Human post-thymic precursor cells in health and disease. VI. Effect of serum thymic factor on the response of cells from patients with systemic lupus erythematosus or mixed connective tissue disease in autologous mixed lymphocyte reaction

Release of granulocyte-macrophage colony-inhibiting activity by normal human postthymic precursor cells

Seven normal human peripheral blood cell fractions (buffy coat, mononuclear cells, non-T, T, Fc-IgM receptor-depleted T-lymphocyte, Fc-IgG receptor-depleted T-lymphocyte, and autologous rosette-forming T-cell-depleted T-lymphocyte subpopulations) treated with phytohemagglutinin (PHA) were examined for the production of granulocyte-macrophage colony-stimulating activity (CSA). It was found that medium conditioned by a T-lymphocyte subpopulation depleted of autologous rosette-forming T-cells (Tar cells, a postthymic precursor subpopulation that inhibits Ig synthesis) stimulated colony-forming units of granulocyte and macrophages (CFU-GM) to a greater extent than did the other conditioned media (CM) analyzed. Based on this finding, CM from an enriched Tar subpopulation was prepared and thus showed that PHA-treated Tar cells release a factor capable of inhibiting CFU-GM growth. The inhibitory activity of this factor persisted-after heat inactivation, suggesting that cause of the colony-inhibiting activity (CIA) is other than interferon. Further studies revealed that Tar-derived inhibitory factor acts either directly upon CFU-GM or via monocytes/macrophages (M phi/Ma), enhancing CIA, and not the level of CSA production by M phi/Ma. The overall data are interpreted as demonstrating the presence of CIA in a specific T-lymphocyte subpopulation that may represent a new relationship between lymphocytic and myelocytic systems in the human.

Effect of periodontal therapy on spontaneous lymphocyte response and neutrophil chemotaxis in localized and generalized juvenile periodontitis patients

The etiology and pathogenesis of juvenile periodontitis may involve dysfunctions of the host response. In particular, the neutrophil and the lymphocyte have been implicated in the disease. The purpose of the present study was to examine the in vitro spontaneous lymphocyte response and neutrophil chemotaxis in populations of localized juvenile periodontitis (LJP) and generalized juvenile periodontitis (GJP) patients and age- and sex-matched healthy subjects (HS). These laboratory values were also evaluated immediately following and 1 year after periodontal therapy. The results show that spontaneous lymphocyte responses reflecting the autologous mixed lymphocyte reaction (AMLR) are depressed for GJP patients. The decreased AMLR in the GJP group appears to represent an abnormal T-cell function which may reflect activity of the periodontal lesion. LJP patients have an increased AMLR response, although it was not statistically significant. 1 year following active periodontal therapy, spontaneous lymphocyte responsiveness returned to normal in most GJP patients. The increased spontaneous lymphocyte responsiveness of LJP patients was not changed either immediately following active periodontal therapy or 1 year later. LJP and GJP patients exhibited a neutrophil chemotaxis defect when compared to cells from HS. This neutrophil defect was still observed 1 year following active therapy.

Thymic peptide hormones: basic properties and clinical applications in cancer

The manuscript will provide an in-depth and critical review of the nomenclature, biochemistry, biological properties, and a summary of published and on-going clinical trials with all reported thymic preparations, including both partially purified thymic factors (e.g., thymosin fraction 5, thymostimulin) as well as purified and synthesized thymic peptides (e.g., thymosin alpha 1, thymulin). Particular emphasis will be placed on which thymic peptides should be categorized as true hormones. In addition, the comparative biochemistry and biological activity in animals will be summarized and contrasted for all the currently available thymic factors. The effects, in vitro of thymic factors, on peripheral blood lymphocytes isolated from normal donors and patients with primary immunodeficiency disorders, autoimmune disorders, and neoplastic disorders will also be reviewed. Finally, a detailed critical summary of the clinical trials performed with each of the thymic preparations will be presented with an emphasis on treatment of patients with cancer.

Differences in the kinetics of the autologous mixed lymphocyte reaction between the various connective tissue diseases

Kinetic studies of autologous mixed lymphocyte reaction (AMLR) over 7 days were made in 86 patients with various connective tissue diseases. None was receiving any treatment and each disease group was controlled with age-sex matched healthy controls. There were exceptions, but, as a rule, SLE patients (n = 22) had decreased responses on days 6-7. This was more apparent in patients with active disease than in those with inactive disease. Patients with scleroderma (n = 21) had early (day 4) proliferative responses. Half of the patients with RA (n = 14) had early (day 3) proliferation, but as a group they had normal increase in 3HtdR uptake on day 7. Patients with primary Sjögren's syndrome showed flat curves throughout and no significant proliferation on days 6-7 of culture. The pattern found in patients with mixed connective tissue disease (n = 11) was also peculiar in that they had peak proliferative responses on day 3 and normal 3HtdR uptake on days 6 and 7 of the AMLR. The number of patients with dermatomyositis or polymyositis was small (n = 6), but they showed a significant mean decrease in uptake on days 6-7. Studies using subpopulations of stimulatory cells further indicate that these patterns reflect immunoregulatory disturbances peculiar to each disease.

The autologous mixed lymphocyte reaction is not primarily due to xenoantigenic stimulation

Autologous mixed lymphocyte reaction (AMLR) is an interesting in vitro system in which T lymphocytes proliferate when cultured with non-T cells from the same individual. Because this system has both memory and specificity and elicits help, suppression, cytotoxicity, and soluble mediators, it has been proposed that it reflects in vitro the complex interactions of the immunologic network as it operates in vivo. A recent study, however, has cast doubt on the significance of this reaction by implicating xenoantigens, present during separation and/or culture procedures (e.g., sheep red blood cells or fetal calf serum), in the proliferative response of T cells. This question is analyzed by performing AMLR studies with cells (from eight normal subjects) that were separated with and without the use of sheep erythrocytes, and incubated with either fetal calf serum on normal human AB serum. Results were similar in all circumstances and negate a primary role of xenoantigens in AMLR.

Interleukin-2 and serum thymic factor enable autologous rosette-forming T lymphocytes to generate helper and cytotoxic functions

The autologous rosette-forming T cells (Tar cells) isolated by means of their ability to form rosettes with autologous erythrocytes were characterized by the use of OKT monoclonal anti-human T-cell subset antibodies and a monoclonal anti-HLA-DR antibody. We found that the phenotype of Tar cells was OKT 3+4+8+Dr- as determined by both indirect immunofluorescence microscopy and complement-mediated killing of 51Cr-labelled Tar cells. In addition, we found that Tar lymphocytes were able to develop cytotoxicity against allogeneic and trinitrophenol (TNP)-conjugated autologous target cells in the presence of interleukin-2 (IL-2) or serum thymic factor. However, these cells showed little or nor cytotoxicity in the absence of interleukin-2 or serum thymic factor. Tar lymphocytes generated helper function for B lymphocytes in the presence of interleukin-2 in both pokeweed mitogen (PWM)- and purified protein derivative (PPD)-stimulated cultures. Nevertheless, non-IL-2-treated Tar cells did not exhibit any helper activity on B cells. Finally, pretreatment of Tar cells with 1000-1500 rad of X ray made these cells unable to develop helper function for B lymphocytes. It is concluded that: (1) OKT 3+4+8+Dr- Tar cells are able to generate cytotoxicity against alloantigens and TNP-labelled self structures provided they are stimulated by IL-2 or serum thymic factor; (2) these cells need both to proliferate and to receive help from IL-2 to develop helper cells capable of assisting B-lymphocyte differentiation into plasma cells in both PWM- and PPD-stimulated cultures.

Hydrocortisone abrogates proliferation of T cells in autologous mixed lymphocyte reaction by rendering the interleukin-2 Producer T cells unresponsive to interleukin-1 and unable to synthesize the T-cell growth factor

Hydrocortisone (HC-A) inhibited the proliferative response in the autologous mixed lymphocyte reaction (AMLR). The inhibitory activity became apparent 48 h after initiation of the cultures and was maintained throughout the culture period. T cells from cultures treated with HC-A showed a proliferative response to interleukin-2 (IL-2) of a similar degree as T cells from cultures not exposed to this drug. Hydrocortisone abrogated the production of IL-2 in AMLR. The addition of interleukin-1 (IL-1) to HC-A-treated cultures did not restore or increase the synthesis of IL-2, whereas IL-1 added to non HC-A treated cultures significantly enhanced the synthesis of IL-2, Finally, IL-2 but not IL-1 could overcome the abrogatory effect of hydrocortisone on proliferation of T cells induced by AMLR. These results indicate that HC-A inhibits proliferation of T cells in AMLR by causing the IL-2 producer T cells to become unresponsive to IL-1 and unable to synthesize IL-2. This drug does not, however, interfere with the process by which resting T cells acquire responsiveness to IL-2.

Epstein-Barr virus increases the proliferative response and the generation of suppressor and cytotoxic T-cell functions in autologous mixed lymphocyte reaction

Epstein-Barr virus (EBV) infection of stimulator cells significantly increased the proliferative response of T cells in the autologous mixed lymphocyte reaction (AMLR). The addition of a monoclonal anti-HLA-DR antibody to AMLR cultures in which either EBV-infected or non-infected non-T cells were used as stimulator cells strongly inhibited the proliferative response irrespective of the presence of EBV. It is concluded that EBV does not by itself activate the responding cells and that HLA-DR antigens are necessary to trigger T cells. Increased generation of suppressor T cells, determined in both alloantigen-induced DNA synthesis and pokeweed-mitogen-stimulated immunoglobulin production, was found after an EBV infection of stimulator cells. Similarly, EBV-infected non-T cells significantly increased the generation of killer T cells, determined in three different types of target cells: phytohaemagglutinin-stimulated mononuclear cells, EBV-transformed cells, and concanavalin-A-activated murine spleen cells. The increased T-cell responses after an EBV infection may reflect the attempts in vivo to control and hold in check the viral infection.

Role of individual chains of HLA-DR antigens in activation of T cells induced by alloantigens

The role of HLA-DR antigens in the activation of T cells in the allogeneic mixed lymphocyte reaction (MLR) was studied by using antibodies raised against the alpha, beta or the complex of both chains of the HLA-DR antigens. Antisera directed against the alpha or the beta chain strongly inhibited the T-cell proliferative response when added at the beginning of MLR cultures but not 72 h later. T cells from MLR cultures treated with either alpha-chain- or beta-chain-specific antibodies did not respond to interleukin-2 (IL-2) by proliferating, whereas T cells from non-anti-DR-treated cultures showed a proliferative response to IL-2-stimulation. However, neither the anti-alpha chain nor the anti-beta chain serum was able to inhibit continuous proliferation of already activated, IL-2-reactive T cells supported by IL-2. In MLR, OKT4+ but not OKT8+ lymphocytes synthesized IL-2. This function was abrogated by the alpha-chain-specific antibody but not by the anti-beta chain serum. Interleukin-1 (IL-1) did not reverse the inhibitory activity on IL-2 synthesis of the alpha-chain antibody, while IL-1 promoted the production of IL-2 in MLR cultures not exposed to the anti-DR sera. In addition, nonstimulated OKT4+ cells were unresponsive to IL-1 and did not produce IL-2. From these results, it is concluded that HLA-DR antigens participate actively in the activation of T cells by allogeneic non-T cells. Thus, both the alpha and beta chains of HLA-DR antigens render resting T cells sensitive to IL-2. In addition, the alpha but not the beta chain participates in the production of IL-2 by enabling OKT4+ lymphocytes to respond to IL-1 and subsequently to synthesize IL-2. Once T cells have acquired responsiveness to IL-2 and this growth factor has been produced there is no further requirement for HLA-DR antigens. Continuous proliferation and growth of IL-2-reactive T cells depends on the availability of interleukin-2.