Eszter Ujhelyi

HIV transmission from female to male at improperly protected sexual intercourse

There is growing evidence that human immunodeficiency virus (HIV) infection can be transmitted from female to male after only 2 sexual contacts. The authors present a case in which the wife was infected with HIV in March 1986 as a result of transfusion of blood from a homosexual. She tested positive for HIV in January 1987 and in February was notified of her positive test result. The couple had had regular unprotected sexual intercourse between April 1986 and February 1987. In February 1987 the patients husband was negative for HIV infection and condom use was initiated. By October 1987 the husband was found to be seropositive for HIV. The couple reported that the condom had torn on several occasions since protected intercourse was initiated. It cannot be determined whether HIV was transmitted before February during unprotected intercourse and the husband seroconverted after the 1st blood sampling or whether HIV was transmitted after notification of the wifes seropositive status.

Single DermaVir immunization: Dose-dependent expansion of precursor/memory T cells against all HIV antigens in HIV-1 infected individuals

Background The GIHU004 study was designed to evaluate the safety and immunogenicity of three doses of DermaVir immunization in HIV-infected subjects on fully suppressive combination antiretroviral therapy (cART). Methodology/Principal Findings This first-in-human dose escalation study was conducted with three topical DermaVir doses targeted to epidermal Langerhans cells to express fifteen HIV antigens in draining lymph nodes: 0.1 mg DNA targeted to two, 0.4 mg and 0.8 mg DNA targeted to four lymph nodes. Particularly, in the medium dose cohort 0.1 mg DNA was targeted per draining lymph node via ∼8 million Langerhans cells located in 80 cm2 epidermis area. The 28-days study with 48-week safety follow-up evaluated HIV-specific T cell responses against Gag p17, Gag p24 and Gag p15, Tat and Rev antigens. DermaVir-associated side effects were mild, transient and not dose-dependent. Boosting of HIV-specific effector CD4+ and CD8+ T cells expressing IFN-gamma and IL-2 was detected against several antigens in every subject of the medium dose cohort. The striking result was the dose-dependent expansion of HIV-specific precursor/memory T cells with high proliferation capacity. In low, medium and high dose cohorts this HIV-specific T cell population increased by 325-, 136,202 and 50,759 counts after 4 weeks, and by 3,899, 9,878 and 18,382 counts after one year, respectively, compared to baseline. Conclusions/Significance Single immunization with the DermaVir candidate therapeutic vaccine was safe and immunogenic in HIV-infected individuals. Based on the potent induction of Gag, Tat and Rev-specific memory T cells, especially in the medium dose cohort, we speculate that DermaVir boost T cell responses specific to all the 15 HIV antigens expressed from the single DNA. For durable immune reactivity repeated DermaVir immunization might be required since the frequency of DermaVir-boosted HIV-specific memory T cells decreased during the 48-week follow up. Trial Registration ClinicalTrial.gov NCT00712530.

Mannan-binding lectin serum concentrations in HIV-infected patients are influenced by the stage of disease

Serum concentrations of mannan-binding lectin (MBL) were determined in the sera of 67 HIV-seropositive patients in different stages of HIV disease and in the sera of 75 HIV-seronegative healthy individuals. In the asymptomatic (AS) HIV-infected persons MBL concentrations were found to be significantly (P < 0.05) lower than in the HIV-seronegative controls, whereas in the AIDS patients they were not. Very low (< or = 25 ng/ml) MBL serum concentrations were detected in 5/19 (26.3%) and 7/75 (9.3%) of the AS HIV-seropositive and HIV-seronegative individuals, respectively (P = 0.06). In the sera of the HIV-infected patients, MBL levels positively correlated to the neopterin concentrations (Spearman correlation coefficient, 0.401, P = 0.0009) while they negatively correlated to the percentage (-0.447, P = 0.0011) and absolute number (-0.453, P = 0.0012) of the CD4+ lymphocytes. These observations indicate that MBL level, which is under strict genetic control, may influence the susceptibility to HIV infection and the progression of HIV disease.

Neutralizing and enhancing antibodies measured in complement-restored serum samples from HIV-1-infected individuals correlate with immunosuppression and disease

ObjectiveTo study the association between the progression of HIV disease and HIV neutralization and enhancement measured in the presence of human complement. DesignTwo studies were performed: (1) longitudinal measurement of the complement-dependent enhancing antibodies in parallel with T-cell subset determination in 55 serum samples from seven HIV-infected patients, and (2) determination of the titres of neutralizing and enhancing antibodies in stored samples of 21 HIV-asymptomatic patients obtained between 1986 and 1987 and follow-up of the patients until October 1992. MethodsHIV-1 [human T-lymphotropic virus (HTLV)HIB strain, 100 median tissue culture infective dose (TCID50)] was incubated with twofold dilutions of sera in the presence of human complement (final dilution, 1 :4) and added to MT-4 cells. HIV growth was monitored daily for 5 days using the reclustering inhibition and p24 immunofluorescence assays. ResultsA significant negative correlation between the titres of enhancing antibodies and CD4+ cell count was found in longitudinal measurements. In the prospective studies, marked differences were observed between patients with undetectable, low, or high titres of enhancing antibodies in the clinical course of HIV disease: CD4+ cell counts and percentages decreased more rapidly in the high titre group within 3 years. After 5 years, AIDS developed in five out of six patients in the high titre group but only in five out of 15 of the low titre group (P<0.05). A similar difference was observed between patients with and without neutralizing antibodies. ConclusionsMeasurement of HIV neutralization and enhancement in complement-containing serum samples using a complement receptor carrying target may provide data of clinical relevance. Neutralization appears to be associated with a favourable prognosis whereas high titre enhancing antibodies predict rapid progression of HIV disease.

Neutralizing and complement-dependent enhancing antibodies in different stages of HIV infection

Reclustering and indirect immunofluorescence assays on MT-4 cells [carrying both CD4 and complement receptor type 2 (CR2)] were used to measure neutralizing and enhancing antibodies in sera obtained from HIV-1-infected individuals. Heat-inactivated sera were tested before and after mixing 1:1 with fresh seronegative human serum. Using heated samples, neutralizing antibodies were found in 20 out of 20 and 11 out of 19 serum samples of asymptomatic and symptomatic [AIDS, AIDS-related complex (ARC)] HIV-seropositive patients, respectively. In complement-restored samples, neutralizing activity was found in eight sera of asymptomatic patients and in none of the sera of AIDS and ARC patients; enhancing activity could be detected in four and 12 sera, respectively. A significant positive correlation was observed between the titres of neutralizing antibodies measured in the complement-restored samples and the absolute number of CD4+ lymphocytes. These findings indicate that the appearance of complement-dependent enhancing antibodies coincident with the loss of neutralizing antibodies may indicate a poor prognosis in HIV infection.

Strong correlation between the complement-mediated antibody-dependent enhancement of HIV-1 infection and plasma viral load.

OBJECTIVE We have previously demonstrated that complement-mediated antibody-dependent enhancement (C-ADE) of HIV-1 infection correlates with accelerated immunosuppression and disease progression in HIV-1-infected individuals. In the present work the relationship between C-ADE and plasma HIV-1 RNA concentrations was studied to determine the effect of C-ADE on viral replication. METHODS Three studies were performed: (a) C-ADE and HIV-1 RNA concentrations were determined in the serum and plasma aliquots taken at the same time from 98 HIV patients, mostly in the advanced stage of the disease; (b) the above two parameters as well as HIV enzyme-linked immunosorbent assay (ELISA)-reactive antibodies (Abbott HIV 1/2 test), and p24 antigen levels (Abbott antigen test; Abbott, Delkenheim, Germany) were determined in four seroconversion panels purchased from the Boston Biomedica firm; (c) changes of HIV-1 RNA concentration and C-ADE during a 17 month follow-up period were determined in 18 HIV-infected patients. C-ADE was measured by the method previously established in our laboratories. The results were expressed by an enhancement/neutralization index (E/NI). HIV-1 RNA levels were determined with the Amplicor monitor kit (Roche, Basel, Switzerland), and in some experiments with the nucleic acid sequence based amplification (Organon Teknika, Turnhout, Belgium) kits. RESULTS (a) We found a highly significant (P<0.0001) positive correlation between E/NI values reflecting the extent of HIV-1 infection enhancement and plasma HIV-1 RNA levels. Both E/NI and HIV-1 RNA levels negatively correlated to the CD4 cell counts. (b) C-ADE was first detected just before, or concomitantly with, seroconversion in 4/4 seroconversion panels. (c) Both E/NI values and HIV-1 RNA levels significantly (P<0.001) increased during a 17 month observation period in 18 HIV-infected patients. CONCLUSION We found strong association between the extent of the complement-mediated antibody-dependent enhancement of HIV-1 infection and the plasma viral load in HIV patients. On the basis of these findings, C-ADE correlates with HIV replication in vivo, and potentially contributes to the progression of HIV disease.

The complement system in HIV disease

Different aspects of the relationship between the HIV infection and the complement system were studied. 1. No significant differences were found between seronegative controls, asymptomatic, and symptomatic (ARC, AIDS) HIV-seropositive patients in the plasma levels of complement components C4, Bf, and C3. 2. Using sensitive ELISA assays, a significant increase was observed in the levels of protein-protein complexes which are formed at the activation of the classical (C1r-C1s-C1-INH) and alternative (C3b-Bb-P) pathways, indicating that both complement pathways are activated in the HIV disease. No significant differences were found, however, in the levels of these complexes between the groups of asymptomatic and symptomatic HIV-infected patients. 3. Artificial immune complexes of synthetic peptides representing some immunodominant epitopes of HIV envelope (gp120, and gp41) proteins, and human polyclonal anti-HIV IgG were found to weakly activate both the classical and alternative complement pathways. 4. An elevated percentage of the lymphocytes carrying a complement activation fragment, C3d, was detected in the blood of HIV seropositive patients as compared to the seronegative controls. No significant positive correlation was found between the percentage of these cells and that of any T cell subsets tested.

High Level of Anticholesterol Antibodies (ACHA) in HIV Patients. Normalization of Serum ACHA Concentration after Introduction of HAART

Anticholesterol antibodies (ACHA) are natural antibodies against the 3beta-OH group of cholesterol. Since lipid disorders are common in HIV infection and HAART may further enhance dislipidaemia, we determined by using an ELISA method serum ACHA concentrations in HIV patients and healthy HIV-seronegative controls. ACHA levels were almost 4 times higher in the sera of 46 patients than in 110 controls. No difference in the specificity of ACHA was found between HIV-seropositive and HIV-seronegative sera. Binding of ACHA to cholesterol-coated plates from a HIV-seropositive serum was dose-dependently inhibited by preincubation with HIV-1(BA-L) preparation. Serum concentration of ACHA was significantly higher in the patients with low serum cholesterol levels than in those with normal cholesterol levels. HAART induced a marked drop of ACHA concentration. We found a significant negative correlation between the length of HAART and the ACHA levels. By contrast, HAART did not significantly influence total IgG concentration and titers of antibodies against 60 kD heat shock protein. Our findings indicate that high levels of ACHA in HIV-infection may contribute to the development of hypocholesterolaemia frequently observed in this disease.

Genetic regulation of the impaired immune response to hepatitis-B vaccine associated with low TCR density in end stage renal disease patients: contribution of complement C4 and factor B alleles.

We have studied the relationship between T-cell receptor (TCR) density, genetic factors and the specific immune response in 153 end stage renal disease (ESRD) patients on haemodialysis immunised with HBsAg vaccine. One-hundred and nineteen patients raised a protective (> 10 U/ml) antibody response to hepatitis-B vaccination (responder, R), while 34 patients were found to be non-responders (NR). The density of the T-cell receptors was determined by flow cytometry. Proliferation of the T-cells induced by autologous monocytes presenting HBsAg was also measured and expressed as a stimulation index (SI). MHC class I, II and III alleles of the patients were also determined. The densities of TCR/CD3 receptors in NR patients were found to be significantly decreased as compared to the R patients (189 +/- 22 vs. 282 +/- 58 arbitrary units, P = 1.3 x 10(-7). TCR/CD3 receptor densities were found to be strongly associated (Spearman correlation coefficient: 0.84, P < 0.000001) with the SI values. Both parameters were found to be under dual genetic control: (a) very low density of the TCR/CD3 receptors and very low SI were found mainly in NR patients carrying HLA-A1, HLA-B8 and HLA-DR3 alleles; and (b) TCR/CD3 densities and function in R group were found to be significantly lower in carriers than in non-carriers of two MHC class III complement protein alleles: C4A*6, and Bf*F. Non-responsiveness to hepatitis-B vaccination was found to be associated with extremely increased neopterin levels. These findings indicate that both genetic and acquired factors contribute to the hepatitis-B vaccination failure in ESRD patients.

Studies on the mechanism of complement-mediated inhibition of antibody binding to HIV gp41.

We have previously demonstrated that HIV envelope gp41 binding to specific antibodies decreases after preincubation of fluid‐phase gp41 in normal human serum. This inhibition is proven to be mediated by the classical complement pathway. In this study recombinant gp41 (rgp41) and/or synthetic peptides were preadsorbed to solid phase, and then complement (normal human serum heated human serum, purified Clq/heated Clq) and anti‐gp41 antibodies were added either after each other or simultaneously, and the amounts of bound antibody, and deposited C3b, C4b and Clq were measured. Complement‐dependent inhibition of antibody binding to solid‐phase rgp41 was found, and Clq seems to be at least partially responsible for this phenomenon. Heating of Clq did not affect this process. Higher amounts of anti‐gp41 antibodies significantly and dose‐dependently enhanced C4b and C3b fixation to solid‐phase rgp41. In the case of synthetic peptides corresponding to the immunodominant region of gp41, significant antibody binding to the solid‐phase peptides was also detected, and pretreatment of peptides preadsorbed to solid phase with normal human serum almost totally abolished the antibody binding.