Sensitive microculture method for isolation of human immunodeficiency virus type 1 from blood leukocytes

Pilot studies for development of an HIV subtype panel for surveillance of global diversity

The continued global spread and evolution of HIV diversity pose significant challenges to diagnostics and vaccine strategies. NIAID partnered with the FDA, WRAIR, academia, and industry to form a Viral Panel Working Group to design and prepare a panel of well-characterized current and diverse HIV isolates. Plasma samples that had screened positive for HIV infection and had evidence of recently acquired infection were donated by blood centers in North and South America, Europe, and Africa. A total of 80 plasma samples were tested by quantitative nucleic acid tests, p24 antigen, EIA, and Western blot to assign a Fiebig stage indicative of approximate time from initial infection. Evaluation of viral load using FDA-cleared assays showed excellent concordance when subtype B virus was tested, but lower correlations for subtype C. Plasma samples were cocultivated with phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMCs) from normal donors to generate 30 viral isolates (50-80% success rate for samples with viral load >10,000 copies/ml), which were then expanded to 10(7)-10(9) virus copies per ml. Analysis of env sequences showed that sequences derived from cultured PBMCs were not distinguishable from those obtained from the original plasma. The pilot collection includes 30 isolates representing subtypes B, C, B/F, CRF04_cpx, and CRF02_AG. These studies will serve as a basis for the development of a comprehensive panel of highly characterized viral isolates that reflects the current dynamic and complex HIV epidemic, and will be made available through the External Quality Assurance Program Oversight Laboratory (EQAPOL).

New methods for the detection of HIV

In the past few years, several strides have been made in the ability to detect the presence of HIV-1 and HIV-2. This article discusses recent advances in serologic testing, including routine ELISA and Western blot tests, rapid HIV tests, home collection kits, and HIV tests using nonserum samples. The clinical application of nucleic acid-based tests also is discussed. Finally, appropriate use of these tests in both acute HIV-1 infection and in infants is reviewed.

Comparison of blood collected in acid-citrate-dextrose and EDTA for use in human immunodeficiency virus peripheral blood mononuclear cell cultures

Paired blood samples collected in acid-citrate-dextrose and EDTA were compared for human immunodeficiency virus (HIV) infectivity on the day of collection or after 1 day of storage at room temperature. No significant differences between the anticoagulants were observed. Culture positivity was significantly associated with HIV RNA viral loads for both anticoagulants.

Phase II, randomized, open-label, community-based trial to compare the safety and activity of combination therapy with recombinant interferon-alpha2b and zidovudine versus zidovudine alone in patients with asymptomatic to mildly symptomatic HIV infection. HIV Protocol C91-253 Study Team

OBJECTIVES

To compare, in a community-based therapeutic setting, the safety, tolerance, and efficacy of combination therapy with recombinant interferon-alpha2b (rIFN-alpha2b) and zidovudine (ZDV) to ZDV monotherapy.

DESIGN

Open-label, two-armed, randomized study.

PATIENTS AND METHODS

Asymptomatic or minimally symptomatic HIV-infected adults without an AIDS-defining illness, a CD4 count of 200 to 500 cells/microl, and < or = 6 months of prior ZDV therapy received ZDV 100 mg orally five times daily. Patients randomized to rIFN-alpha2b received 3 million IU subcutaneously three times weekly for 2 weeks and 5 million IU three times weekly thereafter. The groups were compared with respect to adverse events (AEs), dosing modifications, treatment discontinuation, clinical endpoints and changes in CD4 count. A virology substudy compared the treatments with respect to HIV viral load and development of ZDV resistance.

RESULTS

Between October, 1991 and January, 1993, 139 patients were randomized to combination therapy and 117 to ZDV alone. Of AEs reported at any grade, fatigue, myalgias, and sweating occurred significantly more often with combination therapy (p < .001). Study subjects receiving combination therapy showed modest but significantly greater weight loss (p = .0001), a significantly higher frequency of any abnormal laboratory test result (p = .002), neutropenia (p = .002), and leukopenia (p = .02), and also required dosage reduction for hematologic toxicity significantly more often (p < .05) than those in the ZDV monotherapy arm. No statistically significant differences were found between the groups with respect to development of specific AIDS-defining events, overall event rate, time to events, or change in performance status or CD4+ counts, or percentages or development of ZDV resistance. Viral burden, reflected by serum p24 antigen and quantitative peripheral blood mononuclear cell (PBMC) microcultures, was greater at baseline in the combination therapy group. Baseline SI phenotype predicted progression to AIDS (p = .004, chi2), whereas intermediate susceptibility to ZDV predicted development of ZDV resistance (p < .005, chi2). The annual rate of development of phenotypic resistance to ZDV was 16.8% and was not affected by administration of rIFN-alpha2b.

CONCLUSIONS

At the doses and schedule used in this study, the combination of ZDV with rIFN-alpha2b was not therapeutically superior to ZDV alone and was less well tolerated. The addition of rIFN-alpha2b to ZDV did not prevent or delay the development of ZDV resistance.

TXU (anti-CD7)-pokeweed antiviral protein as a potent inhibitor of human immunodeficiency virus

We have evaluated the clinical potential of TXU (anti-CD7)-pokeweed antiviral protein (PAP) immunoconjugate (TXU-PAP) as a new biotherapeutic anti-human immunodeficiency virus (anti-HIV) agent by evaluating its anti-HIV type 1 (anti-HIV-1) activity in vitro, as well as in a surrogate human peripheral blood lymphocyte-severe combined immunodeficient (Hu-PBL-SCID) mouse model of human AIDS. The present report documents in a side-by-side comparison the superior in vitro anti-HIV-1 activity of TXU-PAP compared to the activities of zidovudine, 2',3'-didehydro-2',3'-dideoxythymidine, unconjugated PAP, and B53-PAP, an anti-CD4-PAP immunoconjugate. Notably, TXU-PAP elicited potent anti-HIV activity in the Hu-PBL-SCID mouse model of human AIDS without any side effects and at doses that were very well tolerated by cynomolgus monkeys. Furthermore, plasma samples from TXU-PAP-treated cynomolgus monkeys showed potent anti-HIV-1 activity in vitro.

Immunological and virological markers of disease progression in HIV-infected children

Polymerase chain reaction (PCR), virus culture and antigen detection assays are useful for early detection of vertically transmitted human immunodeficiency virus type 1 (HIV-1) infection in infants under 12 months of age. Sixty-four children born to HIV-1-seropositive mothers were evaluated. Thirteen children (20.3%) were repeatedly positive by PCR analysis. There was 100% concordance between the results obtained from PCR and culture assays. Measurement of p24 antigen in serum was, in contrast, a less sensitive marker of HIV infection: only 5/13 infants had positive p24 antigen results. We have investigated the relationship among the HIV-1 biological phenotype, replicative capacity of viral isolates, HIV RNA copy number in plasma, p24 antigenaemia, CD4 T lymphocyte counts and the clinical status in 13 HIV-infected infants. Six out of 13 HIV-1 isolates from these patients were classified as rapid/high and seven as slow/low. We have found a significantly positive correlation between the replication rate of HIV isolates and their capacity to induce syncytia in vitro. The HIV-1 isolates with rapid/high and syncytium-inducing phenotype, and isolates with slow/low and non-syncytium-inducing phenotype were obtained from infants who had HIV-1 RNA copy number ml(-1) plasma values of 27654-83520 and 1342-34321, respectively. Levels of HIV-1 RNA were measured in sequential plasma samples from three HIV-infected infants and their biological properties determined in vitro. Our findings indicate that infants who carried viruses with more cytophatic biological phenotype and who had higher viral RNA copy numbers in blood were more likely to have lower CD4+ T cell counts and more likely to develop full-blown AIDS.

Relationship of virologic, immunologic, and clinical parameters in infants with vertically acquired human immunodeficiency virus type 1 infection

We have investigated the relationship among the HIV-1 biologic phenotype, replicative capacity of virus isolates, HIV-RNA copy number in plasma, p24 antigenemia, CD4+ T lymphocyte counts in peripheral blood, and the clinical status in a cohort of 13 HIV-infected children younger than 12 mo of age, born of HIV-1 seropositive mothers. Six out of 13 HIV-1 isolates from these patients were classified as rapid/high and seven as slow/low. We have found a significantly positive correlation between the replication rate of HIV isolates and their capacity to induce syncytia in vitro. Most of the serial HIV-1 isolates obtained from infants with AIDS had the rapid/high phenotype and induced syncytia, whereas only two out of 23 HIV-1 isolates obtained from infants without AIDS showed these properties. In sequential analysis of HIV-1 isolates from infants with AIDS, the presence of viral isolates with rapid/high and SI phenotype was associated with higher levels of HIV-1 RNA in plasma, CD4+ T cell depletion, and clinical progression. By contrast, infants whose viruses exhibited nonsyncytium-inducing phenotype throughout the follow-up showed lower levels of HIV RNA, stable CD4+ T cell counts, and mild symptomatic HIV infection. Our findings indicate that infants who carried viruses with more cytopathic biologic phenotype and who had higher viral RNA coy numbers in blood were more likely to have lower CD4+ T cell counts and more likely to have AIDS.

Evaluation of an infectivity standard for real-time quality control of human immunodeficiency virus type 1 quantitative micrococulture assays. Participating Laboratories of The AIDS Clinical Trials Group

Quantitative microculture assays of cryopreserved human immunodeficiency virus type 1-infected cell suspensions and culture supernatants were compared among seven assays sites. There was no significant change in titer during 1 year of storage. The overall standard deviation for infected cell suspensions was approximately 0.8 log10 virus titer. A method for detecting deviant assay results was developed and was used to identify two donor cell preparations (n = 54) that gave consistently low titers.

Resistance of microorganisms to disinfection in dental and medical devices

The U.S. Centers for Disease Control and Prevention (CDC) recommends that only heat sterilization be used for all reusable devices entering the oral cavity. However, chemical disinfection is still employed for reprocessing dental devices in many areas of the world. In an analysis of a Florida dental practice responsible for nosocomial human immunodeficiency virus (HIV) transmissions, the possible role of contaminated devices was deemed unlikely in part because they were subjected to high-level disinfection with 2% glutaraldehyde. Disease transmissions have, however, been documented for endoscopes used in diagnostic and surgical procedures even after this treatment. In some dental devices, lubricants mix with potentially infectious patient materials, and organic debris has been observed in endoscopes after cleaning. We have investigated whether lubricants can render high-level chemical disinfection procedures ineffective and have addressed the role that some common devices may play in disease transmission. We report here that HIV in whole-blood samples and Pseudomonas aeruginosa in blood and plasma survived high-level disinfection when entrapped in lubricants used in dental handpieces and endoscopes. We also found that lubricated dental devices used to clean and polish teeth (prophylaxis angles) have the potential to transfer sufficient amounts of blood to infect human lymphocyte cultures with HIV. These results emphasize the need to subject reusable dental devices to a heat-sterilization protocol that penetrates the lubricant.

Detection of human immunodeficiency virus type 1 proviral DNA by PCR using an electrochemiluminescence-tagged probe

We have developed a rapid, pseudohomogeneous assay for the detection of PCR amplicons, based on the use of electrochemiluminescence generated from a Tris-bipyridine ruthenium(II) label. PCR amplification of highly conserved human immunodeficiency virus type 1 (HIV-1) gag gene sequences was performed with SK38 and SK39 primers, the latter of which was 5' biotinylated. Post-PCR reaction mixtures were combined with 10(12) copies of the SK19 probe-Tris-bipyridine ruthenium(II) conjugate, denatured by heating at 100 degrees C for 5 min, and hybridized at 55 degrees C for an additional 15 min. Hybridization to the biotinylated strand of the amplified DNA was determined by the addition of streptavidin-conjugated magnetic particles and analyzed by using an Origen-1 electrochemiluminescence analyzer. Our results demonstrated a sensitivity of fewer than five copies of HIV-1 (pre-PCR), by using either purified plasmid DNA containing one complete copy of the HIV-1 cDNA genome or lysed, proteinase K-treated 8E5 cells as the starting material. In an evaluation of actual clinical specimens (peripheral blood monocytes from both healthy and HIV-1-infected children), the electrochemiluminescent detection assay correlated 100% with both our standard method (solution hybridization with a radiolabeled probe followed by polyacrylamide gel electrophoresis [PAGE] and autoradiography) and a commercial method (Roche Amplicor). The electrochemiluminescent method was substantially easier to perform than either the PAGE or microtiter plate assays and was considerable faster to perform than either of these alternative formats.

Prospective study of antigenemia, plasma viremia and lymphocytic viremia in HIV-infected hemophiliacs

A total of 186 blood samples from 24 HIV-1 seropositive hemophiliac patients, monitored every four months for 29 months, were investigated for the presence of viral antigen in plasma. In addition, peripheral blood mononuclear cells (PBMC) were cultured for HIV-1, using normal PBMC as a target for replication. Antigenemia was detected in 51% of the patients and from PBMC in 87.5% of the patients. The incidence of HIV isolation in asymptomatic patients (42.8%) was similar to that found in symptomatic patients (51.4%). Patients with opportunistic infections had a higher incidence of lymphocytic viremia (p < 0.05). Plasma viremia was closely associated (p < 0.05) with low CD4+ counts and infection progression. The persistence of antigenemia was also a marker of a poor clinical course. In treated patients, plasma viremia was the marker that better correlated with the clinical course, and it did not appear during the first nine months of therapy. Zidovudine doses of > 500 mg/day significantly lowered the appearance of antigenemia and lymphocytic viremia (p < 0.05).

Length of incubation time for human immunodeficiency virus cultures

Qualitative human immunodeficiency virus culture is a slow, labor-intensive, and expensive procedure, yet critical for the diagnosis of infants born to human immunodeficiency virus-seropositive mothers. We report that the cultures can be terminated at day 21 with minimal false-negative results but with considerable savings in both time and money.

Isolation, characterization, and transmission of human T-lymphotropic virus types I and II in culture

Highly sensitive coculture methods were developed both for isolation of human T-lymphotropic virus types I and II (HTLV-1 and HTLV-II) from infected individuals and for productive infection of lymphoid cells. Mitogen-activated peripheral blood mononuclear cells (PBMC) from 13 HTLV-I- and 20 HTLV-II-positive specimens were cocultured with an equal number of mitogen-activated PBMC from HTLV-seronegative individuals, and culture supernatants were tested for the presence of soluble p24gag antigens at weekly intervals for 4 weeks. Eleven of 13 (85%) HTLV-I and 14 of 20 (70%) HTLV-II cultures were positive for p24 antigens. None of the 17 HTLV-seroindeterminate or six HTLV-seronegative specimens were positive for the presence of p24 antigen. The isolation rates for HTLV-I and HTLV-II by an alternative whole-blood lysis procedure were comparable to those obtained by standard PBMC cultures. Furthermore, cocultivation of PHA-stimulated PBMC from healthy donors with lethally irradiated HTLV-I- and HTLV-II-infected cell lines (SP and Mo-T, respectively) resulted in productive viral infection, as reflected by the appearance of p24gag antigens concomitant with specific genomic amplification of HTLV proviral DNA after 3 weeks of cocultivation. Thus, the cocultivation technique provides a highly sensitive and specific procedure both for HTLV isolation and for infection of target cells.