The role of transforming growth factor beta in the generation of suppression: an interaction between CD8+ T and NK cells.

CD8+ T cells have suppressor effector functions, but the mechanisms involved in the generation of this activity are poorly understood. We report that natural killer (NK) cells have an important role in the acquisition of this function. CD8+ cells induce NK cells to produce transforming growth factor-beta (TGF-beta) which, in turn, stimulates CD8+ T cells to become suppressors of antibody production. Using a monocyte-dependent and -independent method to induce antibody production, we first observed that the addition of NK cells to CD8+ cells was required for optimal suppression. Next, we determined that the interaction of CD8+ T cells with NK cells resulted in a striking increase NK cell TGF-beta mRNA and its production. This cytokine appeared to be involved in the induction of T suppressor cell activity since: (a) anti-TGF-beta 1 completely abrogated the suppression of immunoglobulin G synthesis; (b) TGF-beta 1 could substitute for NK cells in inducing CD8+ T cells to develop suppressor activity; and (c) a short exposure of T cells to TGF-beta 1 in the absence of B cells was sufficient for the generation of suppressor activity by CD8+ T cells. Interferon gamma did not have this property. These studies provide strong evidence that in addition to its suppressive properties, TGF-beta is involved in the generation of CD8+ T suppressor effector cells. Because NK cell function is decreased in many autoimmune diseases, these cells may fail to interact properly with these individuals' CD8+ cells in generating suppressors of aggressive anti-self responses.

Depressed cell-mediated immunity in patients with primary intracranial tumors. Characterization of a humoral immunosuppressive factor.

Tumor immunity in patients with primary intracranial tumors was assessed in relation to the general status of host immunocompetence. Lymphocyte sensitization to tumor-specific membrane antigens was demonstrated by the proliferative response of lymphocytes in the presence of autochthonous tumor cells. Paradoxically, one-half of the patients could not be sensitized to a primary antigen, dinitrochlorobenzene; existing delayed hypersensitivity was also depressed, as measured by skin tests and lymphocyte transformation in response to common antigens. A heat-stable factor in patients' sera blocked cell-mediated tumor immunity. In addition, these "enhancing" sera consistently suppressed the blastogenic response of autologous and homologous lymphocytes to phytohemagglutinin and to membrane antigens on allogeneic cells in the one-way mixed lymphocyte culture. When patients' leukocytes were washed and autologous plasma replaced with normal plasma, reactivity in the mixed lymphocyte culture increased to normal values. In vitro immunosuppressive activity in patients' plasma or sera correlated with depressed delayed hypersensitivity. After removal of the tumor, suppressor activity disappeared. IgG fractions of patient sera contained strong immunosuppressive activity. These data suggest that the suppressor factor may be an isoantibody elicited by the tumor that also binds to receptors on the lymphocyte membrane. In addition to specifically blocking cell-mediated tumor immunity, enhancing sera may broadly depress host immunocompetence.

The development of macrophages from large mononuclear cells in the blood of patients with inflammatory disease.

The origin and function of the increased of "atypical lymphocytes" which appear in the blood of patients with many inflammatory diseases is not known. Leukocyte suspensions from eight patients with systemic lupus erythematosus (SLE), five patients with other rheumatic diseases, and five patients with infectious diseases were pulse-labeled with tritiated thymidine (Tdr-(3)H) and sampled after 5 and 72 hr in vitro. Radioautographs indicated that 35% of the total large, nonphagocytic mononuclear leukocytes incorporated Tdr-(3)H during the initial 5 hr of culture. Tdr-(3)H-labeled large phagocytic or glass-adherent cells were observed only infrequently. After 72 hr one-third of the original number of Tdr-(3)H-labeled cells from patients with SLE developed the morphology of macrophages and the capacity to phagocytose latex particles. Similar findings were observed in patients with other rheumatic diseases and bacterial infections. In contrast, the thymidine-labeled cells from patients with infectious hepatitis and infectious mononucleosis were poorly viable in culture and rarely became macrophages. Tdr-(3)H-labeled small lymphocytes were uncommon. The present experiments suggest that in patients with certain inflammatory diseases large, proliferating "lymphocytelike" cells are very immature monocyte precursors which appear in response to tissue injury. These DNA-synthesizing cells together with mature monocytes may serve as the circulating source of macrophages.

Lymphocytes expressing type 3 complement receptors proliferate in response to interleukin 2 and are the precursors of lymphokine-activated killer cells.

In the absence of antigenic or mitogenic stimulation, certain peripheral blood lymphocytes exhibit proliferative and lymphokine-activated killer (LAK) cell activities when cultured with recombinant IL-2. Both activities were found to be an exclusive property of lymphocytes expressing type 3 complement receptors (CR3) identified by anti-CD11 monoclonal antibodies. CD11+ lymphocytes were then fractionated into three subsets by two-color flow cytometry. These included CD16+ cells, which display distinctive Fc receptors for IgG (CD16). Using anti-CD5, the CD11+ CD16- lymphocytes were separated into non-T cell and T cell subsets. The two non-T cell subsets (CD11+ CD16+ and CD11+ CD16- CD5-), but not the T cell subset (CD11+ CD16- CD5+), could proliferate in response to IL-2. Both CD11+ non-T cell subsets, but not the CD11+ T cell subset, had the capacity to mediate natural killer cell activity. However, all three CD11+ lymphocyte subsets were capable of generating LAK activity. These findings are consistent with the concept that two signals are required to stimulate T cells to proliferate. However, at least a small subset of blood T cells can be activated by IL-2 to become LAK cells.

Evidence by reactivity with hybridoma antibodies for a probable myeloid origin of peripheral blood cells active in natural cytotoxicity and antibody-dependent cell-mediated cytotoxicity.

Lymphocytes with Fc receptors (FcR) for IgG active in natural cytotoxicity and antibody-dependent cellular cytotoxicity were separated into sheep erythrocyte rosetting (E+) and nonrosetting (E-) fractions, and examined for reactivity with the OK panel of hybridoma-produced monoclonal antibodies. Few cells in either the E+ FcR+ or the E- FcR+ fraction reacted with seven antibodies used to define T cells in various stages of differentiation (OK3, OKT4, OKT5, OKT6, OKT8, OKT9, OKT10). Neither fraction expressed an Ia-like antigen (detected by OKI1), but both were highly reactive with OKM1, an antibody that reacts with monocytes and granulocytes. Incubation of these cytotoxic effector cells with OKM1 plus complement abolished all cytotoxic reactivity, but incubation with a pan-T cell antibody (OKT3) plus complement had no significant effect. These cells were not monocyte precursors, because they could not be induced in vitro to develop macrophage characteristics. The data indicate that most cytotoxic effector cells in natural cytotoxicity and antibody-dependent cellular cytotoxicity are not in the T cell lineage, but have a myeloid origin.

Characterizaiton of two populations of human lymphocytes bearing easily detectable surface immunoglobulin.

Two separate lymphocyte populations, each bearing easily detectable surface immunoglobulin, have been detected in human peripheral blood. The first, B cells, has surface determinants that are stable at 37degreeC, but are removed by pronase and regenerate in culture. The cells are nylon adherent and have a receptor for C3, and studies with unit gravity sedimentation indicate they are mostly small lymphocytes. B cells comprise 9.5% of the total lymphocytes, with the normal range from 3-16%. As many or more lymphocytes lack membrane-incorporated Ig determinants but have an Fc receptor that binds IgG1 and IgG3 in normal serum maximally at 4degreeC. This receptor for cytophilic IgG is removed by pronase but not by trypsin. The second population has been named L lymphocytes because of membrane-labile IgG determinants. L cells do not adhere to nylon, do not form rosettes with sheep erythrocytes sensitized with antibody and mouse complement, and are larger than small lymphocytes. These lymphocytes with cold-reactive Fc receptors for serum IgG do not form E-rosettes or respond to phytohemaggutinin. Since L cells do not have surface markers of T and B lymphocytes, it is likely that they comprise a separate population.

Correction of interleukin-2 production in patients with systemic lupus erythematosus by removal of spontaneously activated suppressor cells.

Interleukin-2 (IL-2) production in vitro is depressed in systemic lupus erythematosus (SLE) patients. It is not known whether this abnormality is caused by a defect in the producer lymphocytes or by excessive suppression. We report that removal of OKT8 (Leu 2a)+ cells increased the IL-2 production by in vitro-stimulated lymphocytes to normal or above normal levels in 19 of 21 SLE patients. This increase was more apparent in those patients with clinically inactive disease and/or receiving less than 7.5 mg of prednisone. Removal of OKT8+ cells from normals did not significantly increase IL-2 activity. SLE, but not normal, OKT8+ cells decreased IL-2 production when added back to autologous OKT8-depleted cells. In some experiments, OKT8+ cells from normal donors also suppressed IL-2 production in SLE. This result suggests that the defect in IL-2 production is complex and may involve multiple cell interactions. Three lines of evidence suggest that the SLE OKT8+ cells actively inhibit the production of IL-2 rather than passively absorb this lymphokine: (a) only 3.2% of SLE lymphocytes expressed IL-2 receptors as detected with anti-Tac; (b) freshly prepared SLE lymphocytes did not absorb IL-2; and (c) cell-free supernatants from SLE OKT8+ cells inhibited IL-2 production, but not IL-2 activity. Double-labeling studies by flow cytometry revealed that 19.3% of SLE OKT8+ cells were also Ia-positive, and approximately 33% co-expressed the natural killer cell marker, HNK-1 (Leu 7). Removal of Leu 7+ cells also significantly elevated IL-2 production in SLE. These studies suggest that one or more circulating mononuclear cell subsets in SLE patients can suppress IL-2 production and that one subset may possibly belong to a non-T, non-B "third mononuclear population."

Disseminated Strongyloides stercoralis infection. Association with ectopic ACTH syndrome and depressed cell-mediated immunity.

A patient with disseminated Strongyloides stercoralis was evaluated to elucidate host factors that may have led to the development of this infection. The patient was found to have oat cell carcinoma with hypercortisolism produced by tumor adrenocorticotropic hormone. His serum contained a potent inhibitor of lymphocyte blastogenesis. This patient's high level of endogenous cortisol may have impaired lymphocyte function and thereby facilitated infection with S stercoralis.

Potential roles of hypochlorous acid and N-chloroamines in collagen breakdown by phagocytic cells in synovitis.

We have tested the effects of the neutrophil/macrophage products, hypochlorous acid (HOCl) and N-chloroamines, on the structural integrity and proteolytic susceptibility of collagen to determine if these agents could play a role in inflammatory joint destruction. Rates of HOCl reaction with collagen, and collagen gelation were monitored by spectrophotometric methods. Direct fragmentation, and degradation by collagenase were measured by the release of acid-soluble counts from 3H-collagen. Physiologically relevant concentrations of HOCl (5-50 microM) reacted rapidly and quantitatively at several sites in the collagen polypeptide chain, causing extensive protein fragmentation and preventing collagen gelation. In contrast, reaction with (5-50 microM) N-chloroalanine induced little direct collagen fragmentation. Oxidative damage by N-chloroamines was, however, evident because collagen displayed greatly increased proteolytic susceptibility following N-chloroamine treatment. Collagen degradation by collagenase increased as much as 3-fold after exposure to N-chloroamine treatment. Collagen degradation by collagenase increased as much as 3-fold after exposure to N-chloroalanine. N-chloroleucine caused a small increase in proteolytic susceptibility, but N-chlorotaurine had no effect. Collagen fragmentation by HOCl, inhibition of gelation by HOCl, and N-chloroalanine-induced proteolytic susceptibility, all increased with linear kinetics at oxidant concentrations of 5 microM to 1.0 mM. In synovitis, phagocytes expose collagen to HOCl, N-chloroamines, and collagenase. It is known that HOCl can activate neutrophil procollagenase. Based on our new findings, we propose a model of inflammatory joint destruction that also includes collagen fragmentation, and increased susceptibility of collagen to degradation by collagenase.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of NK cells and TGF-beta in the regulation of T-cell-dependent antibody production in health and autoimmune disease.

Natural killer (NK) cells are a third lymphocyte population especially important in innate immunity. NK cells may also have an important role in the regulation of acquired immunity. These lymphocytes spontaneously produce large amounts of both active and latent transforming growth factor-beta (TGF-beta). NK-cell-derived TGF-beta1 enabled activated CD8(+) T cells to inhibit antibody production by blocking the induction of this response. Production of lymphocyte-derived TGF-beta is decreased in systemic lupus erythematosus. Insufficient levels of this cytokine in SLE and other autoimmune diseases may contribute to defective T regulatory cell function characteristic of this and other autoimmune diseases. NK cells are found in mucosal tissues and the TGF-beta spontaneously released by these cells could contribute to the usual tolerogenic response of T cells to antigens presented at these sites. Thus, in addition to its well known immunosuppressive effects, TGF-beta could have an equally important role in the generation of regulatory T cells.

A relationship between impaired cellular immunity humoral suppression of lymphocyte function and severity of systemic lupus erythematosus.

Eighteen newly diagnosed, untreated patients with systemic lupus erythematosus (SLE) were divided into two groups based on the severity of the disease. Patients with very active disease were nonresponsive to skin test antigens used to assess delayed hypersensitivity. Skin test reactivity was intact in most patients with mildly active disease. Lymphocytes from subjects in both groups responded normally to phytohemagglutinin (PHA) when the results were expressed as counts per minute per million small lymphocytes. Serum from patients with severely active disease markedly suppressed lymphocyte responsiveness of autologous and allogeneic lymphocytes. Serum from patients with mild disease had significantly less suppressor activity. Lymphocytotoxic antibodies and suppressor activity were not correlated. Suppressor activity in immunoglobulin G fraction paralleled that found in whole serum. The present studies suggest that impaired delayed whole serum. The present studies suggest that impaired delayed hypersensitivity in SLE is a consequence of disease activity rather than an inherent feature of this disease. The strong correlation between serum suppression of PHA reactivity and anergy suggests that the humoral immunosuppressive effects described may be responsible, in part, for impaired delayed hypersensitivity in this disease.

Transforming growth factor beta enhances the expression of CD154 (CD40L) and production of tumor necrosis factor alpha by human T lymphocytes.

Activation of lymphocytes in the presence of transforming growth factor beta (TGFbeta) can impair or enhance their functional activity. We have found that TGFbeta is important in the generation of lymphocytes, which are capable of suppressing antibody production. To better understand how this cytokine affects lymphocyte activity, we looked at the expression of early activation events of T cells stimulated in the presence or absence of TGFbeta. The results show that TGFbeta enhances the expression of CD154 (CD40L), TNFR2 and the production of TNFalpha. These findings clarify the co-stimulatory effects of TGFbeta that enhance T lymphocyte activation.

Pseudomonas botryomycosis.

A patient had cutaneous botryomycosis due to Pseudomonas aeruginosa. The diagnosis of botryomycosis was based on the clinical manifestations, results of bacterial culture, and demonstraction of the Gram-negative organisms by tissue Gram stain of the granules in the dermis and subcutaneous fat. Numerous laboratory tests, including tissue immunofluorescence and special studies with the patient's lymphocytes, failed to demonstrate an abnormality that might help to explain the pathogenesis of the granular tissue reaction in this patient.

Tissue and blood T-lymphocyte subpopulations in erythema nodosum leprosum.

To study T lymphocytes in erythema nodosum leprosum (ENL), monoclonal antibodies were used to identify T-lymphocyte subpopulations in the blood and skin lesions of patients with ENL and patients with nonreactional lepromatous leprosy. The blood of nonreactional lepromatous patients had a lymphopenia and a proportionate reduction in pan T cells, helper-inducer, and suppressor-cytotoxic subsets, but a normal helper-suppressor ratio, as compared with controls. Patients with ENL did not differ significantly from the controls. In skin lesions, an admixture of helper and suppressor phenotypes among foamy histiocytes was found. The ENL tissue had more numerous cells of the helper-inducer phenotype and fewer of the suppressor-cytotoxic phenotype, as compared with nonreaction lepromatous tissues. In 22 patients with simultaneous examination of tissue and blood T-cell subsets, there was no correlation between tissue and blood helper-suppressor ratios, indicating that some sort of selection process brings lymphocytes into tissues from peripheral blood.

Diagnostic flexible bronchoscopy in human immunodeficiency virus (HIV)-positive children.

Twelve children with laboratory evidence of human immunodeficiency virus (HIV) infection underwent diagnostic flexible bronchoscopy with washings or bronchoalveolar lavage at Bellevue Hospital Center from October 1987 to April 1989. The patients included 7 boys and 5 girls ranging from age 3.5 months to 10 years 5 months. Indications for bronchoscopy included respiratory distress with or without focal changes on chest radiograph in 11 patients, and persistent but asymptomatic right middle lobe collapse in one child. The etiology of pneumonia was diagnosed in 7 children and included Pneumocystis carinii, (PCP) (17%), Streptococcus viridans (17%), mechanical obstruction (17%) and cytomegalovirus (CMV) (8%). Bronchoscopy was non-diagnostic in 5 cases. Techniques for maximal yield of information using flexible bronchoscopy in HIV-positive children are discussed.

Functional properties of CD8 positive lymphocyte subsets in systemic lupus erythematosus.

CD8+ lymphocytes comprise several cell subpopulations that differ phenotypically and functionally. Although the percentage of T cytotoxic/suppressor cells (CD3+ CD8+) is usually increased in patients with active SLE, these lymphocytes are unable to suppress immunoglobulin (Ig) synthesis. However, freshly prepared lymphocytes from patients with SLE contain CD8+ DR+ cells which spontaneously suppress lymphocyte production of mitogen induced interleukin 2 (IL-2). Furthermore, CD8+ Leu 11+ non-T cells which comprise only 5% of total lymphocytes are also potent suppressors of IL-2 production. At the present time it is not known whether CD8+ suppressors of Ig synthesis and CD8+ suppressors of IL-2 production represent different maturation stages of common precursor cells or represent true heterogeneity of CD8+ lymphocytes.