Phosphorylation of 3'-azido-3'-deoxythymidine and selective interaction of the 5'-triphosphate with human immunodeficiency virus reverse transcriptase

The thymidine analog 3'-azido-3'-deoxythymidine (BW A509U, azidothymidine) can inhibit human immunodeficiency virus (HIV) replication effectively in the 50-500 nM range [Mitsuya, H., Weinhold, K. J., Furman, P. A., St. Clair, M. H., Nusinoff-Lehrman, S., Gallo, R. C., Bolognesi, D., Barry, D. W. & Broder, S. (1985) Proc. Natl. Acad. Sci. USA 82, 7096-7100]. In contrast, inhibition of the growth of uninfected human fibroblasts and lymphocytes has been observed only at concentrations above 1 mM. The nature of this selectivity was investigated. Azidothymidine anabolism to the 5'-mono-, di-, and -triphosphate derivatives was similar in uninfected and HIV-infected cells. The level of azidothymidine monophosphate was high, whereas the levels of the di- and triphosphate were low (less than or equal to 5 microM and less than or equal to 2 microM, respectively). Cytosolic thymidine kinase (EC 2.7.1.21) was responsible for phosphorylation of azidothymidine to its monophosphate. Purified thymidine kinase catalyzed the phosphorylations of thymidine and azidothymidine with apparent Km values of 2.9 microM and 3.0 microM. The maximal rate of phosphorylation with azidothymidine was equal to 60% of the rate with thymidine. Phosphorylation of azidothymidine monophosphate to the diphosphate also appeared to be catalyzed by a host-cell enzyme, thymidylate kinase (EC 2.7.4.9). The apparent Km value for azidothymidine monophosphate was 2-fold greater than the value for dTMP (8.6 microM vs. 4.1 microM), but the maximal phosphorylation rate was only 0.3% of the dTMP rate. These kinetic constants were consistent with the anabolism results and indicated that azidothymidine monophosphate is an alternative-substrate inhibitor of thymidylate kinase. This conclusion was reflected in the observation that cells incubated with azidothymidine had reduced intracellular levels of dTTP. IC50 (concentration of inhibitor that inhibits enzyme activity 50%) values were determined for azidothymidine triphosphate with HIV reverse transcriptase and with immortalized human lymphocyte (H9 cell) DNA polymerase alpha. Azidothymidine triphosphate competed about 100-fold better for the HIV reverse transcriptase than for the cellular DNA polymerase alpha. The results reported here suggest that azidothymidine is nonselectively phosphorylated but that the triphosphate derivative efficiently and selectively binds to the HIV reverse transcriptase. Incorporation of azidothymidylate into a growing DNA strand should terminate DNA elongation and thus inhibit DNA synthesis.

Infection of human T lymphotropic virus-I-specific immune T cell clones by human T lymphotropic virus-I

Human T lymphotropic virus-I (HTLV-I)-specific T cell lines were established and cloned. K5, an OKT8+ clone bearing multiple proviral integration sites, retained its HTLV-I-specific cytotoxicity and a normal dependence on interleukin 2 (IL-2), indicating that there is a finite number of transforming integration sites. R2, an OKT4+ HTLV-I-infected clone, initially mounted a proliferative response to HTLV-I; but then its IL-2-independent proliferation increased and the antigen specificity was lost. All HTLV-I-infected clones tested including K7, another OKT8+ transformed cytotoxic clone that had lost its reactivity, expressed comparable levels of T cell receptor beta-chain (TCR-beta) messenger (m)RNA. Although clones K5 and K7 had different functional properties, they had the same rearrangement of the TCR-beta gene, suggesting that they had the same clonal origin. These data indicate that HTLV-I-specific T cells retain their immune reactivity for variable periods of time following infection, but then usually lose it; in some cases, however, no alteration in function can be detected. The data also suggest that different consequences can take place in the same clone depending on the pattern of retroviral infection.

Potent and selective anti-HTLV-III/LAV activity of 2',3'-dideoxycytidinene, the 2',3'-unsaturated derivative of 2',3'-dideoxycytidine

2',3'-Dideoxycytidinene (ddeCyd), the 2',3'-unsaturated derivative of 2',3'-dideoxycytidine (ddCyd) is, like ddCyd itself, a potent and selective inhibitor of HTLV-III/LAV in vitro. This conclusion is based on the relatively high ratio of effective antiviral dose (0.3 microM) versus cell growth inhibitory concentration (20-35 microM) and the lack of any appreciable inhibitory activity against a series of non-oncogenic RNA and DNA viruses. Both compounds were considerably more inhibitory to human lymphoid cell lines than human nonlymphoid or murine cell lines. They were highly dependent on prior activation by deoxycytidine kinase to exert their anti-HTLV-III/LAV and cytostatic effects. In contrast with ddCyd, ddeCyd lost part of its anti-retrovirus effect upon prolonged incubation (10 days) with the virus-infected cells in culture.

Infectious mutants of HTLV-III with changes in the 3' region and markedly reduced cytopathic effects

A variant of human T-lymphotropic virus type III (HTLV-III) is described that replicates but does not kill normal human T cells in vitro. This variant, designated X10-1, was derived from the genome of a cytopathic HTLV-III clone (pHXB2D) by excision of a 200-base pair segment in the 3' region of the virus, spanning the env and 3'-orf genes. Comparable variants with 55 to 109 base pairs deleted exclusively in 3'-orf produced, in contrast, virus that was extremely cytopathic. On the basis of these findings it is concluded that the 3'-orf gene is not required for cytopathogenicity or replication of HTLV-III. In addition, the results suggest that virus replication and cytotoxicity are not intrinsically coupled. Furthermore, since clone X10-1 retains the ability to trans-activate genes linked to the viral long terminal repeats, trans-activation per se is not responsible for T-cell killing by HTLV-III. These results also raise the possibility that the carboxyl terminus of the envelope gene of HTLV-III has a direct role in T-cell killing by this virus.

Mechanisms of B cell activation in patients with acquired immunodeficiency syndrome and related disorders. Contribution of antibody-producing B cells, of Epstein-Barr virus-infected B cells, and of immunoglobulin production induced by human T cell lymphotropic virus, type III/lymphadenopathy-associated virus

Patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) have hyperimmunoglobulinemia and increased numbers of circulating immunoglobulin-secreting cells. In this paper, we studied the basis for this B cell hyperactivity. Limiting dilution studies of B cells from seven patients with ARC and four with AIDS revealed that some B cells spontaneously produced antibodies to human T cell lymphotropic virus, type III/lymphadenopathy-associated virus (HTLV-III/LAV) (39:10(6) and 7:10(6) B cells, respectively), suggesting that chronic antigenic stimulation by HTLV-III/LAV was one contributing factor. The patients also had an increased number of spontaneously outgrowing B cells than did normals (6:10(6) vs. less than 2:10(6) B cells), suggesting that they had an increased number of Epstein-Barr virus (EBV)-infected B cells. However, fewer B cells from patients were immortalized by exogenously added EBV than were B cells from normals. In additional studies, HTLV-III/LAV induced immunoglobulin secretion (mean 2,860 ng/ml) by peripheral blood mononuclear cells from normals; this HTLV-III/LAV-induced immunoglobulin secretion required the presence of both B and T cells. Thus, antigenic stimulation by HTLV-III/LAV, increased numbers of EBV-infected B cells, and HTLV-III/LAV-induced T cell-dependent B cell activation all contribute to the B cell hyperactivity in patients with HTLV-III/LAV disease.

Alterations in cytotoxic and helper T cell function after infection of T cell clones with human T cell leukemia virus, type I

HTLV-I is a transforming human retrovirus that is an etiologic agent of adult T cell leukemia/lymphoma. To investigate the effects of this virus on T cell functions, two OKT3+, OKT4+, OKT8- cytotoxic clones (8.7 and 8.8) specific for allogeneic cells bearing DPw2, a class II histocompatibility antigen, were studied before and after infection with HTLV-I. The clones retained cytotoxic function for up to 70 d after exposure to HTLV-I, even without subsequent antigenic stimulation, but then lost their cytotoxic activity. Prior to infection with HTLV-I, clone 8.8 also lysed OKT3 hybridoma cells; after infection, cytotoxic activity against these OKT3-antibody bearing cells was lost in parallel with the loss of activity against DPw2-bearing target cells. In addition, expression of T3 surface antigen by HTLV-I-infected 8.8 cells was decreased at a time when they lost their cytotoxic activity, possibly contributing to the loss of cytotoxic function. Finally, clone 8.8 could provide help for nonspecific IgG production by autologous B cells when stimulated with irradiated DPw2-bearing non-T cells. After infection with HTLV-I, this helper function became independent of DPw2-stimulation and persisted even when the cytotoxic activity was lost. An OKT4+ T cell clone thus could simultaneously manifest both cytotoxic and helper T cell activities, and these activities were differentially affected after HTLV-I infection.

Aurintricarboxylic acid and Evans Blue represent two different classes of anionic compounds which selectively inhibit the cytopathogenicity of human T-cell lymphotropic virus type III/lymphadenopathy-associated virus

Aurintricarboxylic acid, an anionic triphenylmethane dye, and Evans Blue, an anionic compound structurally related to suramin, are, like suramin itself, inhibitors of human T-cell lymphotropic virus type III (HTLV-III)/-lymphadenopathy-associated virus (LAV) in vitro. These compounds may be targeted, at least in part, at the HTLV-III/LAV reverse transcriptase. The lack of any appreciable cytostatic action of aurintricarboxylic acid, Evans Blue and suramin against several murine and human cell lines, their inability to inhibit cellular DNA, RNA and protein synthesis, and their high lethal dose-50 (greater than or equal to 0.340 g/kg) for NMRI mice point to the selectivity of the compounds as inhibitors of HTLV-III/LAV.

Comparative inhibitory effects of suramin and other selected compounds on the infectivity and replication of human T-cell lymphotropic virus (HTLV-III)/lymphadenopathy-associated virus (LAV)

Suramin and various other selected compounds were evaluated for their in vitro inhibitory effects on the infectivity and replication of human T-cell lymphotropic virus (HTLV/III)/lymphadenopathy-associated virus (LAV). As parameters for infectivity and replication, respectively, we followed the cytopathic effect of HTLV-III/LAV on ATH 8 cells, a T-cell clone with high susceptibility to HTLV-III/LAV, and the expression of HTLV-III/LAV p24 gag protein in H9 cells infected with HTLV-III/LAV. As the most effective inhibitors of HTLV-III/LAV the following substances emerged (in order of decreasing activity): Evans Blue approximately equal to suramin greater than phosphonoformic acid greater than Direct Yellow 50. Several purine nucleoside analogues including vidarabine, tubercidin, neplanocin A, dihydroxypropyladenine, pyrazofurin and ribavirin were not inhibitory to HTLV-III/LAV. In our test systems, involving a high multiplicity of infection, HPA-23, previously reported to be effective against LAV reverse transcriptase, showed no inhibitory effect on HTLV-III/LAV infectivity for ATH 8 cells and proved only weakly inhibitory to HTLV-III/LAV replication in H9 cells. Thus, among the anionic dyes that are structurally related to suramin, compounds were found which were as active as suramin itself, if not more so.

Inhibition of the in vitro infectivity and cytopathic effect of human T-lymphotrophic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) by 2',3'-dideoxynucleosides

Human T-lymphotropic virus type III (HTLV-III)/lymphadenopathy-associated virus (LAV) is a a newly discovered lymphotropic retrovirus that is cytopathic for helper/inducer T cells in vitro. This virus is the etiologic agent of the acquired immunodeficiency syndrome and related diseases. In the current study, we tested the capacity of purine and pyrimidine nucleoside derivatives to inhibit the infectivity and cytopathic effect of human T-lymphotropic virus type III in vitro. With the ribose moiety of the molecule in a 2',3'-dideoxy configuration, every purine (adenosine, guanosine, and inosine) and pyrimidine (cytidine and thymidine) nucleoside tested suppressed the virus, although the thymidine derivative seemed to have substantially less activity in our system than the others. In general, we observed essentially complete suppression of the virus at doses that were lower by a factor of 10 to 20 than those needed to inhibit the proliferation of the target T cells and the immune reactivity of normal T cells in vitro. An analysis of five adenosine congeners, which differed only in the sugar moiety, revealed that reduction (an absence of hydroxyl determinants) at both the 2' and 3' carbons of the ribose was necessary for an anti-viral effect, and an additional reduction at the 5' carbon nullified the anti-viral activity. These observations may be of value in developing a new class of experimental drugs for the therapy of human T-lymphotropic virus type III infections.

Configuration and expression of the T cell receptor beta chain gene in human T-lymphotrophic virus I-infected cells

We studied the configuration and expression of the gene encoding the beta chain of the T cell receptor (TCR beta) in cell lines and primary tumor cells infected by the human T cell leukemia/lymphoma (lymphotrophic) virus type I (HTLV-I). Most of the cell lines and all the primary tumor cells showed rearrangement of the TCR beta gene, and in each case the rearrangement was distinct. The majority of cases examined were clonal with respect to a particular TCR beta gene rearrangement. Primary tumor cells from one case (SD) were found to have a tandem duplication of a portion of chromosome 7; this appears to have resulted in the presence of three alleles of the TCR beta gene, each of which is arranged differently. This suggests that the chromosomal abnormality, and possibly infection by HTLV-I, occurred before TCR beta gene rearrangement. Cell lines infected by HTLV-I express levels of TCR beta mRNA similar to PHA stimulated lymphocytes, suggesting that this gene is not transcriptionally activated as a result of infection by HTLV-I. Cloned T cells of known antigen specificity that are infected by HTLV-I in vitro show impairment of immune function, including loss of antigen-specific responsiveness and the acquisition of alloreactivity. Comparison of the configuration of the TCR beta gene before and after infection revealed no changes detectable by Southern blot analysis. Levels of expression of the TCR beta gene at the mRNA level and surface expression of the T3 complex were also not significantly altered, suggesting that changes in immune function cannot be attributed to quantitative changes in the TCR molecule. The configuration of the TCR beta gene in primary tumor cells infected by HTLV-I was compared with that in the derived cell lines. In all pairs examined, the configuration in the primary tumor cells was different from that in the cell lines, strongly suggesting that the cells that grow in culture are not the original neoplastic cells.

Clinical pharmacokinetics of suramin in patients with HTLV-III/LAV infection

Suramin has been reported to inhibit the reverse transcriptase activity of a number of retroviruses and to reduce the in vitro infectivity and cytopathic effect of HTLV-III/LAV, the etiologic agent of acquired immune deficiency syndrome (AIDS). The clinical pharmacokinetics of suramin were investigated as part of a pilot study to evaluate the safety and efficacy of this drug for the treatment of patients with diseases caused by HTLV-III/LAV. A dose of suramin 6.2 g was given intravenously over a five-week period to four patients. After the last dose, the plasma half-life of suramin was 44 to 54 days. This is among the longest half-lives reported for any therapeutic substance given to humans. Total plasma levels of suramin were greater than 100 micrograms/mL for several weeks. In vitro activity of suramin was found at concentrations as low as 50 micrograms/mL. Metabolites were not found in plasma, and urinary excretion accounts for elimination of most of the drug. Suramin is approximately 99.7% bound to plasma proteins. The results from these initial clinical pharmacokinetic studies might assist the design of further therapeutic trials of suramin, especially the selection of frequency of dosing and adjustments for renal impairment.

Effects of suramin on HTLV-III/LAV infection presenting as Kaposi's sarcoma or AIDS-related complex: clinical pharmacology and suppression of virus replication in vivo

Suramin was given to ten outpatients with acquired immunodeficiency syndrome (AIDS) presenting as Kaposi's sarcoma (KS) or as an AIDS-related complex (ARC). Side-effects associated with the administration of 6.2 g of suramin over 5 weeks included fevers, rashes, urinary abnormalities, and transient rises in hepatic aminotransferases. Peak serum levels of over 100 micrograms/ml were attained. There was evidence of HTLV-III infectivity and replication in lymphocytes from four patients before therapy. The detectable virus level fell in each case by the time of the last dose, and in three cases it became undetectable at the end of therapy. In each case, viral replication was again detected in the weeks or months following the administration of suramin. Despite this in-vivo virustatic effect, no significant clinical or immunological improvement was observed using this short-term regimen. However, the results provide a rationale for investigating longer-term regimens.

Pharmacological inhibition of infectivity of HTLV-III in vitro

Acquired immunodeficiency syndrome (AIDS) is a pandemic immunosuppressive disease that predisposes to life-threatening opportunistic infections and unusual forms of neoplasms. A recently discovered member of the human T-lymphotrophic virus (HTLV) family, designated HTLV-III, has been shown to be the etiological agent of AIDS. We have shown previously that a trypanosomicidal drug, suramin, can block the in vitro infectivity and cytopathic effect of HTLV-III at doses that are attainable in human beings. In the present work we report our findings that suramin can block the cytopathic effect of HTLV-III even after a defined exposure of the target helper/inducer T-cells to the virus and that the T-cells protected by suramin remain immunologically functional.

Implications of the discovery of HTLV-III for the treatment of AIDS

The recent discovery of HTLV-III, a cytopathic member of the family of human T-cell lymphotropic viruses (HTLV), and its identification as the etiological agent of acquired immunodeficiency syndrome (AIDS) have important implications for the treatment of this disorder. The pathogenesis of AIDS involves the destruction of helper/inducer T-lymphocytes by active viral infection, and drugs which inhibit the replication of HTLV-III or monoclonal antibodies directed at viral antigens may be important components of future therapeutic strategies. There are a number of steps in the replication of HTLV-III which might potentially be susceptible to antiviral agents. One drug, suramin, which was originally developed as an antitrypanosomal agent, has been found to be an inhibitor of reverse transcriptase. This drug has been shown to block the infectivity and cytopathic effect of HTLV-III [Mitsuya, H., Popovic, M., Yarchoan, R., Matsushita, S., Gallo, R. C., and Broder, S. Science (Wash. DC), 266: 172-174, 1984]; in addition, it is able to block the in vitro replication of another member of the HTLV family, HTLV-I, at concentrations of 25 to 75 micrograms/ml. Lymphocyte proliferation in vitro is minimally inhibited at these concentrations of suramin, and the ratios of helper/inducer to cytotoxic/suppressor T-lymphocytes are not affected. Clinical trials are being initiated to study the effect of suramin on patients with AIDS. Evaluation of this and other antiviral treatments for AIDS will optimally involve direct assessment of its effects on HTLV-III replication in vivo. Recent evidence, however, suggests that these patients have a low level of viral replication in lymphoid tissue which may spontaneously fluctuate, making such evaluation complex.

Cytogenetic studies in human T-cell lymphoma virus (HTLV)-positive leukemia-lymphoma in the United States

Cytogenetic studies were conducted on fresh and cultured cells from 11 patients with human T-cell leukemia virus-associated adult T-cell leukemia-lymphoma. Clones with abnormal karyotypes were detected in 9 of the 11 patients. Chromosome numbers were near-diploid in cells from all but 1 patient who also had a tetraploid clone. The chromosome abnormalities in these cells were extensive; numerous complex structural changes were seen in every chromosome pair. Structural abnormalities occurred most frequently in chromosome 6. The 6 patients with chromosome 6 deletions had breakpoints at bands q11, q13, q16q23, q21q23, q22q24, and q23q24. The characteristic clinical features of these 6 patients were aggressive course, short survival, poor response to chemotherapy, high white blood cell counts, hypercalcemia, and bone lesions, whereas cytogenetically abnormal patients without chromosome 6q deletions tended to have a more indolent course. The precise role of the 6q deletion cannot be established with certainty from these data. However, this abnormality appears to occur with a greater than expected frequency in this large cell aggressive lymphoma, in association with hypercalcemia and lytic bone lesions.

Suramin protection of T cells in vitro against infectivity and cytopathic effect of HTLV-III

A recently discovered member of the human T-cell leukemia virus (HTLV) family of retroviruses has been etiologically linked to the acquired immune deficiency syndrome (AIDS). This virus, which has been designated HTLV-III, is tropic for OKT4-bearing (helper-inducer) T cells. Moreover, the virus is cytopathic for these cells. Suramin is a drug used in the therapy of Rhodesian trypanosomiasis and onchocerciasis, and it is known to inhibit the reverse transcriptase of a number of retroviruses. Suramin has now been found to block in vitro the infectivity and cytopathic effect of HTLV-III at doses that are clinically attainable in human beings.

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.

NIH conference. T-cell lymphoproliferative syndrome associated with human T-cell leukemia/lymphoma virus

Human T-cell leukemia/lymphoma virus is a unique family of T-cell tropic, human, type-C retroviruses. The discovery of this class of retroviruses provides the first proven link between retroviruses and cancer in humans. This virus is endemic in certain parts of the world, including the southeastern United States, and is associated with the development of adult T-cell leukemia/lymphoma, a fulminant lymphoproliferative disorder frequently accompanied by opportunistic infections and hypercalcemia. Over the last few years, major advances have been made in understanding the clinical, epidemiologic, molecular biologic, and immunologic features of this unique class of human RNA tumor viruses.

Immune T cells reactive against human T-cell leukaemia/lymphoma virus

Six patients with malignant disorders associated with human T-cell leukaemia/lymphoma virus (HTLV) were studied to see whether long-term cultures of immune T cells reactive against HTLV-infected tumour cells could be achieved. Immune T-cell lines could not be developed from the cells of five patients who died or eventually had a relapse of disease, but in one patient who had an unusually long remission of his disease after therapy, immune T-cell lines were propagated that could produce their own T-cell growth factor and proliferate upon stimulation with autologous tumour cells and also specifically lyse HTLV-infected target cells. These immune T cells recognised the presence of circulating HTLV-bearing neoplastic cells in another patient with HTLV-associated T-cell leukaemia, who had been in clinical remission after chemotherapy when this study started, thereby providing early evidence of relapse.

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.

Association of human T-cell leukaemia/lymphoma virus with the Tac antigen marker for the human T-cell growth factor receptor

Certain adult T-cell lymphoproliferative disorders are associated with human T-cell leukaemia virus (HTLV), a unique human type C retrovirus. (The strains of HTLV used in these studies belong to the subgroup HTLV-I.) HTLV is not an endogenous agent in man, but rather is an acquired virus with T-cell tropism. Neoplastic cells from patients infected with HTLV generally express receptors for T-cell growth factor (TCGF) (interleukin-2), and do not require prior activation with antigens or lectins to undergo TCGF-induced proliferation. Furthermore, neoplastic T-cell lines originating from such patients may constitutively produce TCGF, TCGF receptors and HTLV virions. HTLV is transmissible from cell to cell, and the infection of human T cells in vitro is associated with the expression of TCGF receptors, which can be identified by the monoclonal antibody termed anti-Tac. In our experience to date, T-cell populations that produce HTLV without exception also express epitopes found on TCGF receptors. Recognition of an association between HTLV virions and the Tac antigen would have clinical and theoretical implications. We now present evidence that during the replication or release of HTLV, the virion becomes preferentially associated with the Tac antigen.

Generation of an HLA-restricted cytotoxic T cell line reactive against cultured tumor cells from a patient infected with human T cell leukemia/lymphoma virus

Lymphocytes from a patient who had an unusually long survival after therapy for a human T cell leukemia/lymphoma virus (HTLV)-associated T cell lymphoma were stimulated in vitro with an autologous tumor cell line, and the generation of cytotoxic T lymphocytes (CTL) was studied. CTL generated were directed against autologous (HTLV-associated tumor cells. These propagated CTL were OKT3+, OKT4-, and OKT8+. The cytotoxic activity required target tumor cells that were infected with HTLV and also expressed histocompatibility antigens in common with the patient, suggesting a major histocompatibility complex-restricted associative recognition of target antigens expressed on the tumor cell membrane.

Clinical course of retrovirus-associated adult T-cell lymphoma in the United States

We studied the clinical features of 11 patients with adult T-cell lymphoma associated with the human T-cell lymphoma virus. The patients were predominantly young, black, and born in the southeastern United States. They had an aggressive course, with the rapid onset of disseminated skin lesions or symptoms related to hypercalcemia and other metabolic disturbances, or both. Common findings included rapid enlargement of peripheral, hilar, and retroperitoneal lymph nodes, with sparing of the mediastinum; invasion of the central nervous system, lungs, or gastrointestinal tract; and opportunistic infections. A paraneoplastic syndrome characterized by increased bone turnover, abnormal bone scintigraphy, and hypercalcemia was present in all patients. Intensive combination chemotherapy produced prompt complete clinical remissions, which were generally of short duration. Similar features have been described in patients in Japan and the West Indies who had adult T-cell lymphoma, which is also associated with the human T-cell lymphoma virus. This syndrome should be suspected in patients presenting with the acute onset of widespread T-cell lymphoma in association with metabolic bone disease and hypercalcemia. The presence of the syndrome can be confirmed by appropriate serologic and virologic studies.

Inhibitory activity of antibodies to human Ia-like determinants: comparison of intact and pepsin-digested antibodies

Antibodies which react with products encoded by the human DR locus precipitate a biomolecular membrane glycoprotein complex with m.w. of 29,000 and 34,000 daltons. Such antibodies are directed against HLA-DR Ia-like antigens found on human B cells and human monocytes and have been shown previously to inhibit a variety of in vitro cellular and humoral immune reactions. We have compared the in vitro effects of such antibodies on two assays of human immunity: antigen-specific proliferation and polyclonal immunoglobulin production. Intact IgG fractions of a rabbit heteroantiserum (anti-P29,34), a human MT-2 locus alloantiserum (Ia 172), and a mouse monoclonal antibody (LB 3.1) markedly inhibited in vitro immune reactivities of human mononuclear cells. Interestingly, F(ab')2 preparations of these antibodies failed to inhibit these in vitro immune responses at the concentrations tested. These data suggest that under certain conditions, Fc domains play a critical role in the inhibitory activity of antibodies to Ia-like molecules.

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.

Inhibitory activity of antibodies to human Ia-like determinants: comparison of intact and pepsin-digested antibodies

Antibodies which react with products encoded by the human DR locus precipitate a biomolecular membrane glycoprotein complex with m.w. of 29,000 and 34,000 daltons. Such antibodies are directed against HLA-DR Ia-like antigens found on human B cells and human monocytes and have been shown previously to inhibit a variety of in vitro cellular and humoral immune reactions. We have compared the in vitro effects of such antibodies on two assays of human immunity: antigen-specific proliferation and polyclonal immunoglobulin production. Intact IgG fractions of a rabbit heteroantiserum (anti-P29,34), a human MT-2 locus alloantiserum (Ia 172), and a mouse monoclonal antibody (LB 3.1) markedly inhibited in vitro immune reactivities of human mononuclear cells. Interestingly, F(ab')2 preparations of these antibodies failed to inhibit these in vitro immune responses at the concentrations tested. These data suggest that under certain conditions, Fc domains play a critical role in the inhibitory activity of antibodies to Ia-like molecules.

Regulation of the humoral immune response: from immunoglobulin genes to regulatory T cell networks

Leukemic lymphocytes were used in studies to define the rearrangements of immunoglobulin genes and the networks of immunoregulatory T cells that are important to the control of immunoglobulin synthesis in humans. Leukemic B cells displayed rearrangements of their expressed mu and k or lambda genes. Surprisingly, the k constant region genes were deleted or rearranged in all lambda-expressing B lymphocytes examined. Most non-T, non-B lymphocytic leukemias had immunoglobulin gene rearrangements, which indicates that these cells were committed to B cell development at the immunoglobulin gene level. The pattern of immunoglobulin gene rearrangements in the B cell precursor and B cell leukemias suggests an ordered hierarchy of somatic rearrangements with mu genes preceding light chains and k light chain genes preceding lambda. Some of the leukemic T cells studied were homogeneous populations of cells that retained immunoregulatory functions with many Sézary T leukemic cells functioning as helper cells in their interactions with B lymphocytes. In contrast, malignant cells from patients with the adult T leukemia of Japan frequently functioned as suppressor cells. In contrast to normal unactivated T cells or other leukemic T cells, the leukemic T cells from all adult T cell leukemia patients studied had an activated receptor for T cell growth factor. The malignant cells of a patient with an acute T cell leukemia functioned as prosuppressor cells. Under the influence of normal T cells or their secreted inducer products, these leukemic cells matured both functionally and in terms of cell surface antigens into suppressor effector cells.

Disorders of B cells and helper T cells in the pathogenesis of the immunoglobulin deficiency of patients with ataxia telangiectasia

The pathogenesis of the immunoglobulin deficiency of 20 patients with ataxia telangiectasia was studied using an in vitro immunoglobulin biosynthesis system. 10 patients had no detectable IgA in their serum as assessed by radial diffusion in agar and 3 had a reduced serum IgA concentration. The peripheral blood mononuclear cells of 17 of the patients and 17 normal controls were cultured with pokeweed mitogen for 12 d and the immunoglobulin in the supernatants measured. The immunoglobulin synthesis was below the lower limit of the normal 95% confidence interval for IgM in 5 patients, for IgG in 8, and for IgA in 14. The mononuclear cells from 9 of the 10 patients with a serum IgA concentration less than 0.1 mg/ml failed to synthesize IgA in vitro. None of the patients manifested excessive suppressor cell activity. All patients had reduced but measurable helper T cell activity for immunoglobulin synthesis by co-cultured normal pokeweed mitogen-stimulated B cells (geometric mean 22% of normal). Furthermore, the addition of normal irradiated T cells to patient peripheral blood mononuclear cells led to an augmentation of IgM synthesis in 15 of 17 and to increased IgG synthesis in 9 of the 17 patients studied, including 9 of the 12 patients who had synthesized IgG before the addition of the irradiated T cells. In addition, IgA synthesis was increased in all eight patients examined that had serum IgA concentrations greater than 0.1 mg/ml. These studies suggest that a helper T cell defect contributes to the diminished immunoglobulin synthesis. However, a helper T cell defect does not appear to be the sole cause since there was no IgA synthesis by the peripheral blood mononuclear cells of 9 of the 10 patients with a profoundly reduced serum IgA even when co-cultured with normal T cells. Furthermore, the cells of the nine patients with profoundly reduced IgA levels examined also failed to produce IgA when stimulated with the relatively helper T cell-independent polyclonal activators, Nocardia water soluble mitogen or Epstein-Barr virus. Taken together these data support the view that the reduced immunoglobulin synthesis of these patients is due to defects of both B cells and helper T cells. Such a broad defect in lymphocyte maturation taken in conjunction with our demonstration of persistent alpha fetoprotein production by ataxia telangiectasia patients provides support for the proposal that these patients exhibit a generalized defect in tissue differentiation.

Interactions between radioresistant T cells from plasmacytoma-bearing mice and radiosensitive T cells from normal mice leading to suppression

Spleens from BALB/c mice bearing the plasmacytoma SPQC 11 contain a population of T cells capable of suppressing the production of antibodies when cultured with normal BALB/c splenocytes, but not with splenocytes from nude BALB/c mice. Inhibition was characteristically the most effective at low suppressor cell numbers using unirradiated T cells. Maximum suppression occurred when a radiosensitive population of T cells from normal mice interacted with a population of radioresistant T cells from plasmacytoma-bearing animals. Accurate characterization of the suppressor T cell activity required testing over a wide range of suppressor/indicator cell ratios. Suppressor activity was eliminated by treatment with anti-Thy 1.2 plus complement, was radioresistant and present over a full range of doses when irradiated cells were used.

Human T-cell leukemia-lymphoma virus (HTLV) is in T but not B lymphocytes from a patient with cutaneous T-cell lymphoma

A human type C retrovirus, designated HTLV, previously was isolated from or identified in some patients with leukemias and lymphomas of mature T lymphocytes. HTLV is genetically and serologically distinct from any known animal retroviruses. The absence of HTLV proviral sequences in DNA from normal humans showed that HTLV is not a ubiquitous endogenous (germ-line transmitted) virus of humans. Antibodies to HTLV core proteins have been identified in some people with T-cell neoplasias and are particularly prevalent in Japanese with adult T-cell leukemia, suggesting that HTLV is acquired horizontally. However, it was possible that HTLV is transmitted through the germ line of some (possibly rare) families and is then expressed in the HTLV- positive malignancies. An opportunity to study this question was provided by the development of several T-cell lines and a B-cell provided by the development of several T-cell lines and a B-cell line from one HTLV-positive patient with a cutaneous T-cell lymphoma. Here we report that HTLV proteins or nucleic acids (or both) are found in three independently derived T-cell lines, all shown by HLA typing to have originated from the patient. In contrast, the B-cell line, the identity of which was also ascertained by HLA typing, contained no detectable HTLV protein, RNA, or proviral DNA. Because the sensitivity of the latter assay is more than sufficient to detect one proviral equivalent per haploid genome, the results indicate that HTLV was not transmitted to this patient through the germ line but rather was acquired by infection.

Chemotherapy for lymphoma in a patient with common variable immunodeficiency: case report, literature review, and recommendations for chemotherapy in immunodeficient patients

A man with long-standing common variable hypogammaglobulinemia was treated with chemotherapy and local radiation for diffuse mixed lymphoma. He continues in complete remission 42 months after the completion of therapy. Vigorous therapy for lymphoma can be used in the face of preexistent immunodeficiency. Complete staging and appropriate combination chemotherapy or radiation therapy should be carried out for lymphomas that occur in certain immunodeficient patients.

Metabolic heterogeneity of eosinophils from normal and hypereosinophilic patients

Eosinophils, which may be associated with allergic, parasitic, or neoplastic disease, have a potent oxidative burst that may be activated by particulate or soluble stimuli. Eosinophils from normal persons and patients with hypereosinophilia were compared with respect to their ability to produce the active oxygen product, superoxide anion. Normal eosinophils produced large amounts of superoxide anion under resting conditions (0.53 +/- 0.15 nmoles cyto-c/10(5) eos/hr) and when stimulated by preopsonized zymosan (0.85 +/0 1.10 nmoles cyto-c/10(5) eos/hr) or phorbol myristate acetate (PMA) (2.38 +/- 0.46 nmoles cyto-c/10(5) eos/hr). Considerable variation was observed in superoxide production by eosinophils from patients with hypereosinophilia. Eosinophils from a group of four patients with hypereosinophilia associated with neoplastic disease produced less superoxide anion than normal eosinophils when stimulated by preopsonized zymosan or PMA (p less than or equal to 0.05). Eosinophils from a group of 5 patients with other causes of hypereosinophilia produced more superoxide anion than normal eosinophils when stimulated by PMA (p less than or equal to 0.01). These studies demonstrate metabolic heterogeneity of eosinophils from patients with hypereosinophilia, and further emphasize that normal eosinophils and eosinophils from hypereosinophilic patients are not functionally equivalent.

Activation of leukemic pro-suppressor cells to become suppressor-effector cells. Influence of cooperating normal T cells

We studied the suppressor activity and surface-membrane antigens of immunoregulatory neoplastic T cells from a child with acute lymphoblastic leukemia and hypogammaglobulinemia. The neoplastic T cells were potent inhibitors of immunoglobulin production by pokeweed-mitogen-stimulated normal B cells when radiosensitive cooperative normal T cells were present. Preculturing the leukemic cells with normal T cells or soluble factors allowed them to mediate suppression without the need for cooperating T cells. While acquiring new functional capabilities, approximately 95 per cent of the leukemic cells displayed an antigen (OKT-3) that is found on mature normal T cells; 77 per cent displayed an antigen (Tac) that is found on normal activated immunoregulatory effector cells but not on thymocytes or circulating T cells that are precursors of these effector cells. The results suggest that a population of leukemic prosuppressor cells can be induced to undergo both functional and antigenic differentiation by the influence of normal T cells.

Homologous artificial insemination after long-term semen cryopreservation

Although there are sporadic reports of pregnancies using semen after long-term cryopreservation, there are no data on the success rate of this procedure and its clinical feasibility. Between 1969 and 1980, 475 men deposited semen specimens prior to vasectomy or therapeutic sterilization. Prefreeze sperm counts and motility were significantly higher in the prevasectomy group. Later, 5 wives of 177 vasectomized men and 16 wives of 183 therapeutically sterilized men returned for artificial insemination with their husbands' semen. Only 1 conception resulted among the 21 women. This occurred after a single insemination of a 7-year-old specimen obtained prevasectomy. The post-thaw motility of this specimen (45%) was better than that of most other thawed specimens. Post-thaw motilities were unpredictable despite comparable prefreeze motilities. Because of this unpredictability, semen cryopreservation is clearly no guarantee of "fertility insurance".

Resolution of longstanding protein-losing enteropathy in a patient with intestinal lymphangiectasia after treatment for malignant lymphoma

In 1956 we evaluated a patient who had a debilitating disease of a 2 yr duration, characterized by recurrent vomiting, diarrhea, cachexia, massive edema, hypoproteinemia, and dilated intestinal lymphatics. During our initial evaluation of this patient, we observed that 42% of her circulating protein pool was lost into her gastrointestinal tract daily, whereas normal gastrointesinal loss of protein does not exceed 1.6%. Her disease appeared to represent a classic example of intestinal lymphangiectasia. She was treated symptomatically for 13 yr with essentially no change. In 1969 the patient developed a stage IV diffuse, undifferentiated (non-Burkitt's) malignant lymphoma. Using immunoperoxidase staining, the neoplastic cells were found to contain cytoplasmic IgMKappa, suggesting that the lymphoma had a monoclonal B-cell origin. She was successfully treated with cyclophosphamide, vincristine, and prednisone. Shortly after the initiation of this systemic combination chemotherapy, her serum protein concentration returned to normal, her edema resolved, and she was cured of gastrointestinal symptoms. Moreover, repeat studies revealed that her protein loss had fallen to only 2%. The simultaneous cure of both the intestinal lymphangiectasia and lymphoma with combination chemotherapy suggests new relationships between these conditions as well as new possibilities for the treatment of acquired forms of intestinal lymphangiectasis associated with overwhelming gastrointestinal protein loss.

Fc receptors on human T lymphocytes. V: Effects of colchicine and cytochalasin B on Fc receptor expression

Previous studies have documented that the interaction of IgG immune complexes with the FcIgG receptor (Fc-IgGR) of human T lymphocytes induces alterations both in the expression of Fc receptors and in the functional capacities of these cells. After IgG immune complex exposure, Fc-IgGR-bearing T lymphocytes lose their Fc-IgGR and generate Fc-IgMR in subsequent culture. This transition phenomenon is mediated via patching and capping of the Fc-IgGR. Since Colchicine and Cytochalasin B have been demonstrated to interfere with capping of other membrane elements by their known effects on cytoskeletal structures, we investigated the effects of these agents on the expression of Fc receptors of human T cells. Neither Colchicine nor Cytochalasin B directly affects Fc-IgGR or Fc-IgMR expression. However, both agents inhibit the loss of Fc-IgGR subsequent to IgG immune complex exposure as well as the development of Fc-IgMR in culture. Immunofluorescent studies illustrate that this inhibition is mediated in part by interference with capping of the Fc-IgGR-immune complex ligand. This study emphasizes the inverse relationship between Fc-IgGR and Fc-IgMR expression on human T lymphocytes.

Fc receptors on human T lymphocytes. V: Effects of colchicine and cytochalasin B on Fc receptor expression

Previous studies have documented that the interaction of IgG immune complexes with the FcIgG receptor (Fc-IgGR) of human T lymphocytes induces alterations both in the expression of Fc receptors and in the functional capacities of these cells. After IgG immune complex exposure, Fc-IgGR-bearing T lymphocytes lose their Fc-IgGR and generate Fc-IgMR in subsequent culture. This transition phenomenon is mediated via patching and capping of the Fc-IgGR. Since Colchicine and Cytochalasin B have been demonstrated to interfere with capping of other membrane elements by their known effects on cytoskeletal structures, we investigated the effects of these agents on the expression of Fc receptors of human T cells. Neither Colchicine nor Cytochalasin B directly affects Fc-IgGR or Fc-IgMR expression. However, both agents inhibit the loss of Fc-IgGR subsequent to IgG immune complex exposure as well as the development of Fc-IgMR in culture. Immunofluorescent studies illustrate that this inhibition is mediated in part by interference with capping of the Fc-IgGR-immune complex ligand. This study emphasizes the inverse relationship between Fc-IgGR and Fc-IgMR expression on human T lymphocytes.

High molecular weight antigens present on human T cells

A series of eight high molecular weight (140,000-220,000) glycoproteins on human peripheral T cells were recognized by radioimmunoprecipitation with a rabbit antiserum. The pattern of antigens present on each of eight human T cell lines studied was unique, and no line displayed the range of antigens present on peripheral T cells. The pattern of bands on peripheral T cells changed after allogeneic or lectin stimulation. Adsorption/elution experiments with antiserum showed that some of these proteins were antigenically related, and at least three different groups of proteins were present. Two of these groups could be partially distinguished by their ability to bind to ricin or lentil lectin and by their reactivity with two additional rabbit antisera. On some cell lines, it was found that proteins bound by lentil lectin but not ricin were precursors of higher molecular weight material recognized by ricin. Taken together, the data suggest that these proteins may be the products of a multigenic or multiallelic system, probably equivalent to the murine Ly 5 antigens.