Human T-cell Leukemia-lymphoma Virus Research Articles

Functional properties of antigen-specific T cells infected by human T-cell leukemia-lymphoma virus (HTLV-I).

Tetanus-toxoid specific helper-inducer T-cell clones, which had been infected and transformed by human T-cell leukemia-lymphoma virus (HTLV-I), were obtained from an antigen-specific human T cell line by using a limiting dilution technique in the presence of the virus. These HTLV-I-infected T-cell clones proliferated specifically in response to soluble tetanus toxoid but, unlike normal T cells, they could do so in the absence of accessory cells. The HTLV-I-infected T-cell clones did not present the antigen to autologous antigen-specific T cells that were not infected with HTLV-I. The capacity of helper-inducer T cells to retain antigen-specific reactivity after infection by HTLV-I, while losing the normal T-cell requirement for accessory cells, has clinical and theoretical implications.

Human T-cell leukemia virus (HTLV-I) antibodies in Africa.

Antibodies specific for human T-cell leukemia-lymphoma virus type I (HTLV-I) were demonstrated in serum samples from various groups of people in South Africa, Uganda, Ghana, Nigeria, Tunisia, and Egypt. The samples had been collected for other purposes and were presumably selected without bias toward clinical conditions associated with HTLV infections. Regional differences in antibody positivity were observed, indicating widely distributed loci of occurrence of HTLV on the African continent in people of both black and white ancestry. Two patients with high titers of antibody to HTLV-I had some signs of adult T-cell leukemia-lymphoma. In several groups a high frequency of false positive serum reactions was indicated when specific confirmation steps were included in the assay. Further characterization of these sera revealed highly elevated immunoglobulin levels, possibly due to polyclonal activation of immunoglobulin synthesis in these subjects. The possibility that related cross-reactive human retroviruses coexist in the same groups was not eliminated.

Effect of tumor promoters on human T cell leukemia/lymphoma virus (HTLV)-structural protein induction in adult T-cell leukemia cells

We assayed the capacity of tumor promoters to induce human T-cell leukemia/lymphoma virus (HTLV) structural proteins p19 and p24 from the HTLV genome-carrying adult T-cell leukemia (ATL) cell lines, MT-1 and KH-2 lo, and fresh ATL cells. Among the tested substances, 12- O-tetradecanoyl phorbol-13-acetate (TPA), 12-hexadecanoyl-phorbol-13-acetate (HPA) and teleocidin induced HTLV structural protein p19 and p24. This suggests that certain environmental substances, especially those known to be tumor promoters, may activate the HTLV-gene in ATL cells.

Establishment of T and B cell lines from patients with mycosis fungoides.

Eighteen patients with mycosis fungoides were studied in order to establish cell lines that might be associated with the human T cell leukaemia-lymphoma virus (HTLV). Three T cell lines were established, two from affected skin and one from a lymph node showing dermatopathic lymphadenopathy. The T cells expressed OKT3 and OKT4 antigens. They temporarily expressed an HTLV p19-like antigen in up to 5% of the cells during culture. None of our patients had lymphocytosis or abnormal lymphocytes, except one patient with Sézary's syndrome. We could not establish T cell lines from peripheral blood, but five B lymphoblastoid cell lines were obtained, all positive for the Epstein-Barr virus nuclear antigen. Our finding that T cell lines can be established from skin biopsies and lymph nodes of patients with mycosis fungoides, but not from the blood, supports the concept of a malignant T lymphocyte primarily localized in the skin. The temporary expression of HTLV p19 antigen may indicate the presence of retrovirus, but further studies are needed.

Cell surface phenotypes and expression of viral antigens of various human cell lines carrying human T-cell leukemia virus.

Human T-cell leukemia/lymphoma virus (HTLV)-carrying cells from various origins were characterized by cell surface markers and expression of HTLV antigens. Eight cell lines named TCL were obtained by transformation of peripheral blood leukocytes (PBL) of healthy donors or HTLV carriers in cocultures with HTLV-producer MT-2 cells. Nine cell lines named ILT were interleukin 2 (IL2)-dependent cell lines cloned from PBL of ATL patients and healthy HTLV-carriers. Tc-Kan9 cell line was also an IL2-dependent cell line clonally established from PBL culture stimulated with autologous TCL cells. Five cell lines named TL were established in vitro directly from PBL of an adult T-cell leukemia (ATL) patient and from ILT cells of an ATL patient and three HTLV-carriers, respectively, to grow autonomously without IL2. All the TCLs, ILTs, TLs and Tc-Kan9 possessed Leu-I antigen, a pan-T-cell marker. Leu3a antigen, a helper/inducer T-cell marker, was expressed on five of eight TCLs and all of the ILTs and TLs. Leu-2a, a cytotoxic/suppressor T-cell marker, was detected only on Tc-Kan9 but not others. Fresh ATL leukemic cells of patients had a helper/inducer T-cell marker. Ia, OKT9 and Tac antigens, markers for activated and differentiated T cells, were strongly expressed on all of the cell lines tested and fresh ATL leukemic cells were weakly positive for these antigens. Expression of HTLV antigens detected by mouse monoclonal antibodies and an ATL-patient serum varied among these cell lines. One TL, two ILTs and most of the fresh ATL leukemic cells did not express HTLV antigens on the cell surface. The other cell lines were all positive for the surface viral antigens. However, molecular species of antigens defined by radioimmunoprecipitation with an ATL-patient serum were not always identical among the cell lines. Molecular weights of polypeptides detectable in most of the cell lines were 62K, 46K, 40K, 24K, 21K and 19K which could never be detected in several control T-cell lines. 68K and 28K polypeptides were frequently detected in MT-2 and TGLs. GIN14, a mouse monoclonal antibody against HTLV core protein (p19) detected not only p19 in various cell lines but also p28, p29, p31 or p40 in certain cell lines tested. B-cell lines named LCL were established and cloned from PBL of two HTLV-carriers by EB-virus-induced transformation and they also expressed HTLV antigens, Ia, OKT9 and Tac antigens.(ABSTRACT TRUNCATED AT 400 WORDS)

Isolation of HTLV-transformed B-lymphocyte clone from a patient with HTLV-associated adult T-cell leukaemia.

The human T-cell leukaemia/lymphoma virus (HTLV) is an exogenous retrovirus which has been associated with adult T-cell leukaemia/lymphoma (ATL). This malignancy of T lymphocytes is endemic to southern Japan, the West Indies, and to a lesser extent, the Middle East, Central Africa and the southeastern United States. ATL cells from patients of diverse geographical origins have been found to be infected with HTLV-1 (ref.6). HTLV is normally tropic for mature T lymphocytes, especially those expressing the helper-inducer surface antigen phenotype (OKT4 or Leu-3-positive), and the neoplastic T cells infected with HTLV generally express receptors for T-cell growth factor (detected by reactivity with anti-Tac antibody). However, we report here the isolation of a HTLV-infected B-lymphocyte clone from the peripheral blood of a patient with ATL. This clone is cytogenetically normal and is not infected with Epstein-Barr virus (EBV). Co-culture of cells from this clone with cord blood lymphocytes resulted in transmission of HTLV and the immortalization of either T or B lymphocytes. These results suggest that HTLV may be associated with a broader range of host cells than previously recognized.

Antigens on HTLV-infected cells recognized by leukemia and AIDS sera are related to HTLV viral glycoprotein.

Cross-reactive antigens of molecular size of 61,000 to 68,000 daltons are found on the surface of human cells infected by human T-cell leukemia-lymphoma virus (HTLV). They are recognized by antibodies from patients with adult T-cell leukemias and lymphomas, from healthy carriers of HTLV, and from patients with the acquired immunodeficiency syndrome (AIDS). The latter finding has been one of the major reasons for suggesting an association of HTLV with AIDS. However, whether these antigens are of cellular or viral origin has not been clear. These antigens have now been shown to be associated with the presence of viral proteins in the cells, and a cross-reactive glycoprotein of molecular size of 46,000 daltons has been found to be a consistent structural part of viruses purified from several HTLV-producer cell lines. The findings thus suggest a viral (HTLV) origin of these antigens.

Methylation of human T-cell leukemia virus proviral DNA and viral RNA expression in short- and long-term cultures of infected cells

Leukemic peripheral blood lymphocytes from individuals infected with the human T-cell leukemia/lymphoma virus (HTLV) were found to express little or no viral RNA before being put into tissue culture. Within 24–48 hr, viral RNA expression increased at least four- to eightfold. Established HTLV-infected cell lines constitutively express viral RNA. Southern blots of DNA from HTLV-infected cells digested with the methylation-sensitive restriction enzyme HpaII showed that the proviral DNA was methylated in all of the uncultured peripheral blood cells tested. In contrast, no proviral methylation was detected in any of the cell lines examined, suggesting a functional correlation between methylation and viral RNA expression. However, DNA from HTLV-infected lymphocytes cultured for 48 hr (by which time increases in viral RNA expression are evident) did not differ detectably with respect to proviral DNA methylation from uncultured cells, suggesting that the increase in viral RNA expression after short-term culture is mediated by mechanisms independent of changes in DNA methylation.

Classification of patients with T-cell chronic lymphocytic leukemia and expansions of granular lymphocytes: Heterogeneity of Italian cases by a multiparameter analysis

The peripheral blood mononuclear cells (PBMC) from 750 Italian patients with chronic lymphocytic leukemia (CLL) were evaluated in order to detect cases with T-cell expansions. The PBMC of 18 patients (2.4%) were found to be capable of rosetting with sheep red blood cells. Further characterization of these cells with a panel of monoclonal antibodies and other immunological and cytochemical tests led us to tentatively subdivide these 18 patients into three groups. The first one included 6 patients whose cells expressed a T-helper phenotype: they exhibited frequent skin involvement and an aggressive clinical course, and some of the patients in this group demonstrated chromosome abnormalities. On the other hand, group 2 (10 cases with expansions of granular lymphocytes and/or T suppressor-bearing phenotype cells) usually presented with a mild clinical course. These cases did not generally require therapy and a diagnosis of leukemia could not be unequivocally confirmed. Cells from the two remaining patients displayed both B-cell markers and E-rosetting ability, thus belonging to the rare group of false T-cell CLL. In fact, the clinical course and management of the latter cases were similar to those of classical B-CLL disease. In the first and second groups, mechanisms reported to be involved in mature T-cell proliferations (response to interleukin-2, production of interleukin-2 or interferon) were investigated, but the cells under study displayed neither growth ability nor lymphokine production in the above assays. In addition, these cells were negative with the anti-Tac monoclonal antibody that appears to recognize the receptor for interleukin-2. More importantly, none of these patients had serum antibodies to the recently described human T-cell leukemia/lymphoma virus (HTLV), possibly responsible for Japanese and West Indian adult T-cell leukemia (ATL) and for sporadic cases of ATL observed in other countries. Taken together, our results outline some differences between European and ATL patients. Furthermore, the data presented point out the heterogeneity of the disease and emphasize that an immunological classification and, in particular, the detection of a helper phenotype have relevant prognostic and therapeutical importance.

DNA methylation and expression of HLA-DR alpha.

B-cell lines established from two individuals with T-cell acute lymphocytic leukemia (T-ALL) express HLA-DR antigens, whereas the isogenic T-cells do not. The lack of expression correlates with a lack of detectable HLA-DR mRNA. All of the DR alpha DNA sequences detected by a cloned DR alpha cDNA probe are contained in a BglII fragment which varies slightly in size (4.0 to 4.8 kilobases) from one individual to another. In DNA from the T-cells not expressing DR alpha mRNA, all of the potential HpaII sites within the BglII fragment appeared to be methylated. In contrast, at least some of these sites were not methylated in DNA from the B-cells expressing high levels of DR alpha mRNA. Treatment of these T-cells with 5-azacytidine resulted in the induction of DR surface antigen expression, the appearance of DR alpha mRNA, and the partial demethylation of the DR alpha DNA sequences. T-cell lines established from human T-cell leukemia-lymphoma virus associated T-cell neoplasias, in contrast to the T-cell acute lymphocytic leukemia cell lines, expressed both DR antigens and DR alpha mRNA; the HpaII sites within the BglII fragment of DR alpha DNA of these human T-cell leukemia-lymphoma virus-positive T-cell lines were in all cases at least partially unmethylated. Uncultured peripheral blood T-cells from human T-cell leukemia-lymphoma virus-infected individuals expressed DR antigens at a low level, and the DR alpha locus was partially unmethylated. After 48 h in culture, DR antigen expression was substantially increased, but no significant changes were observed in methylation of the DR alpha locus or in the amount of DR mRNA which was present. This suggests that expression of DR antigens also can be modulated post-transcriptionally.

DNA methylation and expression of HLA-DR alpha.

B-cell lines established from two individuals with T-cell acute lymphocytic leukemia (T-ALL) express HLA-DR antigens, whereas the isogenic T-cells do not. The lack of expression correlates with a lack of detectable HLA-DR mRNA. All of the DR alpha DNA sequences detected by a cloned DR alpha cDNA probe are contained in a BglII fragment which varies slightly in size (4.0 to 4.8 kilobases) from one individual to another. In DNA from the T-cells not expressing DR alpha mRNA, all of the potential HpaII sites within the BglII fragment appeared to be methylated. In contrast, at least some of these sites were not methylated in DNA from the B-cells expressing high levels of DR alpha mRNA. Treatment of these T-cells with 5-azacytidine resulted in the induction of DR surface antigen expression, the appearance of DR alpha mRNA, and the partial demethylation of the DR alpha DNA sequences. T-cell lines established from human T-cell leukemia-lymphoma virus associated T-cell neoplasias, in contrast to the T-cell acute lymphocytic leukemia cell lines, expressed both DR antigens and DR alpha mRNA; the HpaII sites within the BglII fragment of DR alpha DNA of these human T-cell leukemia-lymphoma virus-positive T-cell lines were in all cases at least partially unmethylated. Uncultured peripheral blood T-cells from human T-cell leukemia-lymphoma virus-infected individuals expressed DR antigens at a low level, and the DR alpha locus was partially unmethylated. After 48 h in culture, DR antigen expression was substantially increased, but no significant changes were observed in methylation of the DR alpha locus or in the amount of DR mRNA which was present. This suggests that expression of DR antigens also can be modulated post-transcriptionally.

Monoclonal antibodies against human T cell leukemia-lymphoma virus (HTLV) p24 internal core protein. Use as diagnostic probes and cellular localization of HTLV.

Four monoclonal antibodies, human T cell leukemia-lymphoma virus (HTLV) 6, 7, 8, and 9, which react with the 24,000 dalton internal core protein of HTLVI, have been developed. These monoclonal antibodies reacted with only HTLV-infected cells and not with a broad spectrum of normal, neoplastic, mitogen-stimulated, or virus-infected cells and tissues. HTLV 6, 7, 8, and 9 identified at least two different antigenic determinants on HTLV p24 that were also recognized by antibodies present in HTLV+ patient sera. Monoclonal antibodies HTLV 6, 7, 8, and 9 reacted in indirect immunofluorescence assays with HTLV p24 localized at the cell surface of 5-d cultures of HTLV-infected T cells and, as well, reacted with T cells infected with HTLVII, a new type of HTLV isolated from a patient (MO) with a T cell variant of hairy cell leukemia. Thus, HTLV 6, 7, 8, and 9 should prove to be useful diagnostic reagents in the identification of HTLV- and HTLVII-infected T cells.

IMMUNOLOGICAL STUDIES AND HTLV ANTIBODY STATUS OF MOTHERS OF INFANTS WITH AIDS

Thirteen infants with acquired immune deficiency syndrome (AIDS) with opportunistic infection and/or Kaposi's sarcoma have been identified in South Florida. The mothers of eight of these infants have been evaluated with regard to their immune status and the presence of antibody to the human T cell leukemia/lymphoma virus (HTLV). Five of the mothers are recent refugees from Haiti. Two have a history of intravenous drug abuse. Their ages range between 19 and 33 years. Two of the mothers have AIDS and one mother has an AIDS-like illness. The remainder of the mothers are healthy. Immunological studies in the mothers were compared to values obtained in healthy American Black and Haitian women. The mothers showed a higher IgG level (mean value - 2919mg%) as compared to controls. The percentage of T lymphocytes and T-helper cells were decreased in mothers as compared to controls. T helper/T suppressor ratios were generally lower in mothers (mean value- 0.47) as compared to Haitian women (mean value - 1.1) and American Black women (mean value - 1.45). Immunofluorescent studies and radioimmuno-assays for HTLV antibody were positive in 75% of mothers and in two of the children with AIDS. HTLV antibodies were found in 20% of Haitian women and none in the American Black women. In conclusion, the mothers show immune abnormalities similar to those found in patients with AIDS but the majority are clinically well. There is an increased incidence of HTLV antibody in the mothers as compared to controls.

The pathologic spectrum of adult T-cell leukemia/lymphoma in the United States

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.

Screening for Human T-Cell Leukemia-Lymphoma Virus

To the Editor.— The human T-cell leukemia-lymphoma virus (HTLV) has been noted to be extremely prevalent in several populations, including southeastern blacks. 1 Interestingly, the four cases of Blayney et al include three patients who in health-related professions: case 1 worked as a hospital nursing and dietetic aide, case 2 worked in the supply department of a hospital, and case 3 worked as a medical assistant. As a physician who trained and in the southeast for more than 15 years, I would like to make the following observation: southern blacks work in hospitals in numbers far out of proportion to their population in any given town. Could there be a connection in this observation relating to cases 1, 2, and 3? Should populations of all races working in hospitals be screened for HTLV?

Transformation and cytopathogenic effect in an immune human T-cell clone infected by HTLV-I.

Human T-cell leukemia-lymphoma virus (HTLV) is a human C-type retrovirus that can transform T lymphocytes in vitro and is associated with certain T-cell neoplasms. Recent data suggest that, in the United States, patients with acquired immunodeficiency syndrome (AIDS), homosexual men with lymphadenopathy, and hemophiliacs have had significant exposure rates to HTLV, whereas matched and unmatched control American subjects have rarely been exposed to this agent. In the present experiments, T cells specifically reactive against HTLV were propagated from a patient whose HTLV-bearing lymphoma was in remission. The T cells were cloned in the presence of the virus and an HTLV-specific cytotoxic T-cell clone was isolated. This clone was infected and transformed by the virus, with one copy of an HTLV-I provirus being integrated into the genome. This T-cell clone did not exhibit the normal dependence on T-cell growth factor (interleukin-2) and proliferated spontaneously in vitro. Exposure of the clone to HTLV-bearing, autologous tumor cells specifically inhibited its proliferation and resulted in its death. These results may have implications for HTLV-associated inhibition of T-cell responses.

Screening for human T-cell leukemia-lymphoma virus

Screening for human T-cell leukemia-lymphoma virus

In vitro antibody‐dependent cellular cytotoxicity against human T‐cell leukemia/lymphoma virus (HTLV)‐producing cells

Human T-cell leukemia/lymphoma virus (HTLV)-producing cells were lysed by peripheral mononuclear cells (PMNC) from both anti-HTLV antibody-positive and -negative healthy persons in the presence of natural humoral antibodies against HTLV-related antigens (antibody-dependent cellular cytotoxicity, ADCC). PMNC from patients with T-cell leukemia, however, did not possess the positive reaction even in the presence of natural antibodies. In contrast, when the antibodies were absent, no cytotoxicity was caused by PMNC from any donors. Additionally, the complement present in the antibody-positive plasma did not contribute to humoral antibody-dependent cytotoxicity in the presence of plasma without PMNC. Therefore, ADCC against HTLV-producing cells may correlate with the prophylaxis of HTLV-induced malignancy in vivo.

T-cell growth factor gene: lack of expression in human T-cell leukemia-lymphoma virus-infected cells.

Activated mature T cells require T-cell growth factor (TCGF) for continuous proliferation. However, many mature T cells infected with human T-cell leukemia-lymphoma virus grow independently of exogenously added TCGF. It is now reported that cells infected with this virus also lack detectable TCGF messenger RNA (less than one copy per cell) and thus do not produce their own growth factor. The results apparently rule out an autostimulation mechanism of growth control.

Nosocomial acquired immunodeficiency syndrome and human T-cell leukaemia lymphoma virus associated disease

Over 1500 cases of acquired immunodeficiency syndrome (AIDS) have been reported in the LJSA since it was first recognized in 1981 [Centers for Disease Control (CDC), 1981.--831 and cases have been observed in other countries including 20 from Britain and 70 from France (October 1983). The exact aetiology of AIDS is unknown but an infective causative agent, spread particularly during homosexual contact and via blood, appear virtually certain. There is intense speculation about the possible role of retroviruses especially human T-cell leukaemia lymphoma virus (HTI,V) or related viruses (I<ssex et ul., 1983; Gallo et al., 1983). Although AIDS is almost entirely a community based problem there is now increasing concern about the possibility of hospital patients and health care personnel contracting the disease. What arc the expected risks and how can they be reduced? ‘l‘here is no doubt that AIDS can be transmitted to haemophiliacs by blood products, particularly large-pool factor VII I concentrates in the USA, although the number of cases affected so far is small (White and I,escsnc, 1983). In Britain there have been two reports of haemophiliac patients developing AIDS including a Bristol man who subsequently died of the disease. Most authorities do not feel that a change in policy is justified at present for haemophiliac patients but efforts to obtain a factor VIII product which is ‘AIDS-free will be intensified (Editorial, 1983~). Recent serological studies in America suggest that blood transfusion with blood products may expose haemophiliacs to a substantial risk of acquiring I ITL,V or related viruses and the long term implications of this are awaited with great interest (Evatt et al., 1983). A few non-haemophiliac cases have acquired AIDS by the transfusion of blood products including a male infant who had received multiple blood products during the first 2 weeks of life while having exchange transfusions for the management of a rhesus sensitization problem. ‘I’his infant died of pneumocystis pneumonia at 2 years of age (Ammann et al., 1983). ‘I’he observations of these and other cases suggest an approximate incubation period for the development of AIDS of between 2 and 6 months for infants and up to 2 years for adults. Patients who require multiple blood transfusions for cardiac or other types of major surgery in urban areas where AIDS epidemics are occurring must be at theoretical risk of subsequently developing AII)S during the next 2 years. In order to minimize these risks