Peripheral blood monocytes in the autologous mixed lymphocyte reaction

Impairment of autologous mixed lymphocyte reaction in the spleen and peripheral blood lymphocytes of patients with idiopathic portal hypertension

The etiology of idiopathic portal hypertension (IPH) is unknown, although many studies have suggested that it might be an autoimmune disease. The autologous mixed lymphocyte reaction (AMLR) involves the proliferation of T lymphocytes when co-cultured with autologous non-T cells and may reflect immune control mechanisms in vivo. The AMLRs in the spleen and peripheral blood of three patients with IPH were measured and it was shown that the AMLRs both in the spleen and peripheral blood were significantly suppressed compared to those of normal healthy subjects. By allogeneic MLR, there was a tendency that the disturbance of non-T cells was more intensive than that of T cells. The AMLR of peripheral blood did not improve by splenectomy. Thus, the depressed cause of AMLR in patients with IPH was suggested mainly to disturbance of the antigen-presenting ability of non-T cells, and it was suggested that not only the spleen cells, but systemic immune disturbance caused the impairment of AMLR in IPH.

Decreased expression of HLA-DR antigens on monocytes in patients with multiple sclerosis

Immunofluorescence, cell binding assays and enzyme immunoassays were used to investigate the expression of class II major histocompatibility antigens on peripheral blood monocytes in 67 patients with multiple sclerosis. Monocytes from patients with active disease expressed fewer HLA-DR molecules on their surface than normal monocytes; furthermore the percentage of cells which exhibited detectable amounts of surface HLA-DR antigens was decreased in patients with active multiple sclerosis. During the inactive stage of the disease both deficiencies were milder, probably representing secondary pathogenetic phenomena. Quantitation of monocyte surface HLA-DR antigen expression could be valuable in assessing the clinical disease activity. The demonstration of a molecular defect in patients with multiple sclerosis will improve our understanding of the pathogenesis of the disease.

In the murine syngeneic mixed lymphocyte reaction, one T cell subset replicates in the presence of B cells or macrophages and replication is inhibited by simultaneous presence of both stimulator cells

The murine T-non-T cell syngeneic mixed lymphocyte reaction has been examined to determine whether B cells and macrophages stimulate the same or different subpopulations of T cells. By using experiments in which replicating T cells were suicided, we found that the two different stimulators caused replication of what appears to be the same subset(s) of T cells. Since B cells and macrophages carry the same stimulating antigens (class II plus mls or others), one would expect them to stimulate the same T cell subpopulations were it not that they have been reported to stimulate two different subpopulations in humans. When B cells and macrophages were simultaneously used as stimulators, diminished T cell replication occurred. We have found the reduced response is not attributable to exhaustion of culture nutrients or to displacement of the response peak. Other possibilities to account for this marked reduction have been discussed from the viewpoint of suppression emanating from macrophages and/or T cells.

Homogeneity of HLA-DQ,DR phenotypes in lymphocyte subsets of normal individuals

The study was performed to evaluate the association of HLA-DQ and DR antigens with the composition of peripheral blood lymphocytes. B cells, T cells, and T subsets were enumerated in 200 normal individuals by indirect immunofluorescence microscopy using the monoclonal antibodies OKT3, OKT4, OKT8, and OKIa1. Results were related to the HLA-DQ,DR phenotypes of the investigated population. No significant correlation between any of the lymphocyte subsets and of the HLA-DQ,DR antigens was found.

Defective autologous mixed lymphocyte reactions in patients with renal insufficiency--evidence for cellular and serum factors

The autologous mixed lymphocyte reaction (AMLR) was studied in 10 patients who were azotemic from renal diseases not considered to be immunologically mediated. These patients were not on chronic dialysis. The AMLR was significantly depressed in patients with azotemia when compared to the AMLR in normals. When the AMLR was performed utilizing lymphocytes from normals, the proliferative response was markedly decreased if azotemic serum was substituted for normal serum. However, when the AMLR was performed utilizing lymphocytes from azotemic patients, the proliferative response did not significantly improve if normal serum was substituted for azotemic serum. In addition, the proliferative responses of T cells to concanavalin A (Con A) and phytohemagglutinin (PHA) were not significantly depressed in azotemic patients when compared to normal controls. These data suggest that the AMLR is abnormal in azotemic patients because of an intrinsic defect in the mononuclear cells, possibly in the stimulating non-T cells, and an inhibitory factor in the serum.

Association of HLA-DR antigens with the autologous mixed lymphocyte reaction

A study was performed to evaluate the association of HLA-DR antigens with the proliferative response of T cells in autologous mixed lymphocyte cultures. Peripheral blood mononuclear cells from 100 normal healthy individuals were typed for HLA-DR antigens and autologous mixed lymphocyte cultures were established. A low proliferative response from autologous cultures was found with individuals bearing HLA-DR3 antigens and in individuals with only one identifiable HLA-DR antigen. In contrast, a strong proliferative response was associated with HLA-DR6 and two identifiable HLA-DR antigens. These data are consistent with the hypothesis that HLA-DR3 antigens are associated with a weak immune response gene and HLA-DR6 antigens are associated with a strong immune response gene.

Role of normal adherent cells in the regulation of the autologous mixed lymphocyte reactions in humans

The effect of normal adherent suppressor cells on the blastogenesis of human T lymphocytes in the mixed lymphocyte reaction (MLR) was studied in both allogeneic and autologous combinations. Non-T cells and Ia+ T lymphocytes were used as stimulator cells in both allogeneic and autologous MLR. The addition of adherent cells to the stimulators inhibited blastogenesis of T lymphocytes in both types of MLR when the stimulator population was made up of non-T lymphocytes but did not interfere with blastogenesis when Ia+ T lymphocytes were used as stimulator cells. The present data indicate that the T lymphocytes able to respond to Ia+ T cells (in the MLR, autologous or allogeneic) may be different from those which respond to non-T lymphocytes or may be less sensitive to the regulatory function of normal adherent cells.

Autologous mixed lymphocyte reaction in health and disease states in man

In this review are discussed the nature of T cell subsets, defined with monoclonal antibodies, responding in T-non-T and T-T autologous mixed-lymphocyte reactions (AMLR) and antigens stimulating in AMLR, soluble products of AMLR and generation of suppressor, helper and cytotoxic functions. On the basis of these data a model of immunoregulation in vivo can be proposed. We believe that AMLR is a real-phenomenon and not an artefact and perhaps represents a mechanism by which various immune functions are regulated, including feedback regulation of AMLR. The significance of AMLR is further supported by studies in various human and animal diseases.

Studies of autologous mixed lymphocyte reactions in patients with systemic lupus erythematosus

The autologous mixed lymphocyte reaction (AMLR) measures the proliferative response of peripheral blood T cells to surface antigens of non T cells. The AMLR of SLE patients with active or inactive disease either with (13) or without (6) immunosuppressive treatment was low compared with age and sex-matched controls, confirming previous reports. Only one patient with inactive, untreated SLE and one with drug induced lupus (procainamide) showed normal AMLR. Autologous reactivity was also reduced in 2 patients without treatment who presented with clinically complex disease syndromes, including primary biliary cirrhosis, or polyarteritis nodosa, together with Sjögren's syndrome and serological evidence of lupus. The AMLR could not be increased by changing the ratio of responder to stimulator cells. Patients with decreased AMLR also showed a decreased response to phytohemagglutinin which suggested a general depression of T cells. There was no correlation between the decreased AMLR and age, clinical features or anti-DNA antibody levels of the patients. In allogeneic mixed lymphocyte reactions (MLR) it was shown that non-T cells from SLE patients were poorer stimulators of allogeneic T cells than normal cells, and T lymphocytes from SLE patients were poorer responders to allogeneic non-T cells than were normal T cells. Both effects were much more marked in patients with active disease than in those with inactive SLE. This suggests a defect in both responder and stimulating cell populations in SLE.

Induction of suppressor cells in autologous mixed lymphocyte culture (AMLC) in humans

T cells stimulated for 6-7 days in autologous mixed lymphocyte culture (AMLC) showed suppressive effects when added to fresh mixed cultures where autologous lymphocytes (A) were stimulated by Mitomycin C-treated allogeneic lymphocytes (Xm), in a ratio of A:Xm:AMLC-activated cells of 1:1:0.5. Both cytotoxic and proliferative activities in second cultures, as assayed after 6 days of incubation, were significantly inhibited (percentage suppression of cytotoxic activity observed in 17 experiments was 75.3 +/- 22.4; percentage suppression of proliferation was 60.6 +/- 18.2). Suppressor cells (SC) generated in AMLC were Mitomycin C sensitive and nonspecific in their action; not only A/Xm but also X/Am and X/Ym cultures were suppressed to the same extent. AMLC-Activated cells showed a considerable degree of proliferation in response to alloantigens but failed to express any cytotoxic activity against autologous or allogeneic phytohemagglutinin blasts. Thus, the inhibitory effect observed in this system is not due to cytotoxic elimination of responding or stimulating cells in the second culture but rather reflects a true regulatory (suppressive) mechanism.

Autologous mixed lymphocyte reaction in man. IV. Decreased autologous mixed lymphocyte culture response in patients with common variable immunodeficiency

The autologous mixed lymphocyte reaction (AMLR) was studied in 18 patients with common variable immunodeficiency. The AMLR was decreased in 10 of 18 (55%) patients with common variable immunodeficiency compared to healthy controls. In allogeneic MLR, T cells from patients were found to be poor responders, and non-T cells poor stimulators, compared to allogeneic MLR between healthy normal controls. In allogeneic MLR, B cells (B cells + null cells) from patients were poor stimulators, whereas macrophages stimulated normally compared to controls. The deficient AMLR could be one of the mechanisms responsible for the increased risk of autoimmune phenomena in a subset of patients with primary immunodeficiency.

Factors influencing the autologous mixed leukocyte reaction in normal subjects

The proliferative response of T cells to autologous non-T cells (autologous mixed leukocyte reaction, AMLR) varies with the duration of incubation as well as the concentration and nature of the stimulator cells. The peak response was generally found on days 6, 7 or 8 of incubation, but with unseparated non-T cells, as well as varying in different individuals this varied in the same individual on different days. Removal of adherent cells from the stimulator population increased the magnitude of the peak response and improved day-to-day consistency both in size of peak response and in the duration of incubation required. Adherent cells were poor stimulators. Some of the variability in AMLR in normals and the differences between normal and disease subjects may relate to inclusion of an adherent cell population in the test and to the use of a fixed time period for incubation.

Diminished autologous mixed lymphocyte reaction in patients with Hodgkin disease: evidence for non-T cell dysfunction

In the autologous mixed lymphocyte reaction (AMLR), T lymphocytes are stimulated to proliferate by autologous non-T mononuclear cells. In five untreated patients with Hodgkin disease, the AMLR was diminished. In addition, in the same five patients, T cell response PHA was inhibited by a cell in the non-T cell fraction, the response of non-T cells to PWM was diminished, and there was a diminished ability of the non-T cell population to stimulate in allogeneic MLR. However, the response of T cells from patients with Hodgkin disease to allogeneic antigen was normal. The AMLR and allogeneic MLR were then studied in an additional five untreated patients before and after monocyte depletion of the stimulating non-T mononuclear cell population. In this second group of Hodgkin disease patients, the AMLR was again diminished when T cells were incubated either with non-T cells or non-T cells depleted of monocytes. In the Hodgkin patients, monocyte depletion did not alter the T cell response in the AMLR. In the controls, monocyte depletion greatly diminished the proliferative response. The diminished AMLR in untreated Hodgkin disease patients may be the result of a failure of adequate monocyte stimulation of autologous T cells.

Autologous and allogeneic mixed lymphocyte reactions in progressive systemic sclerosis

The autologous and allogeneic mixed lymphocyte reactions (MLR), observed when peripheral blood mononuclear cells from 20 patients with progressive systemic sclerosis were used, were compared with those of age-, sex-, and race-matched normal controls. Such cells were separated by gradient centrifugation of sheep red blood cell (E) rosettes into stimulator (E- or non-T cell) and responder (E + or T cell) populations. The autologous MLR of both the progressive systemic sclerosis and normal peripheral blood mononuclear cells varied widely but there was no statistical difference between the means of each group. In the allogeneic MLR, proliferation between progressive systemic sclerosis non-T cells and normal T cells was significantly less than that of normal non-T cells and progressive systemic sclerosis T cells (P = 0.001). A decreased autologous MLR, while noted with other autoimmune diseases, was lacking in progressive systemic sclerosis. This suggests a different defect. The differences in the allogeneic MLR also suggest that either progressive systemic sclerosis non-T cells were poor stimulators or T cells associated with this disease were better responders when compared with similarly prepared cell populations from normal individuals. The MLR differences could have also resulted from compositional subset alterations or the sharing of a common antigen. HLA-DR5 was found in 9 of the 17 white patients with progressive systemic sclerosis. Although these individuals were evenly distributed as low, medium, and high responders, this finding showed that some progressive systemic sclerosis non-T cells shared a common antigen.

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.

Cell volumes of normal and malignant mononuclear cells

The cell volumes of mononuclear cells, T lymphocytes, B lymphocytes, and monocytes from the peripheral blood of 20 normal individuals were compared to neoplastic lymphoid cells from 14 patients with chronic lymphocytic leukaemia (CLL), 20 individuals with acute lymphocytic leukaemia (ALL), and 18 cases of non-Hodgkin's lymphoma (NHL). Normal T cells were obtained by rosetting mononuclear cells with sheep erythrocytes followed by centrifugation on a gradient composed of Ficoll and diatrizoate salts. Monocyte populations were prepared by adhering mononuclear cells to plastic dishes and B cells were obtained by the depletion of T lymphocytes and monocytes from a mononuclear cell population. Cell volumes were determined on a Coulter Counter Model H4 Channelyzer. In normals, the average mean cell volume (MCV) of T lymphocytes was smaller than B lymphocytes and the average MCV of B lymphocytes was smaller than the average MCV of monocytes (p less than 0.05). The average MCV of lymphocytes from patients with CLL was smaller than the average MCV of normal B cells (p less than 0.01). The average MCV of lymphoblasts from cases of ALL was larger than the average MCV of normal peripheral blood lymphocytes (p less than 0.01). In addition, the size of lymphoblasts showed great variation within and among cases of ALL. The MCV of lymphocytes from most cases of NHL was larger than the MCV of lymphocytes from reactive lymph nodes and from the peripheral blood of normal individuals. An association was observed between the MCV of neoplastic cells and the classification according to Rappaport. We believe that the measurement of lymphoid cell volumes may be helpful in the diagnosis and prognosis of patients with a variety of lymphoproliferative disorders.

Autologous mixed lymphocyte reaction in man. III. Regulation of autologous MLR by theophylline-resistant and -sensitive human T-lymphocyte subpopulations

Human peripheral blood T lymphocytes were separated into theophylline-resistant (TR) and -sensitive (TS) subpopulations. Proliferative responses TR, TS and unfractionated T cells were studied, using irradiated autologous or allogeneic non-T cells as stimulators. TR cells proliferated vigorously in both autologous and allogeneic mixed lymphocyte cultures (MLC). TS cells. which constitute about 20% of unfractionated T cells, exhibited poor proliferative responses to autologous and allogeneic stimulation. The magnitude of proliferation in autologous and in allogeneic MLC was found to be directly dependent on the number of TR cells in the culture. Mitomycin-C (MMC)-treated TR cells augmented and MMC-treated TS cells suppressed (P less than 0.05) the autologous and allogeneic MLC responses of unfractionated T cells. However, the response of TS cells did not increase in autologous or allogeneic MLC when co-cultured with MMC-treated TR cells. MMC-treated TS cells, when co-cultured with TR cells, suppressed the responses of TR cells (P less than 0.05). The enhancing effect of TR cells was radiation-resistant. Suppressor influence of TS cells, in contrast, was abolished by irradiation (P less than 0.05). These findings demonstrate that TR cells are the responding cell in autologous MLR and augment the MLC responses of unfractionated T cells. TS cells, on the other hand, respond poorly in autologous or allogeneic MLC and suppress the response of TR cells.