Cellular immune responses in human immunodeficiency virus (HIV)-1-infected children: Is immune restoration by highly active anti-retroviral therapy comparable to non-progression?

The objective of this study was to investigate whether the restored immune functions of vertically human immunodeficiency virus (HIV)-infected children who were severely immunodeficient before the initiation of highly active anti-retroviral therapy (HAART) are comparable to those of untreated slow progressors. We therefore assessed T cell proliferation and cytokine [interferon (IFN)-γ, interleukin (IL)-5 and IL-13] secretions after mitogen, recall antigens and HIV-1-specific stimulation in 12 untreated slow progressors, 16 untreated progressors and 18 treated patients. Treated children were profoundly immunodeficient before the initiation of HAART and had long-lasting suppression of viral replication on treatment. We demonstrated that slow progressors are characterized not only by the preservation of HIV-1-specific lymphoproliferative responses but also by the fact that these responses are clearly T helper type 1 (Th1)-polarized. Children on HAART had proliferative responses to HIV-1 p24 antigen, purified protein derivative (PPD) and tetanus antigen similar to slow progressors and higher than those of progressors. However, in contrast to slow progressors, most treated children exhibited a release of Th2 cytokines accompanying the IFN-γ secretion in response to the HIV-1 p24 antigen. Moreover, despite higher proliferative responses to phytohaemagglutinin (PHA) than the two groups of untreated children, treated children had lower levels of IFN-γ secretion in response to PHA than slow progressors. These data show that in severely immunodeficient vertically HIV-infected children, a long-lasting HAART allows recovering lymphoproliferative responses similar to untreated slow progressors. However, alterations in IFN-γ secretion in response to the mitogen PHA persisted, and their cytokine release after HIV-specific stimulation was biased towards a Th2 response. © 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.

Age-related immune reconstitution during highly active antiretroviral therapy in human immunodeficiency virus type 1-infected children [2] (multiple letters)

SCOPUS: le.j

Recurrent lower gastrointestinal bleeding secondary to cytomegalovirus-associated colonic ulcer in a non human immunodeficiency virus infected patient:Timely diagnosis and treatment averted surgery

Mr C, a 68-year-old Chinese male with diabetes mellitus, previous stroke and ischaemic cardiomyopathy on clopidogrel, presented with haematochezia. Colonoscopy showed a sigmoid ulcer, which was treated endoscopically. Histology of the biopsy from the ulcer revealed non-specific changes. However, he presented with recurrent bleeding from this non-healing sigmoid ulcer. A review of the histologic specimen revealed CMV intranuclear inclusion bodies. He was treated with intravenous ganciclovir, with no further hematochezia.

Keywords Hematochezia, cytomegalovirus, ulcer

Presentation of a plasmablastic lymphoma in a human immunodeficiency virus-positive patient after administration of an inferior alveolar dental block

Human immunodeficiency virus (HIV) is a serious worldwide healthcare problem with implications for all healthcare workers. The reported oral manifestations of the disease are numerous and have been categorised according to the strength of their association with HIV infection. Oral non-Hodgkin's lymphoma is strongly associated with HIV infection, and an increased incidence of such neoplasms is widely reported. This case report details the presentation of a rare subcategory of plasmablastic lymphoma in an HIV-positive patient after administration of an inferior alveolar dental block to facilitate extraction of mandibular teeth. This highly aggressive neoplasm is a large B-cell lymphoma with a predilection for the oral cavity. Unfortunately, the prognosis for such a tumour is poor as detailed in this case.

Association between disruption of CD4 receptor dimerization and increased human immunodeficiency virus type 1 entry

Affiliation: Département de microbiologie et immunologie, Faculté de médecine, Université de Montréal & Institut de Recherches Cliniques de Montréal

Contribution of the C-terminal tri-lysine regions of human immunodeficiency virus type 1 integrase for efficient reverse transcription and viral DNA nuclear import

Affiliation: Zhujun Ao, Éric Cohen & Xiaojian Yao : Département de microbiologie et immunologie, Faculté de Médecine, Université de Montréal

Requirements for the selective degradation of CD4 receptor molecules by the human immunodeficiency virus type 1 Vpu protein in the endoplasmic reticulum.

BACKGROUND: HIV-1 Vpu targets newly synthesized CD4 receptor for rapid degradation by a process reminiscent of endoplasmic reticulum (ER)-associated protein degradation (ERAD). Vpu is thought to act as an adaptor protein, connecting CD4 to the ubiquitin (Ub)-proteasome degradative system through an interaction with beta-TrCP, a component of the SCFbeta-TrCP E3 Ub ligase complex. RESULTS: Here, we provide direct evidence indicating that Vpu promotes trans-ubiquitination of CD4 through recruitment of SCFbeta-TrCP in human cells. To examine whether Ub conjugation occurs on the cytosolic tail of CD4, we substituted all four Ub acceptor lysine residues for arginines. Replacement of cytosolic lysine residues reduced but did not prevent Vpu-mediated CD4 degradation and ubiquitination, suggesting that Vpu-mediated CD4 degradation is not entirely dependent on the ubiquitination of cytosolic lysines and as such might also involve ubiquitination of other sites. Cell fractionation studies revealed that Vpu enhanced the levels of ubiquitinated forms of CD4 detected in association with not only the ER membrane but also the cytosol. Interestingly, significant amounts of membrane-associated ubiquitinated CD4 appeared to be fully dislocated since they could be recovered following sodium carbonate salt treatment. Finally, expression of a transdominant negative mutant of the AAA ATPase Cdc48/p97 involved in the extraction of ERAD substrates from the ER membrane inhibited Vpu-mediated CD4 degradation. CONCLUSION: Taken together, these results are consistent with a model whereby HIV-1 Vpu targets CD4 for degradation by an ERAD-like process involving most likely poly-ubiquitination of the CD4 cytosolic tail by SCFbeta-TrCP prior to dislocation of receptor molecules across the ER membrane by a process that depends on the AAA ATPase Cdc48/p97.

Effect of calcium-modulating cyclophilin ligand on human immunodeficiency virus type 1 particle release and cell surface expression of Tetherin

The HIV-1 accessory protein Vpu enhances virus particle release by counteracting a host factor that retains virions at the cell surface of infected cells. It was recently demonstrated that cellular protein BST2/CD317/Tetherin restricts HIV-1 release in a Vpu-dependent manner. CAML was also proposed to be involved in this process. We investigated whether CAML is involved in Tetherin cell-surface expression. Here, we show that CAML over-expression in permissive Cos-7 cells or CAML depletion in restrictive HeLa cells has no effect on HIV-1 release nor on Tetherin surface expression, indicating that CAML is not required for Tetherin-mediated restriction of HIV-1 release.

Sexual sensation-seeking and worry about sexually transmitted diseases (STD) and human immunodeficiency virus (HIV) infection among Spanish adolescents. = B??squeda de sensaciones y preocupaci??n por las Enfermedades de Transmisi??n Sexual y VIH en adolescentes espa??oles

Resumen tomado de la publicaci??n. Resumen tambi??n en ingl??s

Human papillomavirus detection from human immunodeficiency virus-infected colombian women's paired urine and cervical samples

Infection, coinfection and type-specific human papillomavirus (HPV) distribution was evaluated in human immunodeficiency virus (HIV)-positive women from paired cervical and urine samples. Paired cervical and urine samples (n = 204) were taken from HIV-positive women for identifying HPV-DNA presence by using polymerase chain reaction (PCR) with three generic primer sets (GP5+/6+, MY09/11 and pU1M/2R). HPV-positive samples were typed for six high-risk HPV (HR-HPV) (HPV-16, -18, -31, -33, -45 and -58) and two low-risk (LR-HPV) (HPV-6/11) types. Agreement between paired sample results and diagnostic performance was evaluated. HPV infection prevalence was 70.6% in cervical and 63.2% in urine samples. HPV-16 was the most prevalent HPV type in both types of sample (66.7% in cervical samples and 62.0% in urine) followed by HPV-31(47.2%) in cervical samples and HPV-58 (35.7%) in urine samples. There was 55.4% coinfection (infection by more than one type of HPV) in cervical samples and 40.2% in urine samples. Abnormal Papanicolau smears were observed in 25.3% of the women, presenting significant association with HPV-DNA being identified in urine samples. There was poor agreement of cervical and urine sample results in generic and type-specific detection of HPV. Urine samples provided the best diagnosis when taking cytological findings as reference. In conclusion including urine samples could be a good strategy for ensuring adherence to screening programs aimed at reducing the impact of cervical cancer, since this sample is easy to obtain and showed good diagnostic performance.

Mapping the immune response to the outer domain of a human immunodeficiency virus-1 clade C gp120

The outer domain (OD) of human immunodeficiency virus (HIV)-1 gp120 represents an attractive, if difficult, target for a beneficial immune response to HIV infection. Unlike the entire gp120, the OD is structurally stable and contains the surfaces that interact with both the primary and secondary cellular receptors. The primary strain-specific neutralizing target, the V3 loop, lies within the OD, as do epitopes for two cross-reactive neutralizing monoclonal antibodies (mAbs), b12 and 2G12, and the contact sites for a number of inhibitory lectins. The OD is poorly immunogenic, at least in the context of complete gp120, but purposeful OD immunization can lead to a substantial antibody response. Here, we map the antibody generated following immunization with a clade C OD. In contrast to published data for the clade B OD, the majority of the polyclonal response to the complete clade C OD is to the V3 loop; deletion of the loop substantially reduces immunogenicity. When the loop sequence was substituted for the epitope for 2F5, a well-characterized human cross-neutralizing mAb, a polyclonal response to the epitope was generated. A panel of mAbs against the clade C OD identified two mAbs that reacted with the loop and were neutralizing for clade C but not B isolates. Other mAbs recognized both linear and conformational epitopes in the OD. We conclude that, as for complete gp120, V3 immunodominance is a property of OD immunogens, that the responses can be neutralizing and that it could be exploited for the presentation of other epitopes.

Control of human immunodeficiency virus type-1 protease activity in insect cells expressing Gag-Pol rescues assembly of immature but not mature virus-like particles

Expression of human immunodeficiency virus type 1 (HIV-1) Gag protein in insect cells using baculovirus vectors leads to the abundant production of virus-like particles (VLPs) that represent the immature form of the virus. When Gag-Pol is included, however, VLP production is abolished, a result attributed to premature protease activation degrading the intracellular pool of Gag precursor before particle assembly can occur. As large-scale synthesis of mature noninfectious VLPs would be useful, we have sought to control HIV protease activity in insect cells to give a balance of Gag and Gag-Pol that is compatible with mature particle formation. We show here that intermediate levels of protease activity in insect cells can be attained through site-directed mutagenesis of the protease and through antiprotease drug treatment. However, despite Gag cleavage patterns that mimicked those seen in mammalian cells, VLP synthesis exhibited an essentially all-or-none response in which VLP synthesis occurred but was immature or failed completely. Our data are consistent with a requirement for specific cellular factors in addition to the correct ratio of Gag and Gag-Pol for assembly of mature retrovirus particles in heterologous cell types. (C) 2003 Elsevier Science (USA). All rights reserved.

Reconstructing the incidence of human immunodeficiency virus (HIV) in Hong Kong by using data from HIV positive tests and diagnoses of acquired immune deficiency syndrome

The human immunodeficiency virus–acquired immune deficiency syndrome (HIV–AIDS) epidemic in Hong Kong has been under surveillance in the form of voluntary reporting since 1984. However, there has been little discussion or research on the reconstruction of the HIV incidence curve. This paper is the first to use a modified back-projection method to estimate the incidence of HIV in Hong Kong on the basis of the number of positive HIV tests only. The model proposed has several advantages over the original back-projection method based on AIDS data only. First, not all HIV-infected individuals will develop AIDS by the time of analysis, but some of them may undertake an HIV test; therefore, the HIV data set contains more information than the AIDS data set. Second, the HIV diagnosis curve usually has a smoother pattern than the AIDS diagnosis curve, as it is not affected by redefinition of AIDS. Third, the time to positive HIV diagnosis is unlikely to be affected by treatment effects, as it is unlikely that an individual receives medication before the diagnosis of HIV. Fourth, the induction period from HIV infection to the first HIV positive test is usually shorter than the incubation period which is from HIV infection to diagnosis of AIDS. With a shorter induction period, more information becomes available for estimating the HIV incidence curve. Finally, this method requires the number of positive HIV diagnoses only, which is readily available from HIV–AIDS surveillance systems in many countries. It is estimated that, in Hong Kong, the cumulative number of HIV infections during the period 1979–2000 is about 2600, whereas an estimate based only on AIDS data seems to give an underestimate.

DNA found in human immunodeficiency virus type 1 particles may not be required for infectivity

We have studied the presence and significance of retroviral genome-derived DNA in the core of human immunodeficiency virus (HIV) particles produced from transfections of HXB2 expression vectors in COS-7 cells and from HIV type 1 IIIB chronically infected H9 cells. Viruses purified by sucrose cushion centrifugation and treated with DNase I contained 1000-fold more viral RNA than DNA. However protease-defective viruses that contained only pl60 ga~p°z had less than 100 times the amount of DNA in their cores than wild-type viruses suggesting that the p66/p51 form of reverse transcriptase was responsible for DNA transcription. Viruses produced by transfections in the presence of 3'-azido-3'-deoxythymidine (AZT) contained the viral RNA genome but only DNA of premature length because of the chain terminating effects of AZT. However such viruses were as infectious for CD4 + cells as wild-type virus. We conclude that retrovirus-derived DNA in HIV-1 particles is not required for infection and does not play a significant role in this process.