Long-term protection of chimpanzees against high-dose HIV-1 challenge induced by immunization.

A combination AIDS vaccine approach consisting of priming with adenovirus-HIV-1MN gp160 recombinants followed by boosting with HIV-1SF2 gp120 was evaluated in chimpanzees. Long-lasting protection, requiring only three immunizations, was achieved against a low-dose challenge with the SF2 strain of HIV-1 and a subsequent high-dose SF2 challenge administered 1 year later without an intervening boost. Notably, neutralizing antibody responses against both clinical and laboratory isolates developed in three chimpanzees and persisted until the time of high-dose challenge. The possibility that cytotoxic T-lymphocytes contribute to low-dose protection of a chimpanzee lacking neutralizing antibodies is suggested. Our results validate the live vector priming/subunit booster approach and should stimulate interest in assessing this combination vaccine approach in humans.

Detection of the human T cell lymphoma virus p19 in cells of some patients with cutaneous T cell lymphoma and leukemia using a monoclonal antibody.

A monoclonal antibody specific for the internal p19 protein of a type-C retrovirus (HTLV) isolated from human neoplastic T cells has been developed. Its specificity has been shown by radioimmune precipitation and by affinity chromatography of iodinated HTLV proteins. By indirect immune fluorescence this antibody recognizes only HTLV-producing cells. Examination of cells from patients with cutaneous T cell lymphomas and leukemias and with other types of lymphomas and leukemias indicated that HTLV p19 expression is rare. The monoclonal antibody will be useful in determining the natural reservoir of HTLV, possibly in a subset of mature T cell neoplasias.

Monoclonal antibody against human T cell leukemia virus p19 defines a human thymic epithelial antigen acquired during ontogeny.

Using monoclonal antibody 12/1-2 against a 19,000-dalton human T cell leukemia virus (HTLV) protein (anti-p19), previously demonstrated to be reactive with HTLV-infected human cells, but not in numerous other uninfected cells, we found a reactive antigen to be expressed on the neuroendocrine component of human thymic epithelial cells but not on any other normal epithelial or neuroendocrine human tissues. Moreover, this reactive antigen is acquired on neuroendocrine thymic epithelium during thymic ontogeny--first appearing on fetal thymic epithelial cells between 8 and 15 wk gestation. While only a portion of thymic epithelial cells in the subcapsular cortical region of 15- and 24-wk fetal thymuses contained anti-p19+ epithelial cells, the entire subcapsular cortical region of newborn thymus epithelium was anti-p19+. By age 3 yr, normal subjects' entire subcapsular cortical and medullary thymic epithelium was anti-p19+. Using antibody against HTLV core protein, p24, and c-DNA probes for HTLV DNA, neither HTLV-specific p24 protein nor proviral DNA could be demonstrated in anti-p19+ thymic epithelial tissue. However, thymic epithelial extracts, disrupted HTLV extracts, as well as purified HTLV p19 antigen all inhibited the binding of anti-p19 antibody to thymic epithelium. Thus, anti-p19 may recognize a determinant on an HTLV-encoded 19,000-dalton structural protein that is shared by human thymic epithelium. Alternatively, anti-p19 defines a host encoded protein that is selectively expressed by normal thymic epithelium, and is induced to be expressed in HTLV-infected malignant T cells.

Natural antibodies to the human T cell lymphoma virus in patients with cutaneous T cell lymphomas.

Sera from patients with cutaneous T cell lymphoma and leukemia were screened for the presence of natural antibody to the human T cell lymphoma (leukemia) virus, HTLVCR, using a solid-phase radioimmunoassay. Sera from two patients, including patient CR, from whose cultured T lymphoblastic cell line (HUT102), the retrovirus HTLVCR was isolated, reacted specifically with proteins of HTLVCR. Serum from patient CR also reacted specifically with proteins of HTLVMB, an independent but highly related retroviral isolate from a patient with Sezary T cell leukemia. The specificity for HTLVCR proteins was demonstrated by solid-phase immunocompetition assays and competition radioimmunoprecipitation assays. Analysis of radioimmunoprecipitates indicated that the natural antibodies were directed against HTLVCR core proteins with molecular weights of 24,000 and 19,000 (p24 and p19). Whereas the serum reactivities for HTLVCR proteins were shown to be highly specific, additional reactivities seen against proteins of animal retroviruses including GaLV, SSV, FeLV, and BaEV were clearly shown not to be viral specific but rather were due to reactivity with cellular antigens contaminating the viral preparations or with related antigens present in fetal calf serum. These results demonstrating natural antibodies to HTLVCR provide the first evidence for a specific antibody response to a retrovirus in humans.

Evidence for human T cell lymphoma-leukemia virus infection of family members of human T cell lymphoma-leukemia virus positive T cell leukemia-lymphoma patients.

Sera of family members of patients from the United States, the Caribbean, and Japan, with human T cell lymphoma-leukemia virus (HTLV) associated T cell malignancies, possess HTLV-specific antibodies directed against internal structural components of HTLV, p24 and p19. The prevalence of antibodies to HTLV is greater in family members than in random healthy donors, which supports the infectious nature of HTLV and its association with particular aggressive T cell malignancies. Expression of HTLV p24 and p19 has also been observed in cultured T cells of some healthy relatives, and intact virus particles have been released from cells of one possibly pre-leukemic family member.

Natural antibodies to human retrovirus HTLV in a cluster of Japanese patients with adult T cell leukemia.

Human T cell lymphoma leukemia virus (HTLV) is a human retrovirus (RNA tumor virus) that was originally isolated from a few patients with leukemias or lymphomas involving mature T lymphocytes. Here we report that the serum of Japanese patients with adult T cell leukemia, but not the serum of tested normal donors, contains high titers of antibodies to HTLV. These observations, together with data from Japan showing that adult T cell leukemia is endemic in southwest Japan, suggest that HTLV is involved in a subtype of human T cell malignancy, including Japanese adult T cell leukemia.

A new subtype of human T-cell leukemia virus (HTLV-II) associated with a T-cell variant of hairy cell leukemia.

Human T-cell leukemia virus (HTLV) is a human type-C RNA tumor virus (retrovirus) previously identified in and isolated from several patients with T-cell leukemias or lymphomas. The known virus isolates from the United States and Japan are closely related and are found in adults with an acute malignancy of mature T cells. A related retrovirus has been found in a patient (Mo) with a somewhat different disease (a T-cell variant of relatively benign hairy cell leukemia). Serum from Mo contains antibodies to the major internal core protein (p24) of HTLV. A T-cell line established from the spleen of Mo expresses HTLV antigens. However, HTLV from Mo is significantly different from all previous HTLV isolates in immunological cross-reactivity tests of p24. The usual prototype HTLV isolate is represented as HTLV-I, and the HTLV from Mo is represented as HTLV-II. Individual members of each subgroup may then be identified by subscript initials of the patient [for example, HTLV-I(CR), HTLV-I(MB), and HTLV-II(Mo)].

Isolation of human T-cell leukemia virus in acquired immune deficiency syndrome (AIDS).

Several isolates of a human type-C retrovirus belonging to one group, known as human T-cell leukemia virus (HTLV), have previously been obtained from patients with adult T-cell leukemia or lymphoma. The T-cell tropism of HTLV and its prevalence in the Caribbean basin prompted a search for it in patients with the epidemic T-cell immune deficiency disorder known as AIDS. Peripheral blood lymphocytes from one patient in the United States and two in France were cultured with T-cell growth factor (TCGF) an shown to express HTLV antigens. Virus from the U.S. patient was isolated and characterized and shown to be related to HTLV subgroup I. The virus was also transmitted into normal human T cells from umbilical cord blood of a newborn. Whether or not HTLV-I or other retroviruses of this family with T-cell tropism cause AIDS, it is possible that patients from whom the virus can be isolated can also transmit it to others. If the target cell of AIDS is the mature T cell as suspected, the methods used in these studies may prove useful for the long-term growth of these cells and for the identification of antigens specific for the etiological agent of AIDS.

HTLV-III/LAV-neutralizing antibodies to an E. coli-produced fragment of the virus envelope.

Immunization with either an Escherichia coli recombinant segment of the human T-cell lymphotropic virus (HTLV-III/LAV) envelope protein (gp 120) or with deglycosylated gp 120 envelope protein produced antibodies that neutralize HTLV-III/LAV infection in vitro. Virus neutralization titers of these antisera were equivalent to those obtained with purified native gp120 as immunogen. This localizes at least one class of neutralizing epitopes to the carboxyl-terminal half of the molecule. In addition, native gp120 prevented HTLV-III/LAV--mediated cell fusion, whereas the recombinant gp120 fragment did not. This shows that although glycosylation is not required for induction of neutralizing antibodies, it may be important for interaction with CD4, the virus receptor. A segment of the HTLV-III/LAV envelope produced in E. coli may be an important ingredient of a vaccine for acquired immune deficiency syndrome.

Antigenicity of human T-cell leukemia virus-associated gp52: greater response in leukemia patients compared to healthy donors exposed to the virus.

Monoclonal antibody HT462 recognizes a human T-cell leukemia virus type I (HTLV-I)-associated Mr 52,000 glycoprotein (HA-gp52), which is found on the surface of HTLV-infected cells. Whether HA-gp52 is encoded by the virus or by the infected cells has not yet been established. Using monoclonal HT462 in a competitive binding assay, natural human antibodies specific for HA-gp52 were detected in 97% of the patients from the United States, the Caribbean, and Japan with adult T-cell leukemia but not in healthy donors not exposed to HTLV-I. In contrast, antibodies to HA-gp52 occur in healthy virus-exposed donors, but at a lower prevalence than that observed in patients. Among Japanese from HTLV-I-endemic areas and exposed to the virus as indicated by the presence of antibodies to disrupted HTLV-I, 93% of adult T-cell leukemia patients were also seropositive for HA-gp52 compared to only 16% of healthy individuals. Differing sensitivities in the methods of assaying antibodies to HTLV and HA-gp52 were not responsible for these observations as shown by the lack of correlation of HTLV-I antibody titer with the presence of antibody to HA-gp52. Among adult T-cell leukemia patients, antibody titers to HTLV-I and HA-gp52 also varied independently. These results indicate that HA-gp52 in humans is antigenic and correlated with disease. Detection of antibody to this protein in asymptomatic individuals may be indicative of a predisease condition.

Human T-cell leukemia-lymphoma virus type 1 and adult T-cell leukemia-lymphoma in Okinawa.

A serological survey for the presence of antibodies against the human T-cell leukemia virus, type 1 (HTLV-1) in patients seen at the Chubu Hospital in Okinawa was undertaken. All patients with the clinicopathological diagnosis of adult T-cell leukemia-lymphoma were positive. These cases had the characteristic features of adult T-cell leukemia-lymphoma: diffuse histology, often mixed cell or pleomorphic, and a high frequency of hypercalcemia, leukemic phase, diffuse visceral involvement, and opportunistic infections. The median survival of these patients was short, being only 18 weeks. Of the other patients with cancers screened, two of five other non-Hodgkin's lymphoma patients were positive and three of eight patients with other hematological cancers were positive. In addition, three of the four immediate family members of one adult T-cell leukemia-lymphoma case had antibodies. Of the other persons (both in- and outpatients) without hematological cancers, those under the age of 50 had a much lower antibody prevalence (4%) than those over 50 (30%). There was no significant difference in antibody prevalence between the two sexes in either the younger or older age group. These findings further document that Okinawa is an endemic area for HTLV-1. None of the 157 individuals screened for antibodies to HTLV-3 were positive, consistent with the fact that no cases of the acquired immune deficiency syndrome have been reported from Okinawa.

Detection of antibodies to HTLV-I and -III in sera from Japanese hemophiliacs.

Sera from 50 Japanese hemophiliacs were screened for antibodies to human T-lymphotropic retrovirus types I and III (HTLV-I and -III). As a whole, antibody to HTLV-I, antibody to HTLV-III, and antibodies to HTLV-I and -III were detected in sera from 2, 17, and 6 hemophiliacs, respectively. Among them, two hemophiliacs developed acquired immunodeficiency syndrome who were positive for both antibodies to HTLV-I and -III in sera. All of the others were asymptomatic. Most of the blood products transfused into these hemophiliacs were imported from abroad, whence the source of HTLV-III infection presumably originated. However, since quite a high percentage of these antibody-positive hemophiliacs was positive for antibody to HTLV-I, even though they are native residents in HTLV-I nonendemic areas of Japan, some special factors may have participated in HTLV-I infection. These special factors should be investigated in the future.

Comparative seroepidemiology of HTLV-I and HTLV-III in the French West Indies and some African countries.

The prevalence of antibodies detected by ELISA against human T-lymphotropic viruses, type I (HTLV-I) and type III (HTLV-III-LAV), is described in a comparative serosurvey in the French West Indies and African countries. The data confirm that the Caribbean basin is endemic for HTLV-I. In this region, HTLV-I antibody prevalence varied from 3.4% to 5.2% among blood donors and increased with age to reach a value of 33% among elderly people from the Dominica Island. In French Guyana, a South American country bordering the Caribbean sea, differences in antibody distribution across three ethnic groups (black Bonis, Indian Wayanas, and Hmongs from Asia) provide clues for investigation of the mode of HTLV-I transmission. Africa appears to be an endemic continent for HTLV-I and HTLV-III. For both viruses, the antibody prevalence exhibited an increasing gradient from northern to equatorial through Sudanic areas. These preliminary data by showing that Africa represents an endemic reservoir of HTLVs and, possibly, of other human retroviruses should stimulate further investigations on the natural history and the geographical origin of these viruses.

Association of the human type C retrovirus with a subset of adult T-cell cancers.

To determine whether the human T-cell lymphoma-leukemia virus (HTLV) is associated with particular cancers, patient sera were surveyed for HTLV-specific antibodies. An association was seen with aggressive cancers of mature T-cells, specifically Japanese adult T-cell leukemia (ATL) and T-cell lymphosarcoma cell leukemia (TLCL), a similar cancer of Caribbean blacks. Ninety to 100% of these patients possessed HTLV-specific antibody. Forty-seven and 20% of relatives of ATL and TLCL patients, respectively, and 12 and 4% of healthy donors from ATL and TLCL endemic areas were also antibody positive. Visceral organ involvement, hypercalcemia, and skin manifestation, features of ATL and TLCL, were often seen in other antibody-positive patients. Childhood cancers, most cutaneous T-cell and all non-T-cell leukemias and lymphomas, myeloid leukemias, Hodgkin's disease, and solid tumors were not associated with HTLV. Healthy United States donors and European patients with non-malignant diseases were antibody negative. HTLV is thus associated with a subtype of adult T-cell leukemia-lymphoma, clustered in viral endemic areas, with apparent racial and geographic predilection.

Cross-protection in NYVAC-HIV-1-immunized/HIV-2-challenged but not in NYVAC-HIV-2-immunized/SHIV-challenged rhesus macaques.

OBJECTIVES: Immunization with attenuated poxvirus-HIV-1 recombinants followed by protein boosting had protected four of eight rhesus macaques from HIV-2SBL6669 challenge. The present study was designed to confirm this result and to conduct the reciprocal cross-protection experiment. METHODS: Twenty-four macaques were primed with NYVAC (a genetically attenuated Copenhagen vaccinia strain) recombinants with HIV-1 and HIV-2 env and gag-pol or NYVAC vector alone and boosted with homologous, oligomeric gp160 proteins or adjuvant only. Binding and neutralizing antibodies, cytotoxic T-lymphocytes (CTL) and CD8 T cell antiviral activity (CD8AA) were evaluated. One half of each immunization and control group were intravenously challenged with SHIV(HXB2) the other half was challenged with HIV-2SBL6669,. Protective outcome was assessed by monitoring virus isolation, proviral DNA and plasma viral RNA. RESULTS: Both immunization groups developed homologous binding antibodies; however, homologous neutralizing antibodies were only observed in NYVAC-HIV-2-immunized macaques. While no cross-reactive neutralizing antibodies were detected, both immunization groups displayed cross-reactive CTL. Significant CD8AA was observed for only one NYVAC-HIV-2-immunized macaque. Virological assessments verified that both NYVAC-HIV-1 and NYVAC-HIV-2 immunization significantly reduced viral burdens and partially protected against HIV-2 challenge, although cross-protection was not at the level that had been previously reported. Humoral antibody and/or CTL and CD8AA were associated with protection against homologous HIV-2 challenge, while cellular immune responses seemed more important for cross-protection. No significant protection was observed in the SHIV-challenged macaques, although NYVAC-HIV-1 immunization resulted in significantly lower viral burdens compared with controls. CONCLUSIONS: Further delineation of cross-reactive mechanisms may aid in the development of a broadly protective vaccine.

Type- and group-specific continuous antigenic determinants of HTLV. Use of synthetic peptides for serotyping of HTLV-I and -II infection.

The human T lymphotropic viruses (HTLV-I and -II) are relatively common in subpopulations of certain countries, notably intravenous drug abusers in North America. Infections with these malignancy-associated human retroviruses are hard to discriminate with currently available commercial serological tests. We studied the distribution of antigenicity and the degree of cross-reactivity of epitopes in gag and env of the two viruses. Sequences in the carboxyl terminus of the matrix protein (MA) and the middle of the outer glycoprotein (SU) reacted in a type-specific fashion, while sequences from the capsid protein (CA), the carboxyl terminus of SU, and conserved portions of the transmembrane protein (TM) mainly reacted in a group-specific fashion, correlating with the degree of sequence dissimilarity between the two viruses. The serological discrimination obtained with the peptides was evaluated in a panel of 25 sera where infection with HTLV-I or -II had been typed by competition in a p24 enzyme-linked immunosorbent assay (ELISA) or by the polymerase chain reaction (PCR). After processing peptide results in a computer program, a typing result concordant with earlier results was obtained in 21 of 25 sera. Of the remaining five sera, four were labeled "too weak for typing" and one "HTLV of uncertain type" by the program. They did not react sufficiently strongly or clearly with the peptides to allow classification. A combination of synthetic peptides may become useful for serotyping HTLV infection and become an alternative to Western blots for confirmation of HTLV positivity.

Human T-cell lymphotropic virus I and adult T-cell leukemia: report of a cluster in North Carolina.

PURPOSE: Human adult T-cell leukemia-lymphoma is a malignant, proliferative disease of CD4+ lymphocytes associated with infection with human T-cell lymphotropic virus type I (HTLV-I). Following the presentation of a patient who was infected with the virus, we undertook a study of his family members and sexual contacts to see if a cluster of infected persons could be identified. CASE REPORT: A black heterosexual North Carolina native with a history of drug abuse presented with jaundice, and pancytopenia subsequently developed. He then became hypercalcemic and leukemic, with high numbers of circulating, morphologically abnormal CD4+ lymphocytes. RESULTS: As determined by radioimmunoassay and immunoblot analyses, the serum of the index case contained antibodies against core proteins (p19 and p24) of HTLV-I. When cultured in vitro with interleukin-2, the lymphocytes expressed HTLV-I specific core proteins. The virus recovered from these T cells was transmitted to cord blood T cells, which became immortalized for continuous growth in vitro, expressed HTLV-I p19 protein, and displayed characteristic C-type particles by electron microscopy. Studies of family members and sexual contacts, all of whom were black, heterosexual central North Carolina natives, revealed five of 28 whose serum had anti-HTLV-I antibodies as determined by radioimmunoassay and immunoblot. Neither the patient nor the seropositive family/contacts had antibodies against human immunodeficiency virus proteins. Four of the six people with HTLV-I infection had no history of intravenous drug abuse. Three of the five seropositive family/contacts had circulating, morphologically abnormal lymphocytes suggestive of "preleukemic" or "smoldering" human adult T-cell leukemia-lymphoma.

The pathologic spectrum of adult T-cell leukemia/lymphoma in the United States. Human T-cell leukemia/lymphoma virus-associated lymphoid malignancies.

The human T-cell leukemia/lymphoma virus (HTLV) is a novel Type-C retrovirus isolated from patients with post-thymic T-cell malignancies. Thirteen patients diagnosed in the United States were identified as having antibodies to HTLV and a typical clinicopathologic syndrome characteristic of adult T-cell leukemia/lymphoma as described in Japan. The most characteristic diagnostic feature in our series was the presence of highly pleomorphic and lobated lymphoid cells in the peripheral blood. Also notable was acid phosphatase activity which was partially tartrate-resistant in the neoplastic cells. The pathologic spectrum of the associated lymphomas was broad and encompassed several diffuse histologic subtypes in the Rappaport classification, the working formulation, and the classification of the Japanese lymphoma study group. However, differences in survival could not be correlated with differences in histologic subtype. All patients presented with Ann Arbor Stage IV lymphoma. Other common clinical features were generalized lymphadenopathy, hepatosplenomegaly, skin and peripheral blood involvement, hypercalcemia, and lytic bone lesions. The clinical course was aggressive with a median survival of 9 months. In two-third of patients with cutaneous involvement, epidermal infiltration resembling Pautrier microabscesses was observed. However, most cases can be readily distinguished from mycosis fungoides/Sézary syndrome on clinical and epidemiologic grounds. The presence of HTLV-antibodies in patients with lymphoid malignancies appears to define a distinct clinicopathologic syndrome which tends to occur in geographic clusters. Adult T-cell leukemia/lymphoma is favored as the diagnostic term for this clinicopathologic entity.

Neurologic manifestations of human immunodeficiency virus infection in children.

This report describes the neurologic manifestations of 36 children with human immunodeficiency virus (HIV) infection. In this cohort, in 16 of 21 children with acquired immunodeficiency syndrome (AIDS), three of 12 children with AIDS-related complex, and one of three asymptomatic seropositive children, a progressive encephalopathy developed. Neurologic signs were often detected early but tended to worsen coincident with progression of the immunodeficiency. The presence of progressive encephalopathy correlated with the absence of serum neutralizing antibodies to HIV and with a poor, usually fatal, outcome. The incubation period from initial HIV infection in the perinatal period to the onset of progressive encephalopathy varied from 2 months to 5 years. Intrablood-brain barrier synthesis of HIV-specific antibodies was demonstrated in eight of 14 children with AIDS and AIDS-related complex, indicating active brain infection with HIV. In three cases this was unassociated with progressive neurologic signs. Unique neuropathologic findings in children who died with HIV infection further suggest that the progressive encephalopathy is the result of primary and persistent infection of the brain with this retrovirus. These findings broaden the spectrum of HIV infection in children and have important implications for the development of antiviral therapy.