Antibodies to cell membrane antigens associated with human T-cell leukemia virus in patients with AIDS

The potential of nucleotide analogs as inhibitors of retroviruses and tumors

The biologically active form of most purine or pyrimidine analogs is the nucleoside 5'-mono, di- or triphosphate. The nucleoside form is most often administered because of the ease with which it penetrates cells by facilitated transport. However, many nucleoside derivatives fail to exhibit significant antiviral or antitumor activity because they are not phosphorylated by cellular enzymes to the active nucleotide form. In this review, the potential use of suitable nucleotide analogs as selective inhibitors of ribonucleotide reductase and viral reverse transcriptase is considered. Masked nucleotides such as phosphoramidates or methyl phosphates could be employed to allow transport across cellular membranes. Furthermore, phosphonocarboxamide, phosphonoformate or sulfamidophosphoramidate may mimic nucleotide di- and triphosphates. Tumor cells and virally infected cells are often more permeable to nucleotides and their analogs than normal cells, which could provide a therapeutic advantage. There could be considerable therapeutic potential for nucleotide analogs that can penetrate the tumor cell membranes and that are resistant to enzymatic hydrolysis and are non-incorporable into DNA or RNA.

HIV/AIDS and drug use in China--interactions, impacts, and issues

The interrelationships of HIV/AIDS and drug use and misuse result in complex problems that have been addressed by a variety of sociolegal approaches that often are in contrast to evidence-based medical practices proven effective in reducing associated harms. Like other countries struggling to reduce the incidence and consequences of addiction and HIV/AIDS, China is working to improve systems of care and to revise policies toward drug use and misuse and HIV/AIDS. Greater interaction with researchers and clinicians from around the world can foster increased awareness of effective practices and help implement effective strategies to deal with the problems of HIV/AIDS, and addiction.

Chapter 9 Infections caused by rubella, reoviridae, retro, Norwalk and ronaviruses

This chapter focuses on infections caused by rubella, reoviridae, retro, Norwalk and coronaviruses. High incidence of acute gastroenteritis caused by rotaviruses calls for prophylactic and therapeutic measures. Although no vaccine is presently available, it seems likely that vaccines will be developed in the next few years. There are also several rotavirus enzymes useful as targets for antiviral drugs. However, no antiviral drugs have shown therapeutic effects against rotavirus infections. The newly discovered human retrovirus (HTLV) has not yet been investigated in such detail as to predict the usefulness of vaccine or antiviral drugs. Several compounds are known to inhibit other retrovirus enzymes but the implication of this for chemotherapy of HTLV infection is unknown at present. The possibility and need for vaccination or chemotherapy against Norwalk virus and related agents is unclear. Very little work has been carried out to date with human coronaviruses, either from the point of view of vaccine development or specific antivirals. Both approaches may be usefully investigated in the future. Genetic cloning may be particularly useful for development of inactivated vaccines because the virus itself would be difficult to replicate and purify in large quantities for conventional vaccines.

Special anniversary review: twenty-five years of human immunodeficiency virus research: successes and challenges

During 25 years of research since HIV-1 was first identified in Paris, there have been great advances in our understanding of the virus and of the immune system. Practical advances include the early development of diagnostic tests of infection that made blood donation safe, and since 1996, combination anti-retroviral therapy that has great reduced incidence of AIDS in HIV-infected people who have access to the drugs. HIV prevention through behavioural change has been successful, and we do not yet have any safe and efficacious microbicides or vaccines.

HIV/AIDS: Lessons from a New Disease Pandemic

The acquired immunodeficiency syndrome (AIDS) was first recognized about 25 years ago (Gottlieb et al., 1981; Masur et al., 1981; Siegal et al., 1981). The best available evidence suggests that HIV newly infected the human species about 50–100 years ago (Korber et al., 2000). It did not originate in Asia. It apparently moved to people from sub-human primates in Africa (Keele et al., 2006; Kanki, 1997). Because of different clinical presentations in different populations of people, and a long incubation period, it was more difficult to diagnose than SARS or avian influenza.

As a new epidemic that originated in the era of modern medicine, it taught us many lessons about the difficulties that a new infectious disease can present. Already claiming at least 60–80 million victims, AIDS seems destined to continue as a pandemic for the foreseeable future. Drugs that control HIV replication and reverse disease progression have been developed, but none eliminate the virus from the body. Sexual transmission can be prevented by abstinence or condoms, but such measures, which prevent procreation, provide only limited value.

Approaches for making a vaccine using conventional techniques have failed. Most experts believe that an effective vaccine will be made eventually, but not for at least 10–20 years. We need to learn more about the immunobiology of acute HIV infection, and about potentially protective immunoepitopes, such as conformational intermediates of the virus envelope. Until a vaccine is available, there is little or no chance that HIV can be eliminated, or even drastically reduced in prevalence. AIDS has presented scientists, political leaders, and health policy experts with unprecedented challenges.

Human retroviruses in leukaemia and AIDS: reflections on their discovery, biology and epidemiology

The study of retroviruses has had a profound impact by unveiling an unusual form of viral replication: the multiplication of RNA viruses via a proviral DNA, for which Jan Svoboda provided the experimental model over forty years ago. In 1970 Temin, Mizutani and Baltimore discovered that this group of viruses contains a unique enzyme catalysing the synthesis of a DNA copy of the viral RNA: reverse transcriptase (RT). The discovery of RT has itself had an enormous impact on molecular biology in general, but also stimulated many premature claims of its detection in human disease. Claims by Gallo's laboratory that the cytoplasm of human leukaemia cells contained RT proved to be unfounded, as did his report in collaboration with Weiss that myeloid leukaemia contained HL23 virus, this organism proving not to be human but a laboratory contaminant of three monkey viruses. Conclusive demonstration of a retroviral involvement in human leukaemia was first provided in 1981 by Hinuma and his associates, showing that adult T-cell leukaemia (ATL), a rare form of leukaemia endemic to south-west Japan, is caused by a new retrovirus (ATLV). Other publications in December 1980 and through 1981 claimed the discovery of a new human T-cell leukaemia virus involved in mycosis fungoides (MF) and Sézary's syndrome (SS). This virus was termed HTLV by Gallo. The nucleotide sequence of ATLV is strongly conserved, that of my 1983 isolate from a black British ATL patient being practically identical with the Japanese virus isolates. After AIDS was recognised in 1981 by Gottlieb and coworkers as a new human disease, several papers were published by Gallo and his associates during 1983-4, invoking the oncovirus responsible for adult T-cell leukaemia as the cause of AIDS. In 1983 the French scientist Barré-Sinoussi and her colleagues succeeded in isolating a new agent in the disease, a lentivirus, which they named LAV. The French immunologist Klatzmann and his colleagues discovered that LAV killed CD4+ T-cells, furnishing an explanation for the pathogenesis of AIDS and providing a mechanism for how AIDS developed. For some time Gallo continued to suggest leukaemia virus involvement, claiming that his independent isolate of the AIDS virus, termed HTLV-III, was closely related to HTLV-I (the Japanese ATLV). Although this created considerable confusion among researchers for a period, the relationship was eventually disproved. Unlike ATLV, whose nucleic acid sequence is very stable, the AIDS virus (now termed HIV by international agreement) is extraordinarily unstable, the sequences of independent HIV isolates being quite unique: this made it possible to establish conclusively that both HTLV-III and another independent isolate CBL-1, from Weiss' laboratory, were actually LAV isolates from the French laboratory. It has been shown by Hayami and his associates that only African primates are infected with similar lentiviruses to HIV which explains why AIDS started in Africa. Further research has clarified the origin of HIV-1 to be a chimpanzee lentivirus and HIV-2 to be the sooty mangabey lentivirus, which began to spread in humans perhaps no more than fifty years ago. The infection has spread rapidly, primarily through sexual intercourse, but also by transmission through blood and its products as well as contaminated needles and syringes. Sexual intercourse has now spread the virus around the World; and there are probably some 70 million infected. 90% of those infected with HIV develop the deadly disease of AIDS within ten years of infection: the death toll from the disease has been enormous. By contrast, HTLV-1 has been infecting man in isolated areas probably for hundreds of years; but it has not spread widely. HTLV causes leukaemia in only less than 1% of those infected. The prime mode of transmission of HTLV-1 is between mother and neonate; infections can be reduced by stopping breast-feeding by infected mothers. The isolation of HIV enabled screening tests to be developed for contaminated blood. However, due to the peculiar biology of HIV infection, unfortunately all efforts to develop an effective vaccine have so far failed.

Nonnucleoside HIV-1 reverse transcriptase inhibitors: Part I. Synthesis and structure-activity relationship of 1-alkoxymethyl-5-alkyl-6-naphthylmethyl uracils as HEPT analogues

1-alkoxymethyl-5-alkyl-6-naphthylmethyl uracils, which are novel 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) analogues, were synthesized for evaluation as selective and potent nonnucleoside human immunodeficiency virus (HIV)-1 reverse transcriptase inhibitors. The anti-HIV-1 activity of these compounds was assayed in vitro using HIV-1 infected MT-4 and CEM bioassays. The EC50, CC50 and SI were recorded and calculated. The appropriate position, especially in the 1-position of the naphthyl ring, led to dramatic increases in potency, in both MT-4 and CEM cellular assays. The most important compounds in this series, 1-ethoxymethyl-5-isopropyl-6-(1-naphthylmethyl)thymine 8l (IC50=17 nM, CC50=38332 nM, SI=2229) and 1-benzyloxymethyl-5-ethyl-6-(1-naphthylmethyl)thymine 8n (IC50=17 nM, CC50=32560 nM, SI=1889) were significantly more potent than HEPT (EC50=7.0 microM, CD50=740 microM) in the anti-HIV-1 in vitro cellular assay.

Human immunodeficiency viruses in the developing world

AIDS has become a major burden in developing countries. At present, more than 90% of new HIV infections are emerging in Asia and Africa. Particularly ominous is the epidemic due to HIV-1 C in southern Africa, where about 25% of adults in several countries are infected. Although most of its spread apparently occurred during the 1990s, HIV-1 C currently accounts for one-half of the infections in the world. Both HIV-2, which is less virulent than HIV-1, and HIV-1 apparently spread to the human population from nonhuman African primates during the twentieth century. HIV-1 infection is usually lethal in the absence of antiretroviral therapy, but clinical disease occurs only after an induction period of several years. Some subtypes of HIV-1, such as C, E, and A, appear to be transmitted more efficiently than HIV-1 B, which is the major subtype in the United States and Europe. Molecular evolutionary changes that include receptor affinity, mediated by the env gene, and increased transcriptional activation, mediated by changes in the LTR and the tat gene, may account for some of the changes in transmission. Current therapies are prohibitively expensive for use in adults in most developing countries, although drugs for maternal-to-infant transmission are becoming accessible. A vaccine for HIV is desperately needed for the developing world.

Intrafamilial transmission of HTLV-I and its association with anti-Tax antibody in an endemic population in Japan

To assess the relationship of anti-Tax antibody to human T-cell lymphotropic virus type-I (HTLV-I) transmission, the sero-prevalence of HTLV-I was analyzed among married couples and among mother/child (both adults) pairs. HTLV-I seroprevalence was significantly higher among wives with anti-Tax+ than those with anti-Tax- HTLV-I carrier husbands (82.4% vs. 59.5%). However, in the group of wives aged 60 years or older, there was no statistical difference in HTLV-I seropositivity based on the husbands' anti-Tax sero-status. In the group whose wives were less than 60 years old, more anti-Tax sero-positive than sero-negative husbands had high DNA levels (57.1% and 20.0%), whereas in the group of husbands whose wives were aged 60 years or older, the number of anti-Tax sero-positive and sero-negative individuals with high DNA levels was similar. HTLV-I sero-prevalence was significantly higher among the adult men with anti-Tax+ carrier mothers than those with anti-Tax- carrier mothers (52.0% vs. 14.3%). For women, HTLV-I sero-prevalence did not differ significantly according to their mothers' anti-Tax sero-status. Our results suggest that the presence of anti-Tax antibody in HTLV-I carriers is an age-dependent risk factor for male-to-female HTLV-I transmission. Furthermore, the effect of the mother's anti-Tax antibody as a risk factor for vertical HTLV-I transmission could be observed in men even after becoming adults.

Reversal of immunosuppression of lymphocyte proliferation caused by sera from persons with AIDS

Sera from persons with AIDS contain inhibitors of lymphocyte proliferation. Inhibitory activity can be detected before the development of AIDS in humans. There appear to be at least three distinct suppressive moieties, one of which is prostaglandin E2. We and others had previously shown that serum samples from subjects with AIDS contained antibody to the cell line HUT 102B2. We attempted to remove this antibody and to determine if that action would also remove the inhibitory activity present in human immunodeficiency virus-positive sera. We incubated sera from subjects with AIDS with HUT 102B2 cells and tested the resultant supernatants for inhibition of cell proliferation. We found that this procedure significantly reversed inhibition by serum. Other cells and cell lines were similarly tested, but only HUT 102B2 cells absorbed the inhibitory product(s). However, we determined that secretory material from another cell line, MLA 144, also reversed inhibition. The physical characteristics of the supernatant were investigated. Thus, two procedures and likely separate products, possibly cytokines, reverse immunosuppression by sera from persons with AIDS.

Laboratory study of HIV-1 and HTLV-I/II coinfection

A Retroviral Coinfection Clinic was established in 1991 at Charity Hospital Medical Center of Louisiana to study patients dually infected with human immunodeficiency virus (HIV) and human T lymphotropic virus (HTLV-I, HTLV-II). Eight patients were evaluated clinically, and by immunological and virological studies. Multiple neuromuscular diseases were observed, including tropical spastic paraparesis, polymyositis, and polyneuropathies. Only one patient developed AIDS. HIV-1 infected patients with HTLV-I, but not HTLV-II, coinfection have maintained stable CD4 counts, despite the fact that quantitative HIV DNA PCR suggests a relatively high copy number. HTLV-I/II antigens were detected in lymphocyte cultures from four patients, and lymphoblastoid cell lines have been established from two. These results support the contention that upregulated HTLV-I/II virus expression and disease manifestations occur during coinfection with HIV, sometimes in association with normal CD4 counts.

Is a positive western blot proof of HIV infection?

It is currently accepted that a positive Western blot (WB) HIV antibody test is synonymous with HIV infection and the attendant risk of developing AIDS. In this communication we present a critical evaluation of the presently available data on HIV isolation and antibody testing. This evidence indicates that: (1) the antibody tests are not standardized; (2) the antibody tests are not reproducible; (3) the WB proteins (bands) which are considered to be encoded by the HIV genome and to be specific to HIV may not be encoded by the HIV genome and may in fact represent normal cellular proteins; (4) even if the proteins are specific to HIV, because no gold standard has been used to determine specificity, a positive WB may represent nothing more than cross-reactivity with non-HIV antibodies present in AIDS patients and those at risk. We conclude that the use of antibody tests as a diagnostic and epidemiological tool for HIV infection needs to be reappraised.

Analysis of anti-Tax antibody of HTLV-I carriers in an endemic area in Japan

Sera from 1197 adult residents in Miyazaki district, an area in Japan endemic for human T-cell leukemia virus type I (HTLV-I), were tested for anti-Tax antibody by the recombinant Tax (r-Tax) Western blot assay. Among HTLV-I-seropositive individuals, including 21.5% of 484 males and 28.6% of 713 females, the prevalence of anti-Tax antibody were 59.6% and 58.3% respectively, with no apparent difference in age. There was a significant 6-fold difference in the prevalence of anti-Tax among seropositive subjects with titer > or = 1:8192 (84.6%) compared with those with the lowest titer of 1:16 (14.3%), suggesting the increased production of antibodies to viral structural proteins in anti-Tax-positive individuals. Furthermore, among those anti-Tax-positive subjects, the intensity of serum reactivity to r-Tax protein in the high antibody titer (1:1024 or higher) group was significantly stronger than that in the lower antibody titer (1:512 or lower) group. We also found that 1.6% (14/889) of individuals without detectable levels of HTLV-I antibody had anti-Tax antibody. HTLV-I pro-viral DNA signals could not be detected in DNA sample from the lymphocytes of these individuals by the nested polymerase chain reaction method. Further evaluation is needed to clarify the significance of an anti-Tax-only status population in which HTLV-I is endemic.

Sexual transmission of human T-lymphotropic virus type I in Peruvian prostitutes

The epidemiology of HTLV-I infection in female prostitutes was studied in a survey of 395 prostitutes from Callao, Peru (the port city of Lima), 72 prostitutes from Iquitos, Peru (another port city on the Amazon River), and 510 prenatal clinic patients from Lima. Prostitutes reported a mean of 8.8 years (range, 1-39 years) of active prostitution and a mean of 205 sexual contacts during the month prior to the study. The percentage of prostitutes with HTLV-I antibody (21.8%) was significantly higher than patients attending a prenatal clinic (3.1%; P less than .0001). The prevalence of HTLV-I antibody increased steadily with age in prostitutes, but no age trend was noted in prenatal patients. By multiple logistic regression analysis, an independent association was found between HTLV-I seropositivity and a history of prostitution in Callao, age, and positive syphilis serology when all 977 study subjects were evaluated. When prostitutes alone were analyzed, the number of years of exposure as a practicing prostitute was associated with HTLV-I seropositivity after controlling for age. These data indicate a greatly increased risk of HTLV-I infection in prostitutes in Callao, Peru, and suggest an association between sexual activity and HTLV-I transmission.

Use of immunoreactive synthetic HTLV-1 peptides in the search for antibody reactivity in multiple sclerosis

The possible association between multiple sclerosis (MS) and antibodies to human T-cell lymphotropic virus type 1 (HTLV-1) was studied. Five synthetic and highly immunoreactive HTLV-1 peptides, four from the envelope (env) region and one from the core (gag) region, were used in an indirect enzyme-linked immunosorbent assay (ELISA). Presence of HTLV-1-specific antibodies in paired serum and cerebrospinal fluid (CSF) samples from 41 MS patients were investigated. No antibody reactivity was demonstrable in samples from 40 of them, whereas one reacted in one serum sample against the gag-peptide. Serum and CSF specimens from 15 with other neurologic diseases (OND), and negative control specimens, i.e. serum and CSF from 9 non-neurologic controls and CSF from 9 healthy controls, did not demonstrate any reactivity in the peptide-ELISAs. Our results do not support involvement of HTLV-1 infection in the etiology of MS.

Human T-cell leukemia virus type-I/II (HTLV-I/II) serologic testing: the importance of assaying for the full complement of viral antigens

Seventy-one Japanese adult T-cell leukemia (ATL) patients and 411 Japanese asymptomatic patients from HTLV-I endemic regions of southern Japan were found to be seropositive by radioimmunoprecipitation assay (RIPA). Of these 482 positive controls, 62% of ATL patients and 67% of the asymptomatic seropositive patients were found to harbor antibodies to p40x. Additionally, 333 preselected Japanese blood donors who were identified as seropositive by particle agglutination (PA) assay were further tested for antibodies to HTLV-I/II gene encoded envelope (env) or group specific antigens (gag) by means of enzyme-linked immunosorbent assay (ELISA) and RIPA. Concordance between ELISA and RIPA was noted in 318 samples (92.5%). Discordance between ELISA and RIPA was observed in 15 sera (7.5%)--2 were seropositive by ELISA and seronegative by RIPA and 13 were seronegative by ELISA and seropositive by RIPA. Seven of these 13 samples (53.8%) contained antibodies to p40x by RIPA and may represent ELISA false negatives on the basis of both clinical and laboratory data. Current HTLV-I/II ELISA kits may yield false negative results. Additional research into the development of rapid detection cost-efficient assays that test for the full compliment of viral antigens is needed.

Advantages of a human immunodeficiency virus type 1 (HIV-1) persistently infected HeLa T4+ cell line for HIV-1 indirect immunofluorescence serology

A HeLa T4+ cell line persistently infected with human immunodeficiency virus type 1 (HIV-1) was used in an indirect immunofluorescent antibody assay (IFA) system to explore its potential suitability as an alternative source of viral antigen for confirmatory IFA in HIV serology. In a study of 121 serum samples chosen because they were reactive on repeat examination by enzyme immunoassay but nonspecific by IFA by using HIV-1-infected H9 cells (H9 IFA) or gave discrepant results by enzyme immunoassay and H9 IFA, the specificity and sensitivity of the HeLa T4+ IFA were comparable to those of Western blot (immunoblot), and identification of the true positive samples among these discrepant or nonspecific samples by HeLa T4+ IFA was approximately twice that by H9 IFA. The primary advantages of using the HeLa cell line rather than lymphoid cell lines in IFA are that cells can be grown as a monolayer and that the individual cells are much larger. The cell membrane, cytoplasm, and nucleus are easily discernible; this allows specific and nonspecific staining to be distinguished. At least eight different nonspecific nuclear and cytoplasmic staining patterns were identified in this study by using T4+ cells.

AIDS epidemiology: inconsistencies with human immunodeficiency virus and with infectious disease

The newly defined syndrome AIDS includes 25 unrelated parasitic, neoplastic, and noninfectious indicator diseases. Based on epidemiological correlations, the syndrome is thought to be due to a new, sexually or parenterally transmitted retrovirus termed human immunodeficiency virus (HIV). The following epidemiological data conflict with this hypothesis. (i) Noncorrelations exist between HIV and AIDS; for example, the AIDS risks of infected subjects vary greater than 10-fold with their gender or country. Abnormal health risks that are never controlled as independent AIDS causes by AIDS statistics, such as drug addiction and hemophilia, correlate directly with an abnormal incidence of AIDS diseases. Above all, the AIDS diseases occur in all risk groups in the absence of HIV. (ii) American AIDS is incompatible with infectious disease, because it is almost exclusively restricted to males (91%), because if it occurs, then only on average 10 years after transfusion of HIV, because specific AIDS diseases are not transmissible among different risk groups, and because unlike a new infectious disease, AIDS has not spread exponentially since the AIDS test was established and AIDS received its current definition in 1987. (iii) Epidemiological evidence indicates that HIV is a long-established, perinatally transmitted retrovirus. HIV acts as a marker for American AIDS risks, because it is rare and not transmissible by horizontal contacts other than frequent transfusions, intravenous drugs, and repeated or promiscuous sex. It is concluded that American AIDS is not infectious, and suggested that unidentified, mostly noninfectious pathogens cause AIDS.

Human immunodeficiency virus 1. Predominance of a group-specific neutralizing epitope that persists despite genetic variation

HIV-1 is known to show a high degree of genetic diversity, which may have major implications for disease pathogenesis and prevention. If every divergent isolate represented a distinct serotype, then effective vaccination might be impossible. However, using a sensitive new plaque-forming assay for HIV-1, we have found that most infected patients make neutralizing antibodies, predominantly to a group-specific epitope shared among three highly divergent isolates. This epitope persists among divergent isolates and rarely mutates, despite the rapid overall mutation rate of HIV-1, suggesting that it may participate in an essential viral function. These findings, plus the rarity of reinfections among these patients, suggest that HIV-1 may be more susceptible to a vaccine strategy based on a group-specific neutralizing epitope than was previously suspected.

The prevalence of antibody to p42 of HTLV-I among ATLL patients in comparison with healthy carriers in Japan

A gene product (p42) of the long open reading frame, now termed tax, of the viral genome of human T-cell leukemia virus type I (HTLV-I) may be related to the transformation of T cells in adult T-cell leukemia-lymphoma (ATLL). To evaluate its association with the disease, we compared the prevalence of antibody to p42 in sera obtained from 105 HTLV-I carriers and 64 ATLL patients from southwest Japan. The prevalence of the anti-p42 antibody reactivity was 63% among carriers and 31% among cases. The cases were more than 3 times as likely to lack antibody to p42 than carriers, the relative odds (OR) = 3.4, p = 0.001. When the samples were tested for antibody against p24, the most immunogenic core protein, the prevalence was somewhat higher among carriers (65%) than in cases (52%), but not significantly so (p = 0.15). Among the healthy carriers, the correlation between the prevalence of both antibodies was high (p = 0.001), and only 25% of those who had antibody to p24 lacked antibody to p42. However, among the cases, reactivity to both antigens was independent (p = 0.52), and 65% of those with antibody to p24 lacked antibody to p42, OR = 6.3, p = 0.0004. Thus the strongest serologic marker of ATLL following diagnosis was lack of reactivity to p42, particularly among those subjects with anti-p24. Whether this altered response is present prior to disease remains to be determined.

Human cell lines stably expressing HIV env and tat gene products

A DNA fragment containing the tat, rev and env genes of the human immunodeficiency virus type 1 was inserted into the retroviral vector pZIPneoAU3. The resulting plasmid penvAU3 was transfected into HeLa and psi CRIP cells. Resulting recombinant retroviruses were used to infect HeLa and Jurkat cells. Immunoprecipitation analysis of stable transformants showed the expression of HIV env glycoproteins gp160, gp120 and gp41. Transactivation assays with a plasmid containing the gene for chloramphenicol acetyltransferase linked to HIV promoter-enhancer sequences demonstrated the expression of functional tat. These cells constitute virus-free tools for functional and structural studies of native env and tat.

FeLV-FAIDS-induced immunodeficiency syndrome in cats

Findings are reviewed, relevant to elucidation of the pathogenic, genetic and biochemical properties of a single, genetically heterogeneous isolate of feline leukemia virus (FeLV-FAIDS) shown to induce fatal immunodeficiency disease in nearly 100% of inoculated cats. Hypotheses are suggested which pertain to the mechanism of T-cell killing by this virus, and which extrapolate findings in the FeLV-FAIDS animal model to AIDS induced in humans by human immunodeficiency virus (HIV).

HIV-1 reverse transcriptase is a target for cytotoxic T lymphocytes in infected individuals

Characterization of the host immune response to human immunodeficiency virus type 1 (HIV-1) is critical to the rational design of an effective AIDS vaccine. In this study, cytotoxic T lymphocytes (CTL) specific for HIV-1 reverse transcriptase (RNA-dependent DNA polymerase) were found in blood samples from HIV-1-infected individuals. CTL targets were prepared by immortalizing B cells from ten seropositive and six seronegative individuals, and then infecting these cells with recombinant vaccinia viruses containing HIV-1 genes. CTL directed against autologous B lymphoblasts expressing HIV-1 reverse transcriptase were detected in fresh blood samples from eight HIV-1 seropositive subjects, but in no seronegative controls. The effector cells were identified as major histocompatibility complex-restricted CD3+CD8+ lymphocytes. Because the HIV-1 pol gene is highly conserved among different isolates and generates both humoral and cellular immune responses, it bears consideration for inclusion in a candidate AIDS vaccine.

Infection with human T-cell leukemia virus type I in patients with leukemia

Among 211 adults with leukemia who received multiple transfusions, 6 were found to be seropositive for human T-cell leukemia virus Type I (HTLV-I). Before the positive serum specimens were obtained, these patients received a mean of 14 units of red cells and 78 units of platelets. Seroconversion could be documented in three patients. None of the 6 patients seropositive for HTLV-I had a T-cell leukemia, other illnesses attributable to HTLV-I infection, or risk factors for HTLV-I infection other than transfusion: none were seropositive for human immunodeficiency virus. Patients with leukemia who receive multiple transfusions appear to be at risk for HTLV-I infection.

Chemotherapy of advanced soft-tissue sarcomas

The most active single agents in soft-tissue sarcomas are doxorubicin (Adriamycin) and ifosfamide, with response rates of 20-35%. Dacarbazine (DTIC) has a response rate of 16%. A randomized trial of 5 g/m2 of ifosfamide versus 1.5 g/m2 of cyclophosphamide noted a higher response rate for ifosfamide with less myelosuppression. Both randomized studies of doxorubicin with or without DTIC documented an increased response rate for the combination. In contrast, three randomized trials of doxorubicin-based regimens with and without cyclophosphamide have failed to detect an advantage for the addition of cyclophosphamide. Thus, the most active combination for soft-tissue sarcomas is doxorubicin and DTIC. The role of the addition of ifosfamide is currently under evaluation.

Inhibition of human immunodeficiency virus syncytium formation and virus replication by castanospermine

Castanospermine (1,6,7,8-tetrahydroxyoctahydroindolizine) is a plant alkaloid that modifies glycosylation by inhibiting alpha-glucosidase I. Castanospermine is shown to inhibit syncytium formation induced by the envelope glycoprotein of the human immunodeficiency virus and to inhibit viral replication. The decrease in syncytium formation in the presence of castanospermine can be attributed to inhibition of processing of the envelope precursor protein gp160, with resultant decreased cell surface expression of the mature envelope glycoprotein gp120. In addition, castanospermine may cause defects in steps involved in membrane fusion after binding of CD4 antigen. The antiviral effects of castanospermine may be due to modifications of the envelope glycoprotein that affect the ability of the virus to enter cells after attachment to the CD4 cell receptor.

Different H-2 subregions influence immunization against retrovirus and immunosuppression

Friend murine leukaemia virus complex (FV) causes an immunosuppressive retrovirus-induced disease. In certain mouse strains, FV shows striking similarities to human immunodeficiency virus (HIV) infection in man in that infected mice have severe T-cell immunosuppression but also develop virus-neutralizing antibodies incapable of eliminating infected cells. Previously we noted the influence of mouse major histocompatibility complex (H-2) genes on both FV-induced immunosuppression and on ability to protect mice against FV by immunizing with a vaccinia-Friend murine leukaemia helper virus (F-MuLV) envelope (env) recombinant virus. Here we show that different subregions of H-2 are involved in susceptibility to virus-induced immunosuppression (H-2D subregion) and protective immunization with a recombinant vaccinia virus (H-2K or I-A subregions). Thus, susceptibility to virus-induced immunosuppression does not preclude protection by vaccinia-Friend immunization. The mechanism of protection seems to involve priming of immune T cells, and not initial induction of neutralizing antibodies or cytotoxic T lymphocytes (CTL) (ref.2). Subsequent virus challenge generates a secondary response, resulting in appearance of IgG antibodies and CTL. In human HIV infection there could also be host genetic influences on elements of disease pathogenesis, such as immunosuppression, and on the success of T-cell priming by potential protective vaccines.

Sensitive reverse transcriptase assay to detect and quantitate human immunodeficiency virus

A sensitive biochemical assay of viral reverse transcriptase (RT) was developed that is useful for both the detection and quantitation of human immunodeficiency virus (HIV), the agent responsible for acquired immune deficiency syndrome in humans. This assay gave a 20- to 40-fold increase in enzyme activity over the current method used for RT detection of HIV. The test is based on a previous biochemical study showing the unusual stability of avian oncornavirus RNA-dependent DNA polymerases at 30 degrees C for at least 2 days. Our study shows that the HIV polymerase is stable at 30 to 37 degrees C for up to 3 days. By using this sensitive RT assay, as few as 250 HIV virions can be quantitated directly in tissue culture medium. This assay should prove useful in studies in which the detection of HIV or the quantitation of the number of virions is required.

Studies of human retroviruses in relation to adult T-cell leukaemia, acquired immune deficiency syndrome, and multiple sclerosis

Studies of adult T-cell leukaemia virus/human T-cell leukaemia/lymphotropic viruses (ATLV/HTLV-I) in Japan indicate that the virus is involved only with the development of ATL. By contrast, reports from the U.S.A. about HTLV have from time to time claimed that related HTLV are concerned not only with ATL of black persons, but also with a wide range of diseases, such as mycosis fungoides/Sezary's syndrome, T-cell hairy cell leukaemia, acquired immune deficiency syndrome (AIDS) and also multiple sclerosis. Using morphological, biological, serological and molecular hybridisation studies, we were able to confirm that the viruses implicated in the development of ATL and AIDS are distinct and that ATLV/HTLV-I is involved only in ATL, and HIV/LAV/HTLV-III only in AIDS. In vitro, ATLV/HTLV-I transformed and immortalised T-cells, while HIV/LAV/HTLV-III killed our T-cells. Failure to detect any serological cross-reaction indicates that all the structural proteins are different. Likewise, Southern blot studies failed to reveal any cross-hybridisation. Sixty patients with multiple sclerosis failed to reveal any association with ATLV/HTLV-I or with HIV/LAV/HTLV-III. Our conclusion is that ATLV/HTLV-I is involved only in ATL of Japanese and of some black persons of African origin, and that HIV/LAV/HTLV-III is associated only in AIDS.

Increased reactivity to HTLV-I in inflammatory nervous system diseases

The presence of IgG antibodies reacting with purified and disrupted human T-lymphotropic virus type I (HTLV-I) was examined by an indirect enzyme-linked immunosorbent assay (ELISA) in sera from 49 patients with multiple sclerosis (MS), 21 patients with aseptic meningoencephalitis (AM), 12 patients with Guillain-Barré syndrome (GB), and 30 patients with tension headache (TH). This was also assessed in the concentrated cerebrospinal fluid (CSF) of most of these patients, as well as in sera of 60 blood donors (BD). Standardized amounts of serum IgG and CSF IgG were used in ELISA. For sera, higher reactivity with HTLV-I was found in all four patient groups compared with the BD group, but no significant differences were observed among the four groups. There was higher reactivity with HTLV-I in the CSF of patients with MS, AM, and GB compared to findings in patients with TH. Ten serum (2 MS, 3 GB, 3 TH, 2 BD) and 3 CSF (1 MS, 1 GB, 1 TH) specimens considered positive by ELISA for HTLV-I were found negative on confirmatory Western blot analysis. We extended this study to analyze the in vitro production of anti-HTLV-I-IgG antibodies by the 24-hour cultivation of unstimulated lymphocytes from peripheral blood and CSF of 6 additional patients with MS directly in HTLV-I antigen-coated wells of microtiter plates. This was followed by determination of specific antibodies by ELISA in the same wells. No antibody production was measurable. Our data do not favor the hypothesis of an HTLV-I-related human retrovirus in the etiology of MS.

Pathogenicity of HIV in lymphatic organs of patients with AIDS

HIV antigens were searched for in the thymus, lymph nodes, bone marrow, and spleen of AIDS patients, by means of immunofluorescence technique. Human IgG against HIV and monoclonal antibodies against viral gag P24 protein yielded strong cytoplasmic fluorescence of cells in sections of the thymus, lymph nodes and spleen. Some cells containing HIV antigens were morphologically multinucleated giant cells. They reacted with monoclonal antibodies against helper/inducer T-cells (OKT4+), and were complexed with antibody or with complement as demonstrated by double-staining immunofluorescence technique. A large number of inflammatory cells infiltrated the thymus in areas containing cells expressing HIV antigens. These studies demonstrated an association of HIV virus with cytopathic and immunopathogenic reactions in lymphatic organs of AIDS patients, and are consistent with previous results, as well as indicative of a primary aetiologic role for the virus.

Anti-HIV seroconversion: initial appearance of antibodies to core proteins and rapid raise in antibody levels. Case report

Anti-HIV seroconversion was recorded in a patient by means of Western blot, immunofluorescence and ELISA analysis on sera taken at one to five day intervals. Seroconversion was first detected in the Western blot by antibodies to p15 and p24 and was followed by a rapid increase in levels of antibodies during the following days and weeks.

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 and Staphylococcus 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.

Fusion as a mediator of cytolysis in mixtures of uninfected CD4+ lymphocytes and cells infected by human immunodeficiency virus

We describe an unusual type of cytopathology in which uninfected CD4+ (helper/inducer) cells (cells expressing the human leukocyte antigen CD4) interact with cells persistently infected with the human immunodeficiency virus (HIV). Prior antigenic stimulation was not required, since CD4+ cells taken either from healthy persons without anti-HIV antibodies or from individuals with anti-HIV antibodies were capable of inducing cytolysis. Neither CD8+ (suppressor/cytotoxic) nor CD16+ (natural killer) cells mediated the reaction. Light microscopic and autoradiographic studies revealed that, prior to cytolysis, multinucleated giant cells were formed from fusions between HIV-infected cells and large numbers of uninfected CD4+ lymphocytes. These data may explain the paradox that exists in vivo in which a dramatic depletion of CD4+ lymphocytes occurs in the presence of a small number of HIV-infected CD4+ cells. These new insights into the pathogenesis of acquired immunodeficiency syndrome (AIDS) may lead to future therapeutic strategies.

Microbial oncogenesis

For more than a century, medical investigators have sought to incriminate microorganisms in the cause of cancer. The first scientific evidence of such a relationship came in 1911, with the first successful induction of a tumor using a cell-free extract. Since that time, considerable data have accrued linking retroviruses, herpes viruses, the hepatitis B virus, papovaviruses, and adenoviruses to various malignant neoplasms. There is also increasing evidence that certain bacteria and parasites participate as cofactors in the development of some cancers. Although proof of cause-and-effect relationships has been difficult to obtain, there can be little doubt that microorganisms occasionally play pivotal roles in the origin of some cancers. Whether attempted intervention against these cancers is best directed against the oncogenic microorganisms themselves or against other environmental cofactors is not yet clear. Nevertheless, the successful application of tumor vaccines in the prevention of Marek's disease in chickens and in modifying the outcome of oncogenic herpesvirus infections in nonhuman primates offers hope of at least limited application of microbial vaccines in the prevention of human cancer.

Genomic diversity of Zairian HIV isolates: biological characteristics and clinical manifestation of HIV infection

We describe here several African isolates of HIV, compare them to U.S.-European prototype isolates and to each other, correlate the number of isolates with serological results, and provide insights into the disease spectrum associated with HIV infection in Africa. Three of 25 healthy Zairian donors and 54 of 87 Zairian patients selected for specific pathology and hospitalized in the internal medicine department of the University Clinic of Kinshasa, Zaire, were HIV positive over a six month period in 1985 either by serum antibody (42 cases) or virus isolation (40 cases). The virus positive cases showed a decrease in number of T4 cells and interleukin-2 (IL2) production by mononuclear cells. Restriction endonuclease analysis of HIV sequences from these isolates showed that genomic diversity is also observed in the Zairian isolates but closely related viruses could also be found, similar to the spectrum of diversity among isolates obtained from the U.S. and Europe. A number of isolates (12 of 40) were obtained from serum antibody negative adults. These results are difficult to explain by viral antigenic diversity alone since hybridization with a HTLV-III-B (clone BH10) probe under stringent conditions indicated an overall high degree of relatedness. Rather, these results indicate that some African HIV infected patients fail to make detectable antibodies to HIV or the antibodies were bound in immune complexes not detectable by current techniques.

Antibodies to HTLV-1 in saliva of seropositive individuals from Japan

Secretory antibodies protect mucosal surfaces against transmission of many viruses. Human T-lymphotropic Virus, Type I (HTLV-I) is transmitted via blood products and via sexual contact across mucosal surfaces. We investigated the presence of HTLV-I-specific antibodies in whole saliva samples from 10 seronegative and 28 seropositive volunteers from a hospital in southern Japan. Antibodies directed to HTLV-I antigens were found in the salivas from 22 of 28 (79%) of the seropositive subjects. None of the seronegative individuals showed evidence of salivary antibodies. Antibodies directed to the envelope antigens of the virus were found in 21 of 22 positive saliva samples. Secretory antibodies may be important in preventing mucosal transmission.

Sensitivity and specificity of commercial ELISA kits for screening anti-LAV/HTLV III

Two panels consisting of 236 and 258 anti-LAV/HTLV III positive and 64 and 50 negative sera, respectively (determined in Western blots), were tested with 8 different, commercially available ELISA test kits for detecting LAV/HTLV III antibodies (Abbott, Dupont, Electro-Nucleonics, Litton, Organon, Pasteur, Sorin, Wellcome). Positive sera were selected for levels of antibodies ranging from average to very high, and the negative sera included both negative sera and sera with antibodies to cellular components such as HLA antigens or nuclear membranes. In examination of the 2 panels, the sensitivity of the tests ranged from 97.2 to 100%, and the specificity from 70.0 to 100%. No test was ideal.