Herpesvirus saimiri strain 11 immortalizes a restricted marmoset T8 lymphocyte subpopulation in vitro.

Herpesvirus saimiri induces a fatal lymphoproliferative syndrome in a variety of New World primate species. We now show that cell lines derived from PBL of the common marmoset by in vitro-immortalization with H. saimiri strain 11 represent a remarkably restricted lymphocyte population. These cell lines have NK cell function, phenotypically express both suppressor/cytotoxic (T8) and NK cell (NKH1)-associated antigens, and express a T cell receptor. This subpopulation of lymphocytes is a very minor population of cells in the peripheral blood of common marmosets (less than or equal to 3%). The specificity in the interaction between H. saimiri strain 11 and a subpopulation of common marmoset lymphocytes represents an example of a restricted viral lymphotropism and may have important implications for the disease induced by this virus in New World monkeys.

Humoral immune responses to T cell tropic retrovirus simian T lymphotropic virus type III in monkeys with experimentally induced acquired immune deficiency-like syndrome.

The T cell tropic retrovirus of macaque monkeys simian T lymphotropic virus type III (STLV-III) has morphologic, growth, and antigenic properties indicating that it is related to human T cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV), the etiologic agent of the acquired immune deficiency syndrome (AIDS) of humans. STLV-III has recently been shown to induce an AIDS-like disease in macaque monkeys. In this study the humoral immune responses of six experimentally infected monkeys have been characterized to determine whether certain parameters of the antibody response to the virus might be predictive of the clinical outcome of this infection. Two distinct patterns of antibody responses were found. Four animals that died within 160 d of inoculation developed low titer anti-STLV-III antibody responses that recognized only the viral envelope protein, and progressive declines in total plasma IgG levels and absolute peripheral blood T4 lymphocyte numbers. The two animals that lived longer (one died at 352 d, the other remains alive at 430 d) developed high titer anti-STLV-III antibody responses that recognized both viral envelope and core proteins, increases in total plasma IgG, and a later decrease in number of peripheral blood T4 lymphocytes. Interestingly, the single animal that has remained clinically healthy after infection was the only one to develop detectable STLV-III neutralizing antibodies.

The cellular basis of impaired T lymphocyte functions in the elderly.

Immunologic changes associated with aging were studied by various immunologic tests in 24 aged persons (age range, 76-83) and 25 young persons (age range, 20-40). The responses to phytohemagglutinin (PHA) and concanavalin A (Con A) were depressed in the aged subjects compared to the young ones (p less than 0.05), whereas the responses to pokeweed mitogen (PWM) were similar. The activity of adhereent and non-adherent cells was assessed in various combinations. The adherent cells of aged persons were indistinguishable from those of young persons in their ability to response to Con A. Lymphocytes from the aged synthesized larger in vitro amounts of immunoglobulin than did lymphocytes from the young, when stimulated with PWM. Con A-stimulated T lymphocytes derived from aged subjects showed a variable loss of suppressor activity. The mixed lymphocyte culture reaction with mitomycin-treated allogeneic and autologous cells was also impaired in aged subjects. Such an impaired response in the aged is related to higher incidences of malignant lesions and auto-antibodies.

Enhancement of lymphocyte response to PHA by lysosomal enzymes from polymorphonuclear leukocytes of RA joint fluid. I. Biological effect on T lymphocyte function.

The effect of polymorphonuclear leukocyte (PMN) granule lysates obtained from joint fluid of RA on the in vitro DNA synthesis of PHA-stimulated autologous lymphocytes from joint fluid was studied. Lymphocytes were cultured for 3 days with or without PMN lysates in 2 ml of RPMI-1640 supplemented with 10% heat-inactivated fetal calf serum (FCS). The lymphocytes were stimulated with phytohemagglutinin (PHA-M). The DNA synthesis was measured by counting the [3H]thymidine incorporation. Lymphocytes from RA joint fluid stimulated with PHA-M showed 19,466+/-987 cpm (mean+/-SE) per 10(6) cells in the absence of PMN lysates. Upon addition PMN lysates to the PHA-stimulated lymphocytes, the maximum in vitro DNA synthesis increased to 44,877+/-1338 cpm. The enhancing effect of PMN lysates was abolished by plasma inhibitors or by passage through a column of protease inhibitor (Trasylol). It was concluded, therefore, that the enhancing effect of PMN lysates on PHA-stimulated lymphocytes may be associated with lysosomal proteases. Based on experiments using separated T and B lymphocytes, the enhancing effect of PMN lysates was considered to result from the activation of T lymphocytes. The results obtained in the present study suggest an important role for lysosomal proteases in the perpetuation of rheumatoid synovitis.

[A case of Plasmodium vivax malaria complicated with pancytopenia due to hypoplasia of the bone marrow].

The patient is a 39 year-old Japanese male who had traveled to Southeast Asia from March 14, 1987 and returned on April 2. On April 3 and 5, he had a high fever with chills and he was admitted to our hospital. Despite initial treatment with antibiotics, a high fever over 39 degrees C appeared with a 48 hour periodicity. On the 8th day after admission, malarial parasites were identified on the peripheral blood smear after repeated trials. Combined with a raised serum antibody titer, Plasmodium vivax malaria was diagnosed. He was successfully treated with the sulfadoxine 500 mg and pyrimethamine 25 mg (Fansidar) and body temperature was normalized after the 12th day. More interestingly, the patient showed pancytopenia without splenomegaly. The bone marrow aspiration revealed hypoplasia of erythroblasts, granulocytes and megakaryocytes. Because of this pancytopenia in the peripheral blood and hypoplasia of the bone marrow which improved after recovery from malarial infection, it was indicated that they were caused by the malarial infection. Generally, it is considered that anemia in malarial patients is caused by destruction of the blood cells by parasites and/or hypersplenism and compensatory hyperplasia of the bone marrow is seen. On the contrary, this case showed pancytopenia accompanied with hypoplasia of the bone marrow probably due to the malarial infection suggesting a new aspect of pathogenesis in the hematological abnormality of the malarial infection.

Herpesvirus ateles immortalizes in vitro a CD3+CD4+CD8+ marmoset lymphocyte with NK function.

Herpesvirus ateles, nonpathogenic in its natural host, the spider monkey, induces a fatal lymphoproliferative syndrome in a variety of New World primate species. Whereas the closely related New World primate virus Herpesvirus saimiri immortalizes in vitro common marmoset lymphocytes that express a TCR and phenotypically are CD4-CD8+NKH1+, we now show that H. ateles-immortalized marmoset lymphocytes are CD3+ and CD4+. Furthermore, these CD4+ lymphocytes coexpress CD8 and NKH1. The NK function of cloned H. ateles-immortalized lymphocyte populations is proportional to the extent to which they express the CD8 antigen. These studies illustrate an interesting example of restricted viral tropism and may indicate a potentially useful means of generating phenotypically stable, functionally competent, cloned lymphocyte populations for study.

Mitogenic responses to lipopolysaccharide by B lymphocytes from patients with systemic lupus erythematosus.

Peripheral blood lymphocytes from 43 patients with systemic lupus erythematosus (SLE) and from age- and sex-matched normal controls were cultured with lipopolysaccharide (LPS) to examine the response to the polyclonal B-cell activator. Lymphocytes from active SLE patients incorporated 4840 +/- 471 (mean +/- SE) cpm in response to LPS, whereas lymphocytes from inactive SLE patients incorporated 6906 +/- 897 cpm. In contrast, lymphocytes from normal individuals incorporated 7452 +/- 1126 cpm. Ig synthesis of lymphocytes from active SLE in response to LPS stimulation was also less than that of normal individuals. The helper T-cell function of active SLE, as examined by co-culturing irradiated SLE lymphocytes with unirradiated normal lymphocytes, was normal. These results thus suggested that a defect of B lymphocytes exists in active SLE patients. This B-cell defect and T suppressor cells apparently play an important role in the pathogenesis of SLE.

Evidence of aberration of T-cell subsets in aged individuals.

In the present study, T-cell subsets from aged individuals were examined by using anti-BAT (brain-associated thymocyte antigen) serum. Anti-BAT serum was raised against the human fetal brain at 28 weeks of gestation. After absorption wit AB erythrocytes, B-cell lines, and leukaemic cells, anti-BAT serum was T cell-specific but unreactive to normal B cells. The ability of anit-BAT serum-treated lymphocytes from aged individuals to respond to concanavalin A, phytohaemagglutinin, and pokeweed mitogen (PWM) was unaltered even at a high concentration. In PWM-stimulated Ig synthesis, T lymphocytes lacking the anti-BAT serum-reactive T-cell subset enhanced the PWM-stimulated Ig synthesis of autologous B lymphocytes from young individuals. The Con A-induced suppressor function of lymphocytes from aged individuals was not significantly abolished by treatment with anti-BAT serum and complement. In the autologous mixed lymphocyte reaction, the decrease in response was minimal when responder cells from aged individuals was treated with anti-BAT serum even at a high concentration. It is concluded that the T-cell subset with suppressor function is defective in aged individuals.

Studies of anti-lymphocyte antibody in patients with active SLE. II. Effect of anti-lymphocyte antibody on autoreactive cell clones.

The effect of anti-lymphocyte antibodies of active systemic lupus erythematosus (SLE) on the immune regulation of autoantibody production was studied. The present study demonstrated that there were native DNA (nDNA)-sensitized T lymphocytes even in inactive SLE and no or few nDNA-sensitized T lymphocytes in normal individuals, and that in the inactive stages of SLE suppressor T lymphocytes might inhibit the activation of nDNA-sensitized T lymphocytes eliciting the production of anti-DNA antibodies by B lymphocytes. In the active stage of SLE, the anti-lymphocyte antibodies could eliminate the suppressor function of T lymphocytes or a subset of cells capable of either regulating their appearance or differentiating into them, which inhibited such responses. The different suppression of DNA and extractable nuclear antigen (ENA)-stimulated blastogenic response is further discussed.

Studies of anti-lymphocyte antibody of patients with active SLE. I. Cause of loss of suppressor T-lymphocyte function.

Effect of anti-lymphocyte antibody of active systemic lupus erythematosus (SLE) on lymphocyte function was examined. Lymphocytes from normal individuals treated with anti-lymphocyte antibody and complement exhibited marked inhibition of response to concanavalin A (Con A), while the response of lymphocytes to phytohaemagglutinin M (PHA-M) and pokeweed mitogen (PWM) was slightly affected. In mixed lymphocyte culture response, both stimulator and responder cells were insensitive to anti-lymphocyte antibody. Treatment of sensitized lymphocytes with anti-lymphocyte antibody and complement caused a dose-dependent suppression of blastogenic response to purified protein derivatives (PPD). No effect, however, was noted on migration-inhibitory factor (MIF)-producing cells. In PWM-driven Ig synthesis, T lymphocytes lacking the anti-lymphocyte antibody-reactive T-cell subset enhanced PWM-driven Ig synthesis of autologous B lymphocytes. Con-A-induced suppressor function of lymphocytes was abolished by the treatment with anti-lymphocyte antibody and complement. The present study demonstrated that lymphocytes from normal individuals after treatment with anti-lymphocyte antibody and complement showed similar immunological reactivities with lymphocytes from active SLE, indicating that those anti-lymphocyte antibodies could play an important role in defective suppressor cell function.

In vitro immune response of SLE lymphocytes. The mechanism involved in B-cell activation.

Peripheral blood lymphocytes from 26 patients with systemic lupus erythematosus (SLE) and six normal individuals were tested for IgG synthesis in the presence or absence of PWM. Lymphocytes from patients with active SLE synthesized increased amounts of IgG in the absence of PWM and reduced amounts of IgG in the presence of PWM. Serum from patients with active SLE had an enhancing effect on the in vitro IgG synthesis of normal lymphocytes. The IgG or F(ab')2 fractions of SLE serum retained the enhancing effect on in vitro IgG synthesis, and the enhancing activity was absorbed by human spleen cells. As little as 4 h of incubation with SLE serum was needed for the enhancing activity of normal lymphocytes. Treatment of B lymphocytes appeared to be of main importance for an increase in the in vitro IgG synthesis of SLE serum-treated lymphocytes. These results suggest that anti-B-lymphocyte antibodies from patients with active SLE are responsible in part for the hyperactive response of SLE B lymphocytes.

Two phenotypically distinct suppressor T cell subpopulations inhibit the induction of B cell differentiation by phytohemagglutinin.

Human B lymphocytes can be induced to differentiate into antibody-secreting plasma cells by Leu-3+ T lymphocytes stimulated with pokeweed mitogen (PWM), a polyclonal T cell activator. In contrast, other polyclonal T cell mitogens, such as phytohemagglutinin (PHA), also activate Leu-3+ T cells but are relatively ineffective inducers of B cell differentiation. We have performed a series of experiments to investigate the mechanism underlying this apparent paradox. When human B cells were cultured with unfractionated T cells and PWM or PHA, only PWM was able to induce plasma cell formation and immunoglobulin (Ig) secretion. However, when the T cells were treated with mitomycin C (MMC) before culture, both PWM and PHA were able to induce significant B cell differentiation. These data indicated that both mitogens were able to activate the helper T cells required for B lymphocyte differentiation and suggested that MMC-sensitive suppressor T cells were responsible for inhibiting the induction of antibody-secreting cells by MMC-untreated T cells stimulated with PHA. Phenotypic analysis of the T cells capable of suppressing PHA-induced B cell differentiation revealed that small numbers of either Leu-2+ or Leu-3+ T cells could profoundly suppress the B cell differentiation induced by PHA. In contrast, significant suppression of PWM-stimulated B cell differentiation was observed only with relatively large numbers of Leu-2+ T cells. These data confirm previous reports that OKT4+/Leu-3+ T cells can suppress human B cell differentiation and indicate that the difference in B cell differentiation induced by PWM and PHA with MMC-untreated T cells is largely a reflection of the relative potency of these mitogens to activate these phenotypically distinct suppressor T cell subpopulations.

Simian immunodeficiency virus induces expression of class II major histocompatibility complex structures on infected target cells in vitro.

The human immunodeficiency virus (HIV) and the closely related simian immunodeficiency virus (SIV) induce profound immune dysfunction in primate species. The present studies show that cell populations infected in vitro with SIV exhibit increases in major histocompatibility complex (MHC) class II antigen expression. Cell lines chronically infected with both the monkey and human viruses express substantially more MHC class II but not more lineage-restricted or activation antigens on their membranes than do uninfected cell lines. Furthermore, 2'-deoxy-5-iodouridine increased MHC class II antigen expression on SIV-infected cell lines in parallel with increased expression of viral antigens. MHC class II induction does not appear to be mediated through the production of a soluble factor, such as gamma interferon, by SIV-infected cells. Interestingly, studies of the kinetics of antigen expression by cell lines after SIV infection indicate that the induction of MHC class II structures is a late event. Immunoelectron microscopy revealed that MHC class II antigen is expressed not only on the surfaces of the SIV-infected cells but also on the envelope of virus particles derived from those cells. MHC antigen expression on virus-infected cells and the expression of those determinants by the virus may play a role in the pathogenesis of acquired immunodeficiency syndrome and the autoimmune abnormalities observed in HIV-infected individuals.

Monoclonal anti-Id antibodies react with varying proportions of human B lineage cells.

Monoclonal antibodies to idiotypic determinants are being used with increasing frequency for analysis and treatment of B cell malignancies. In the present study we have compared the idiotypic specificities of a panel of 39 mouse monoclonal anti-idiotype (anti-Id) antibodies developed against 16 monoclonal human immunoglobulins (Ig). The Id cross-reactivities of these antibodies with Ig products of normal and abnormal B cells were examined by immunofluorescence and immunochemical methods. The reactivity patterns of these anti-Id antibodies with a normal population of plasma cells were highly variable in the immunofluorescence assay. Six were reactive with 2 to 10% of normal plasma cells, 30 with 0.1 to 2% of plasma cells, and three with less than 0.1% of plasma cells from blood, bone marrow, spleen, or tonsils. These reactivity patterns were relatively consistent among samples from 23 Caucasian, black, and Oriental adults. Although the reactivities of most anti-Id antibodies in the panel were not restricted to a particular Ig isotype, several were preferentially reactive with a particular heavy or light chain isotype: one IgM-, two IgA-, two kappa-, and three lambda-restricted antibodies. The immunofluorescence data was confirmed by biosynthetic analysis of Id+ molecules produced by a normal plasma cell population. When the reactivity of this panel of anti-Id antibodies with nonhomologous B cell neoplasms was examined, seven of 30 myelomas or leukemia-derived products and one of nine B cell leukemias or lymphomas without paraproteins were found to be cross-reactive with one or two of the anti-Id antibodies. Although clearly significant, the cross-reactivity between the Id of these paraproteins appeared to be of lower affinity than the reactivity of the homologous Id with their respective anti-Id antibodies. The results reveal a remarkable diversity in the specificities of monoclonal antibodies classified by conventional criteria as anti-Id antibodies, and indicate the potential usefulness of a panel of antibodies for analyzing clonal diversity in normal and abnormal B cell development.

Functional differences of anti-T-cell antibody in patients with systemic lupus erythematosus and ulcerative colitis.

The loss of suppressor T-cell function results in an abundant production of autoantibodies in systemic lupus erythematosus (SLE). As a cause of this suppressor T-cell defect, anti-T-cell antibody seems to be of prime importance. On the other hand, anti-T-cell antibodies can be detected in various other autoimmune diseases, but their functional characteristics have not been determined. In the present study, the functional characteristics of anti-T-cell antibody from a selected subgroup of patients with ulcerative colitis (UC) were compared with those from patients with SLE. Anti-T-cell antibody from the patients with SLE reacted with a T8 subset, resulting in a suppressor defect, whereas anti-T-cell antibody from the UC patients reacted primarily with a T4 subset. Functionally, SLE- T cells failed to proliferate in response to concanavalin A, whereas UC- T cells from UC patients failed to proliferate in response to phytohaemagglutinin. In the Ig synthesis system, both SLE- and UC- T cells increased Ig production of B cells. Since UC+ T cells did not contribute to the generation of Con-A-inducible suppressor activity, we believe that serum from the selected subgroup of patients with UC reacted with the inducer T-cell subset.

Anti-idiotypic antibodies in a patient with monoclonal rheumatoid factor after pneumococcal bacteremia.

A 51-yr-old Japanese female patient with monoclonal IgM gammopathy with rheumatoid factor activity was admitted because of pneumococcal bacteremia. About 2 wk after admission, her rheumatoid factor activity became undetectable by RAHA test and radioimmunoassay, subsequent to the initial marked elevation. The suppressive capacity of the patient's IgG fraction on the rheumatoid activity of her monoclonal IgM on January 11 was determined. The IgG fraction obtained on February 22 blocked the binding of the rheumatoid factor to rabbit IgG. The suppressive activity in the IgG fraction of February 22 was shown to be localized within the F(ab')2 fragment. Furthermore, the specificity of the suppressive serum factor was shown by the inability to block the binding of SRBC coupled with diazotized phosphorylcholine to anti-pneumococcal antibody. Thus, the marked reduction of rheumatoid factor activity was considered to result from anti-idiotypic antibody transiently appearing in her serum after pneumococcal bacteremia.