Retrobulbar T cells from patients with Graves' ophthalmopathy are CD8+ and specifically recognize autologous fibroblasts

Graves' ophthalmopathy is an autoimmune condition characterized by T cell infiltration of the retrobulbar tissue. Phenotypic and functional analysis of these infiltrating cells may provide insight into the pathogenesis of the disease. IL-2-responsive cells were therefore grown out of the retrobulbar tissue from two patients with severe Graves' ophthalmopathy undergoing orbital decompression surgery, and six T cell lines were established and characterized. They consisted predominantly of CD8 + CD45RO+ cells and secreted IL-4, IFN-gamma, and IL-10 upon activation. When screened for their antigen reactivity, all lines proliferated in response to stimulation with autologous retrobulbar fibroblasts in an HLA class I-restricted manner, but did not recognize autologous peripheral blood mononuclear cells, crude eye muscle extract, allogeneic cells, or purified protein derivate of Mycobacterium tuberculosis. In contrast, PBMC from the same patients responded readily to purified protein derivate of Mycobacterium tuberculosis and allogeneic PBMC, but did not recognize autologous fibroblasts. Interestingly, only one of the six retrobulbar T cell lines displayed cytotoxicity towards its specific target cell population. These results suggest that the retrobulbar fibroblasts are a major T cell target in Graves' ophthalmopathy. Pronounced cytokine production in the absence of target cell cytotoxicity may explain fibroblast proliferation, glycosaminoglycan secretion, and secondary eye muscle enlargement in this condition.

A single injection of Staphylococcus aureus enterotoxin B reduces autoimmunity in MRL/lpr mice

MRL/Mp-lpr/lpr (MRL/lpr) mice carry a mutation in the Fas gene whose product is involved in the regulation of lymphocyte apoptosis. This mutation is associated with the lpr phenomenon, i.e., a massive expansion of phenotypically abnormal CD4-CD8- cells ("double negative," DN) alpha/beta T cells (lpr cells) that becomes manifest at 3-4 months of age. As in normal mice, intravenous SEB injection into 2- or 6-month-old female MRL/lpr mice causes a transient expansion of SEB-reactive V beta 8+ T cells, followed by a deletion of this subset. In contrast, in the same animals, the frequency of abnormal V beta 8+CD4-CD8- cells is not modulated by SEB. Whereas DN T cells are completely resistant to SEB-mediated deletion in vivo, their precursors appear susceptible to SEB-induced deletion. Thus, a single injection of SEB prior to the surge of DN T cells in peripheral lymphoid organs, at 2 months of age, is sufficient to cause a stable long-term (6 months) deletion of DN cells. This is accompanied by a significant amelioration of autoimmune parameters (autoantibody titers, incidence of arthritis and nephritis), thus pointing to the feasibility of employing superantigens for simple manipulations of the immune repertoire that result in the long-term prophylaxis of autoimmune diseases.

Thymocyte apoptosis induced by elevated endogenous corticosterone levels

A well-known model of apoptosis is induction in thymocytes by injection of pharmacological doses of exogenous steroids. The aim of this study was to investigate whether this process also occurs under physiological conditions, i.e. by stimulation of endogenous glucocorticoid release, using the chicken as an experimental model. Endogenous glucocorticoid levels can be elevated by immunization with exogenous antigens or by injection of conditioned medium, e.g. supernatant of mitogen-stimulated spleen cells. This effect is mediated by so-called glucocorticoid-increasing factors, and is considered to act as an immunoregulatory principle. Thymocyte DNA of so treated birds showed a typical "ladder" pattern after electrophoresis in a 1.8% agarose gel, and degradation could be prevented by RU 38,486. This provides evidence that apoptosis can be induced by elevating endogenous corticosterone levels in vivo. By means of in situ nick translation (ISNT) and simultaneous immunofluorescence tests, it was possible to analyze various thymic subpopulations during apoptosis after treatment with exogenous glucocorticoids. Additionally, using confocal microscopical techniques, apoptosis of the same cells as analyzed by ISNT is shown. The possible role of elevated concentrations of endogenous glucocorticoids in regulating thymocyte cell death and autoimmune diseases is discussed.

The molecular basis for epitopes on the free beta-subunit of human chorionic gonadotrophin (hCG), its carboxyl-terminal peptide and the hCG beta-core fragment

The molecular basis for antigenic determinants on the free beta-subunit of human chorionic gonadotrophin (hCG beta), its carboxyl-terminal peptide (hCG beta CTP) and the hCG beta-core fragment (hCG beta cf) was elucidated by means of monoclonal antibodies (MCAs). The objective of the present study was to resolve the antigenic topography of these three molecules in terms of epitope identification at different levels of structural organization as well as analysis of their spatial arrangement. An hCG beta cf preparation, a synthetic peptide corresponding to the hCG beta CTP (beta 109-145), overlapping synthetic peptides spanning the entire amino acid sequence of hCG beta, and a reduced and alkylated hCG beta preparation were assayed in a solid-phase one-site enzyme-linked immunoassay and in a soluble-phase direct-binding radioimmunoassay (RIA) or competitive RIA. The antigenic topography was mapped by incorporating the MCAs into two-site binding assays. On the surface of free hCG beta, nine different epitopes (beta 1-beta 9), arranged in three spatially distinct domains, could be distinguished. Epitopes beta 1-beta 7 were located in a single large domain on both hCG beta and the hCG beta cf whereas hCG beta CTP contained two topographically distant determinants, designated beta 8 and beta 9 respectively. All but the two epitopes located on hCG beta CTP (beta 8 and beta 9) were destroyed by reducing and alkylating hCG beta, suggesting that most antigenic determinants are predominantly non-contiguous and require an intact tertiary structure whereas the molecular structure of hCG beta CTP is linear. At a molecular level, amino acid residues spanning hCG beta 45-52, hCG beta 137-144 and hCG beta 113-116 contributed to the formation of epitopes beta 5, beta 8 and beta 9 respectively. We have also shown that the hCG beta cf represents the immunodominant part of the free beta-subunit of hCG, containing seven mainly conformationally determined epitopes, one of which has a share of the sequence beta 45-52. The hCG beta CTP does not play a critical role in the immunologically important tertiary structure of hCG beta and was itself found to be a predominantly continuous sequence also within the native hormone, expressing two spatially distant antigenic determinants located within residues beta 113-116 and beta 137-144 respectively.

Immune response in the lungs following oral immunization with bacterial lysates of respiratory pathogens

We have investigated the local immune response of the BALB/c mouse respiratory tract after oral immunization with a bacterial lysate of seven common respiratory pathogens. After two immunization on five consecutive days, we examined the immunoglobulin (immunoglobulin G [IgG], IgM, and IgA) secretion rates of cells isolated from the lungs and compared them with those of spleen cells of orally immunized and nonimmunized animals by using a new test system based on time-resolved fluorescence. The procedure followed the principle of the classical ELISPOT test with nitrocellulose-bottomed microtiter plates, but europium (Eu3+)-linked streptavidin rather than enzyme-conjugated streptavidin was used, with the advantage of quantifying secreted immunoglobulins instead of detecting single antibody-secreting cells. Lymphocytes isolated from the lungs of treated animals revealed significant increases in total and antigen-specific IgA synthesis compared with the rates of the controls, whereas IgG and IgM production rates showed no remarkable differences. In addition, the sera of treated mice revealed higher antigen-specific IgA titers but not increased IgM and IgG levels. We conclude that priming the gut-associated lymphoid tissue with bacterial antigens of pneumotropic microorganisms can elicit an enhanced IgA response in a distant mucosal effector site, such as the respiratory tract, according to the concept of a common mucosa-associated immune system.

Asbestos fibers in bronchoalveolar lavage and lung tissue of former asbestos workers

Bronchoalveolar lavage (BAL) provides a simple method of sampling inhaled particles deposited in the lower respiratory tract. We hypothesized that BAL could be used to measure the quantity and quality of lung asbestos burden. This would be true if BAL fluid asbestos fiber content reflected the total content as well as the size distribution of both uncoated and coated asbestos fibers in lung parenchyma. Therefore, we analyzed the asbestos fiber counts of 23 individual sample pairs in both BAL fluid and lung tissue samples obtained from 20 patients with occupational asbestos exposure using transmission electron microscopy (TEM). In addition, fiber type, fiber size, and aspect ratio were compared. Coated asbestos fibers were found in 10 of 23 BAL samples and 16 of 23 biopsies. The mean concentrations of coated asbestos fibers (i.e., asbestos bodies) in BAL and lung parenchyma showed a positive correlation (r = 0.75, p < 0.001). Likewise, the mean amphibole fiber concentrations correlated positively (r = 0.55, p < 0.01). However, there was no relationship between the mean chrysotile fiber counts in BAL and lung parenchyma (r = 0.18, p = 0.40). Asbestos fibers in lung tissue were significantly longer (8.2 +/- 0.5 versus 4.8 +/- 0.6 microns; p < 0.001) but had the same width (0.12 +/- 0.27 versus 0.11 +/- 0.15 microns; p = 0.24) when compared with those retrieved by BAL from the airspace compartment. The aspect ratio (dividing fiber length by width) was much higher in lung tissue than in BAL fluid (66.4 +/- 0.4 versus 42.9 +/- 0.5; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Genetically determined target organ susceptibility in the pathogenesis of spontaneous autoimmune thyroiditis: aberrant expression of MHC-class II antigens and the possible role of virus

Considerable controversy exists concerning the role of aberrant MHC-class II antigen expression in the pathogenesis of organ-specific auto-immune disease. Since Obese strain (OS) chickens are afflicted with a spontaneously occurring autoimmune thyroiditis (SAT), we have readdressed this pivotal question by investigating the chronical appearance of MHC-class II antigens on thyroid epithelial cells (TEC) of OS and normal healthy CB chickens before onset of overt clinical symptoms in the former. Among the candidates as potent inducers of aberrant MHC-class II antigen expression, interest in our studies focussed on the potential role of viruses in the development of SAT. Since aberrant MHC-class II antigen expression could prove to be an epiphenomenon of virally afflicted TEC, we determined 2,5-oligoadenylate synthetase and 2,5-oligoadenylatepolymer cytosol levels in both chicken lines. Our results indicate that the presence of infiltrating lymphocytes does not necessarily represent a prerequisite for the aberrant expression of MHC-class II antigens but coincides in most cases. However, the phenomenon seems to play a perpetuating rather than a causative role. Moreover, in support of a possible viral involvement, elevated levels of the 2,5-oligoadenylate synthetase and 2,5-oligomers could be demonstrated in TEC cytosol of OS chickens.

A novel and sensitive method for the detection of secreted cell products using time-resolved fluorescence

A new test has been developed for the quantitative detection of products secreted from isolated cells, based on the use of lanthanide- rather than enzyme-linked streptavidin. Used as a label, europium (Eu3+) can be measured with high sensitivity by time-resolved fluorescence. The main advantages of this assay are both an increased sensitivity and measuring range of cell released substances, when compared to the standard "wet" ELISA. Thus, the immunoglobulin secretion rate of 10(5) splenocytes could be easily measured by time-resolved fluoroimmunoassay (TR-FIA), while it remained below the detection limit of the 'wet' ELISA. In contrast to the classical ELISPOT test, this assay does not detect single antibody secreting cells (ASC), but would be useful for precise quantification of secreted cell products, such as immunoglobulins, cytokines, growth factors.

Ultrastructural analysis of thymic nurse cell epithelium

Thymic nurse cells (TNC), a paradigmatic cell type of cortical epithelium, are large lymphoid-epithelial cell complexes of thymocytes enclosed within vacuoles lined by the epithelial cell membrane. TNC express major histocompatibility complex (MHC) class I and class II molecules on their surface and vacuole-lining membranes at high density and it was suggested that TNC provide an optimal microenvironment for positive selection of T cells. In this report we present electron microscopical data demonstrating that chicken TNC display morphological structures of exocytosis previously shown for hormone-secreting cells. In TNC, however, exocytosis is restricted to the capillary cleft between the epithelial cell and engulfed thymocytes. Thus, besides physical contact between the epithelial cell and enclosed thymocytes, TNC may additionally influence the development of thymocytes through release of soluble factors in a restricted microenvironment. By employing the 3-(2,4-dinitroanilino)-3'-amino-N-methyl-propylamine technique which at the ultrastructural level detects acidic organelles involved in processing of antigens presented by MHC class II molecules, we also show that TNC contain acidic compartments similar to classical antigen-presenting cells, i.e. early and late endosomes and lysosomes, albeit in a lower amount than in thymic dendritic cells. This fact provides evidence that TNC not only are capable of antigen presentation but also possess the intracellular machinery for antigen processing.

Free alpha subunit of human chorionic gonadotrophin: molecular basis of immunologically and biologically active domains

Immunochemical studies were undertaken to identify surface-orientated epitopes of the free alpha subunit of human chorionic gonadotrophin (hCG-alpha) at the amino acid sequence level. We investigated the molecular organization of these epitopes, resolved the immunological topography in terms of spatial arrangement of antigenic domains and related structures to functions such as subunit association or receptor binding. Overlapping synthetic peptides covering the entire amino acid sequence of hCG-alpha, an enzymatically digested hCG-alpha subunit, and a reduced and alkylated hCG-alpha preparation were assayed in a solid-phase one-site enzyme-linked immunoassay, and in a solution-phase competitive radioimmunoassay (RIA). The antigenic topography was mapped by monoclonal antibodies (MCAs) in two-site binding assays (sandwich RIA). On the surface of hCG-alpha, seven different epitopes (alpha 1-alpha 7), arranged in four spatially distinct domains, could be distinguished: A, alpha 1,2,4; B, alpha 3,5; C, alpha 6; D, alpha 7. The peptides spanning hCG-alpha(13-18), hCG-alpha(17-22) and hCG-alpha(33-42) appeared to contribute to the formation of epitopes alpha 2, alpha 4 and alpha 6 respectively. Since epitope alpha 6 is present only on the free non-assembled subunit of different species, we concluded that the region hCG-alpha(33-42), which is evolutionarily highly conserved, represents a subunit assembly site. All but one epitope (alpha 7) are destroyed by reducing and alkylating hCG-alpha. In contrast, chymotryptic digestion of hCG-alpha, leading to release of the heptapeptide hCG-alpha(41-47), did not affect epitope expression, indicating that this sequence is not involved in the formation of antigenic determinants. Addressing the biological properties of hCG-alpha epitopes by radioreceptor assay revealed that the three hCG-alpha peptides corresponding to epitopes alpha 2, alpha 4 and alpha 6 did not displace radiolabelled hCG from its receptor, whereas any of the MCAs directed against determinants (alpha 1-alpha 5), shared by hCG and hCG-alpha, totally inhibited binding. Consistent with this, the antibodies neutralized the biological activity of hCG in terms of testosterone production in a mouse Leydig cell in vitro bioassay. We therefore concluded that hormone antibody-binding sites differ from those of hormone receptor binding, revealing no essential congruence of immunologically and biologically active domains.

Effects of cytokine application on glucocorticoid secretion in an animal model for systemic scleroderma

We previously reported on an altered immune-endocrine feedback loop via the hypothalamo-pituitary-adrenal (HPA) axis in Obese strain (OS) chickens afflicted with spontaneous autoimmune thyroiditis. These animals are deficient in plasma corticosterone increase after antigenic challenge or application of cytokine-containing conditioned medium of mitogen-stimulated spleen cells (CM). To investigate whether the impaired ability to respond to cytokines with glucocorticoid-increasing factor (GIF) activity, e.g. interleukin 1 (IL 1), is restricted to OS chickens as a model for an organ-specific autoimmune disease, we extended our experiments to another autoimmune-prone animal strain, the chickens of the University of California at Davis line 200 (UCD-200). These animals develop an inherited inflammatory fibrotic disease that closely resembles human progressive systemic sclerosis (scleroderma). Application of GIF-containing CM to UCD-200 chickens leads to a transient increase in glucocorticoid serum levels within 1-2 hours comparable to that of controls. But, while corticosterone levels in the latter returned to normal baseline levels after 4 hours, they were still elevated in autoimmune chickens. Although the peak of the glucocorticoid hormone serum concentrations was equal to that of controls, UCD-200 had to secrete twice as much adrenocorticotropic hormone to achieve this corticosterone serum level due to an apparent hyporesponsiveness of the adrenal gland to this secretagogue. The altered cytokine-induced glucocorticoid secretion is found in early as well as in chronic, sclerotic stages of the disease. Cellular alterations in the peripheral blood of UCD-200 chickens during the prolonged elevated corticosterone section, i.e. between 2-4 hours after CM application, are characterized by a significant decrease in the percentage of CD4+ and CD8+ cells. Furthermore, a significant increase in B cells up to 24 hours with a maximum after 1 hour was found. The proliferative response to the mitogen concanavalin A of peripheral mononuclear cells was inversely correlated to the serum corticosterone level, showing a permanent decrease of 80-90% after 1-4 hours in autoimmune animals. This functional alteration in UCD-200 was accompanied by an 80% decrease in serum interleukin 2 (sIL 2) activity 4 hours after CM application. Twenty-four hours later an eight-fold increase in sIL 2 rebound activity was found, indicating that the inhibitory effect of corticosterone in UCD-200 chickens is not long-lasting.

Staining of endothelial cells and macrophages in atherosclerotic lesions with human heat-shock protein-reactive antisera

Our previous epidemiological studies have shown that levels of serum antibodies against mycobacterial heat-shock protein (hsp) 65 correlate positively with carotid atherosclerosis in subjects aged 40 to 79 years. To determine whether these high-titer sera also react with homologous human hsp60 and/or cell components of atherosclerotic lesions, we selected 15 human sera samples, each with high or low titers to recombinant mycobacterial hsp65, and investigated their reactivity with human arterial lesion components by immunoblotting and immunofluorescence techniques. All five higher-titer sera against hsp65 reacted with a 60-kDa band of atherosclerotic lesion proteins and human recombinant hsp60 on Western blots. Pooled sera with low antibody titers to hsp65 diluted similarly as high-titer sera did not show reactivity with atherosclerotic lesion and media proteins. By immunohistochemistry and immunofluorescence with human immunoglobulin G isolated from different sera, labeled with biotin, and visualized with a streptavidin conjugate, positive staining was observed in sections of fatty streaks and atherosclerotic plaques of carotid arteries, and weak staining was observed in the normal intima. Double immunofluorescence identified the majority of positively stained cells as macrophages, endothelial cells, and a few smooth muscle cells. In summary, serum antibodies against hsp65 cross-react with the human 60-kDa homologue present in high levels in atherosclerotic lesions and are mainly reacting with macrophages and endothelial cells, supporting our concept of a possible involvement of humoral-mediated immune reaction against hsp60 in atherogenesis.

Functional and immunological relevance of the COOH-terminal extension of human chorionic gonadotropin beta: implications for the WHO birth control vaccine

The World Health Organisation (WHO) Task Force on Birth Control Vaccines has selected the pregnancy hormone human chorionic gonadotropin (hCG) as a target molecule for a contraceptive vaccine. A synthetic peptide antigen corresponding to the amino acid sequence 109-145 of the carboxyl-terminal portion of the hCG beta-subunit (hCG beta CTP), which is supposed to elicit hCG-immunoneutralizing antibodies, has been submitted to clinical trials. Recent findings suggest that hCG beta CTP does not play a role in the biological activity of hCG. This raises the question concerning the assumed mechanism of action of the hCG beta CTP-based birth control vaccine. We therefore investigated the immunoneutralizing capacity of antibodies directed against hCG beta CTP. Although it is possible to generate specific monoclonal and polyclonal antibodies for hCG by using hCG beta CTP as an immunogen, it appeared that the biological response to hCG was not affected by such antibodies. The reason for this is that the hCG-antibody-complex is still able to bind to target cell receptors and therefore the intended contraceptive effect should not occur. In addition there is a risk of hazardous possible side effects such as an autoimmune reaction against the ovary because we found that at least one epitope is still accessible for antibody binding on receptor-bound hCG. We conclude from our results that both the efficacy and safety of the WHO vaccine are not yet ensured.

Serum glycoprotein hormones and their free alpha-subunit in a healthy elderly population selected according to the SENIEUR protocol. Analyses with ultrasensitive time resolved fluoroimmunoassays

The SENIEUR protocol was elaborated by a working party of European Community's Concerted Action Programme on Aging (EURAGE) to define strict admission criteria for 'healthy' elderly subjects and young controls for immunogerontological studies. This protocol, which is based on case history, laboratory values and drug consumption, intends to limit the influence of underlying disease and/or medication in order to allow analyses of the aging process per se. In a group of 38 male and 37 female individuals we determined the impact of age and classification according to the SENIEUR protocol on luteinizing hormone (LH), follicle stimulating hormone (FSH), human chorionic gonadotropin (hCG) and free glycoprotein hormone alpha-subunit serum values. Analyses were performed by a set of ultrasensitive time-resolved immunofluorometric assays (IFMA) using our own panel of monoclonal antibodies (MCA). HLH and hFSH, but also hCG and free alpha serum levels increased highly significantly with age in the female population (P < 0.001). In males hFSH, hLH hCG and the free alpha-subunit increased with age. However, only the rise of hFSH and of Free alpha was statistically significant (P < 0.01). The influence of the SENIEUR status on the respective hormone serum levels was determined using two factor analysis of variance, which revealed no statistically significant difference (P > 0.01) between SENIEUR and NON-SENIEUR individuals for all four analytes in both sexes. We conclude that the age related increase of hLH, hFSH, hCG and free alpha is an intrinsic age-dependent phenomen and is not modified by or due to underlying disease or medication as demonstrated by analyses of SENIEUR individuals. Since SENIEUR and NON-SENIEUR individuals had comparable hormone values, a randomly chosen, 'apparently healthy' population seems to be sufficient for physiological studies on serum GPH levels. Lastly, these age related hormonal changes in an extremely well defined healthy population underline the need for age adjusted 'normal' hormone values as elaborated in this communication.

Variants of human chorionic gonadotropin from pregnant women and tumor patients recognized by monoclonal antibodies

In biological fluids, hCG and its free alpha- (hCG alpha) and beta-subunits (hCG beta), occur in multiple forms. These various forms differ at the molecular level primarily in glycosylation, but also differ in protein backbone modifications corresponding to the urinary low molecular weight fragment of the hCG beta-subunit (beta-core fragment). This microheterogeneous nature can be demonstrated by isoelectric focusing in which variants are separated into bands with different isoelectric points (pI). To determine whether such isoelectric variants differ in antigenicity and consequently might escape immunoassay detection due to overspecificity of monoclonal antibodies (MCA), urinary pregnancy hCG (NIH, CR123) and tumor hCG preparations, such as a tumor-specific acidic variant of hCG (hCGav) and the hCG beta-core fragment, were separated by isoelectric focusing in the absence or presence of 8 M urea, or by sodium docedyl sulfate-polyacrylamide gel electrophoresis and enzymatically immunostained using an MCA panel directed against 17 different hCG epitopes. MCA against 14 different epitopes accessible on holo-hCG recognized all pI variants of pregnancy holo-hCG or tumor-derived hCGav, as was true for the three MCA recognizing epitopes hidden on holo-hCG but accessible on the free subunits after hCG dissociation by urea. We conclude that each individual pI-isoform of holo-hCG and its free subunits expresses the entire set of epitopes recognized by our MCA panel. The carbohydrate moieties that form a biochemical basis for hCG heterogeneity seem to be neither of major antigenic relevance, nor are they structurally related to any particular epitope. Thus, various glycosylation forms of hCG, hCG alpha, hCG beta, and hCG beta-core in normal as well as in pathological samples should safely be detectable and measureable by immunoassays employing MCA with appropriate subunit specificity.

Time-resolved immunofluorometry and other frequently used immunoassay types for follicle-stimulating hormone compared by using identical monoclonal antibodies

The influence of assay design and quantification system on assay performance was investigated by developing, optimizing, and comparing a time-resolved immunofluorometric assay (IFMA), an immunoenzymometric assay (IEMA), an immunoradiometric assay (IRMA), and a competitive radioimmunoassay (RIA), all performed with the same monoclonal antibodies (MCA) directed against human follicle-stimulating hormone (hFSH). The lowest detection limit (2 ng/L for hFSH-I-3, corresponding to 2.5 mIU of 1st International Reference Preparation of hFSH 78/549 per liter), the widest measuring range (2-160,000 ng/L), and the greatest signal-to-noise ratio (13,000:1 at 160,000 ng/L) were obtained in the IFMA. For analysis of serum samples from 101 male (ages 2-91 years) and 99 female (ages 2-90 years) individuals at a single dilution, 100% of samples were within the measuring range of the IFMA, whereas only 87%, 55%, 32%, and 8% of the sera were for the IRMA, the IEMA evaluated with double-wavelength measurement, the conventional IEMA, and the competitive MCA-based RIA, respectively. These studies demonstrate clear advantages of the IFMA in sensitivity and assay range, which allows reliable and cost- and time-effective determination of hFSH in individuals from infancy to senescence.

Time-resolved immunofluorometry and other frequently used immunoassay types for follicle-stimulating hormone compared by using identical monoclonal antibodies

The influence of assay design and quantification system on assay performance was investigated by developing, optimizing, and comparing a time-resolved immunofluorometric assay (IFMA), an immunoenzymometric assay (IEMA), an immunoradiometric assay (IRMA), and a competitive radioimmunoassay (RIA), all performed with the same monoclonal antibodies (MCA) directed against human follicle-stimulating hormone (hFSH). The lowest detection limit (2 ng/L for hFSH-I-3, corresponding to 2.5 mIU of 1st International Reference Preparation of hFSH 78/549 per liter), the widest measuring range (2-160,000 ng/L), and the greatest signal-to-noise ratio (13,000:1 at 160,000 ng/L) were obtained in the IFMA. For analysis of serum samples from 101 male (ages 2-91 years) and 99 female (ages 2-90 years) individuals at a single dilution, 100% of samples were within the measuring range of the IFMA, whereas only 87%, 55%, 32%, and 8% of the sera were for the IRMA, the IEMA evaluated with double-wavelength measurement, the conventional IEMA, and the competitive MCA-based RIA, respectively. These studies demonstrate clear advantages of the IFMA in sensitivity and assay range, which allows reliable and cost- and time-effective determination of hFSH in individuals from infancy to senescence.

Immunology of atherosclerosis. Demonstration of heat shock protein 60 expression and T lymphocytes bearing alpha/beta or gamma/delta receptor in human atherosclerotic lesions

Our previous work revealed the presence of a great number of activated T lymphocytes in early human atherosclerotic lesions, and we were able to induce atherosclerosis in normocholesterolemic rabbits by immunization with Mycobacterium tuberculosis heat-shock protein (HSP) 65. We hypothesized this latter phenomenon to arise from cross-reactivity of mycobacterial HSP 65 with the endogenously expressed homologous 60-kd form of this stress protein. To study HSP 60 expression and the phenotype of intima infiltrating T lymphocytes relative to the T cell receptor (TCR) in human atherosclerotic lesions, specimens of aorta, carotid arteries, and internal mammary arteries and veins, as well as saphenous veins and vena cava from 27 subjects, aged 23 to 80 years, were examined using immunohistochemical and immunofluorescence techniques on serial frozen tissue sections. HSP 60 was detected on endothelium, smooth muscle cells, and/or mononuclear cells of all carotid and aortic specimens, whereas vessels of smaller diameter, serving as reference specimens for normal intima without atherosclerotic lesions and mononuclear infiltration, showed no detectable expression of this stress protein. Furthermore, although the majority of CD3+ cells within the mononuclear cell infiltrates of atherosclerotic lesions bear the alpha/beta TCR, a considerable portion also consisted of gamma/delta TCR+ cells. Thus, 9.7% of T cells in the transition zone between normal intima and fatty streaks carry the gamma/delta TCR, a proportion that decreases to 6.6% and 4.3% in fatty streaks and atherosclerotic plaques, respectively. We conclude that the intensity of HSP 60 expression correlates positively with the atherosclerotic severity and that most lymphocytes participating in atherogenesis bear the alpha/beta TCR, although gamma/delta TCR+ cells are also enriched in atherosclerotic lesions. Expression of HSP 60 by intimal cells, caused, eg, by hemodynamic shear forces, may be responsible for recruitment of HSP-sensitized T cells, thus leading to the induction of an initiating inflammatory process in atherosclerosis. Other risk factors, such as high serum cholesterol levels, contribute to the final outcome of the disease.

Increased expression of heat shock protein 65 coincides with a population of infiltrating T lymphocytes in atherosclerotic lesions of rabbits specifically responding to heat shock protein 65

We have shown previously that atherosclerotic lesions can be induced in normocholesterolemic rabbits by immunization with mycobacterial heat shock protein 65 (hsp65), which has a high degree of sequence homology with mammalian hsp60. To investigate a possible relationship between hsp60 expression and the antigenic specificities of infiltrating T cells in the lesion, 38 New Zealand White rabbits were treated either by immunization with recombinant mycobacterial hsp65 or by administration of a 0.2% cholesterol diet. Atherosclerotic lesions were observed after 16 wk, particularly in the aortic arch and arterial bifurcations of rabbits immunized with hsp65 or fed with a cholesterol-rich diet. Hsp65 staining of aortas showed a heterogeneous distribution, and significantly increased staining intensity in atherosclerotic lesions compared to aortic media or adventitia. This abundantly expressed hsp65 was observed in atherosclerotic lesions induced by hsp65 immunization as well as those induced by cholesterol-rich diet alone. Interestingly, a population of the T lymphocytes isolated from all forms of atherosclerotic lesions specifically responded to hsp65 in vitro. IL-2-expanded T cell lines derived from atherosclerotic lesions showed a significantly higher hsp65 reactivity than those developed from peripheral blood of the same donor. Furthermore, levels of circulating antibodies and numbers of spleen cells specifically reacting against hsp65 were elevated in all experimental animals. Flow cytometric analysis of spleen cells showed elevated immune response-associated antigen expression in treated animals. In conclusion, increased hsp65 expression in intimal cells and the presence of hsp65-specific T cells in blood and in atherosclerotic lesions may be important in initiating the development of atherosclerosis and perpetuating the lesions.

Estimation of reference intervals from a SENIEUR protocol compatible aged population for immunogerontological studies

Because many laboratory values change with age, the study of healthy aging as well as diagnosis of disease in geriatric patients requires specific age-corrected reference intervals. We have established such reference intervals for a healthy population aged 65-74 years by selection of a sample group applying the clinical criteria of the SENIEUR protocol and we have compared them with those of a young control group (20-33 years) fulfilling the same criteria. Significant or minor elevations were seen, e.g. for plasma concentrations of fasting glucose, urea, total and LDL-cholesterol, triglycerides, gamma-glutamyl-transferase, alkaline phosphatase, erythrocyte sedimentation rate and serum neopterin levels. These reference intervals can be used for selecting a SENIEUR compatible population aged between 65 and 74 years. Additionally, plasma lipid parameters (cholesterol, triglycerides) are proposed to be included in the SENIEUR protocol.

In situ analyses of in ovo graft-vs.-host reaction induced by thymic nurse cell lymphocytes

In both mammalian and avian systems, thymic nurse cells (TNC) have been shown to harbor a heterogeneous population of T lymphocytes (TNC-L) some of which exhibit a postselectional phenotype. By transplanting micromanipulated single chicken TNC onto the chorionallantoic membrane (CAM) of major histocompatibility complex (MHC)-disparate embryos, an experimental system which allows for the detection of lymphocytes with graft-vs.-host (GVH) reactivity, we demonstrate here that TNC enclose lymphocytes that can develop into both CD4+ single-positive (sp) and CD8+ sp, T cell receptor (TcR) alpha beta+, or TcR gamma delta+ cells. This finding was additionally confirmed by serial transfer of primary expanded alloreactive T cells onto the CAM of secondary hosts. All donor TNC-L expressed MHC class II molecules and the interleukin-2 receptor alpha chain in primary and secondary GVH reactions. Furthermore, we observed selective accumulation of CD8+ and TcR gamma delta+ host lymphocytes in the CAM upon the induction of a local GVH reaction, most probably as a consequence of the pathological alteration of the epithelium.

Does tumor-derived human chorionic gonadotropin act as a thyroid stimulator in vivo?

To evaluate in vivo the proposed intrinsic thyroid-stimulating hormone (TSH) activity (TSA) of human chorionic gonadotropin (hCG), we monitored over 0.5-1 years the thyroid status of eight patients with hCG-producing non-seminomatous testicular cancer. The patients' sera were analyzed for concentrations of hCG, free thyroxine (fT4), hTSH, and thyroxine-binding globulin (TBG). All patients had excessively high concentrations of hCG (1 x 10(5)-5 x 10(8) ng/L, mean: 1 x 10(7) ng/L) before polychemotherapy, which decreased under successful therapy to physiological values (< 240 ng/L). Although the serum concentrations of hCG varied by more than six orders of magnitude, we saw no changes and no correlation (P > 0.05) between the concentrations of hCG and the concentrations of fT4 and hTSH. Not even when hCG concentrations were greatest (> 5 x 10(7) ng/L) were any signs of hyperthyroidism observed: fT4 (3.5-13 ng/L) and hTSH (9-700 ng/L) were in the physiological range in all patients and remained so during chemotherapy. The results of this longitudinal study were confirmed in analyzing the data for all eight patients (total: 82 samples) cross-sectionally. Again, we found no correlation (P > 0.05) between the concentrations of hCG and fT4 or hCG and hTSH. We conclude that even excessive amounts of testicular tumor-derived hCG do not display any TSH-like activity in vivo.

Does tumor-derived human chorionic gonadotropin act as a thyroid stimulator in vivo?

To evaluate in vivo the proposed intrinsic thyroid-stimulating hormone (TSH) activity (TSA) of human chorionic gonadotropin (hCG), we monitored over 0.5-1 years the thyroid status of eight patients with hCG-producing non-seminomatous testicular cancer. The patients' sera were analyzed for concentrations of hCG, free thyroxine (fT4), hTSH, and thyroxine-binding globulin (TBG). All patients had excessively high concentrations of hCG (1 x 10(5)-5 x 10(8) ng/L, mean: 1 x 10(7) ng/L) before polychemotherapy, which decreased under successful therapy to physiological values (&lt; 240 ng/L). Although the serum concentrations of hCG varied by more than six orders of magnitude, we saw no changes and no correlation (P &gt; 0.05) between the concentrations of hCG and the concentrations of fT4 and hTSH. Not even when hCG concentrations were greatest (&gt; 5 x 10(7) ng/L) were any signs of hyperthyroidism observed: fT4 (3.5-13 ng/L) and hTSH (9-700 ng/L) were in the physiological range in all patients and remained so during chemotherapy. The results of this longitudinal study were confirmed in analyzing the data for all eight patients (total: 82 samples) cross-sectionally. Again, we found no correlation (P &gt; 0.05) between the concentrations of hCG and fT4 or hCG and hTSH. We conclude that even excessive amounts of testicular tumor-derived hCG do not display any TSH-like activity in vivo.

Altered immunoendocrine dialogue in autoimmune disease

Autoimmune diseases have a multifactorial pathogenesis including essential genetic and nonessential modulatory factors. Among the essential factors, not only should genes coding for an abnormal reactivity of the immune system be considered, but we have, in addition, provided experimental evidence for the existence of genes responsible for a susceptibility of the target organ/structure for the autoimmune attack. Only when both sets of essential genes are present does an autoimmune disease develop at all. The modulatory factors then determine the final outcome in each case. The present contribution discusses the immunomodulating role of glucocorticoid and sex steroids focussing on the Obese Strain (OS) of chickens, a model for Hashimoto thyroiditis.

Association of serum antibodies to heat-shock protein 65 with carotid atherosclerosis

Arteriosclerotic lesions can be induced in normocholesterolaemic rabbits by immunisation with heat-shock protein (hsp) 65, a stress protein expressed in high concentrations in human atherosclerotic lesions. If an immune reaction to hsp65 also plays a part in human atherogenesis, it should be possible to detect anti-hsp65 antibodies in patients with atherosclerotic lesions. To study the possible relation between immune reaction to hsp65 and atherosclerosis, 867 normal inhabitants of South Tyrol, aged 40-79 years, were selected randomly for determination of serum antibodies against hsp65, simultaneous sonographic assessment of carotid atherosclerotic lesions, and evaluation of established risk factors--ie, blood cholesterol, hypertension, smoking, diabetes mellitus, and obesity. Autoantibodies to nuclear antigens, thyroid antigens, and rheumatoid factors were also measured. Serum anti-hsp65 antibodies were significantly (p < 0.05) increased in subjects aged 60-79 years with carotid atherosclerosis compared with those without lesions, and increased antibody concentration was independent of age, sex, and other established risk factors. On the other hand, the incidence and titres of autoantibodies did not correlate with carotid atherosclerotic lesions. Our data provide the first evidence of a strong correlation between anti-hsp65 antibodies and carotid atherosclerosis, suggesting that hsp65 might be involved in the pathogenesis of atherosclerosis.

Oral administration of a bacterial immunomodulator enhances murine intestinal lamina propria and Peyer's patch lymphocyte traffic to the lung: possible implications for infectious disease prophylaxis and therapy

LW50020, a bacterial immunomodulator, is a preparation consisting of seven bacteria, commonly causing respiratory disease. When given orally, LW50020 has been shown to enhance the host defense of the respiratory tract. Intestinal lamina propria lymphocytes (LPL), Peyer's patch lymphocytes (PPL), and splenocytes from BALB/c mice gavaged either with LW50020 or carrier alone were isolated, labeled with either H33342, a supravital nuclear fluorochrome, or 51Cr, and injected i.v. into untreated, age-matched BALB/c mice. Two hours later, spleen, liver, lung, kidneys, Peyer's patch, and mesenteric lymph nodes of the recipients were harvested and screened for the presence of labeled cells. LPL from mice gavaged with carrier only (controls) migrated preferentially to the lung, PPL equally well to the lung, and the spleen and splenocytes were found mostly in the spleen. LPL and PPL from LW50020-treated mice were found in significantly larger numbers in the lungs of recipients than LPL and PPL from control animals. Both labeling techniques gave roughly the same results. Sixty-five per cent of LPL in the lung were Thy-1.2+ and 20% B cells. These findings should contribute to the understanding of parameters necessary for the assessment of the mode of action and efficacy of immunomodulation and vaccination via the mucosa-associated lymphoid tissue.

Possible role of human foamy virus in Graves' disease

Human foamy virus (HFV) is a member of the retroviral family of Spumaretrovirinae. In addition to the three retroviral structural genes, gag, pol and env, HFV also contains regulatory sequences, called bel. Foamy viruses have been previously associated with human thyroid disease, notably DeQuervain's thyroiditis. In indirect immunofluorescence tests we have demonstrated the reactivity of the thyroid glands of 7/7 patients with Graves' disease and antibodies to HFV gag proteins. No reactivity was observed with antibodies to pol, env and bel proteins. Nine thyroids of patients with struma parenchymatosa, 4 with follicular carcinoma and 2 normal thyroids were negative throughout. From the thyroids of 5 patients with Hashimoto's disease, 4 were negative and 1 showed a single small focus of anti-gag antibody reactivity. The uniform immunofluorescent staining was restricted to the basal and lateral intercellular areas between the thyroid epithelial cells. Extension of these studies to the retrobulbar tissue of 1 Graves' disease patient with malignant exophthalmus revealed positive staining with anti-gag antibodies of fibroblasts and fat cells but not eye muscles. Furthermore, we were successful in establishing several T-cell lines derived from the retrobulbar tissue of this patient. They were CD8+ and proliferated, in contrast to peripheral blood cells, upon cocultivation with autologous retroorbital fibroblasts. It remains to be determined whether these observations are of relevance in the pathogenesis of Graves' disease.

Disturbed immuno-endocrine communication via the hypothalamo-pituitary-adrenal axis in autoimmune disease

Previous studies in our laboratory demonstrated an altered immuno-endocrine feedback communication via the hypothalamo-pituitary-adrenal (HPA) axis, which may be an important modulatory factor in the development of spontaneous autoimmune thyroiditis in Obese strain (OS) chickens. These birds show a significantly lower, or even absent, increase in serum glucocorticoid levels in response to an intravenous injection of antigen or conditioned medium (CM) from mitogen-stimulated spleen cells known to contain glucocorticoid-increasing factors (GIFs), notably interleukin-1 (IL-1). The present study was aimed at investigating this feedback regulation in animal models with spontaneous systemic autoimmune diseases, such as the UCD-200 chicken, which serves as a model for human scleroderma, and various murine lupus models. In contrast to OS chickens, UCD-200 chickens displayed a nearly normal plasma corticosterone surge in response to CM, and IL-1 was again identified as the primary GIF in CM. Recombinant IL-1 also induced a drastic increase in plasma corticosterone levels in various strains of normal mice. A similar increase was observed in the bacterial lipopolysaccharide-resistant C3H/HeJ strain, thus excluding the possibility of bacterial endotoxin contamination. However, in young lupus-prone (NZB/W)F1 and MRL/MP-lpr mice, a significantly lower increase in plasma corticosterone levels was observed after injection of recombinant IL-1, suggesting a deficient immuno-endocrine communication via the HPA loop in this instance as well. Detailed studies to identify further cytokines with GIF activity in the avian and murine systems showed that both IL-6 and tumor necrosis factor-alpha could induce increased plasma corticosterone levels in mice, but not in chickens. IL-3, IL-8, transforming growth factor-beta, interferon-gamma and granulocyte-macrophage colony-stimulating factor were devoid of GIF activity in both chickens and mice.

Antinuclear antibody profile in UCD line 200 chickens: a model for progressive systemic sclerosis

The fully blown disease of human progressive systemic sclerosis (PSS, scleroderma) is serologically associated with the emergence of several types of autoantibodies, some of them regarded as more specific for scleroderma (e.g. Scl-70, anti-centromere) and some common also to other connective tissue diseases (e.g. anti-ssDNA). Since most patients suffering from PSS are not under medical control until clinical manifestations are fully established, only scarce data are available on the dynamics and clinical significance of autoantibodies in the very early stages of this systemic fibrotic disease. The University of California at Davis line 200 (UCD 200) of chickens spontaneously develop a PSS-like disorder with an acute inflammatory stage around 60 days after hatching, leading to fibrosis with fast progression. In order to address a possible correlation between the occurrence and titer of autoantibodies and the initial disease activity, we have chronologically investigated the presence and titer of autoantibodies directed against several human nuclear antigens in this animal strain. In UCD-200 chickens, we found a progressive increase in autoantibodies to histones, to ssDNA and--to a lesser degree--dsDNA with peaks at the age of 60 and 120 days, to poly(I) and poly(G) with a peak at 120 days and an elevation in anti-cardiolipin antibodies. Total immunoglobulin concentrations, anti-Ro, anti-La and anti-Sm showed no significant differences as compared to negative results in healthy normal controls. Our data reveal parallels in the antinuclear antibody (ANA) spectrum between UCD-200 chickens and human autoimmune collagen diseases, but do not reflect the typical ANA spectrum found in the foudroyant form of diffuse scleroderma.(ABSTRACT TRUNCATED AT 250 WORDS)

Investigation of ACTH responses of chickens with autoimmune disease

An altered immunoendocrine feedback regulation within the hypothalamo-pituitary-adrenal axis may modulate the pathogenesis of an avian autoimmune disease. To date studies have been hampered by a lack of reliable, specific, and sensitive methods for determining adrenocorticotropic hormone (ACTH) in chickens. The present study describes the determination of ACTH in plasma of chickens with a commercial radioimmunoassay, the antibody of which binds to the midregion of human ACTH 1-39. The chickens, kept on a 12-hr day and 12-hr night shift with artificial light, showed changes in plasma ACTH concentrations during the light phase with maximum values 8 hr after the light was turned on. ACTH was not measurable after treatment with dexamethasone. Intravenous administration of supernatants from concanavalin A-stimulated spleen cells increased basal plasma ACTH concentrations more than 20-fold within 1 hr. This increase in plasma ACTH was higher and longer lasting in UCD 200 chickens, an animal model for scleroderma, compared with outbred and inbred normal White Leghorn chickens.

A high-density-lipoprotein receptor appears to mediate the transfer of essential fatty acids from high-density lipoprotein to lymphocytes

It has been shown previously that a specific high-density lipoprotein (HDL) receptor exists on human lymphocytes that recognizes apoprotein (apo) A1 as its ligand, and may be responsible for utilization of HDL lipids to respond optimally to mitogenic stimulation when cultured in serum-free medium supplemented with HDL. To clarify further the relationship between various HDL lipids used by lymphocytes and HDL receptor activity, the lipid composition of the cells and the regulation of HDL and low-density lipoprotein (LDL) receptors on freshly isolated lymphocytes and mitogen-activated T-blasts after treatment with lipoproteins, liposomes or fatty acids were investigated. Our data show that the linear increase in cell proliferation correlates with the presence of HDL in fatty-acid-free culture medium in the concentration range of HDL receptor saturation. Decreased binding/uptake of dioctadecylindocarbocyanine (DiI)-fluorescence-labelled HDL by freshly isolated lymphocytes was observed in the presence of unlabelled HDL in 4-day culture, whereas T-blast binding/uptake was down-regulated by preincubation not only with HDL but also with LDL. T-blasts pretreated with HDL showed increased cellular contents of phosphatidylcholine, oleic acid (C18:1,n-9) and linoleic acid (C18:2,n-6), which are essential for optimal proliferation of mitogen-stimulated lymphocytes. Furthermore, DiI-HDL binding on lymphocytes was down-regulated by up to 20% (resting T cells) and 50% (T-blasts) when cultured in the presence of apoA1-phosphatidylcholine liposomes (T-blasts only), oleic acid or linoleic acid, but not by stearic acid (C18:0). The results indicate that HDL provide lymphocytes with essential fatty acids, which in turn regulate HDL receptor activity.

Cultured fibroblasts in avian scleroderma, an autoimmune fibrotic disease, display an activated phenotype

University of California, Davis, line 200 and 206 chickens spontaneously develop an autoimmune syndrome that has many features analogous to human scleroderma, including dermal fibrosis, antinuclear antibodies and antibodies to type II collagen. These birds also have thymic subcapsular epithelial defects and an abnormality in T cell calcium influx and proliferation in response to both T cell receptor-dependent and -independent activators. To determine whether fibroblast activation is a contributing factor to development of skin fibrosis in line 200/206 chickens, as it is in human scleroderma, we studied the collagen, non-collagenous protein and glycosaminoglycan (GAG) production of 34 separate fibroblast lines derived from the normal and fibrotic skin of line 200 and 206 chickens and from the skin of control chicken lines 058 and 254. The mean +/- SEM 24-h incorporation of 3H-proline or 3H-glucosamine into extracellular collagen, non-collagenous protein or GAG by first passage fibroblast lines derived from the fibrotic skin of diseased birds was 1,526 +/- 136, 859 +/- 82 and 25.7 +/- 1.3 dpm/10(3) cells, respectively, while fibroblast lines derived from the skin of control birds produced only 341 +/- 36, 343 +/- 42 and 15.2 +/- 1.4 dpm/10(3) cells. Similar differences in results were recorded for cell-associated production, and when collagen and non-collagenous protein production were assessed using non-radioactive electrophoretic methods. The activated phenotype of the fibroblast lines derived from the fibrotic skin of diseased birds persisted through 10 cell doublings in tissue culture. However, the ratio of type I:III collagen and the profile of GAG types produced were similar in all fibroblast lines studied. These results suggest that fibroblast activation is responsible for the skin fibrosis observed in this avian model of scleroderma.

Induction of arteriosclerosis in normocholesterolemic rabbits by immunization with heat shock protein 65

Previous studies have established the presence of high numbers of activated T lymphocytes and "aberrant" expression of major histocompatibility complex class II antigens by endothelial and smooth muscle cells in human atherosclerotic lesions, implicating the involvement of a local cellular immune response. The identity of the antigen(s) eliciting this immune response, the extent of their effect, and the atherogenic stage at which they occur remain to be determined. In the present studies, 120 normocholesterolemic New Zealand White rabbits were immunized one or more times with various antigens, with or without adjuvants. The antigens and adjuvants included human or rabbit atherosclerotic lesion proteins, ovalbumin, Freund's complete and/or incomplete adjuvants, recombinant mycobacterial heat shock protein 65 (hsp65), and two hsp-free adjuvants, Ribi complete adjuvant and lipopeptide. In addition, some groups received a high-cholesterol diet. Sixteen weeks after the first immunization the animals were killed, and arteriosclerotic lesions in the intima of the aortic arch were found to have developed only in those animals immunized with antigenic preparations containing hsp, either in the form of whole mycobacteria or as purified recombinant hsp65, although their serum cholesterol levels were normal. No arteriosclerotic changes exceeding those of controls were found in the other groups, irrespective of the antigen used. Immunohistopathologic examination revealed that the lesions contained 20% T cells, 10-30% macrophages, and 10-40% smooth muscle cells. Analysis of the peripheral blood T-lymphocyte proliferative responses revealed that the occurrence of lesions was positively correlated with the presence of hsp65-reactive T cells, suggesting that hsp65 is involved in the induction of arteriosclerotic lesions. Furthermore, combined immunization with hsp-containing material and a cholesterol-rich diet provoked development of significantly more severe atherosclerosis and the appearance of characteristic foam cells. We conclude that an (auto)immune response to hsp may initiate the development of atherosclerosis and that a high blood cholesterol level is only one albeit a very important risk factor.

Lipid utilization by human lymphocytes is correlated with high-density-lipoprotein binding site activity

The nature and physiological importance of high-density lipoprotein (HDL) binding sites on unstimulated (resting) and mitogen-activated (blast) human peripheral blood lymphocytes were investigated. Specific HDL binding on resting and blast T-lymphocytes was saturable at 50 micrograms of 125I-HDL/ml and of high affinity, with Kd values of 8.1 x 10(-8) M and 6.5 x 10(-8) M, respectively, and Bmax. values of 79 ng and 180 ng/mg of cell protein respectively at 4 degrees C. Binding of HDL double-labelled with fluorescent dioctadecylindocarbocyanine (Dil) and isotope (125I) as well as of single fluorescence- or isotope-labelled HDL was inhibited competitively by HDL apoproteins. Studies of the cholesterol flux between the cells and HDL showed that HDL, low-density lipoprotein (LDL) or BSA at a concentration of 100 micrograms/ml in the tissue culture medium did not result in a significant difference in exogenous [3H]cholesterol efflux from the cell membrane at 37 degrees C. Proliferating T-blasts incorporated more cholesterol from HDL or LDL than did resting lymphocytes. When the cells were pulsed with 125I-HDL and chased in fresh lipid-free medium, up to 80% of the radioactivity released was not precipitable with trichloroacetic acid. This percentage decreased in a competitive manner when unlabelled HDL was present in the chase incubation medium. Finally, cultivation of lymphocytes with conditioned medium from macrophages increased Dil-HDL binding/uptake, while it was decreased by mevinolin-induced inhibition of hydroxymethylglutaryl-coA reductase. In conclusion, human lymphocytes possess a HDL binding site (receptor) responsible for lipid binding/uptake and concomitant internalization and degradation of apoproteins from HDL, but not for reverse cell membrane cholesterol transport. The activity of the binding site is up-regulated during cell proliferation and down-regulated during cell growth suppression.

Avian scleroderma: evidence for qualitative and quantitative T cell defects

T cell activation is dependent upon calcium influx and protein kinase C activation, with subsequent lymphocyte proliferation dependent upon IL-2. Abnormalities in T cell proliferation, including abnormal calcium influx and defective protein kinase C activation, have been identified in aged mice and humans and many autoimmune diseases including diabetes, lupus and scleroderma. Since UCD line 200 chickens, which spontaneously develop a scleroderma-like disease, have both thymic defects and a diminished peripheral blood lymphocyte response to IL-2, we have further investigated T cell function in these birds. Interestingly, line 200 T cells respond poorly in vitro to a variety of diversely acting T cell mitogens including concanavalin A, phytohemagglutinin and anti-chicken CD3 monoclonal antibody. Moreover, they do not respond well even to phorbol myristate acetate in conjunction with ionomycin. Addition of exogenous IL-2-containing supernatant concurrently with mitogenic stimulation also had no significant effect. Analysis of intracellular free calcium demonstrated that the lymphocytes from diseased birds had a reduced influx of calcium (or release for intracellular stores) following stimulation. These data clearly reflect a unique defect in T cell activation associated with avian scleroderma. Analysis of chicken CD3, CD4 and CD8 expression revealed a 39% decrease in peripheral blood CD4+ cells in scleroderma birds, although this decrease was not sufficient to explain the 80-90% decrease observed in proliferation assays and calcium influx. Our data support the hypothesis that avian scleroderma is mediated via abnormal function of lymphocyte co-stimulatory molecules or intracellular calcium regulators.

The role of the immunoendocrine interaction via the hypothalamo-pituitary-adrenal axis in autoimmune disease Emphasis on the obese strain chicken model

The key to the molecular basis of the pathogenesis of autoimmune disease (AID) certainly lies in the identification of genes coding for the altered immune response and those responsible for the susceptibility of the target organ to the autoimmune attack. The elucidation of nonessential modulatory factors is, however, also of great importance, because it is via these routes that an effective AID therapy is practical at the present time. Hormones in general, and those affecting the hypothalamo-pituitary-adrenal (HPA) axis in particular, are among the best candidates for more rational new therapeutic approaches. Studies of immune-endocrine communication in animal models with spontaneously occurring organ-specific or systemic autoimmune diseases are ideal for this kind of investigation, since immunologic studies commencing prior to onset of the AID in question can be performed.

Free α-Subunit, Free β-Subunit of Human Chorionic Gonadotropin (hCG), and Intact hCG in Sera of Healthy Individuals and Testicular Cancer Patients

To determine the serum concentrations of human chorionic gonadotropin (hCG), its free beta-subunit (hCG beta), and the free alpha-subunit (free alpha) common to all human glycoprotein hormones under physiological and pathological conditions, we developed monoclonal antibody-based immunoenzymometric assays. Free alpha-subunit was detected in the sera of all healthy individuals of both sexes; hCG was measurable in sera of 54% of the men, and 46% were positive for free hCG beta; in nonpregnant women, 69.5% were positive for hCG, 68.4% for the free beta-subunit. Pathological conditions, i.e., hCG-producing tumors, were studied in vitro and in vivo. In vitro, the concentrations of hCG, free hCG beta, and free alpha in tissue-culture supernates of a choriocarcinoma cell-line ("JAR") showed a parallel pattern during time-course analysis. In vivo, in long-term follow-up studies of 13 patients with testicular cancer, serum concentrations of the three analytes paralleled each other, whether the disease was in remission or not. Because of a selective increase of free hCG beta and free alpha in 27% of seminomatous tumor patients and in 13% of the nonseminomatous patients, the percentage of tumor-marker-positive sera was increased from 15% to 42% and 57% to 70%, respectively, by the additional measurement of free hCG beta and free alpha. Thus hCG, free hCG beta, and free alpha are physiologically present in a high percentage of the sera from healthy men, and the determination of free hCG beta and free alpha, although not of prognostic value, improves the diagnostic possibilities in patients with testicular cancer.

Free alpha-subunit, free beta-subunit of human chorionic gonadotropin (hCG), and intact hCG in sera of healthy individuals and testicular cancer patients

To determine the serum concentrations of human chorionic gonadotropin (hCG), its free beta-subunit (hCG beta), and the free alpha-subunit (free alpha) common to all human glycoprotein hormones under physiological and pathological conditions, we developed monoclonal antibody-based immunoenzymometric assays. Free alpha-subunit was detected in the sera of all healthy individuals of both sexes; hCG was measurable in sera of 54% of the men, and 46% were positive for free hCG beta; in nonpregnant women, 69.5% were positive for hCG, 68.4% for the free beta-subunit. Pathological conditions, i.e., hCG-producing tumors, were studied in vitro and in vivo. In vitro, the concentrations of hCG, free hCG beta, and free alpha in tissue-culture supernates of a choriocarcinoma cell-line ("JAR") showed a parallel pattern during time-course analysis. In vivo, in long-term follow-up studies of 13 patients with testicular cancer, serum concentrations of the three analytes paralleled each other, whether the disease was in remission or not. Because of a selective increase of free hCG beta and free alpha in 27% of seminomatous tumor patients and in 13% of the nonseminomatous patients, the percentage of tumor-marker-positive sera was increased from 15% to 42% and 57% to 70%, respectively, by the additional measurement of free hCG beta and free alpha. Thus hCG, free hCG beta, and free alpha are physiologically present in a high percentage of the sera from healthy men, and the determination of free hCG beta and free alpha, although not of prognostic value, improves the diagnostic possibilities in patients with testicular cancer.

Effects of sex steroid analogs on spontaneous autoimmune thyroiditis in obese strain chickens

Treatment of obese strain chickens, either in ovo or after hatching, with testosterone or various testosterone-derived steroid analogs having no or only weak endocrine activities causes significant protection from spontaneous autoimmune thyroiditis occurring in these birds. This effect is not correlated with the endocrinological properties of these steroids. This observation and similar results in other models for autoimmunity may present a basis for a more selective therapy in human autoimmune diseases in that hormonal side effects no longer preclude this approach.

Thymic nurse cell lymphocytes react against self major histocompatibility complex

It has been postulated that thymic nurse cells (TNC), lymphoid-epithelial complexes composed of thymocytes enclosed within major histocompatibility complex (MHC) class I+ and class II+ cortical epithelial cells, may provide an optimal microenvironment for the process of T cell selection. By transplanting single TNC in the avian chorionallantoic membrane assay we demonstrate that a significant portion of intra-TNC lymphocytes (TNC-L) possess reactivity against self-MHC molecules. The frequency of these autoreactive cells among TNC-L exceeds by far that of thymocytes or peripheral blood lymphocytes of the same donor. These results indicate that TNC-L constitute a T cell population enriched for self-MHC reactivity, i.e. cells that have undergone positive selection, but not yet deletion and/or deactivation.

Target organ susceptibility and autoantibody production in an animal model of spontaneous autoimmune thyroiditis

F1-hybrids of Obese strain (OS) chickens, afflicted with spontaneous autoimmune thyroiditis (SAT), and normal, inbred CB chickens, do not develop severe thyroiditis. About 50% of these crosses show circulating autoantibodies to thyroglobulin (TgAAb), but the thyroid glands are only slightly infiltrated, suggesting that the target organ is not susceptible to autoimmune attack. In the present study we show that despite this mild infiltration TgAAb are only synthesized by lymphoid cells within the thyroid gland. Furthermore, we demonstrate that immunization with chicken thyroglobulin (Tg) in complete Freund's adjuvant causes severe experimental autoimmune thyroiditis (EAT) in F1(OSxCB) hybrids.

Human foamy virus antigens in thyroid tissue of Graves' disease patients

Human foamy virus (HFV) is a recently characterized member of the retrovirus subfamily Spumaretrovirinae. HFV has a complex structure: it encodes the classical three retroviral structural genes gag, pol and env, but also possesses additional regulatory, so-called bel sequences. Foamy viruses have been discussed occasionally as being possibly involved in the pathogenesis of autoimmune thyroiditis. By indirect immunofluorescence we were able to demonstrate the expression of HFV gag proteins on the epithelial cells of 7/7 thyroid glands of patients with Graves' disease, but not in those of 9 patients with struma parenchymatosa, 3 with follicular carcinoma and 2 normal thyroids. The thyroids of 5 patients with Hashimoto's disease were also negative with the exception of a single small focus in 1 case. These observations may have importance for our understanding of the development of Graves' disease.

Electron microscopy analysis of mineral fibers in human lung tissue

In the present study, lung samples from 126 autopsied cases were examined to determine the content of mineral fibers using analytical transmission electron microscopy (ATEM). The cases were divided into four groups (22 lungs of persons exposed to ambient environmental pollution, 32 cases of mesothelioma, 38 cases of primary lung cancer, and 34 asbestosis cases, 13 of these with additional pleural plaques). Fibers were counted, measured, and mineralogically identified using a combination of X-ray microanalysis and electron diffraction of the non-oriented fiber. Concentration of fibrous particles (defined as particles above 1 micron in length with roughly parallel long sides and an aspect ratio of 5:1 and greater) was calculated as fibers 10(6)/g dry lung weight. The concentration of chrysotile was found to be similar throughout the groups except for two cases in the asbestosis group with comparably high numbers of chrysotile. However, a remarkable difference for amphiboles could be observed between the groups. Asbestos bodies were mostly found in the asbestosis group. There was a rather good correlation between numbers of amphibole fibers and asbestos bodies, with an average ratio of 10:1. For comparison purposes between occupationally exposed/non-exposed individuals, a transition was found in the concentration range of 3-10(7) asbestos fibers/g dried lung weight.

Complete clarification of a case of farmer's lung

The diagnostic curriculum to clarify a case of farmer's lung in a fibrotic stage is presented, including clinical functional tests, X-ray, analysis of cellular elements recovered from bronchioalveolar lavage, determination of precipitating antibodies in the circulation, histological and immunohistological studies of transbronchial lung biopsies. The patient had precipitating antibodies against several species of hay molds, especially Micropolyspora faeni, and immune complex deposition in the lung. Elution experiments on frozen sections of the lung biopsies and subsequent administration of patient's serum- or mold antigen-specific antibodies combined with appropriate serum absorption experiments allowed the identification of the relevant antigen, i.e. M. faeni, in the deposited immune complexes. The immunohistological analysis of extracellular matrix components revealed an interstitial increase in procollagen and collagen type I and an even more pronounced augmentation of procollagen type III and fibronectin, i.e. a constellation characteristic for a chronic, active lung fibrosis that developed on the basis of an immune complex disease.