HIV-specific cellular and humoral immune responses in primary HIV infection.

Primary human immunodeficiency virus (HIV) infection is characterized by a high-titer viremia that declines precipitously within weeks, most likely as a result of host immune responses. Peripheral blood mononuclear cells (PBMCs) and plasma of four recently HIV-infected individuals were examined to assess the humoral and cellular immune responses potentially involved in early suppression of viral replication. Neutralizing antibodies against autologous viral isolates were low or undetectable in three subjects studied.

Phase 1 study of combination therapy with L-697,661 and zidovudine. The ACTG 184 Protocol Team.

We performed a pilot study that examined the clinical and pharmacokinetic interactions between zidovudine (ZDV) and a pyridinone derivative, L-697-661. The results indicate that the drugs were well tolerated, with no important pharmacokinetic interactions, when administered concomitantly for as long as 8 weeks. Although the number of study participants was small, we noted rapid emergence of resistance to L-697,661 among ZDV-naive study subjects who were administered L-697,661 as monotherapy but did not observe isolates of human immunodeficiency virus type 1 (HIV-1) resistant to L-697,661 among those who were administered concomitant ZDV.

Antiretroviral therapy for HIV infection in 1996. Recommendations of an international panel. International AIDS Society-USA.

Objective: To provide clinical recommendations for antiretroviral therapy for human immunodeficiency virus (HIV) disease with currently (mid 1996) available drugs. When to start therapy, what to start with, when to change, and what to change to were addressed.

Participants: A 13-member panel representing international expertise in antiretroviral research and HIV patient care was selected by the international AIDS Society-USA.

Virologic and immunologic benefits of initial combination therapy with zidovudine and zalcitabine or didanosine compared with zidovudine monotherapy. Wellcome Resistance Study Collaborative Group.

A randomized controlled study was done to determine whether initial combination therapy with zidovudine and zalcitabine or zidovudine and didanosine would delay the emergence of zidovudine-resistant virus. Human immunodeficiency virus (HIV)-1-infected patients with <300 CD4 cells/mm3 and <4 weeks of prior zidovudine therapy were randomized to zidovudine, zidovudine plus zalcitabine, or zidovudine plus didanosine. Combination therapy did not delay the emergence of zidovudine-resistant virus isolates.

Managing HIV. Part 4: Primary therapy. 4.2 Immune-based therapy for HIV infection.

Immune-based therapy is in its infancy and to date no therapies are licensed in Australia. A number of the reagents are reaching phase III clinical trials and may be available within two years. Patient and physician interest is high because antiretroviral agents have not as yet had a significant impact on survival.

Enhancing HIV-1 specific immunity as a therapeutic strategy in AIDS.

HIV-1 specific immune responses unequivocally play a major role in determining the natural history of HIV-1 infection. The decreases in viral load which occur during primary infection are several orders of magnitude greater than the decreases observed when antiretroviral chemotherapy is initiated. Delineation of the range of immune effector mechanisms responsible for the brick decrease in viral replication during primary HIV-1 infection is an active research topic of high priority.

Correlation between viral load measurements and outcome in clinical trials of antiviral drugs.

Background: As evidence is emerging that viral load can be correlated with clinical outcome in HIV-infected patients, new assays have been developed to measure viral load in vivo. These include biological assays that involve assessment of viral load by limiting dilution cultures of plasma or peripheral blood mononuclear cells and nucleic acid-based amplification techniques including RNA-based polymerase chain reaction and branched-chain DNA signal amplification. VIRAL LOAD QUANTITATION IN CLINICAL INVESTIGATION: The advent of RNA polymerase chain reaction and branched-chain DNA technology has allowed direct measurements of plasma HIV RNA levels.

Psychiatric disease and cytomegalovirus viremia in renal transplant recipients.

Although cytomegalovirus (CMV) is rarely cultured from peripheral-blood leukocytes of immunocompetent patients, it may be cultured from up to 60% of renal transplant recipients, 1 to 4 months after transplantation. During this same period, renal transplant recipients are often referred for psychiatric evaluation. Since CMV may infect the central nervous system, the relationship between isolation of CMV from peripheral-blood leukocytes (viremia) and psychiatric evaluation was investigated in 80 renal allograft recipients at the Massachusetts General Hospital.

Immunomodulatory effects of antiretroviral chemotherapy.

Antiretroviral chemotherapeutic agents exhibit complex immunoregulatory changes in HIV-1 infected individuals that reflect the summation of the direct effects of the agents on the immune response and indirect effects through the amelioration of viral replication. Immunological parameters are useful in the context of clinical investigation and in the management of HIV-1 infected individuals in that they serve as prognostic indicators of disease, markers of biologic activity of antiretroviral drugs, and, to a lesser extent, predictors of clinical outcome. Many questions remain in the evaluation of these parameters in the context of clinical trials and in the management of individual patients.

CD4+ lymphocytes are an incomplete surrogate marker for clinical progression in persons with asymptomatic HIV infection taking zidovudine.

Objective: To determine the extent to which lymphocytes, particularly those with the CD4 surface antigen, are a surrogate marker for the development of the acquired immunodeficiency syndrome (AIDS) in persons with asymptomatic human immunodeficiency virus (HIV) infection.

Design: Analysis of data from the AIDS Clinical Trials Group Protocol 019, a placebo-controlled, double-blind, randomized trial.

Setting: University-based referral centers.

Cytotoxic T lymphocyte lines specific for human immunodeficiency virus type 1 Gag and reverse transcriptase derived from a vertically infected child.

Cytotoxic T lymphocytes (CTL) specific for human immunodeficiency virus type 1 (HIV-1) are thought to play an important role in controlling HIV-1 infection. HIV-1-specific CTL are readily demonstrated in unstimulated peripheral blood mononuclear cells (PBMC) of HIV-infected adults but less frequently in PBMC from vertically infected children. HIV-1-specific CTL lines were derived from a long-term survivor of vertical HIV-1 infection using PBMC stimulated with a CD3-specific monoclonal antibody and interleukin-2; these lines had Gag- or reverse transcriptase (RT)-specific cytotoxicity.

Idiopathic CD4+ T-lymphocytopenia--immunodeficiency without evidence of HIV infection.

Background: The human immunodeficiency virus (HIV), the etiologic agent of the acquired immunodeficiency syndrome (AIDS), infects and depletes CD4+ T lymphocytes. Recently, patients have been described with profound CD4+ T-lymphocytopenia but without evident HIV infection, a condition now termed idiopathic CD4+ T-lymphocytopenia, and a national surveillance network has been set up to investigate such cases.

Methods: We studied 12 patients with CD4+ T-lymphocytopenia who were referred to us from three U.

CD4+ human immunodeficiency virus type 1 (HIV-1) envelope-specific cytotoxic T lymphocytes derived from the peripheral blood cells of an HIV-1-infected individual.

Virus-specific cytotoxic T lymphocytes (CTL) are frequently of the CD8+ surface phenotype, although CTL of the CD4+ surface phenotype have also been described. Published reports of CTL derived from peripheral blood mononuclear cells (PBMC) of individuals infected with human immunodeficiency virus type 1 (HIV-1) have described primarily cells of the CD8+ surface phenotype. However, CD4+ HIV-1 envelope-specific CTL have been reported after in vitro stimulation with HIV-1 envelope protein of peripheral blood cells obtained from HIV-1-seronegative donors, in peripheral blood cells after vaccination of HIV-1-seronegative persons with HIV-1 envelope proteins, and in cerebrospinal fluid cells of HIV-1-infected individuals.

Human T lymphotropic virus types I- and II-specific antibody-dependent cellular cytotoxicity: strain specificity and epitope mapping.

Antibody-dependent cellular cytotoxicity (ADCC) against human T lymphotropic virus (HTLV) types I and II was investigated using sera obtained from infected individuals or from rabbits immunized with HTLV-I or -II envelope peptides. Target cells included an HTLV-I-transformed cell line (C91/PL), an HTLV-II-transformed cell line (729pH6neo), and Epstein Barr virus (EBV)-transformed B lymphocytes expressing HTLV-I or -II env or gag gene products after infection with vaccinia/HTLV recombinants. ADCC activity was directed at HTLV-I and -II envelope glycoproteins but not against core (gag) components.

Status of immune-based therapies in HIV infection and AIDS.

As our understanding of HIV disease pathogenesis progresses, approaches to immune-based therapy are evolving. Initial therapies aiming to alter immune function in patients with HIV infection have had mixed results. Clinical benefit in the trials so far has not been dramatic, although the studies are still at an early stage, and the correct protocols for the various agents or combinations of agents have yet to be established.

Resistance of primary isolates of human immunodeficiency virus type 1 to neutralization by soluble CD4 is not due to lower affinity with the viral envelope glycoprotein gp120.

Recombinant soluble CD4 (rsCD4) has potent antiviral activity against cell line-adapted isolates of the human immunodeficiency virus type 1 (HIV-1) but low activity toward HIV-1 primary isolates from patients. A simple hypothesis proposed to explain this discrepancy, which questions the therapeutic utility of soluble CD4-based approaches, is that the major envelope glycoprotein, gp120, of patient virus has lower affinity for CD4 than does gp120 from laboratory viruses. To test this hypothesis, we have produced pairs of low- and high-passage HIV-1 isolates which, depending on culture passage history, display dramatically different sensitivities to neutralization by rsCD4.

Symptomatic cytomegalovirus disease in the cytomegalovirus antibody seropositive renal transplant recipient treated with OKT3.

A prospective study to investigate risk factors for CMV disease was conducted in 94 renal transplant recipients. CMV disease was defined as either unexplained fever for greater than 3 days with viremia or unexplained fever for greater than 3 days with isolation of CMV from the urine or throat wash and at least one of the following: leukopenia, elevated serum alanine aminotransferase, or biopsy-proved invasive tissue infection of the lung or gastrointestinal tract. Fifty-three patients received immunosuppressive regimens consisting of prednisone and cyclosporine, with or without azathioprine.

Progressive increases in serum catalase activity in advancing human immunodeficiency virus infection.

We found that serum from individuals with Acquired Immunodeficiency Syndrome (AIDS) had more (p less than .05) catalase activity (31.5 +/- 5.

Eosinophils as host cells for HIV-1.

Transient expression of HIV-1 p24 antigen was observed in eosinophils acutely infected with the HTLV-IIIB strain of HIV-1. PCR analysis of eosinophils isolated from 18 seropositive individuals showed HIV-1 sequences to be present in 2 subjects. These data suggest that eosinophils may act as host cells for HIV-1.

Delineation of type-specific regions on the envelope glycoproteins of human T cell leukemia viruses.

Two different approaches were used to map the type-specific regions on human T cell leukemia virus (HTLV) envelope glycoproteins. 1) Antibody reactivities of polymerase chain reaction-confirmed HTLV-I or HTLV-II carriers' sera were analyzed by Western blot assay with seven recombinant proteins containing different regions of HTLV-I or HTLV-II envelope proteins. 2) Rabbit antibodies elicited by nine HTLV-I Env synthetic peptides were used to react with the native HTLV envelope glycoproteins in an antibody-dependent cellular cytotoxicity (ADCC) assay.