L-chicoric acid inhibits human immunodeficiency virus type 1 integration in vivo and is a noncompetitive but reversible inhibitor of HIV-1 integrase in vitro

The human immunodeficiency virus (HIV) integrase (IN) must covalently join the viral cDNA into a host chromosome for productive HIV infection. l-Chicoric acid (l-CA) enters cells poorly but is a potent inhibitor of IN in vitro. Using quantitative real-time polymerase chain reaction (PCR), l-CA inhibits integration at concentrations from 500 nM to 10 microM but also inhibits entry at concentrations above 1 microM. Using recombinant HIV IN, steady-state kinetic analyses with l-CA were consistent with a noncompetitive or irreversible mechanism of inhibition. IN, in the presence or absence of l-CA, was successively washed. Inhibition of IN diminished, demonstrating that l-CA was reversibly bound to the protein. These data demonstrate that l-CA is a noncompetitive but reversible inhibitor of IN in vitro and of HIV integration in vivo. Thus, l-CA likely interacts with amino acids other than those which bind substrate.     

Human cytomegalovirus infection is not increased in common variable immunodeficiency

It has been postulated that human cytomegalovirus (HCMV) infection may have a role in the pathogenesis of common variable immunodeficiency (CVID). Many patients have a lymphocyte phenotype similar to that seen in HCMV infection, HCMV mononucleosis may precipitate hypogammaglobulinaemia, and a previous small study of common variable immunodeficient patients reported a high rate of active HCMV infection. This study investigated the presence and activity of HCMV infection in 102 CVID patients. Buffy coats were examined for the presence of HCMV IE and glycoprotein B genes using highly sensitive nested PCR. 30 blood donors of known HCMV serologic status were used as controls. There was no significant difference in HCMV positivity by PCR between patients and controls. Enrichment for mononuclear cells prior to PCR had no effect on sensitivity. Twenty-five patients were also examined for HCMV antigenaemia by staining buffy coat cytospins with monoclonal antibodies directed against the HCMV pp65 lower matrix protein, a technique widely used for diagnosis of active HCMV disease. Only one patient was positive (and also positive by PCR). Whilst these results do not exclude prior infection contributing to antibody deficiency in a small proportion of CVID patients, this study refutes the previously reported increase in active HCMV infection in CVID.     

Serum and effector-cell antibody-dependent cellular cytotoxicity (ADCC) activity remains high during human immunodeficiency virus (HIV) disease progression

The activity of both serum and effector cell antibody-dependent cellular cytotoxicity (ADCC) against human immunodeficiency virus (HIV-1, HIV) was assessed in HIV-infected individuals. The goal was to relate ADCC levels with the stage or progression of HIV disease. Serial serum samples, usually collected at 6-month intervals, from individuals at defined stages of HIV disease (sero-conversion, the HIV-seropositive period before AIDS, and around the time of clinical AIDS diagnosis) were tested. HIV-coated CEM tumor cells were used as targets. Effector-cell ADCC activity was evaluated using fresh peripheral blood mononuclear cells (PBMC) from HIV-infected individuals at different stages of HIV disease. Samples were obtained from male homosexual participants in the Multicenter AIDS Cohort Study (MACS). In seroconverters, ADCC-inducing HIV-specific antibodies were detected at the time that the ELISA antibody test was first positive. Within several months, serum ADCC activity stabilized in each individual. In 29 HIV-seroprevalent individuals (HIV seropositive on their first visit), serum ADCC activity remained constant regardless of whether the individual's HIV disease was stable (high stable CD4;n=9) or rapidly deteriorating (sharply declining CD4,n=10; AIDS progressors,n=10). With respect to effector-cell activity, PBMC from HIV-infected individuals with or without AIDS were capable of mediating ADCC with heterologous and usually with autologous sera. Although the level of NK cytotoxic activity and the level of antibody-armed effector cell activity have been reported to decline as disease progresses, our results support previous observations that ADCC effector-cell activity against antibody-coated targets does not decline in HIV infection. These results indicate that both serum and effector cells with ADCC activity are present in HIV-infected individuals shortly after seroconversion and are maintained throughout HIV disease. Although levels of serum and effector-cell ADCC activity do not predict whether an individual will develop AIDS, CD4 cells which express HIV antigens (either produced endogenously or adsorbed onto the surface) could serve as targets for anti-HIV-mediated ADCCin vivo. ADCC could, thereby, contribute to CD4 T-cell depletion in infected individuals. However, since serum and effector-cell ADCC levels do not seem to relate to disease stage or progression, the protective or pathogenic role that ADCC plays in HIV-disease remains unresolved.     

Speculations on Sequence Homologies between the fibronectin cell-attachment site, major histocompatibility antigens, and a putative AIDS virus polypeptide

The core of the fibronectin cell-attachment site has been shown to be the tetrapeptide sequence Arg-Gly-Asp-Ser (RGDS). This peptide as well as its inverted analogue Ser-Asp-Gly-Arg (SDGR) efficiently inhibit fibronectin-mediated cell attachment in vivo and in vitro. Homology searches in protein data banks revealed the presence of the peptide SDGR in the 2 domain of MHC class I antigens, and a variant of RGDS, Arg-Phe-Asp-Ser (RFDS), was found highly conserved in MHC class I (1 domain) and class II antigens (β1 domain). Three-dimensional models of MHC class I antigens suggested that the two tetrapeptide sequences may be located at the surface of the molecule, readily available for intermolecular contacts. We propose that fibronectin-mediated and MHC-mediated cell-cell interactions have similar molecular bases and that the RGDS-like sequences participate in specific cell adhesion between lymphoid cells. The RFDS tetrapeptide was also found in the sequence of a putative polypeptide chain encoded by the HTLVIII/LAV retrovirus family, the causative agent of AIDS. These amino acid sequence homologies suggest a common molecular basis for specific interactions between the MHC class II antigens, or the AIDS virus, and the T-cell specific T4 glycoprotein.     

Human immunodeficiency virus type-1 integrase containing a glycine to serine mutation at position 140 is attenuated for catalysis and resistant to integrase inhibitors

L-chicoric acid (L-CA) is a potent inhibitor of HIV integrase (IN) in vitro. In this report, the effects of a glycine to serine mutation at position 140 (G140S) on HIV IN and its effects on IN inhibitor resistance are described. HIV containing the G140S mutation showed a delay in replication. Using real-time polymerase chain reaction, the delay was secondary to a failure in integration. The mutant protein (IN(G140S)) was attenuated approximately four-fold for catalysis under equilibrium conditions compared to wild-type IN (IN(WT)) and attenuated five-fold in steady-state kinetic analysis of disintegration. Fifty percent inhibitory concentration assays were performed with IN inhibitors against both IN proteins in disintegration and strand transfer reactions. IN(G140S) was resistant to both L-CA and L-731,988, a diketoacid. HIV containing the mutation was resistant to both inhibitors as well. The G140S mutation attenuates IN activity and confers resistance to IN inhibitors, suggesting that diketoacids and L-CA interact with a similar binding site on HIV IN.     

Methionine-enkephalin as immunomodulator therapy in human immunodeficiency virus infections: Clinical and immunological effects

Enkephalins have been shown to enhance T cell-mediated immune responses and natural killer-cell activityin vitro. We have studied the effects of infusions of methionine-enkephalin on immune functions and clinical courses in seven patients with various stages of infection with human immunodeficiency virus (HIV). All patients were clinically stable at the time of entry into the study. Each received 10 µg/kg of methionine-enkephalin in an intravenous infusion three times weekly for up to 12 weeks. Evaluation of cellular immunity (T-cell subsets,in vitro interleukin-2 production and interleukin-2 receptor expression, T-cell responses to mitogens and antigens, and delayed-hypersensitivity skin tests) as well as clinical and toxicity monitoring was performed prior to treatment, at 2-week intervals during treatment, and after the cessation of treatment. Increases in interleukin-2 receptor expression were seen on lymphocytes collected on one occasion from each of two patients 30 min postinfusion. Studies done 24 hr after infusions revealed increases in interleukin-2 production in one patient, but when pre- and posttreatment values were compared there were no significant changes in numbers of circulating T cells of any phenotype or in T-cell responses to mitogens or antigens. None of the patients with Kaposi's sarcoma had regression of tumor; one patient dropped out of the study at week 5 because of deteriorating clinical status and progression of tumor. There were no adverse reactions or evidence of toxicity. We conclude that methionine-enkephalin appears to enhance temporarily selected immune responses in patients with HIV infection, however, in the schedule used in this study it was not clinically efficacious.     

Clinical utility of an enhanced human immunodeficiency virus type 1 p24 antigen capture assay

The presence of p24 core antigen in the serum of individuals with human acquired immunodeficiency syndrome has been used as one of the important prognostic markers of HIV-1 infection and also as an end point in evaluating antiviral drugs and vaccines. Unfortunately the majority of p24 antigen present in serum exists as an antigenantibody complex and is not detected with the commercial kits currently available to measure p24 antigen. In this study, we report a simple procedure utilizing treatment of serum samples with glycine buffer (pH 1.85) to dissociate antigen-antibody complexes prior to assaying for p24 antigen. A 300% increase in the number of p24-reactive samples and a 3- to 12-fold increase in the quantity of antigen detected were observed when samples were pretreated with 1.5M glycine buffer (pH 1.85) for 1 hr. Glycine treatment of samples did not result in nonspecific positive tests and samples previously shown to be reactive remained positive. In reconstruction experiments the release of antigen was found to be inversely proportional to the amount of p24 antibody present in the serum. The percentage of HIV-1-infected patients positive for p24 antigen was clearly a function of CD4 count. Forty-nine percent of patients with more than 500 CD4 cells and 100% of patients with less than 200 CD4 were p24 positive. The improved sensitivity for detection of p24 provided by this procedure enhances our understanding of the pathogenesis of AIDS by showing that the majority of patients with HIV-1 infection is p24 positive and facilitates the analysis of data obtained in clinical trials involving anti-HIV compounds.     

Cell-mediated immunity to cytomegalovirus (CMV) and herpes simplex virus (HSV) antigens in the acquired immune deficiency syndrome: Interleukin-1 and interleukin-2 modifyin vitro responses

Peripheral blood lymphocytes (PBL) were obtained from five patients with the acquired immune deficiency syndrome (AIDS), six homosexual males with lymphadenopathy, and five normal heterosexual controls. Modulation of virus-specific immunity was assayedin vitro by measuring the lymphocyte blastogenic response and the production of lymphokine (leukocyte inhibition factor; LIF) by PBL stimulated with herpes simplex virus (HSV) or cytomegalovirus (CMV) antigens in the presence or absence of interleukin-1 (IL-1) and interleukin-2 (IL-2). PBL from the control and lymphadenopathy subjects responded to both antigens in the lymphocyte transformation assay (LT) measured on day 7, and the responses were significantly enhanced in cultures grown in the presence of antigen and IL-2 (1 U/ml). PBL from the AIDS patients were unresponsive, but responsiveness was restored by the addition of IL-2. The addition of IL-1 (0.02 µg/ml) to antigen-stimulated PBL cultures failed to enhance the proliferative responses in all three study groups. LIF production was assayed in the supernatants from day 1 PBL cultures. LIF was not produced by PBL from AIDS patients grown in the presence of viral antigens, whereas three of five patients from the lymphadenopathy group, and three of five control subjects gave rise to positive responses. The addition of IL-1 to the antigenstimulated cultures enhanced LIF production in the control and lymphadenopathy groups but not in the AIDS patients. The addition of IL-2 did not modulate LIF production by antigen-stimulated PBL from the control oR AIDS patients while suppressing the LIF response of the similarly stimulated PBL from the lymphadenopathy patients.     

Monte Carlo simulation of the heterosexual selective spread of the human immunodeficiency virus

The spread of human immunodeficiency virus (HIV) by heterosexual intercourse, during the first 2 years following the introduction of the virus among a sexually active and unprotected group of men and women, is modelled by Monte Carlo simulation. A beta distribution of the infectee's risks of infection per infected partner-month is assumed, with the same coefficient of variation as used in previous studies for risk of conception (natural fecundability), but with a mean of 0.04 per infected partner-month, after scaling the distribution. The number of sexual partners that one sex has (here, the women), is assumed to be more variable than for the other, with a mean of 2 partners each. The individual infection risks per infected partner-month are generated initially and do not change, but some random gains and losses of partners occur each month. Infections are updated each month. It is found in this simple model that women who become infected by 2 years had a mean risk of infection (not counting the original infector) only about 13% higher than the others. Some implications of the low selection are noted. Very great variability in the number of infections subsequently due to an index seropositive is found, which prevents easy discrimination in the characteristics of "at-risk" persons.     

Deterioration in immunologic status of human immunodeficiency virus (HIV)-infected homosexual men with lymphadenopathy: Prognostic implications

Changes in immunologic parameters were followed in members of a cohort of human immunodeficiency virus (HIV)-positive homosexual or bisexual men with lymphadenopathy and were analyzed for differences between those who have and those who have not progressed to the acquired immunodeficiency syndrome (AIDS) (progressors, nonprogressors). T helpers and the Th/Ts ratio were lower in progressors than in nonprogressors both at entry into the study and at the latest visit. T suppressors were not different in the two groups at entry but were higher in nonprogressors at the latest visit. Evaluation of the patterns of change over time showed that T helpers and Th/Ts ratios tended to decrease over time in both nonprogressors and progressors, while T suppressors increased in nonprogressors and decreased in progressors. Although progressors had a greater deterioration in immunologic parameters over time, nonprogressors also had significant deterioration when compared with controls. Based on the respective percentages of men with abnormal or normal T helpers or Th/Ts ratio at entry who have already progressed to AIDS, we would conservatively estimate, considering their latest T helpers and Th/Ts ratio, that at least an additional 16 (32%) of our nonprogressors will develop AIDS in the next 5 years.     

Patterns of antibody reactivity to selected human immunodeficiency virus type 1 (HIV-1) gp160 epitopes in infected individuals grouped according to CD4+ cell levels

We examined sera from 160 HIV-infected individuals for antibodies reactive to HIV-1 gp160 epitopes defined by seven synthetic peptides. Seropositive individuals were placed into three groups based upon levels of circulating CD4+ cells. These groups consisted of individuals with (1) more than 400 CD4+ cells, (2) 200–400 CD4+ cells, and (3) fewer than 200 CD4+ cells/mm³. The percentage of sera containing antibodies reactive with two immunodominant gp160 epitopes (a.a. 304–321 and 600–611) was unchanged between groups, regardless of CD4 cell numbers. The percentage of sera containing antibodies reactive with weakly immunogenic gp160 epitopes, such as those defined by peptides 425–448 and 846–860, declined in the groups as CD4 values decreased. Our results suggest that the patterns of antibody reactivity to gp160 epitopes change as CD4 levels decline. A narrowing of the humoral immune response to epitopes on the envelope of HIV-1 appears to occur with disease progression.     

Distress,denial, and low adherence to behavioral interventions predict faster disease progression in gay men infected with human immunodeficiency virus

This study examined psychological predictors of 2-year disease progression in gay men after finding out their human immunodeficiency virus (HIV) serostatus. Psychological and immune status of asymptomatic gay men who did not know their HIV serostatus was monitored during the 5 weeks before and after serostatus notification. The men were randomly assigned to an exercise, cognitive-behavioral stress-management intervention, or control group. At 2-year follow-up for the 23 men who turned out to be seropositive, 9 had developed symptoms, including 5 with acquired immune deficiency syndrome—4 of whom died. Distress at diagnosis, denial (5 weeks postdiagnosis minus pre-diagnosis), and low adherence during interventions were significant predictors of 2-year disease progression. Denial and adherence remained significant predictors of disease progression even after controlling for CD4 number at entry. Furthermore, change in denial was significantly correlated with immune status 1 year later; 1-year immune status was significantly correlated with 2-year disease progression. The present study therefore demonstrates significant relations between psychological variables on the one hand and both immune measures and IIIV-1 disease progression on the other. We conclude that distress, denial, and low protocol compliance predict subsequent disease progression. This research was supported by National Institute of Menial Health Grants P50-MH4355, PO1-MH49548, and T32-MH18917.     

Quantitation of antigen-specific immune responses in human immunodeficiency virus (HIV)-infected individuals by limiting dilution analysis

The lymphocyte proliferative response to recall antigens is lost following HIV infection. We sought to devise a means by which the functional immune status of persons in the early stages of HIV infection could be monitored quantitatively. The response to tetanus toxoid was examined in 45 HIV-infected individuals and 11 controls using conventional lymphocyte proliferative assays concurrently with limiting dilution analysis utilizing the secretion of interleukin-2 as the measure of a response. Our data show that the limiting dilution analysis detects tetanus toxoid-reactive T cells in 80% of those tested, as compared to only 44% by proliferation. However, the frequency of tetanus-reactive T cells in HIV-infected individuals (median frequency = 1/59,156) is decrease five-fold as compared to seronegative controls (median frequency = 1/11,599). Longitudinal studies demonstrated a time-dependent decrease in the frequency of tetanus-specific T cell responses in the HIV-infected individuals. Thus, the limiting dilution analysis is a quantitative approach for detecting antigen-specific T cells in HIV-infected individuals, and may be used to monitor changes in T cell function in HIV infection.     

Anticardiolipin antibodies in homosexual men: Prevalence and lack of association with human immunodeficiency virus (HIV) infection

Tests for anticardiolipin antibodies (ACL) on sera from 100 male homosexuals and 60 male heterosexuals showed that 57% of the homosexuals, in contrast to none of the heterosexuals, were ACL positive. The ACL were predominantly of the immunoglobulin G isotype and, in a high proportion of cases tested (82%), were reactive with other phospholipids, especially those with a negative charge. ACL were not related to the clinical status of the homosexuals, being evenly distributed among 40 with acquired immunodeficiency syndrome (AIDS), 20 with AIDS-related complex (ARC), 20 with asymptomatic infection with human immunodeficiency virus (HIV) and/or lymphadenopathy syndrome, and 20 who were HIV-antibody negative. Nor were they associated with thrombocytopenia, thrombosis, neurologic disease, a biological false-positive test for syphilis (BFP), or antibodies to DNA. It is concluded that factors other than infection with HIV are responsible for ACL positivity in homosexual males and that the epitopes recognized by ACL in this group are distinct from those associated with thromboembolism or the BFP reaction or cross-reactive with DNA.     

Twenty years of human immunodeficiency virus care at the Mayo Clinic: Past,present and future

The Mayo human immunodeficiency virus (HIV) Clinic has been providing patient centered care for persons living with HIV in Minnesota and beyond for the past 20 years. Through multidisciplinary engagement, vital clinical outcomes such as retention in care, initiation of antiretroviral therapy and virologic suppression are maximized. In this commentary, we describe the history of the Mayo HIV Clinic and its best practices, providing a “Mayo Model” of HIV care that exceeds national outcomes and may be applicable in other settings.     

T-cell lymphoma associated with human immunodeficiency virus (HIV) infection

A patient with pneumococcal septicaemia and serological evidence of infection with human immunodeficiency virus (HIV) presented with a peripheral T-cell lymphoma. As far as we are aware this association has not been reported previously.     

Human immunodeficiency virus/acquired immune deficiency syndrome: Using drug from mathematical perceptive

Entry of acquired immune deficiency syndrome virus into the host immune cell involves the participation of various components of host and viral cell unit. These components may be categorized as attachment of the viral surface envelope protein subunit, gp120, to the CD4+ receptor and chemokine coreceptors, CCR5 and CXCR4, present on T cell surface. The viral fusion protein, gp41, the second cleaved subunit of Env undergoes reconfiguration and the membrane fusion reaction itself. Since the CD4+ T cell population is actively involved; the ultimate outcome of human immunodeficiency virus infection is total collapse of the host immune system. Mathematical modeling of the stages in viral membrane protein-host cell receptor-coreceptor interaction and the effect of antibody vaccine on the viral entry into the susceptible host cell has been carried out using as impulsive differential equations. We have studied the effect of antibody vaccination and determined analytically the threshold value of drug dosage and dosing interval for optimum levels of infection. We have also investigated the effect of perfect adherence of drug dose on the immune cell count in extreme cases and observed that systematic drug dosage of the immune cells leads to longer and improved lives.     

The significance of antilymphocyte antibodies in patients with acquired immune deficiency syndrome (AIDS) and their sexual partners

Antilymphocyte antibodies have been demonstrated in autoimmune diseases, acute viral infections, and acquired immune deficiency syndrome (AIDS) by using either the conventional microlymphocytotoxicity or the double fluorescence technique. In the present study, we used both methods to detect the antilymphocyte antibodies and to characterize further their immunologic significance in patients with AIDS and their sexual partners. The results using the conventional microlymphocytotoxicity method demonstrated that 8 of 10 patients with AIDS and 6 of 10 partners had significant levels of antilymphocyte antibodies which were reactive with B and T cells at cold and warm temperatures. A significant loss in antibody activity following absorption with B, T, and Daudi cells andStaphylococcus aureus, but not platelets or red cells, indicated that these antibodies are not directed to HLA class I antigens but, rather, to antigens that are common to both groups of lymphocytes. There is a close association between antilymphocyte antibodies and lymphopenia in patients but not in partners. Antibodies against lymphocyte subclasses [helper (T4) and suppressor (T8)] were detected by the double fluorescence staining technique, which employs C6-deficient serum as a nonlytic source of complement, and demonstrated the binding of antibodies to target cells, in contrast to lysing of the target cells as in the microlymphocytotoxicity method. The results of this assay showed that antibodies were directed to both populations, and there was no correlation or association between the absolute numbers of peripheral T4 and T8 cells and the percentage of antibody binding. Taken together, there appear to be at least two kinds of antilymphocyte antibodies: lymphocytotoxic antibodies detected by the conventional microlymphocytotoxicity assay and noncytotoxic antibodies detected by the double fluorescence staining technique. The former may be responsible in part for the lymphopenia. The latter may alter lymphocyte function. The patients and partners who had antilymphocyte antibodies also had anti-HTLV-III antibodies, although there was not any close correlation between titers. These findings support the possibility that both types of antibodies occur as part of a generalized immune response, possibly stimulated by the same viral agent.