A population of lymphocytes bearing a membrane receptor for antigen-antibody-complement complexes. I. Separation and characterization

Advancement in COVID-19 detection using nanomaterial-based biosensors

Coronavirus disease 2019 (COVID-19) pandemic has exemplified how viral growth and transmission are a significant threat to global biosecurity. The early detection and treatment of viral infections is the top priority to prevent fresh waves and control the pandemic. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified through several conventional molecular methodologies that are time-consuming and require high-skill labor, apparatus, and biochemical reagents but have a low detection accuracy. These bottlenecks hamper conventional methods from resolving the COVID-19 emergency. However, interdisciplinary advances in nanomaterials and biotechnology, such as nanomaterials-based biosensors, have opened new avenues for rapid and ultrasensitive detection of pathogens in the field of healthcare. Many updated nanomaterials-based biosensors, namely electrochemical, field-effect transistor, plasmonic, and colorimetric biosensors, employ nucleic acid and antigen-antibody interactions for SARS-CoV-2 detection in a highly efficient, reliable, sensitive, and rapid manner. This systematic review summarizes the mechanisms and characteristics of nanomaterials-based biosensors for SARS-CoV-2 detection. Moreover, continuing challenges and emerging trends in biosensor development are also discussed.

Depression and monocyte dysfunction: a follow-up study

Several studies have reported immune cellular and humoral dysfunction during depression. We specifically focused on the study of the monocyte as it has a key role in the activation of the immune response. To examine the association between severity of depressive symptoms and values of monocyte parameters (HLA-DR, CD35, phagocytic activity and vimentin filaments), we used a longitudinal design and assessed monocyte markers at intake and at follow-up 12 weeks after discharge from the hospital in 49 depressed patients. Seventy percent of patients showed pretreatment a marked monocyte dysfunction (82.5% had at least one parameter altered). After treatment, alterations in immunological variables were significantly associated (P< 0.05) with depression scores higher than 15. The findings indicate that the monocyte dysfunction is temporally associated with the state of depression. Before and after treatment the immunoreactive vimentin filaments significantly increased (P< 0.01) after incubation of monocytes with naloxone, suggesting that an increased opioid activity might account for the monocyte dysfunction.

Purification of T Cell Populations

This article describes a procedure for isolating T cell subpopulations using various methods including indirect panning and immunopanning by microarray. In these methods, cells are selected by their capacity to bind to antibody-coated plates (or slides) on the basis of particular cell-surface markers. Such methods can be superior to the antibody/complement lysis method (Alternate Protocol), as they can select additional cell population for analysis. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Isolation of T cell populations by indirect panning Basic Protocol 2: Immunopanning with microarray Alternate Protocol: Isolation of T cell populations by antibody/complement-mediated cytotoxicity.

Lymphocyte-based model systems for allergy research: a historic overview

During the last decades, a multitude of studies applying distinct in vitro and in vivo model systems have contributed greatly to our better understanding of the initiation and regulation of inflammatory processes leading to allergic diseases. Over the years, it has become evident that among lymphocytes, not only IgE-producing B cells and allergy-orchestrating CD4(+) helper cells but also cytotoxic CD8(+) T cells, γδ-T cells and innate lymphoid cells, as well as regulatory lymphocytes, might critically shape the immune response towards usually innocuous allergens. In this review, we provide a historic overview of pioneering work leading to the establishment of important lymphocyte-based model systems for allergy research. Moreover, we contrast the original findings with our currently more refined knowledge to appreciate the actual validity of the respective models and to reassess the conclusions obtained from them. Conflicting studies and interpretations are identified and discussed. The tables are intended to provide an easy overview of the field not only for scientists newly entering the field but also for the broader readership interested in updating their knowledge. Along those lines, herein we discuss in vitro and in vivo approaches to the investigation of lymphocyte effector cell activation, polarization and regulation, and describe depletion and adoptive transfer models along with gene knockout and transgenic (tg) methodologies. In addition, novel attempts to establish humanized T cell antigen receptor tg mouse models for allergy research are described and discussed.

Selective individual primary cell capture using locally bio-functionalized micropores

Background

Solid-state micropores have been widely employed for 6 decades to recognize and size flowing unlabeled cells. However, the resistive-pulse technique presents limitations when the cells to be differentiated have overlapping dimension ranges such as B and T lymphocytes. An alternative approach would be to specifically capture cells by solid-state micropores. Here, the inner wall of 15-µm pores made in 10 µm-thick silicon membranes was covered with antibodies specific to cell surface proteins of B or T lymphocytes. The selective trapping of individual unlabeled cells in a bio-functionalized micropore makes them recognizable just using optical microscopy.

Methodology/Principal Findings

We locally deposited oligodeoxynucleotide (ODN) and ODN-conjugated antibody probes on the inner wall of the micropores by forming thin films of polypyrrole-ODN copolymers using contactless electro-functionalization. The trapping capabilities of the bio-functionalized micropores were validated using optical microscopy and the resistive-pulse technique by selectively capturing polystyrene microbeads coated with complementary ODN. B or T lymphocytes from a mouse splenocyte suspension were specifically immobilized on micropore walls functionalized with complementary ODN-conjugated antibodies targeting cell surface proteins.

Conclusions/Significance

The results showed that locally bio-functionalized micropores can isolate target cells from a suspension during their translocation throughout the pore, including among cells of similar dimensions in complex mixtures.

Extracellular ubiquitin: immune modulator and endogenous opponent of damage-associated molecular pattern molecules

Ubiquitin is a post-translational protein modifier and plays essential roles in all aspects of biology. Although the discovery of ubiquitin introduced this highly conserved protein as a molecule with extracellular actions, the identification of ubiquitin as the ATP-dependent proteolysis factor 1 has focused subsequent research on its important intracellular functions. Little attention has since been paid to its role outside of the cell. During recent years, multiple observations suggest that extracellular ubiquitin can modulate immune responses and that exogenous ubiquitin has therapeutic potential to attenuate exuberant inflammation and organ injury. These observations have not been integrated into a comprehensive assessment of its possible role as an endogenous immune modulator. This review recapitulates the current knowledge about extracellular ubiquitin and discusses an emerging facet of its role in biology during infectious and noninfectious inflammation. The synopsis of these data along with the recent identification of ubiquitin as a CXCR4 agonist suggest that extracellular ubiquitin may have pleiotropic roles in the immune system and functions as an endogenous opponent of DAMPs. Functions of extracellular ubiquitin could constitute an evolutionary conserved control mechanism aimed to balance the immune response and prevent exuberant inflammation. Further characterization of its mechanism of action and cellular signaling pathways is expected to provide novel insights into the regulation of the innate immune response and opportunities for therapeutic interventions.

Histochemical contributions to the binding mechanism of complement (CR1, CR2) receptors

Complement receptors (CR1, CR2, CR3), and their ligands (C3b, C3d, iC3b) are essentially involved in germinal center development and in binding, trapping, and retaining immunocomplexes. Methods studying complement receptor (CR1/CR2)-ligand (C3b/C3d) interactions mostly involve coating of sheep erythrocytes (E), sheep erythrocyte-antisheep erythrocyte antibody (EA complexes) and whole human (h) or mouse (m) sera as a source of complement, EACh/m complexes, as reagents. The observation of Dukor et al. (1970), that EACm complexes in native cryostat sections bind selectively and very strongly to the B lymphocyte regions of lymphoid organs allowed the topo-histochemical analysis of receptor (CR1/CR2)-ligand (C3b/C3d) interactions in such an immunologically important area as the germinal centers. The main finding of this study is, that periodic acid pretreatment of unfixed cryostat tonsil sections-oxidizing vicinal glycol groups of polysaccharide chains into dialdehydes-completely abolished the binding of all EAC/EC complexes to germinal center area. It may suggest the involvement of receptor carbohydrate in C3 receptor/ligand binding. In addition to, the subsequent sodium borohydride reduction-converting aldehydes (produced by periodic acid oxidation) into primary alcohols-restored selectively the binding of all applied EAC/EC complexes to follicular centers. These in vitro topo-histochemical studies give a strong hint for the participation of-OH groups of sugar residues in CR1/CR2 ligand (C3b/C3d) binding.

Purification of T cell subpopulations

This unit describes a procedure for isolating T cell populations or subpopulations using the method of indirect panning. In this method, cells are selected by their capacity to bind to antibody-coated plates on the basis of particular cell-surface markers. It is superior to the antibody/complement lysis method (also presented) because the nonselected cell population can be retrieved.

Identification of resting human T and B lymphocytes by acid alpha-naphthyl acetate esterase staining combined with rosette formation with Staphylococcus aureus strain Cowan 1

We describe a method enabling the identification of both lymphocyte class and morphology from a single microscopic slide. As a marker for B cells we used surface immunoglobulin. The surface-Ig-carrying cells were rosetted after poly-valent anti-Ig treatment with Staphylococcus aureus strain Cowan 1 (StaCw) and the cells were cytocentrifuged onto a microscope slide. The lymphocytes forming rosettes with StaCw were identical with cells expressing surface Ig studied by fluorescein-isothiocyanate-conjugated anti-Ig. As a marker for T cells we used the acid alpha-naphthyl acetate esterase (ANAE) histochemical marker. The cell smears were first stained for ANAE and subsequently counterstained to distinguish also cell morphology. The ANAE-marker-carrying cells were all included in the population of lymphocytes forming rosettes with sheep erythrocytes. Thus both T and B lymphocytes could be simultaneously identified from a single microscopic slide, and we therefore recommend the method for routine clinical work.

Lymphocyte Differentiation in the Nasal Mucosa

Few cytological studies have investigated the morphologic changes occurring during lymphocyte differentiation in the nose. The aim of the study is to investigate lymphocyte and plasma cell morphology in patients with allergic rhinitis. Nasal cytology was performed in 110 patients (61 men, 49 women) of ages ranging from 12 to 47 years (mean age, 27), 72 of whom were affected by pollen allergic rhinitis (32 allergic to olive, 21 to Parietaria, 13 to grasses, and 6 to cypress) and 38 by perennial allergic rhinitis (allergy to house dust mites). Cytological samples were obtained by scraping with Rhino-Probe™. The samples were collected from the inferior middle turbinate. After fixing and drying, the samples were stained and counted. Cells belonging to the lymphocyte-plasma cell lineage were analyzed. Within this population, 5 different cellular types were identified displaying particular morphologic features of the nucleus and the cytoplasm. These morphological variants constitute various functional stages of B lymphocytes. In allergic inflammation, antigen stimulation induces B lymphocytes to differentiate and become plasma cells. The findings from this strictly morphological study will need to be confirmed by immunohistochemical and immunophenotypic studies.

Classical and alternative pathway complement activation are not required for reactive systemic AA amyloid deposition in mice

During induction of reactive systemic amyloid A protein (AA) amyloidosis in mice, either by chronic inflammation or by severe acute inflammation following injection of amyloid enhancing factor, the earliest deposits form in a perifollicular distribution in the spleen. Because the splenic follicular localization of immune complexes and of the scrapie agent are both complement dependent in mice, we investigated the possible complement dependence of AA amyloid deposition. In preliminary experiments, substantial depletion of circulating C3 by cobra venom factor had little effect on experimental amyloid deposition. More importantly, mice with targeted deletion of the genes for C1q or for both factor B and C2, and therefore unable to sustain activation, respectively, of either the classical complement pathway or both the classical and alternative pathways, showed amyloid deposition similar to wild type controls. Complement activation by either the classical or alternative pathways is thus not apparently necessary for the experimental induction of systemic AA amyloid in mice.

Internalization of circulating apoptotic cells by splenic marginal zone dendritic cells: dependence on complement receptors and effect on cytokine production

Under steady-state conditions, internalization of self-antigens embodied in apoptotic cells by dendritic cells (DCs) resident in peripheral tissue followed by DC migration and presentation of self-peptides to T cells in secondary lymphoid organs are key steps for induction and maintenance of peripheral T-cell tolerance. We show here that, besides this traffic of apoptotic cells mediated by peripheral tissue-resident DCs, splenic marginal zone DCs rapidly ingest circulating apoptotic leukocytes, process apoptotic cell-derived peptides into major histocompatibility complex class II (MHC-II) molecules, and acquire CD8alpha during their mobilization to T-cell areas of splenic follicles. Because apoptotic cells activate complement and some complement factors are opsonins for phagocytosis and play roles in the maintenance of peripheral tolerance, we investigated the role of complement receptors (CRs) in relation to phagocytosis of apoptotic cells by DCs. Apoptotic cell uptake by marginal zone DCs was mediated in part via CR3 (CD11b/CD18) and, to a lesser extent, CR4 (CD11c/CD18) and was reduced significantly in vivo in hypocomplementemic animals. Following phagocytosis of apoptotic cells, DCs exhibited decreased levels of mRNA and secretion of the proinflammatory cytokines interleukin 1alpha (IL-1alpha), IL-1beta, IL-6, IL-12p70, and tumor necrosis factor alpha (TNF-alpha), without effect on the anti-inflammatory mediator transforming growth factor beta1 (TGF-beta1). This selective inhibitory effect was at least partially mediated through C3bi-CD11b/CD18 interaction. Characterization of apoptotic cell/DC interaction and its outcome provides insight into the mechanisms by which apoptotic cells affect DC function without disrupting peripheral tolerance.

Urokinase is required for the formation of mactinin, an alpha-actinin fragment that promotes monocyte/macrophage maturation

We have previously shown that lysates from HL-60 myeloid leukemia cells or from peripheral blood monocytes are able to degrade alpha-actinin to form a 31-kDa amino-terminal fragment with monocyte/macrophage maturation promoting activity. In contrast, intact alpha-actinin, which is a 100-kDa actin-binding protein, has no differentiating activity. The aim of this study was to investigate the enzyme responsible for the degradation of alpha-actinin to form this fragment, named mactinin. The ability of cell lysates to degrade [125I]alpha-actinin in the presence of various enzyme inhibitors, including inhibitors of metalloproteinases, cysteine proteinases, and serine proteases, was measured. Phenylmethylsulfonyl fluoride (PMSF) was the only inhibitor able to prevent formation of mactinin by cell lysate degradation of alpha-actinin, suggesting that a serine protease is responsible for the digestion. Of the various serine proteases tested (thrombin, plasmin, and urokinase), only urokinase was able to produce a 31-kDa band. The urokinase-generated 31-kDa band promoted maturation in HL-60 cells. Amiloride, a specific inhibitor of urokinase, inhibited production of the 31-kDa alpha-actinin fragment by HL-60 cell lysates. For in vivo tests, inflammatory fluid (from bronchoalvelolar lavage) was collected from uPA (urokinase) knockout mice and their wild-type counterparts after intratracheal challenge with Pneumocystis carinii. Although most (6 of 8) wild-type mice had mactinin in their inflammatory fluid samples, none (0 of 8) of the uPA knockout mice had mactinin present (P<0.01). These results demonstrate that urokinase is necessary and sufficient for the formation of the monocyte/macrophage maturation promoting fragment, mactinin, in vitro and in vivo. These findings support the role of urokinase in the regulation of monocyte/macrophage functions, such as that occurring in inflammatory reactions.

Studies of the humoral immune response

The humoral immune response arises from a complex choreography of cells and molecules that interact to produce lasting and effective defenses against pathogens. For more than fifteen years, our laboratory has studied how humoral responses are initiated, how they mature, and how they are remembered. This work has come from many hands and in this brief synopsis, I cannot provide the full recognition that my students, postdoctoral fellows, and collaborators merit. I hope that my colleagues can accept this translucence and know that their efforts are recognized and deeply appreciated, nonetheless.

Regulation of humoral immune responses by CD21/CD35

Before antigen-specific immunity arises, the complement system responds by activation through the classical and/or alternative pathways leading to the covalent deposition of complement fragments. Three models, not mutually exclusive, have been proposed to explain how these complement fragments interact with their receptors, CD21/CD35, to enhance humoral immune responses: i) CD21/CD35 retain and focus antigens for optimal presentation; ii) CD21/CD35 on B cells serve as enhancing co-receptors for B-cell antigen receptor (BCR) signaling; iii) CD21/CD35 regulate B-cell responses, by CD19 aggregation. The coreceptor model led us to predict that CD21/CD3 5 may lower the threshold of BCR affinity to diversify the repertoire of humoral immune responses, but surprisingly, CD21/CD3 5-deficient mice expressing a transgenic BCR with very low affinity (Kalpha approximately =1.2 x 10(5) M(-1)) for the (4-hydroxy-3-nitrophenyl)acetyl hapten generated significant antibody and germinal center responses to even low doses of antigens in alum. The magnitudes of these responses were much below those of normal controls but higher doses of antigens substantially rectified these deficits. Thus, while CD21/CD35 play important roles in humoral immunity, our observations provide little support to the hypothesis that CD21/CD35 promote clonal diversity in immune responses by helping recruit low-affinity B cells.

Humoral immune responses in Cr2-/- mice: enhanced affinity maturation but impaired antibody persistence

Deficiency in CD21/CD35 by disruption of the Cr2 loci leads to impaired humoral immune responses. In this study, we detail the role of CD21/CD35 on Ab responses to the hapten (4-hydroxy-3-nitrophenyl)acetyl conjugated to chicken gamma-globulin. Surprisingly, Cr2-/- mice generate significant Ab responses and germinal center (GC) reactions to low doses of this Ag in alum, although the magnitude of their responses is much reduced in comparison with those of Cr2+/- and C57BL/6 controls. Increasing Ag dose partially corrected this deficit. In situ study of the somatic genetics of GC B cells demonstrated that VDJ hypermutation does not require CD21/CD35, and Cr2-/- mice exhibited enhanced affinity maturation of serum Ab in the post-GC phase of the primary response. On the other hand, Cr2-/- mice displayed accelerated loss of serum Ab and long-lived Ab-forming cells. These observations suggest that B cell activation/survival signals mediated by CD21 and/or the retention of Ag by CD21/CD35 play important roles in the generation, quality, and maintenance of serum Ab.

HL-60 cells degrade alpha-actinin to produce a fragment that promotes monocyte/macrophage maturation

An amino-terminal fragment of alpha-actinin can promote monocyte/macrophage maturation. This fragment was initially isolated from media of HL-60 myeloid leukemia cells cultured on extracellular bone marrow matrix. To determine the source of this fragment in this culture system, we investigated whether HL-60 cells grown on bone marrow stroma have increased intracellular levels of alpha-actinin that may be released into the media during cell apoptosis. HL-60 cells grown on matrix showed no evidence of increased cellular alpha-actinin compared to cells grown on plastic substrata as measured by flow cytometry. In addition, there was no evidence of increased apoptosis as determined by DNA fragmentation assays or flow cytometry. However, 100 kD alpha-actinin was found in the extracellular matrix of bone marrow stroma by Western blot analysis and immunofluorescence microscopy. The alpha-actinin content in the stroma was markedly decreased after exposure to HL-60 cells. Furthermore, lysates of HL-60 cells or of peripheral blood monocytes can degrade exogenous alpha-actinin to produce a 31 kD fragment, which promotes monocyte/macrophage maturation. We conclude that when alpha-actinin is present in the extracellular matrix, it can be modified by HL-60 cells to produce a maturation promoting 31 kD fragment.

A fragment of alpha-actinin promotes monocyte/macrophage maturation in vitro

Conditioned media (CM) from cultures of HL-60 myeloid leukemia cells grown on extracellular bone marrow matrix contains a factor that induces macrophage-like maturation of HL-60 cells. This factor was purified from the CM of HL-60 cells grown on bone marrow stroma by ammonium sulfate precipitation, then sequential chromatography on DEAE, affi-gel blue affinity, gel exclusion, and wheat germ affinity columns, followed by C-4 reverse phase HPLC, and SDS-PAGE. The maturation promoting activity of the CM was identified in a single 31 kD protein. Amino acid sequence analysis of four internal tryptic peptides of this protein confirmed significant homology with amino acid residues 48-60, 138-147, 215-220, and 221-236 of human cytoskeletal alpha-actinin. An immunoaffinity purified rabbit polyclonal anti-chicken alpha-actinin inhibited the activity of HL-60 conditioned media. A 27 kD amino-terminal fragment of alpha-actinin produced by thermolysin digestion of chicken gizzard alpha-actinin, but not intact alpha-actinin, had maturation promoting activity on several cell types, including blood monocytes, as measured by lysozyme secretion and tartrate-resistant acid phosphatase staining. We conclude that an extracellular alpha-actinin fragment can promote monocyte/macrophage maturation. This represents the first example of a fragment of a cytoskeletal component, which may be released during tissue remodeling and repair, playing a role in phagocyte maturation.

T cell-dependent immune response in C1q-deficient mice: defective interferon gamma production by antigen-specific T cells

The role of the classical complement pathway in humoral immune responses was investigated in gene-targeted C1q-deficient mice (C1qA-/-). Production of antigen-specific immunoglobulin (Ig)G2a and IgG3 in primary and secondary responses to T cell-dependent antigen was significantly reduced, whereas IgM, IgG1, and IgG2b responses were similar in control and C1qA-/- mice. Despite abnormal humoral responses, B cells from C1qA-/- mice proliferated normally to a number of stimuli in vitro. Immune complex localization to follicular dendritic cells within splenic follicles was lacking in C1qA-/- mice. The precursor frequency of antigen-specific T cells was similar in C1qA-/- and wild-type mice. However, analysis of cytokine production by primed T cells in response to keyhole limpet hemocyanin revealed a significant reduction in interferon-gamma production in C1qA-/- mice compared with control mice, whereas interleukin 4 secretion was equivalent. These data suggest that the classical pathway of complement may influence the cytokine profile of antigen-specific T lymphocytes and the subsequent immune response.

Activation of human T and B cells by rabbit anti-human beta 2-microglobulin

Rabbit anti-human beta 2-microglobulin (anti-beta 2m) increased the highest DNA synthesis in unseparated lymphocytes or artificially composed mixtures enriched in T and B cells. In enriched T and B cells no or low stimulation was seen. The maximal response by IgG anti-beta 2m was seen in proportions of enriched T/B cells, being 3:1 for blood lymphocytes and 1:1 for spleen cells, which are the same as the physiological proportions of T and B cells in these lymphoid organs. Whereas unseparated lymphocytes gave a peak response on day 3, enriched B cells had a peak response on day 6. Fab anti-beta 2m did not activate enriched T cells but increased DNA synthesis in enriched B cells to about the same extent as unseparated lymphocytes and mixtures of enriched T and B cells. The proportion of sheep erythrocyte rosette-forming cells (E-RFC) decreased after stimulation by anti-beta 2m and increased after stimulation by phytohaemagglutinin. However, as revealed by autoradiography, a proportion of lymphocytes activated by anti-beta 2m were E-RFC and this proportion increased with increasing stimulation by anti-beta 2m. DNA synthesis induced by anti-beta 2m was unchanged for spleen cells and slightly decreased for blood lymphocytes when phagocytic cells were removed by iron treatment. Supernatants from lymphocytes activated by anti-beta 2m only induced low DNA synthesis in enriched T or B cells. Experiments with mitomycin treated cells indicate that cooperation and close contact between T and B cells are needed for activation by IgG anti-beta 2m. T cells are needed for B cell activation by anti-beta 2m and B cells are required for T cell activation to occur.

Antibody secretion and DNA synthesis induced by lipopolysaccharide in enriched human lymphocyte subpopulations

Lipopolysaccharide (LPS)-induced human lymphocyte activation was analysed with regard to DNA synthesis and antibody secretion. Antibody secretion was measured as plaque-forming cells (PFC) against fluorescein isothiocyanate (FITC)-coupled sheep erythrocytes (SRBC) or protein-A-coupled SRBC in the presence of developing antiserum against human IgG, IgA and IgM subclasses. By co-culturing lymphocytes with various concentrations of mitomycin, without impairing cell viability, inhibition of DNA synthesis and antibody secretion by LPS was correlated. Antibody secretion against FITC-SRBC or protein A-SRBC was not stimulated by LPS in B cells enriched by elimination of SRBC rosette-forming cells (E-RFC). In mixtures of enriched T and B cells the number of PFC was much lower than in unseparated lymphocytes, but the highest number of PFC was seen in the enriched E-RFC. However, DNA synthesis by LPS was induced in enriched B cells and not in enriched T cells. The highest DNA synthesis was seen for unseparated lymphocytes. Furthermore, autoradiography studies and experiments in which activated lymphocytes were separated revealed that LPS predominantly stimulated DNA synthesis in non-E-RFC, presumably B cells and only activated a small proportion of E-RFC. Finally, antibody secretion induced by LPS was unchanged following iron treatment but was inhibited by cells adherent to plastic.

Study on adhesion factors in lymphocyte migration to the middle ear mucosa

We investigated influences of adhesion factors on the migration of antigen-specific IgA-forming cells (ASAFCs) to the middle ear mucosa by means of an in vitro lymphocyte binding assay. Peyer's patch (PP) lymphocytes from guinea pigs with mucosal immunization, which are rich in ASAFCs, more frequently bound with the inflamed middle ear mucosa than those of PP and spleen cells from animals with systemic immunization, in which antigen-specific IgG-forming cells (ASGFCs) were induced (p > .001). The bindings were not affected by antigenic and nonantigenic stimuli to the middle ear mucosa for producing otitis media. On human middle ear mucosa from 10 patients with acute mastoiditis and chronic otitis media, endothelial cells of newly grown vessels were stained strongly with intercellular adhesion molecule (ICAM)-1, and weakly with vascular cell adhesion molecule (VCAM)-1, platelet endothelial cell adhesion molecule (PECAM), and endothelial leukocyte adhesion molecule (ELAM)-1. Many lymphocytes bound mainly to these endothelial cells, and a few cells were observed bound to the basal portion of epithelial cells. The binding of lymphocytes was significantly, but not completely, inhibited by anti-ICAM-1 antibody (p < .001). These findings suggest that PP lymphocytes with activated mucosal immunity more frequently migrate to the inflamed middle ear mucosa, and that those migrations, after extravasation, may be regulated by the interaction between various binding factors and their receptors on lymphocytes, which is different from that of adhesion molecules and their ligands in the extravasation.

Mycoplasma arthritidis mitogen up-regulates human NK cell activity

While the effects of superantigens on T lymphocytes are well characterized, how superantigens interact with other immune cells is less clear. This report examines the effects of Mycoplasma arthritidis mitogen (MAM) on human natural killer (NK) cell activity. Incubation of peripheral blood mononuclear cells (PBMC) with MAM for 16 to 20 h augmented NK cytotoxicity (against K562) in a dose-dependent manner (P < or = 0.05). Superantigen-dependent cellular cytotoxicity, an activity of superantigen-activated cytotoxic T cells, was not involved in lysis of K562 cells because the erythroleukemic tumor target cells expressed no class II major histocompatibility complex by fluorescence-activated cell sorter analysis. Kinetic experiments showed that the largest increase in NK activity induced by MAM occurred within 48 h. Incubation with MAM caused a portion of NK cells to become adherent to tissue culture flasks, a quality associated with activation, and augmented NK activity was found in both adherent and nonadherent subpopulations. Experiments using cytokine-specific neutralizing antibodies showed that interleukin-2 contributed to enhancement of the NK activity observed in superantigen-stimulated PBMC. Interestingly, MAM was able to augment NK lysis of highly purified NK (CD56+) cells in the absence of other immune cells in 9 of 12 blood specimens, with the augmented lytic activity ranging from 110 to 170% of unstimulated NK activity. In summary, data presented in this report show for the first time that MAM affects human NK cells directly by increasing their lytic capacity and indirectly in PBMC as a consequence of cytokines produced by T cells. Results of this work suggest that, in vivo, one consequence of interaction with superantigen-secreting microorganisms may be up-regulation of NK lytic activity. These findings may have clinical application as a means of generating augmented NK effector cells useful in the immunotherapy of parasitic infections or neoplasms.

Human bone marrow heparan sulfate induces leukemia cell differentiation

The proliferation and development of hematopoietic cells occurs in close association with bone marrow stroma. Heparan sulfate is a major component of the stroma. We have isolated a form of heparan sulfate proteoglycan from a human stromal cell line grown in vitro in the presence of [35S]sulfate. This proteoglycan contains a phosphatidylinositol component which likely anchors it to the stromal cell membrane. The glycosaminoglycan chains of this proteoglycan could induce maturation of the HL-60 myeloid leukemia cell line. A less hydrophobic heparan sulfate proteoglycan was also present in the stroma, but could not induce HL-60 maturation. The two heparan sulfates had glycosaminoglycan chains that were similar in size (36 Kd) and charge density. Structural studies suggested only minor but perhaps significant differences in the carbohydrate sequences of the two heparan sulfates. The relationship of these subtle structural differences to the difference observed in differentiation-inducing activity remains to be elucidated.

Neuroendocrine and immunological functions in depressed patients: a follow-up study

The development, evaluation and use of biological markers with a diagnostic purpose in psychiatry is extremely important. However, with certain exceptions, truly sensitive and specific markers have not yet emerged. In order to investigate the relationship between the immune apparatus and the hypothalamic-pituitary activity on the one hand, and the psychopathological state of the patients on the other, we used a longitudinal design and assessed monocyte parameters (HLA-DR, CD 35, vimentin filaments, and phagocytosis index) and neuroendocrine tests (dexamethasone suppression test [DST] and thyrotropin-releasing hormone [TRH] stimulation test) at intake and at follow-up in 49 depressed patients. Immunological parameters were compared with neuroendocrine tests in both phases of the study. The combined use of both immunological and neuroendocrine tests did not add sensitivity to the immunological identification of depressed patients. The findings lead us to consider the role of the monocyte parameters as sensitive depressive state markers, while the combined use of both neuroendocrine and immunological tests in current clinical practice would be debatable.

The effect of DTC on humoral response restoration and thymocyte subpopulations in cyclophosphamide-immunosuppressed mice

The effects of sodium diethyldithiocarbamate (DTC) on humoral response to SRBC and restoration of the response impaired by a single cyclophosphamide dose (200 mg/kg) were tested on mice. Moreover, the effect of DTC (20 mg/kg) on thymocyte subpopulations was tested on non-immunized mice previously treated with cyclophosphamide. It was found that DTC (20 mg/kg) administered to the immunized mice enhanced humoral response to SRBC, which was reflected in the increased number of PFC and (7S) serum hemagglutinin titer. In contrast, partial restoration of the primary humoral response after DTC injection was observed in the mice administered a single cyclophosphamide dose. The effect of DTC was stronger after 6 days following cyclophosphamide injection, i.e. at the time when spontaneous restoration of T lymphocytes begins. In addition, it was found that DTC given to non-immunized mice treated with cyclophosphamide had a modulating effect on thymocyte subpopulations. Depending on the time of exposure to cyclophosphamide, DTC either increased the percentage of CD4 thymocytes or decreased the percentage of CD8, which subsequently led increased CD4/CD8 coefficient. DTC did not change the suppressing action of cyclophosphamide on the percentage of double-positive thymocytes.

The dose-dependent influence of mechloretamine on the response to sheep erythrocytes in mice. Comparison of immunostimulating properties of mechloretamine with levamisole

The effect of the following doses of mechloretamine: 1, 5, 10, 25, 50, 100, 250 and 500 micrograms/kg on the immunological response in mice immunized with sheep red blood cells (SRBC) was investigated. The number of plaque forming cells (PFC) to SRBC, the serum hemagglutinins level and the number of lymphocytes forming E or EAC-rosettes were determined. Depending on mechloretamine dose the following effects on the tested parameters were obtained: (i) only stimulating--1 and 5 micrograms/kg, (ii) stimulating or suppressive according to the test--10-100 micrograms/kg, (iii) only suppressive--250 and 500 micrograms/kg. Mechloretamine (5 micrograms/kg) induced the increase in PFC in comparison with levamisole (2 mg/kg). The difference between the action of mechloretamine and levamisole used in immunostimulating doses on the increased anti-SRBC antibodies or on the E-rosette forming lymphocytes was revealed.

Appearance of the T-cell marker CD8 on B chronic lymphatic leukemia cells in long-term cultures

Long-term cultures of highly purified B chronic lymphatic leukemia cells (B-CLL), were established. The B-CLL lymphocytes acquired the CD8 T cell marker in long-term cultures while still retaining their surface immunoglobulins. In confirmation of previous results, the cultured B-CLL lymphocytes released factor(s) into the culture medium that suppressed the allogeneic mixed-lymphocyte reaction. No correlation was found between the appearance of the CD8 T cell surface marker and onset of suppressor activity.

Cell mediated immunity in herpes simplex keratitis in man

Varied manifestations of herpes simplex keratitis are postulated to be related to alterations or paucity of protective immune response to the virus. In this study lymphocyte subpopulations and macrophage inhibition factor (MIF) assay are investigated in herpes simplex keratitis. Active T-lymphocytes are detected to be significantly low in active keratitis as compared to the healed stage (P less than 0.001) and normal control subjects (P less than 0.01). Active T-cells are also lower in bilateral keratitis than in unilateral keratitis (P less than 0.01), and in stromal keratitis than in epithelial keratitis (P less than 0.05). Total E-rosette-forming cells and leucocyte migration inhibition factor (MIF) assay demonstrates significantly lower values in bilateral keratitis than in unilateral keratitis, and in stromal keratitis than in epithelial keratitis. On healing, total E-RFC, active T-cells and MIF values improved and are comparable to those found in normal subjects. Enumeration of absolute lymphocyte counts and EAC rosette-forming cells (B-lymphocyte cells) did not yield any differences. Our observations demonstrate paucity of cell-mediated immune response in stromal keratitis. More marked deficiency is demonstrable in bilateral keratitis. Manifestations of herpes simplex keratitis and their healing is observed to be relatable to the level of cell mediated immune response.

Increased thymocyte differentiation in myasthenia gravis: a dual-color immunofluorescence phenotypic analysis

Thymocytes express multiple, different surface antigens according to their stage of maturation. Surface differentiation antigens have been studied with the technique of simultaneous dual-color, direct immunofluorescence in the thymuses of 20 patients with myasthenia gravis (MG) and 10 control subjects with cardiac diseases. Fluorescein isothiocyanate-conjugated and phycoerythrin-conjugated monoclonal antibodies were used to stain thymic cell suspensions. A significant decrease in the percentage of immature and common thymocyte phenotypes (CD1+,3+ and CD4+,8+) and a significant increase in the percentage of mature thymocyte phenotypes (CD1-,3+; CD4+,8-; and CD4-,8+) and of B cells (CD20+) were found in MG thymuses compared with controls. These data, indicating an increased availability of mature, fully immunocompetent T and B cells, indirectly suggest the occurrence of an active immune response in MG thymus.

Naloxone-reversible monocyte dysfunction in patients with chronic fatigue syndrome

We studied monocyte function in 35 consecutive patients with chronic fatigue syndrome (CFS) and 25 healthy controls. Eighty-five per cent of the patients showed monocyte dysfunction characterized by marked reduction in the number of monocytes displaying immunoreactive cytoskeletal vimentin filaments, a low phagocytosis index, and a reduced expression of HLA-DR antigens. These values increased dramatically after incubation of the patients' monocytes with the opioid antagonist naloxone. Other immunological abnormalities also noted in the patients were low lymphocyte blastogenesis and diminished numbers of monocytes displaying receptors for Fc of IgG (FcR) and C3b (CR1). These findings suggest that an increased opioid activity acting through a classical receptor mechanism is active on monocytes from a high proportion of patients with CFS and that this represents a novel example of immunomodulation by opioid peptides in human disease. We suggest that endogenous opioids are involved in the pathogenesis of the chronic fatigue syndrome.

Evidences that fibroblasts and epithelial cells produce a specific type of macrophage and granulocyte inducer, also known as colony-stimulating factor, and that monocyte-macrophages can produce another factor with proliferative inducing activity on myeloid cells and differentiative activity on macrophages

Molecules with the property to induce proliferation of bone marrow cells in liquid cultures, and with colony-stimulating activity, were found on media conditioned (MC) by lung fibroblasts and kidney epithelial cells. These factors presented an apparent mol wt of 70,000 and 22,000 d respectively. Also when MC by epithelial cells from lungs was tested for the induction of proliferation of bone marrow cells a molecule with 22,000 d was detected. These molecules are thought to be CSF because they induce colony formation, and they are also similar in mol wt to two of the already known CSF. In fact the GM-CSF obtained from endotoxic lungs with a large epithelial cell content has a mot wt of 22,000 d, and the CSF-1 produced by a fibroblast cell line had 70,000. When the MC by fibroblast was used to induce bone marrow cells to proliferate, three new molecules with colony-stimulating activity were secreted. These molecules with apparent mol wts of 45,000, 30,000 and 17,000 d were also found in the MC by bone marrow cells when induced to proliferate with MC by epithelial cells. When the 45,000-d molecules was used in induced bone marrow cells to proliferate, once again the 30,000- and the 17,000-d molecules were secreted. Evidence is also provided that the 45,000-d molecule is produced by the monocyte-macrophage cells, and that it can induce Fc receptors or resident and elicited peritoneal macrophages. The possibility that the production of CSF is cell specific is discussed together with two models to explain the way in which these molecules can participate as proliferative (MGI-1) and differentiative (MGI-2) function in normal myeloid cell differentiation. Finally, a new terminology is proposed to classify this family of molecules.

Identification of murine complement receptor type 2

A rabbit antiserum reactive with the human complement component C3d/Epstein-Barr virus receptor (complement receptor type 2, CR2) immunoprecipitates a Mr 155,000 murine B-cell surface antigen. The apparent molecular weight and cellular distribution of this murine antigen are similar to those of human CR2. Cells expressing the murine protein bind sheep erythrocytes coated with antibody and murine C1-C3d but do not bind Epstein-Barr virus at all. The monospecific antiserum to human CR2 together with goat F(ab')2 anti-rabbit IgG blocks attachment of the C3d-coated erythrocytes to receptor-bearing murine B lymphocytes. To further characterize murine CR2, a lambda gt11 library from the murine late pre-B-cell line 70Z/3 was screened with human CR2 cDNA. A partial cDNA clone of 3.5 kilobases with 79% amino acid sequence identity to human CR2 in the unique intracytoplasmic region and 63% identity to the sixth human CR2 repeat was obtained. Blot hybridization with the murine cDNA clone identified an RNA species of approximately 4.7 kilobases, similar in size to human CR2 mRNA, from a murine B-cell line but not from a murine T-cell line.

Relationship of fluorescence polarization to cell lineage in lymphocytes from normal subjects and patients with chronic lymphocytic leukemia

Previous investigations have shown differences in fluorescence polarization between normal and chronic lymphocytic leukemia lymphocytes following incubation with the probe 1,6-diphenyl-1,3,5-hexatriene. In the present study, we determined the fluorescence polarization of unseparated or enriched subpopulations of T and B lymphocytes from normal subjects and patients with chronic lymphocytic leukemia. As had been observed by others, the mean polarization (P) value at 25 degrees C for unseparated chronic lymphocytic leukemia lymphocytes, .240 +/- .007 (N = 22), was lower than that of unseparated normal lymphocytes, .248 +/- .005 (N = 18), P less than .001 (Student's t-test). The difference was greater when B-enriched populations were compared. The mean P value of B-cell-enriched chronic lymphocytic leukemia lymphocytes, .240 +/- .007 (N = 5), was significantly lower than that of B-cell-enriched normal preparations, .256 +/- .004 (N = 5), P less than .001. In contrast, no significant difference was found between normal and chronic lymphocytic leukemia T cells. The anomalous fluorescence polarization manifested by chronic lymphocytic leukemia lymphocytes of B-cell origin serves to distinguish this lineage from its normal counterpart and from T cells of either source.