Interactions of single and combined human immunodeficiency virus type 1 (HIV-1) DNA vaccines

DNA immunization permits evaluation of possible antagonistic or synergistic effects between the encoded components. The protein expression capacity in vitro was related to the immunogenicity in vivo of plasmids encoding the HIV-1 regulatory genes tat rev, and nef. Neither Tat nor Rev expression was influenced by co-expression in vitro of all three proteins, while Nef expression was slightly inhibited. With the combination of genes, the T-cellular responses of mice against Rev and Nef were inhibited compared with those when single gene immunization was used. No interference was detected for the Tat T-cell response. Thus, co-immunization with certain genes may result in inhibition of specific immune responses.     

Evaluation of two commercially available anti human immunodeficiency virus antibody ELISA Kits using clinical samples

Laboratory diagnosis is the mainstay in the diagnosis of HIV infection in an individual. The wide range of diagnostic kits available, for the detection of anti HIV antibodies, makes it mandatory that the kits are evaluated before they are made available in the market. We evaluated the performance of a Microlisa HIV kit (J. Mitra & Co.) using a panel of HIV reactive and non reactive clinical specimens. The sensitivity and specificity of the kit were found to be 100% as compared to the UBI HIV 1/2 EIA kit. The ease of testing, the assay characteristics including efficiency of the Microlisa favour its use by laboratories as a primary screen for HIV infection.     

Human immunodeficiency virus (HIV) antibody avidity testing to identify recent infection in newly diagnosed HIV type 1 (HIV-1)-seropositive persons infected with diverse HIV-1 subtypes

A guanidine-based antibody avidity assay for the identification of recently acquired human immunodeficiency virus type 1 (HIV-1) infection was evaluated. The kinetics of maturation of antibody avidity were determined prospectively in 23 persons undergoing acute seroconversion followed for up to 1,075 days. Avidity indices (AI) of 相似文献   

Detection of human immunodeficiency virus type 1 (HIV-1) antibody by western blotting and HIV-1 DNA by PCR in patients with AIDS.

The human immunodeficiency virus type 1 (HIV-1) Western blotting (immunoblotting) band patterns and the sensitivity of an HIV-1 DNA PCR assay were determined by testing the blood of patients with AIDS. Plasma and cell pellets processed from the peripheral blood of 199 patients with absolute CD4 cell counts of less than 200 cells per mm3 were tested by a licensed enzyme immunoassay (EIA; Abbott HIV-1) and Western blot assay (Cambridge-Biotech) for HIV-1 antibody. The Roache HIV-1 AMPLICOR DNA PCR assay was used to test cell pellets from 125 of the 199 patients for HIV-1 gag DNA sequences. All plasma samples from these 199 sequential patients were reactive for HIV-1 antibody by EIA and were positive by Western blot assay using the criteria recommended by the Centers for Disease Control and Prevention. The majority of samples (192 of 199; 96.5%) displayed at least six of nine bands characteristic of the virus by Western blotting, with the lowest number of bands characteristic of the virus displayed by any sample being three. However, 39 and 48% of all patients exhibited no bands to p17 and p55 antigens, respectively, whereas 0 to 7.5% of all patients exhibited no bands to the other antigens. HIV-1 gag DNA sequences were detected in 117 (93.6%) of 125 cell pellets processed from the peripheral blood of these same patients. All eight patients initially negative by PCR tested positive when a second pellet which had been produced from the same blood sample was tested. Despite a decrease in antibody reactivity to HIV Gag and Pol proteins, patients with advanced HIV-1 infection remained positive for HIV-1 antibody by EIA and Western blot testing. Confirmation by the HIV-1 Western blot assay still appears to be the more sensitive assay for the diagnosis of HIV-1 infection in those individuals with advanced HIV-1 infection in the United States.     

Differentiation of human immunodeficiency virus type 1 (HIV-1) infections with HIV-2-cross-reacting antibody from mixed infections with HIV-1 and HIV-2 by serological absorption test.

The interpretation of dual seroreactivity with human immunodeficiency virus type 1 (HIV-1) and HIV-2 in blood samples is a serious problem facing AIDS researchers worldwide. Some samples of sera from HIV-1-infected patients showed a serological cross-reaction with HIV-2, causing confusion regarding the serodiagnosis. Therefore, we tried to differentiate these serum samples from those containing real mixed infections with both types of virus. Sera from patients with HIV-1 infections with HIV-2 cross-reacting antibody in Japan were distinguished from sera from patients with mixed infections with HIV-1 and HIV-2 in West Africa by our serological cross-absorption test, which proved to be highly specific and useful for serodiagnosis.     

The effect of human immunodeficiency virus type 1 (HIV-1) gp41 variability on antibody detection

To determine whether genetic variability influences the ability to detect antibody, nine gp41 ectodomain recombinant proteins from human immunodeficiency virus type 1 (HIV-1) CRF07_BC, CRF01_AE and subtype B′ were expressed in a bacterial expression system and purified. An indirect sandwich ELISA was developed with individual purified recombinant proteins. Plasma samples from 26 individuals infected with HIV-1 of different subtypes and four samples from the 1st international antibody reference panel were tested against each recombinant protein by ELISA. Heat-map and two-dimensional hierarchical clustering methods revealed that ELISA reactivity against antigens derived from the same subtypes clustered together. This suggests a similar reactivity pattern among infections of the same subtype, and thus the antigenicity of gp41 recombinant proteins may vary depending on the subtype, and subtype-related serotypes may exist among these antigens. Using association analysis methods, eight signature sites related to the subtype-specific reactivity patterns were identified. This study provides valuable information for the development of diagnostic assays with the ability to detect broadly cross-reactive antibodies induced by infection with different HIV-1 subtypes.     

Salivary human immunodeficiency virus (HIV)-1-specific immunoglobulin A in HIV-1-exposed infants in Kenya

Humoral immunity, and specifically immunoglobulin A (IgA) that is directed against human immunodeficiency virus (HIV)-1, may contribute to protection against HIV-1 acquisition at mucosal surfaces. HIV-1-specific IgA has been detected in genital tract secretions of HIV-1-uninfected commercial sex workers with HIV-1 exposure, and may be produced in parotid saliva by infants exposed orally to HIV-1 during delivery and breastfeeding. To explore this hypothesis, we collected saliva from 145 infants aged < or = 6 months enrolled in a perinatal HIV-1 transmission study in Nairobi and from 55 control infants without HIV-1 exposure who were born to HIV-1-seronegative mothers. Among the 145 infants, 115 (79%) remained uninfected during the 12-month study period and 30 (21%) became HIV-1-infected during follow-up. Nine (8%) of the 115 HIV-1-exposed, uninfected infants had detectable levels of HIV-1 gp160-specific IgA compared with four (13%) of 30 infected infants and none of 55 control infants (P = 0.47 and P = 0.03 respectively). Among the nine HIV-1-exposed, uninfected infants with positive assays, median age was 1 month and none acquired HIV-1 during follow-up. We conclude that HIV-1-specific salivary IgA responses may be generated by very young infants exposed perinatally to maternal HIV-1. Mucosal responses would be an appropriate target for paediatric vaccines against breast milk HIV-1 transmission.     

Transmission of human immunodeficiency virus (HIV) by blood transfusions screened as negative for HIV antibody

Since early 1985, blood donations in the United States have been screened for antibody to human immunodeficiency virus (HIV). To identify instances of HIV transmission by antibody-negative donations, we investigated 13 persons seropositive for HIV who had received blood from 7 donors who were screened as negative for HIV antibody at the time of donation. Twelve of the 13 recipients had no identifiable risk factors for HIV infection other than the transfusions they had received. On evaluation 8 to 20 months after transfusion, HIV-related illnesses had developed in three recipients, and the acquired immunodeficiency syndrome had developed in one. All seven donors were found to be infected with HIV. On interview, six reported a risk factor for HIV infection, and five had engaged in high-risk activities or had had an illness suggestive of acute retroviral syndrome within the four months preceding their HIV-seronegative donation. Thus, these donors had apparently been infected only recently, and so were negative at the time of blood donation according to available antibody tests. We conclude that there is a small but identifiable risk of HIV infection for recipients of screened blood. To minimize this risk, the reasons for deferral of donation need to be communicated more effectively to blood donors who are at high risk of HIV infection, and new assays that detect HIV infection earlier should be evaluated for their effectiveness in screening donated blood.     

Modification of rapid human immunodeficiency virus (HIV) antibody assay protocols for detecting recent HIV seroconversion

Assay protocols of three rapid human immunodeficiency virus (HIV) assays, OraQuick-1/2, SeroStrip-1/2, and Determine-1/2, were modified to detect recent HIV seroconversion using a higher dilution of serum specimens. Optimal predilution of specimens resulted in negative test results during early periods of seroconversion (about 6 months), when antibody levels were low. A total of 269 seropositive specimens from routine HIV type 1 testing and from commercial sources (low-titer and seroconversion panels) were tested, and results were recorded as negative (score=0) or positive using intensity scores from 0.5 (weak positive) to 4 (strongly positive). The same specimens were previously tested by a less sensitive (LS) enzyme immunoassay (EIA), Abbott 3A 11-LS, and were classified as recent or long-term infections based on the standardized optical density (SOD) cutoff of 0.75. Overall concordance of >94% was observed between 3A 11-LS and modified rapid tests (RT-LSs) for detecting and distinguishing recent HIV seroconversion from long-term HIV infection (kappa statistics=0.894 to 0.901). Moreover, intensity scores on RT-LSs correlated well with median 3A 11-LS SOD values (R(2)>0.98). Our results indicate that rapid HIV tests can be modified to detect recent seroconversion with results comparable to those from less sensitive EIA.     

False positive indirect fluorescent antibody (IFA) tests for antibody to herpes simplex virus 1. Comparison of four commercially available methods

Four commercially available herpes simplex virus 1 (HSV-1) indirect fluorescent antibody (IFA) kits were compared with the use of sera selected because they were negative for HSV antibody by complement fixation (CF less than 1:8) and by ELISA (less than 1:100). However, 14 of 24 (58.3%) of these HSV-1 antibody-negative sera were positive at greater than or equal to 1:10 with the use of the HSV-1 IFA kit from Electronucleonics, 15 of 24 (62.5%) were positive with the Clinical Sciences HSV-1 IFA kit, 4 of 24 (16.7%) were positive with Zeus Scientific, and 4 of 18 (22.2%) were positive with the Gull Laboratories product. HSV-1 induces Fc receptors that commonly cause false positive IFA tests for HSV antibody. Therefore, further studies were undertaken to determine whether Fc receptors accounted for these false positive results. Staphylococcal protein A (SPA) is known to bind to the Fc portion of human IgG and therefore could be used to distinguish between the binding of an antibody by its Fab or its Fc portion. Thus, when fluorescein isothiocyanate conjugated (FITC) SPA was used as conjugate instead of FITC antibody to human IgG, true HSV-1 antibody-containing sera remained positive, but the false positives identified in the commercial IFA kits did not. The authors conclude that HSV-1-induced Fc receptors are responsible for most of the problem of these false positives and that HSV-1 serology probably should not be done by this type of IFA method until this problem is corrected.     

Biological mechanisms of vertical human immunodeficiency virus (HIV-1) transmission

In the absence of interventions, 30-45% of exposed infants acquire human immunodeficiency virus type 1 (HIV-1) through mother-to-child transmission. It remains unclear why some infants become infected while others do not, despite significant exposure to HIV-1 in utero, during delivery and while breastfeeding. Here we discuss the correlates of vertical transmission with an emphasis on factors that increase maternal HIV-1 levels, either systemically or locally in genital secretions and breast milk. Immune responses may influence maternal viral load, and data suggest that maternal neutralising antibodies reduce infection rates. In addition, infants may be capable of mounting HIV-specific cellular immune responses. We propose that both humoral and cellular responses are necessary to reduce infection because cell-free as well as cell-associated virus appears to play a role in vertical transmission. These distinct forms of the virus may be targeted most effectively by different components of the immune system. We also discuss the use of antiretrovirals to reduce transmission, focusing on the mechanisms of action of regimens currently used in developing country settings. We conclude that prevention relies not only on reducing maternal HIV-1 levels within blood, genital tract and breast milk, but also on pre- and/or post-exposure prophylaxis to the infant. However, HIV-1 has the capacity to mutate under drug pressure and rapidly acquires mutations conferring antiretroviral resistance. This review concludes with data on persistence of low-level resistance after delivery as well as recent guidelines for maternal and infant regimens designed to limit resistance.     

Interaction with human immunodeficiency virus (HIV) type 2 predicts HIV type 1 genotype

In West Africa, India, and certain regions of Europe, both human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2) are known to cocirculate. To investigate the HIV-1 subtypes involved in dual HIV-1 and HIV-2 infections, we sequenced the envelope C2-V3 region from 29 dually infected female commercial sex workers from Senegal. The majority of women (23 of 29) were infected by HIV-1 subtype A. Within the HIV-1 subtype A sequences, 14 of 23 (60.8%) clustered with the West African associated A/G recombinant form (IbNG), and 9 of 23 (39.2%) formed a separate cluster distinct from the A/G IbNG. In contrast, in HIV-1 singly infected individuals, non-IbNG subtype A was found in only 13 of 98 (13.3%). Therefore, the lack of protection and/or interaction with HIV-2 was associated with a distinct HIV-1 A genotype. These results suggest differences in the biological properties of HIV-1 genotypes and their in vivo interaction with HIV-2.     

Comparison of an avidin-biotin immunoassay with three commercially available immunofluorescence kits for typing of herpes simplex virus.

An avidin-biotin complex system was compared with three commercially available immunofluorescence kits for serotyping herpes simplex virus isolates from clinical specimens. Sensitivity values showed that the Electro-Nucleonics and Immulok reagents were useful in detecting the presence of virus, whereas the predictive values showed that the Syva and Immulok reagents possessed adequate discrimination between the herpes simplex virus serotypes. The avidin-biotin complex system was equal or superior to the immunofluorescence reagents tested both in detecting herpes simplex virus antigens in cell culture and in serotyping herpes simplex virus isolates.     

Tuberculous lymphadenitis associated with human immunodeficiency virus (HIV) in Uganda.

Sixteen adults presented with lymphadenopathy which was tuberculous on biopsy; they were all seropositive for human immunodeficiency virus (HIV-1), but none had the clinical criteria of the acquired immunodeficiency syndrome (AIDS). The biopsy specimen showed caseating tuberculosis, with scanty or no visible acid fast bacilli in seven cases; the remaining nine had a poor cellular reactivity with numerous bacilli. Antituberculous chemotherapy for two months reduced the lymphadenopathy. Two patients subsequently developed AIDS. Mycobacterial cultures were not performed, but the infection was almost certainly Mycobacterium tuberculosis. The space-time clustering of tuberculous lymphadenitis now seen in Kampala, and the unusual non-reactive histopathology, are typical of the impairment of cellular immunity induced by HIV infection.     

Chemokine receptors as fusion cofactors for human immunodeficiency virus type 1 (HIV-1)

CD4 is the primary cellular receptor for human immunodeficiency virus type 1 (HIV-1), but is not sufficient for entry of HIV-1 into cells. After a decade-long search, the cellular coreceptors that HIV-1 requires in conjunction with CD4 have been identified as members of the chemokine receptor family of seven-transmembrane G-protein coupled receptors. The discovery of distinct chemokine receptors that support entry of T-cell tropic (CXCR-4) and macrophage tropic HIV-1 strains (CCR-5) explains the differences in cell tropism between viral strains, the inability of HIV-1 to infect most nonprimate cells, and the resistance of a small percentage of the population to HIV-1 infection. Further understanding of the role of chemokine receptors in viral entry may also help explain the evolution of more pathogenic forms of the virus, viral transmission, and HIV-induced pathogenesis. These recent discoveries will aid the development of strategies for combating HIV-1 transmission and spread, the understanding of HIV-1 fusion mechanisms, and the possible development of small animal models for HIV-1 drug and vaccine testing.     

Haematological abnormalities in human immunodeficiency virus (HIV) disease.

Peripheral blood and bone marrow changes are commonly seen in disease associated with human immunodeficiency virus (HIV). This annotation aims to summarise these changes and to suggest possible factors entailed in their occurrence.