solid tumours when injected into nude mice. FT lines belong to the very immature T cell lineage as they exhibit rearranged TCR genes but no expression of T cell membrane antigens, including CD2, CD3, CD4, CD6, CD7 and CD8. They also contain an HIV-1 genome that was detected only in an extra-chromosomal DNA form, even after several passages in vitro. The presence of unintegrated viral DNA was also detected by polymerase chain reaction analysis in the same sample of fresh uncultured PBLs. Furthermore, despite the absence of CD4 expression, both T cell lines were susceptible to CD4-independent HIV-1 superinfection (lack of superinfection inhibition in the presence of OKT4A monoclonal antibodies).
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PMID:Extrachromosomal human immunodeficiency virus type 1 DNA forms in fresh peripheral blood lymphocytes and in two interleukin-2-independent T cell lines derived from peripheral blood lymphocytes of an asymptomatic seropositive subject. 133 22

Seven immortalized B cell clones, five of which secreted specific human monoclonal antibodies (MAbs) against hepatitis B, tetanus toxoid, and Rhesus D antigens, were evaluated for their susceptibility to infection by human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2). Infection was confirmed in three human MAb-producing lines by detection of infectious virus and p24 antigen in culture supernates, by immunofluorescence, and by detection of viral DNA in cells by polymerase chain reaction. The infectable lines were as susceptible to HIV-1 infection as several T cell lines and remained persistently infected for several months, but in contrast to T cell controls, viral cytopathic effects were not observed. Levels of unintegrated viral DNA in the HB1 B cell line were significantly lower than in the HUT78 T cell line. Cell lines that were susceptible to HIV expressed HLA DR, CD20, and CD21, whereas the uninfectable cell lines did not express any of the markers tested. CD4 was undetectable or present on a small percentage of cells in two of the infectable cell lines. However, infection with HIV-1 was blocked more efficiently in B cells than in T cells by soluble CD4, anti-CD4 MAb, and dextran sulphate. The effect of HIV infection on human MAb secretion was variable, being reduced on a per-cell basis in one line, increased in another, and unchanged in a third.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Susceptibility of human monoclonal antibody-producing B cell lines to infection by human immunodeficiency virus. 133 86

This study demonstrates the transmission of feline immunodeficiency virus (FIV) from infected queens to kittens in two separate litters. Queen 1 was infected by intravenous administration of FIV at 22 days prior to parturition. Two out of three kittens from the litter were found to be viremic at 10 weeks of age as detected by culture isolation and polymerase chain reaction detection of FIV DNA in peripheral blood mononuclear leukocytes. The third kitten remained aviremic through 40 weeks of age. Queen 2 was infected by subcutaneous administration of FIV 2 days prior to parturition. This litter also had two out of three kittens infected with FIV; however, viremia was not detected in one of the kittens until 21 weeks of age. Culture isolation was found to be superior to polymerase chain reaction for the early detection of FIV, and viremia was found to precede seroconversion by up to 4 weeks. Although all infected kittens have remained healthy, depressed CD4:CD8 lymphocyte ratios suggest that clinical disease may develop. This study suggests that FIV infection in cats may be a useful model system for the study of HIV transmission from mothers to infants.
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PMID:Transmission of feline immunodeficiency virus from infected queens to kittens. 133 4

In the course of HIV infection "atopic" symptoms can often be experienced (atopic dermatitis, asthmatic like symptoms in upper respiratory tract, sensitivity to drugs). Total IgE increase has been detected which is in inverse correlation with CD4 positive lymphocytes. Using semi quantitative and quantitative methods total and specific IgE levels of 30 HIV positive and 30 HIV negative homosexual men without atopic anamnestic data and symptoms have been determined. The age matched control groups were of 30 atopic men with active symptoms and 30 healthy, HIV negative heterosexual men. Determination of CD4, CD8 positive number of lymphocytes as well as B-2 microglobulin have been carried out. Total IgE level of HIV positive and HIV negative homosexuals was higher than that of the healthy controls and lower than that of the "atopic" controls. Specific IgE-s have been found more often in HIV positive and HIV negative homosexuals than in the normal controls. The correlation among CD4 and CD8 positive lymphocytes, and B-2 microglobulin level and total IgE level was not significant.
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PMID:Total and specific IgE in sera of HIV positive and HIV negative homosexual male (regulation of IgE synthesis in HIV infection). 134 Jun 58

1. Toxoplasma gondii is a ubiquitous, obligate intracellular parasite of worldwide distribution. In humans, the parasite exists in two forms: the tachyzoite is the rapidly multiplying stage of the parasite which actively invades host cells and represents the principal pathogenic form at the acute phase of the disease; the bradyzoite is the form which multiplies slowly in host cells, resulting in the formation of cysts which persist in tissues. Several antigenic components have been identified, some of which are characteristic for each parasitic stage; particularly, in tachyzoites, the 30 kDa membrane protein represents up to 5% of the total protein content. 2. Toxoplasma infection in humans is usually asymptomatic because of effective immunity involving antibodies, T cells and cytokines. Activated macrophages, CD4 and CD8 lymphocytes and cytokines, such IFN gamma, play a major role in the control of acute infection and the maintenance of infection at the chronic stage. The alteration of immune functions, as observed in congenitally infected children and in HIV-infected patients, may induce the recrudescence of previously latent toxoplasmosis, in relation to disruption of the cyst form of the parasite. The resulting reactivation is responsible for life-threatening infections which are frequently manifested as toxoplasmic encephalitis. 3. In this review, the parasite and immunological factors participating in the pathogenesis of the lesions associated with acute, chronic and reactivated toxoplasmosis are presented.
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PMID:Pathogeny and immunological control of toxoplasmosis. 134 11

Nervous system opportunistic infections are seen in about one fifth of AIDS cases and account for over 40% of the patients with neurological manifestations. Serious infections are seen in severely immunosuppressed patients, usually with CD4 counts of 200 ml-1 or less. The commonest is CMV, which can produce acute encephalitis, sometimes with focal hemisphere or brain-stem signs, dementia, retinitis, optic neuritis and an ascending radiculomyeloencephalitis. Cryptococcal meningitis is the most frequent fungal disease; a high degree of clinical suspicion is required in patients with fever, malaise, headache or seizures. Only CSF cultures are always positive; both serum and CSF cryptococcal antigen tests are highly sensitive and specific. Treatment with amphotericin B and flucytosine is successful in at least 70% of first episodes but side-effects are common. Without maintenance therapy 50% of patients relapse; fluconazole is recommended. Cerebral toxoplasmosis can present with focal cerebral or spinal cord signs but also as a diffuse encephalopathy; negative T. gondii serology is exceptional but positive serum titres are usually unhelpful. Treatment with sulfadiazine, pyrimethamine and folinic acid achieves good results in 90% of the first episodes, but side-effects are common. Appearances on CT scan or MRI may take several weeks to improve. The value of an empirical approach to treatment is well-established; an initial cerebral biopsy is difficult to justify. Without maintenance therapy a relapse rate of 50% can be expected; therapy with sulfadiazine and pyrimethamine may also prevent pneumocystosis. HIV disease appears to increase the likelihood of neurosyphilis, and the risk of relapse after conventional penicillin doses, in patients with syphilis; at least 3-4 weeks of appropriate therapy are recommended. A number of other diseases caused by viruses, fungi, bacteria and parasites are less common; these include progressive multifocal leukoencephalopathy, herpes simplex and zoster infections and tuberculosis.
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PMID:Central nervous system opportunistic infections in HIV disease: clinical aspects. 134 47


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