Cooperation between mononuclear phagocytes and lymphocytes in immunity

Estrogen Receptor Functions and Pathways at the Vascular Immune Interface

Estrogen receptor (ER) activity mediates multiple physiological processes in the cardiovascular system. ERα and ERβ are ligand-activated transcription factors of the nuclear hormone receptor superfamily, while the G protein-coupled estrogen receptor (GPER) mediates estrogenic signals by modulating non-nuclear second messengers, including activation of the MAP kinase signaling cascade. Membrane localizations of ERs are generally associated with rapid, non-genomic effects while nuclear localizations are associated with nuclear activities/transcriptional modulation of target genes. Gender dependence of endothelial biology, either through the action of sex hormones or sex chromosome-related factors, is becoming increasingly evident. Accordingly, cardiometabolic risk increases as women transition to menopause. Estrogen pathways control angiogenesis progression through complex mechanisms. The classic ERs have been acknowledged to function in mediating estrogen effects on glucose metabolism, but 17β-estradiol also rapidly promotes endothelial glycolysis by increasing glucose transporter 1 (GLUT1) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) levels through GPER-dependent mechanisms. Estrogens alter monocyte and macrophage phenotype(s), and induce effects on other estrogen-responsive cell lineages (e.g., secretion of cytokines/chemokines/growth factors) that impact macrophage function. The pharmacological modulation of ERs for therapeutic purposes, however, is particularly challenging due to the lack of ER subtype selectivity of currently used agents. Identifying the determinants of biological responses to estrogenic agents at the vascular immune interface and developing targeted pharmacological interventions may result in novel improved therapeutic solutions.

Effects of Sensitization to Dinitrochlorobenzene (DNCB) on Clinical Pathology Parameters and Mitogen-Mediated Blastogenesis in Cynomolgus Monkeys (Macaca, fascicularis)

Immunotoxicologic testing of drug candidates and environmental contaminants is of growing importance. Cutaneous delayed type hypersensitivity (DTH) is a convenient way of testing immune function in vivo. However, DTH testing must not interfere with interpretation of other relevant parameters. We have evaluated the effects of sensitization and challenge with dinitrochlorobenzene (DNCB) on clinical parameters routinely evaluated in toxicity testing and on lectin-mediated blastogenesis. Female cynomolgus monkeys were sensitized to DNCB with 4 daily applications of DNCB in acetone to the skin of the axilla. Fifteen days later, the monkeys were challenged for DTH by applying DNCB to the antecubital skin. Skin fold thickness was measured and the macroscopic appearance of the challenge site was scored 24 and 48 hr after challenge. All 5 monkeys were successfully sensitized to DNCB. There was a significant increase in the mean skin fold thickness (compared to pre-challenge thickness) of 2 mm at 24 hr and 1 mm at 48 hr ( p < 0.001). The clinical score of the challenge site was also increased. Histologic examination of the sensitization and challenge sites from a second group of monkeys exposed to DNCB in an identical manner showed the perivascular inflammatory cell infiltrate typical of DTH. Evaluation of hematologic parameters at days 7, 14, and 21 revealed no change in the erythron at any interval and a mild decrease in total WBC, neutrophil and lymphocyte counts on day 7 in 4/5 monkeys. The WBC parameters remained within the normal range and returned to pre-sensitization values at the later intervals. Clinical biochemical parameters related to liver and kidney function were evaluated at the same intervals and no changes were found. The blastogenic response of peripheral blood leukocytes to concanavalin A, phytohemagglutinin and pokeweed mitogen was mildly but not significantly decreased at day 7 but not on day 14 or 21. This study has shown that sensitization to DNCB in cynomolgus monkeys is a reliable means of evoking a DTH response which is quantifiable. It has also shown that sensitization and challenge with DNCB can be incorporated into toxicity studies without confounding interpretation of other toxicity data.

[History and perspectives of the monocyte-macrophage system]

The macrophage cell system was identified by Metchnikoff on the basis of its phagocytic ability. Later on, the reticulohistiocytic system was defined as being composed of antigen-presenting reticulum cells and macrophages. Van Furth proposed that the mononuclear phagocyte system includes all tissue macrophages as well as antigen-presenting cells and blood monocytes as their precursors. Recent findings have shown that blood monocytes are not just transient forms involved in the recruitment of macrophages but that different dendritic and monocytic subpopulations can be observed in blood. In tissue, self-renewing macrophages derived from the yolk sac as well as monocyte-derived dendritic cells and monocyte-derived macrophages can be distinguished. Due to their plasticity and polarization, under inflammatory conditions monocyte-derived macrophages may be beneficial for the reestablishment of homeostasis or may contribute to mostly chronic diseases. Because of their ubiquitous distribution, monocytes and macrophages are increasingly considered to be possible therapeutic targets.

Macrophage phenotype is associated with disease severity in preterm infants with chronic lung disease

BACKGROUND

The etiology of persistent lung inflammation in preterm infants with chronic lung disease of prematurity (CLD) is poorly characterized, hampering efforts to stratify prognosis and treatment. Airway macrophages are important innate immune cells with roles in both the induction and resolution of tissue inflammation.

OBJECTIVES

To investigate airway innate immune cellular phenotypes in preterm infants with respiratory distress syndrome (RDS) or CLD.

METHODS

Bronchoalveolar lavage (BAL) fluid was obtained from term and preterm infants requiring mechanical ventilation. BAL cells were phenotyped by flow cytometry.

RESULTS

Preterm birth was associated with an increase in the proportion of non-classical CD14(+)/CD16(+) monocytes on the day of delivery (58.9 ± 5.8% of total mononuclear cells in preterm vs 33.0 ± 6.1% in term infants, p = 0.02). Infants with RDS were born with significantly more CD36(+) macrophages compared with the CLD group (70.3 ± 5.3% in RDS vs 37.6 ± 8.9% in control, p = 0.02). At day 3, infants born at a low gestational age are more likely to have greater numbers of CD14(+) mononuclear phagocytes in the airway (p = 0.03), but fewer of these cells are functionally polarized as assessed by HLA-DR (p = 0.05) or CD36 (p = 0.05) positivity, suggesting increased recruitment of monocytes or a failure to mature these cells in the lung.

CONCLUSIONS

These findings suggest that macrophage polarization may be affected by gestational maturity, that more immature macrophage phenotypes may be associated with the progression of RDS to CLD and that phenotyping mononuclear cells in BAL could predict disease outcome.

Regulatory T cells restrain CD4+ T cells from causing unregulated immune activation and hypersensitivity to lipopolysaccharide challenge

Regulatory T cells (Tregs) are essential for maintenance of peripheral tolerance, and defects in Treg function have been linked to several autoimmune diseases. We previously reported that depletion of Tregs resulted in mortality to an otherwise nonlethal dose of LPS or Escherichia coli challenge. In this study, we investigated the mechanism by which Treg depletion leads to enhanced susceptibility to LPS. Using different murine lymphocyte gene knockout models, we show that the enhanced sensitivity to LPS following Treg depletion is mediated by T cells. SCID or RAG1-deficient mice, which lack T and B cells, do not show enhanced susceptibility to LPS. However, reconstitution of SCID mice with wild-type CD4(+) T cells restored Treg depletion-induced sensitivity to LPS. This CD4(+) T cell-mediated hypersensitivity to LPS challenge in the absence of Tregs was also observed upon reconstitution of SCID mice with CD4(+) T cells from CD25 knockout mice (which lack functional Tregs). Additionally, depletion of Tregs leads to increased CD4(+) T cell proliferation and proinflammatory cytokine production in response to LPS challenge. Some CD4(+) T cells express TLR4, and pretreatment of CD4(+) T cells with LPS dramatically enhanced their ability to induce inflammatory cytokine production by macrophages. Collectively, our results indicate that in the absence of functional Tregs, CD4(+) T cells are pathologic and contribute to exaggerated immune activation that is detrimental for survival in LPS-induced acute inflammation. Our data also provide evidence for direct activation of CD4(+) T cells by LPS through TLR4.

The evolution of adaptive immunity in vertebrates

Approximately 500 million years ago, two types of recombinatorial adaptive immune systems (AISs) arose in vertebrates. The jawed vertebrates diversify their repertoire of immunoglobulin domain-based T and B cell antigen receptors mainly through the rearrangement of V(D)J gene segments and somatic hypermutation, but none of the fundamental AIS recognition elements in jawed vertebrates have been found in jawless vertebrates. Instead, the AIS of jawless vertebrates is based on variable lymphocyte receptors (VLRs) that are generated through recombinatorial usage of a large panel of highly diverse leucine-rich-repeat (LRR) sequences. Whereas the appearance of transposon-like, recombination-activating genes contributed uniquely to the origin of the AIS in jawed vertebrates, the use of activation-induced cytidine deaminase for receptor diversification is common to both the jawed and jawless vertebrates. Despite these differences in anticipatory receptor construction, the basic AIS design featuring two interactive T and B lymphocyte arms apparently evolved in an ancestor of jawed and jawless vertebrates within the context of preexisting innate immunity and has been maintained since as a consequence of powerful and enduring selection, most probably for pathogen defense purposes.

Vitamin E and immunity

Vitamin E is the most important chain-breaking, lipid-soluble antioxidant present in body tissues of all cells and is considered the first line of defense against lipid peroxidation and it is important for normal function of the immune cells. However, vitamin E deficiency is rare in well-nourished healthy subjects and is not a problem, even among people living on relatively poor diets, both T- and B-cell functions are impaired by vitamin E deficiency. While immune cells are particularly enriched in vitamin E because of their high polyunsaturated fatty acid content, this point puts them at especially high risk for oxidative damage. Besides its immunomodulatory effects, vitamin E also plays an important role in carcinogenesis with its antioxidant properties against cancer, and ischemic heart disease with limiting the progression of atherosclerosis. Supplementation of vitamin E significantly enhances both cell mediated and humoral immune functions in humans, especially in the elderly and animals.

Giant cell formation in sarcoidosis: cell fusion or proliferation with non-division?

Granulomas are inflammatory reactions featuring macrophages, epithelioid, T and multi-nucleated giant cells (MGC). Giant cells are present in a number of granulomatous reactions, but little is known about their formation and function, especially in man. We studied MGC in the granulomatous disorder sarcoidosis. In situ labelling of lymph nodes by means of [(3)H]-thymidine showed that proliferation and non-division of epithelioid cells leading towards giant cells was not observed in these granulomas. However, [(3)H]-uridine incorporation showed MGC with labelled as well as unlabelled nuclei in the same cell, pointing to a process of fusion of epithelioid cells to form giant cells. Apoptotic bodies were incidentally found in granulomas. A novel finding was that such bodies were statistically more often found in the close vicinity of MGC, but not within these cells. These apoptotic cells appeared to be CD4(+) lymphocytes or histiocytes. CD44 and CCR-5 involved in the process of fusion were expressed in MGC. In conclusion, MGC in sarcoidosis derive by cell fusion rather than by proliferation and non-division, and seem to play an active role in the induction of apoptosis in granulomas.

The phagocytes: neutrophils and monocytes

The production and deployment of phagocytes are central functions of the hematopoietic system. In the 1950s, radioisotopic studies demonstrated the high production rate and short lifespan of neutrophils and allowed researchers to follow the monocytes as they moved from the marrow through the blood to become tissue macrophages, histiocytes, and dendritic cells. Subsequently, the discovery of the colony-stimulating factors greatly improved understanding the regulation of phagocyte production. The discovery of the microbicidal myeloperoxidase-H2O2-halide system and the importance of NADPH oxidase to the generation of H2O2 also stimulated intense interest in phagocyte disorders. More recent research has focused on membrane receptors and the dynamics of the responses of phagocytes to external factors including immunoglobulins, complement proteins, cytokines, chemokines, integrins, and selectins. Phagocytes express toll-like receptors that aid in the clearance of a wide range of microbial pathogens and their products. Phagocytes are also important sources of pro- and anti-inflammatory cytokines, thus participating in host defenses through a variety of mechanisms. Over the last 50 years, many genetic and molecular disorders of phagocytes have been identified, leading to improved diagnosis and treatment of conditions which predispose patients to the risk of recurrent fevers and infectious diseases.

The cancer stem cell: evidence for its origin as an injured autoreactive T cell

This review explores similarities between lymphocytes and cancer cells, and proposes a new model for the genesis of human cancer. We suggest that the development of cancer requires infection(s) during which antigenic determinants from pathogens mimicking self-antigens are co-presented to the immune system, leading to breaking T cell tolerance. Some level of autoimmunity is normal and necessary for effective pathogen eradication. However, autoreactive T cells must be eliminated by apoptosis when the immune response is terminated. Apoptosis can be deficient in the event of a weakened immune system, the causes of which are multifactorial. Some autoreactive T cells suffer genomic damage in this process, but manage to survive. The resulting cancer stem cell still retains some functions of an inflammatory T cell, so it seeks out sites of inflammation inside the body. Due to its defective constitutive production of inflammatory cytokines and other growth factors, a stroma is built at the site of inflammation similar to the temporary stroma built during wound healing. The cancer cells grow inside this stroma, forming a tumor that provides their vascular supply and protects them from cellular immune response.

As cancer stem cells have plasticity comparable to normal stem cells, interactions with surrounding normal tissues cause them to give rise to all the various types of cancers, resembling differentiated tissue types. Metastases form at an advanced stage of the disease, with the proliferation of sites of inflammation inside the body following a similar mechanism. Immunosuppressive cancer therapies inadvertently re-invigorate pathogenic microorganisms and parasitic infections common to cancer, leading to a vicious circle of infection, autoimmunity and malignancy that ultimately dooms cancer patients. Based on this new understanding, we recommend a systemic approach to the development of cancer therapies that supports rather than antagonizes the immune system.

Dietary vitamin E and T cell-mediated function in the elderly: effectiveness and mechanism of action

One of the most dramatic and consequence-bearing age-related phenomena is the decline of the immune function with old age. Age-related T cell-mediated immunity dysfunction has been implicated in the etiology of many of the chronic degenerative diseases of the elderly, including arthritis, cancer, autoimmune diseases and increased susceptibility to infectious diseases. T cells from aged individuals are impaired in their response to mitogens and in their cytokine production. In recent years, several studies have emphasized the importance of intracellular anti-oxidant levels for preserving the immune function. Recent progress in understanding the mechanisms of action of anti-oxidants on cellular metabolism, have shown that anti-oxidants may modulate signal transduction and gene expression in immune cells. Vitamin E is widely recognized as a major lipid-soluble chain-breaking anti-oxidant in the biological membrane, where it scavenges free radicals, inhibiting the initiation and chain propagation of lipid peroxidation and protecting cellular structures against oxidative stress damage. Experimental studies have provided evidences for a role of vitamin E in protecting the immune system of elderly subjects. This article reviews the studies concerning the effect of both vitamin E deficiency and supplementation on T cell-mediated immune function in aging. Following a chronological pathway, the present article will also discuss the knowledge regarding the underlying mechanism of action of vitamin E.

Macrophage prostaglandin production contributes to the age-associated decrease in T cell function which is reversed by the dietary antioxidant vitamin E

The aging process is associated with a decline in T cell-mediated immunity, including decreased interleukin (IL)-2 production and mitogen-induced T cell proliferation. Because macrophages (M phi) from old mice have higher production of prostaglandin (PG) E2 than young mice, and PGE2 has been shown to suppress T cell-mediated function, we hypothesized that increased production of PGE2 would contribute to decreased T cell function with aging and that decrease in PGE2 production by dietary antioxidants would enhance T cell-mediated function. Experiments were conducted in which combinations of purified M phi and T cells (> 95% pure) from young or old C57BL/6N1A mice were cultured together. Co-cultures containing T cells and M phi from old mice had reduced ConA-stimulated proliferation and IL-2 secretion than those consisting of T cells and M phi from young mice. Addition of M phi from old mice suppressed proliferation and IL-2 secretion by T cells from young mice. Likewise, T cells from old mice secreted more IL-2 when cultured with M phi from young mice compared to those cultured with M phi from old mice. Addition of PGE2, at concentrations produced by old M phi, decreased proliferation and IL-2 production by young but not old T cells. Neither addition of H2O2 at physiological levels, nor catalase changed the response of cultures from young or old mice. However, addition of indomethacin and the antioxidant nutrient vitamin E, both of which decreased PGE2 production, improved T cell proliferation and IL-2 production. These experiments demonstrate that increased production of PGE2 by M phi contributes to the age-associated decline in T cell function. Vitamin E improves T cell responsiveness in old mice mostly by reducing M phi PGE2 production, although a direct effect of vitamin E on T cells was also observed.

Impairment of non-specific immunity in patients in persistent vegetative state

In fourteen patients in persistent vegetative state (PVS) immune responsiveness was investigated. In particular, we studied the relationship between brain lesions following traumatic injury and immune system. In this respect, phagocytosis and killing of Candida albicans by polymorphonuclear cells (PMN) and monocytes were tested. In addition serum levels of Interferon-gamma (IFN-gamma) were evaluated. The patients come out from PVS by 3-4 month were used as control group. Data shown a profound impairement of phagocytosis and killing of monocytes and low serum levels of IFN gamma when compared with normal values. Taken together, these findings suggest that brain lesions, may affect non-specific immune response.

Dietary Spirulina platensis enhances humoral and cell-mediated immune functions in chickens

Cornell K-strain White Leghorns and broiler chicks were raised to 7 wks and 3 wks of age respectively, with diets containing various levels (0, 10, 100, 1,000 and 10,000 ppm) of Spirulina platensis from day of hatch. Chicks in all treatment groups had comparable body weights. While bursal and splenic weights did not change, the K-strain chicks had larger thymuses (P < or = .05) over the controls (0 ppm group). No differences were observed in anti-sheep red blood cells antibodies during primary response. However, during secondary response, K-strain chicks in all Spirulina-dietary groups had higher total anti-SRBC titers with 10,000 ppm group being the highest (6.8 Log2) versus the 0 ppm (5.5 Log2) group. In broiler chicks, a one Log increase in IgG (P < or = .05) was observed in 10,000 ppm group over the controls. Similarly, chicks in 10,000 ppm Spirulina group had a higher PHA-P-mediated lymphoproliferative response over the 0 ppm controls. Macrophages isolated from both K-strain (10,000 ppm group) and broilers from all Spirulina groups had higher phagocytic potential than the 0 ppm groups. Spirulina supplementation at 10,000 ppm level also increased NK-cell activity by two fold over the controls. These studies show that Spirulina supplementation increases several immunological functions implying that a dietary inclusion of Spirulina at a level of 10,000 ppm may enhance disease resistance potential in chickens.

The infectiousness of pompous prose

For centuries, scientists have been bombarded with pleas for plain language. Why have these pleas had no effect, when the problem of unreadable prose could be solved at a stroke?

Hypersensitivity pneumonitis

Hypersensitivity pneumonitis or extrinsic allergic alveolitis is an immunologically mediated lung disease caused by repeated inhalations of organic antigens. The basic histologic lesion consists of a diffuse mononuclear cell infiltration of alveolar wall, alveoli, terminal bronchioles, and neighboring interstitium. The inflammation is often followed by granulomas, which then may progress to fibrosis. Although there is no single radiologic, physiologic, or immunologic test specific for hypersensitivity pneumonitis, the diagnosis can often be suspected on the basis of a compatible temporal relationship of pulmonary symptoms to the history of environmental or occupational exposure. Once the diagnosis is suspected, the presence of serum precipitating antibodies (IgG), suppressor cytotoxic lymphocytosis in bronchoalveolar lavage fluid, and granulomatous alveolitis in lung biopsy specimens are extremely helpful in confirming the diagnosis. In patients where the diagnosis is confirmed, avoidance of the causative antigen is the best therapy, although corticosteroids are used to suppress inflammation. Once the fibrosis is set in, the patient may gradually slide into respiratory failure, cor pulmonale, and death.

Macrophage-T suppressor cell interference in the lungs of steroid-treated sarcoidosis patients

In the bronchoalveolar lavage of sarcoidosis patients the mononuclear cell infiltrate was enumerated on T helper and suppressor lymphocytes as well as macrophages by means of a triple-staining assay on cytospin slides. As was seen on the slides, lymphocytes were often adhered very closely to macrophages. This phenomenon, many times described but not understood, was studied in a group of 13 sarcoidosis patients, of whom 7 received prednisolone treatment. It could be shown that treatment with the corticosteroid was followed by an increase in the percentage of suppressor lymphocytes adhered to macrophages. Second, the number of such alveolar T suppressor lymphocyte-macrophage aggregates was dramatically increased in the prednisolone-treated patients.

Interaction of monocytes and T cells in the regulation of normal human megakaryocytopoiesis in vitro: role of IL-1 and IL-2

Autologous or allogeneic peripheral blood T cells can stimulate the human megakaryocyte progenitor cell (CFU-Meg)-derived colony formation in a dose-dependent fashion in agar cultures of nonadherent (NA), T cell-depleted (NT) bone marrow (BM) cells. Low concentrations of monocytes and T cells can collaborate in the stimulation of CFU-Meg colony formation or in the production of megakaryocyte colony stimulating factor (Meg-CSF) by T cells in the presence of mitogens or IL-2. Monocytes alone can produce only negligible Meg-CSF under any conditions. When monocyte conditioned medium (CM) was added to T cell-stimulated NA, NT BM cell cultures, CFU-Meg colony growth was appreciably increased compared with that stimulated by T cells alone. Dose-dependent increase in CFU-Meg colony growth was noted when varying concentrations of IL-1 were added to T cell-stimulated NA, NT cell cultures, although IL-1 itself could support no CFU-Meg colony growth in the absence of T cells. These data suggest that a synergistic interaction between T cells and monocytes during the production of Meg-CSF by T cells could be partly mediated by IL-1. IL-2 was found to stimulate Meg-CSF production by T cells in the presence or absence of mitogens. IL-2-stimulated Meg-CSF production by T cells was augmented by the addition of monocytes. Although IL-2 itself had no stimulatory effect on CFU-Meg colony growth, dramatic augmentation in the CFU-Meg colony number was noted when IL-2 was added to T cell-stimulated NA, NT cell cultures. High concentrations of monocytes and prostaglandin E (PGE) inhibited the CFU-Meg colony formation. These results suggest that IL-1 and IL-2 may play a stimulatory role on the normal human in vitro megakaryocytopoiesis, and may be involved in the development of reactive thrombocytosis and bone marrow megakaryocytic hyperplasia in various inflammatory diseases.

Effects of sensitization to dinitrochlorobenzene (DNCB) on clinical pathology parameters and mitogen-mediated blastogenesis in cynomolgus monkeys (Macaca fascicularis)

Immunotoxicologic testing of drug candidates and environmental contaminants is of growing importance. Cutaneous delayed type hypersensitivity (DTH) is a convenient way of testing immune function in vivo. However, DTH testing must not interfere with interpretation of other relevant parameters. We have evaluated the effects of sensitization and challenge with dinitrochlorobenzene (DNCB) on clinical parameters routinely evaluated in toxicity testing and on lectin-mediated blastogenesis. Female cynomolgus monkeys were sensitized to DNCB with 4 daily applications of DNCB in acetone to the skin of the axilla. Fifteen days later, the monkeys were challenged for DTH by applying DNCB to the antecubital skin. Skin fold thickness was measured and the macroscopic appearance of the challenge site was scored 24 and 48 hr after challenge. All 5 monkeys were successfully sensitized to DNCB. There was a significant increase in the mean skin fold thickness (compared to pre-challenge thickness) of 2 mm at 24 hr and 1 mm at 48 hr (p less than 0.001). The clinical score of the challenge site was also increased. Histologic examination of the sensitization and challenge sites from a second group of monkeys exposed to DNCB in an identical manner showed the perivascular inflammatory cell infiltrate typical of DTH. Evaluation of hematologic parameters at days 7, 14, and 21 revealed no change in the erythron at any interval and a mild decrease in total WBC, neutrophil and lymphocyte counts on day 7 in 4/5 monkeys. The WBC parameters remained within the normal range and returned to pre-sensitization values at the later intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure to demonstrate significant antisperm antibodies in peritoneal fluid of patients with endometriosis

Endometriosis, even in mild cases, decreases monthly fecundity. Immunologic disorders have been suggested as the mechanism. In light of possible increases in serum autoimmune antibodies, increased peritoneal macrophages, and increased sperm phagocytosis associated with this disease, we postulated that peritoneal fluid antisperm antibodies would be increased and might be the cause of increased sperm phagocytosis and its associated infertility. Peritoneal fluid, from 18 patients with endometriosis and 10 infertile controls, was tested with the antisperm antibody immunobead test validated for peritoneal fluid. One of 18 patients with endometriosis and none of 10 controls had antisperm antibodies present. Therefore, increased sperm phagocytosis is unlikely a result of peritoneal antisperm antibodies in endometriosis patients.

The basics of immunological tests

This review article describes the cells and the humoral factors of the immune system. It also explains what tests are available to assess the immune functions of patients. Each test listed states the amount of blood needed and the time required to perform the assays.

Human mononuclear cells and neutral proteinases. III. Neutral proteinases and rheumatoid arthritis: monocytes as a source of cathepsin G and proteinase potentiation of IgM rheumatoid factor elaboration

We have been interested in contributions of certain cells and mediators to synovial inflammation rheumatoid arthritis (RA). The present studies were designed to determine (1) whether monocytes contained the neutral proteinase cathepsin G and (2) if neutral proteinase could induce or potentiate cellular IgM rheumatoid factor (RF) production. Monocyte-rich and monocyte-poor populations were isolated by Ficoll-Hypaque density sedimentation followed by glass adherence, and cellular lysates were obtained by repetitive freezing and thawing as we have reported for neutrophil-derived neutral proteinase. Cathepsin G was quantified immunochemically by an enzyme-linked immunoassay (ELISA) we developed utilizing commercially available anti-cathepsin G antibodies. Mononuclear and B-cell-enriched cell cultures were prepared by standard methods and IgM RF measured by our ELISA. Cell-derived lysates from monocyte-enriched populations (84 +/- 3% monocytes, less than 1% neutrophils) contained considerably greater amounts of measurable cathepsin G (OD280 = 0.393 +/- 0.153) than lysates from equal numbers of monocyte (15 +/- 2% monocytes, less than 1% neutrophils)-depleted cells (OD280 = 0.071 +/- 0.038; P less than 0.05). Eighteen patients with RA and three normal individuals did not have consistently increased cellular elaboration of Ig or IgM RF in vitro in response to proteinase (trypsin) stimulation; however, patients manifested 80% potentiation by trypsin of pokeweed-stimulated cellular IgM RF production in vitro (pokeweed-stimulated IgM RF 137 +/- 53 ng/ml, pokeweed/trypsin-induced IgM RF 246 +/- 100 ng/ml; P less than 0.02), changes being most striking for those patients seropositive by latex fixation test (84% increase, P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Immunophenotyping in the classification of acute leukemia in adults. Interpretation of multiple lineage reactivity

Fifty-nine adult patients with acute leukemia were classified using a combination of the French-American-British (FAB) criteria and characterization by immunophenotyping using flow cytometric study. The authors identified 51 patients with acute myeloblastic leukemia and eight with acute lymphoblastic leukemia. This procedure permitted lineage assignment in leukemias that otherwise might have been unclassifiable. In addition, the authors demonstrated that the leukemic blasts of 29% of patients with myeloblastic disease exhibited one or more T-cell antigens on their surface. The use of immunophenotyping has greatly enhanced the authors' ability to correctly identify the lineage of acute leukemias. The data, however, must be interpreted with caution with respect to diagnosing acute mixed lineage leukemias and must be integrated with the morphologic and cytochemical evaluation of traditional classification schemes. The possible significance of T-cell markers in myeloblastic leukemia is discussed.

Phenotypic dynamics of macrophage subpopulations during human experimental gingivitis

The purpose of the present study was to investigate whether functionally different macrophages are present in clinically healthy gingiva and during human experimental gingivitis. Eight male probands were introduced to an oral hygiene program until all reached mean Plaque and Gingival Index scores approaching zero. During the following 19 days all oral hygiene was abandoned. At d -14, 0, 2, 4, 7, 11 and 19 clinical indices and gingival biopsies were taken. Cryostat sections were incubated with monoclonal antibodies against mature macrophages (25F9), inflammatory macrophages (27E10) and anti-inflammatory macrophages (RM 3/1). Positive cells were counted in the inflammatory infiltrate (IF) and the connective tissue (CT). At d -14 elevated numbers of 27E10-positive cells were observed which decreased significantly at d 0 (p less than 0.018) and increased again at d 19 (p less than 0.026). Significant differences in the number of RM 3/1-positive cells were found between d 0 and d -14, 2, 4 and 7 (p less than 0.05) while no differences in the number of 25F9-positive cells were observed throughout this study. It was concluded that experimental gingival inflammation is characterized by the appearance and disappearance of functionally different macrophage subpopulations.

Cancer-induced immunosuppression: implications for therapy?

Cancer-induced immunosuppression can be caused by a variety of effects. These include factors produced by the host in response to the presence of tumor or factors elaborated by the tumor itself. Disseminated tumor can lead to host debility with associated anergy. Some immunosuppressive effects are due to the manner in which the host processes (or fails to process) the tumor as an antigenic stimulus. Lastly, antitumor treatments can have a detrimental impact on host antitumor immunity. Recent research findings from our laboratories implicate surgical stress effects and tumor-mediated production of growth factors such as transforming growth factor beta (TGF-beta) as being important causes of host immune impairment. An accurate understanding of the mechanisms underlying host antitumor immune impairment will be critical in the successful development of immunotherapy strategies for use in the surgical oncology patient.

Whipple's disease. Demonstration of a persisting monocyte and macrophage dysfunction

A patient with Whipple's disease has been followed up for 4 years. Primary involvement was limited to the small intestines, and accumulation of periodic acid-Schiff-positive material, containing typical more or less intact bacillary bodies, was demonstrated within macrophages of affected tissue. After initial oxytetracycline treatment and clinical remission, the patient relapsed, with multiorgan affections. The antibiotic regimen was changed to chloramphenicol, followed by continuous trimethoprim-sulfamethoxazole. Flow cytometric studies showed persisting impairment of monocyte and macrophage intracellular degradation of bacteria during all the 4 years tested. After relapse, reduced activity of several brush border enzymes was demonstrated in distal duodenal biopsy specimens. After 17 months of continuous trimethoprim-sulfamethoxazole therapy complete clinical remission, regression of histopathologic abnormalities, and restoration of duodenal enzyme activities had occurred. The results demonstrate a persisting dysfunction of mononuclear phagocytes from a patient with Whipple's disease, suggesting a primary abnormality of cell-mediated immunity which may promote the susceptibility to the causative bacillus.

Interleukin 1 stimulates T lymphocytes to produce granulocyte-monocyte colony-stimulating factor

T lymphocytes are thought to cooperatively interact with monocytes to produce colony-stimulating factors (CSF). However, little is known about monocyte-mediated signals leading to CSF-secretion by T lymphocytes, although soluble monocyte products have been implicated. We have employed monoclonal antibody anti-T3B covalently coupled to CnBr-activated Sepharose 4B beads, to show that multimeric ligation of T cell antigen receptor leads to T cell receptiveness to interleukin 1 (IL-1), as indicated by T cell production of CSF, which induces growth of myeloid progenitor cells into neutrophil, eosinophil, and monocyte colonies. To investigate the molecular basis of these findings, total RNA was extracted from T3B Sepharose-primed and IL-1-stimulated T lymphocytes and probed for granulocyte-monocyte-CSF (GM-CSF), granulocyte-CSF (G-CSF), and monocyte-CSF (M-CSF) mRNA. GM-CSF, but not G-CSF or M-CSF, messages were detected. Nuclear "run on" assays revealed that IL-1 action is effective primarily at the level of GM-CSF gene transcription. These results suggest a previously unrecognized role of IL-1 in the regulation of GM-CSF secretion by T cells.

Relationship between macrophage infiltration and epidermopoiesis in delayed-type hypersensitivity

The relationship between epidermopoiesis and macrophage infiltration was studied in delayed-type hypersensitivity (DTH) skin lesions in guinea pigs that had been sensitized with heat-killed tubercle bacilli or bovine serum albumin (BSA). Macrophages were identified with acid-phosphatase and nonspecific esterase stains, and the epidermal proliferative response was studied at DTH challenge sites by autoradiography. The number of macrophages in the sensitized animals was higher than that in the nonsensitized animals 48-72 h following challenge injections, when labelling indices were also elevated in the former group. Soluble factor(s) from cultured macrophages transiently enhanced the DNA synthesis of epidermal cells in cultures and in the sites injected with the factor(s). These results suggest that macrophages retained in the DTH lesion may play a role in an acceleration of epidermal proliferation, thus leading to acanthosis and lichenification.

The AHA syndrome: arthritis, hives and angioedema

Nine patients who have intermittently exhibited the concurrent triad of arthritis or arthralgia (A), hives or urticaria (H) and angioedema (A), in the absence of associated infection or connective-tissue disease, are reported. The ratio of women to men is 4:1, with no apparent age specificity. The duration of the disease has been up to 16 years, with an average of seven acute episodes per year, lasting up to 14 days. Upper-airway angioedema has been severe in four patients. Routine laboratory studies were normal, as were studies of complement levels, and both humoral and cellular immunity. Two samples of synovial fluid from one patient contained a marked preponderance of Ia-positive macrophages. The absence of associated infection and connective-tissue disease suggests this recurrent triad represents a distinct entity, which is designated the AHA syndrome.

Ingestion of Giardia lamblia trophozoites by human mononuclear phagocytes

Mononuclear phagocytes may be important effector cells against Giardia lamblia. Human monocyte-derived macrophages were incubated with G. lamblia trophozoites in 13% heat-inactivated autologous serum. At a G. lamblia/macrophage ratio of 1:1, the number of trophozoites ingested per 100 macrophages ranged from 1 to 12 at 0.5 h and increased for all donors (n = 6) to 10 to 92 at 8 h. Ingestion was confirmed by electron microscopy. Increasing the parasite/phagocyte ratio to 5:1 increased the percentage of macrophages with adherent but not ingested trophozoites. Incubating Giardia cells and macrophages with 20% immune serum increased ingestion of parasites eightfold, indicating that anti-G. lamblia antibody can enhance ingestion. Both phase-contrast microscopy and electron microscopy documented trophozoite destruction within macrophages. Ingestion of parasites elicited an oxidative burst as measured by luminol-enhanced chemiluminescence. In vitro, Giardia trophozoites were killed by greater than or equal to 5 X 10(-5) M H2O2. Fusion of lysosomes with parasite-containing phagosomes was suggested by acridine orange-stained preparations. Human macrophages have the capacity to ingest Giardia trophozoites and to kill intracellular parasites, possibly by oxidative microbicidal mechanisms.

Suppression of humoral immunity in chickens with carrageenans

Carrageenans (CGN), sulphated polygalactans, have been reported to be cytotoxic for macrophages in vitro. On this basis, the effect of the 3 major CGN types on humoral immune responses in chickens was investigated. Carrageenan had no effect on body and lymphoid organ weights. Histologically, CGN produced a significant proliferation of reticuloendothelial cells in liver and spleen, but no changes were observed in lymphocyte populations of the bursa of Fabricius, thymus, or spleen. Intracoelomic pretreatment with high doses of CGN induced a marked suppression of primary responses to sheep red blood cells (SRBC) given by the same route. However, if SRBC were injected intravenously into chickens already treated intracoelomically with CGN, no evidence of suppression was demonstrated. Antibody responses to Brucella abortus (BA), a T-independent antigen, were not affected by intracoelomic treatment with CGN. Intravenous pretreatment with CGN did not alter antibody responses to SRBC and BA given by the same route.

Idiopathic production of interleukin-1 in acquired immune deficiency syndrome

We determined the capacity of peripheral blood monocytes from 19 patients with acquired immune deficiency syndrome (AIDS) or related conditions (1 with lymphadenopathy, 8 with AIDS-related complex, and 10 with AIDS) to produce intracellular and extracellular interleukin-1 (IL-1) spontaneously and upon stimulation with bacterial endotoxin. All patients were anti-human T-cell lymphotropic virus type III antibody positive. Results were compared with those obtained with 10 normal controls of similar age. A subset of patients who spontaneously produced high amounts of intracellular and extracellular IL-1 was identified. Total production of IL-1 in this subset was an average of 2.9 times that of controls. It is suggested that spontaneous production of IL-1 in this group represents an in vivo phenomenon since it was associated with more than 3 g of globulins per deciliter of serum, more than 2,300 mg of immunoglobulins per deciliter of serum, higher IgA values, higher titers of anti-Epstein-Barr virus antibodies, and lower neutrophil counts in peripheral blood. The role of Epstein-Barr virus, human immunodeficiency virus itself, or other infectious agents in spontaneous IL-1 production by these patients remains to be determined. Stimulation with endotoxin induced intracellular and extracellular IL-1 production to similar levels in patients and controls. These results show that AIDS patients are able to produce and release IL-1. High idiopathic production of IL-1 identified in some patients can help to explain the hypergammaglobulinemia seen in AIDS patients and might also be related to progression and severity of the disease.

Stimulation of prostaglandin E2 and thromboxane B2 production by human monocytes in response to interleukin-2

Interleukin 2 (IL-2) is a potent lymphokine involved in the regulation of immune responses and is classically regarded as a stimulus for the activation and growth of T-cells. Recent reports have demonstrated the IL-2 dependent activation of human peripheral blood lymphocytes into lymphokine activated killer cells capable of lysing tumor cells both in vitro and in vivo. In this study we report data which clearly show IL-2 may also act to down-regulate the immune response by inducing the synthesis of arachidonic acid metabolites with known immunosuppressive actions. Stimulation of peripheral human blood monocytes with IL-2 caused an increased production of prostaglandin E2 (PGE2) and thromboxane (TXB2) in a dose-dependent manner. Kinetic analysis showed no increase above controls after 6 hours and maximal levels by 10 hours; elevated levels were maintained after 45 hours of incubation. After 20 hours of stimulation with 2000 U/ml IL-2, the level of PGE2 and TXB2 were greater than three-fold above controls, 0.7 and 19 ng/10(6) cells, respectively. The stimulation was relatively specific in that neither prostacyclin nor leukotrienes were produced in response to IL-2. These data demonstrate that IL-2 acts on human monocytes to induce the secretion of PGE2 and TXB2.

Defective monokine production and decreased responsiveness of polymorphonuclear leukocytes to recombinant interleukin-1 in asthmatic patients

Augmented IgE production and increased infections are often seen in allergic patients. As monocytes (MN) and polymorphonuclear leukocytes (PMN) are involved in both immune regulation and inflammatory reaction, MN function in terms of monokine production stimulated with lipopolysaccharide (MN supernatant; MN-sup) and its biological activity and the response of PMN to MN-sup and recombinant interleukin-1 (rIL-1) regarding chemotactic activity and expression of IgG Fc receptor (FcR) were studied in 26 normal children and 28 new and 22 hyposensitized (HS) asthmatic children. The results showed the following. There was no difference in IL-1 production, as assayed by thymocyte proliferation, among the three groups. All MN-sup from the three groups could enhance IL-2 production, but that of new patients was less efficient. In the absence of PWM, MN-sup of new patients greatly augmented the production of IgG, IgA, IgM, and IgE, but that of HS patients could enhance only IgE synthesis. MN-sup of patients enhanced less efficiently the chemotactic activity and FcR expression of PMN from healthy volunteers, and PMN from asthmatics responded much less vigorously to rIL-1 regarding the above-mentioned functions. The number of PMN with membrane IL-1 was much lower in allergic patients. Thus the abnormal MN and PMN functions may be used to explain partly the augmented IgE production and increased infections in allergic patients.

Stimulation of peripheral blood lymphocytes with autologous tumor and serum-derived fractions from patients with laryngeal carcinomas

We investigated the in vitro stimulation of peripheral blood lymphocytes with tumor extracts and serum-derived fractions from five patients with laryngeal carcinomas. Lymphocyte cultures were propagated by Interleukin-2 or phytohemagglutinin. Sera of the same patients were fractionated and the amount of circulating immune complexes present was measured by a Raji cell assay. A positive lymphocyte reaction was found in only two of the five cases after stimulation with autologous tumor extract. This response was determined by an increased 3H-thymidine incorporation. The reactive lymphocytes could be restimulated by autologous serum-derived fractions, which contained high or very low levels of circulating immune complexes. A characterization of different lymphocyte subsets revealed an elimination of natural killer cells and a relative enrichment of T-helper cells during in vitro stimulation and cultivation.

Mitogenic activity of snake venom lectins

Five lactose-inhibitable lectins have been isolated from snake venoms. These five share certain biochemical properties but are not identical (Gartner, Stocker & Williams, 1980; Gartner & Ogilvie, 1984). In this study the lectins were tested for their ability to stimulate lymphocytes to undergo DNA synthesis. We found that three of the lectins were comparable in mitogenic activity to the T cell lectin, concanavalin A (Con A). The mitogenic activity was blocked by lactose, a sugar which also blocks the haemagglutination activity of these lectins. Although mitogenic response appeared to be due to T cells, it depended on the presence of accessory cells in the culture. This requirement for macrophages could be replaced by the phorbol ester tumour promoter, 12-o-tetradecanoylphorbol-13-acetate (TPA).

Phenotypic differentiation patterns of the human monocyte/macrophage system

In the present study phenotypic properties of non-stimulated and stimulated blood monocytes and of their normal macrophage derivatives were studied applying enzyme cytochemistry, isoenzyme analysis of acid esterase (EC 3.1.1.6), and immunohistochemical staining using a panel of newly established monoclonal antibodies specific for the monocyte/macrophage lineage. Certain marker profiles could be established for the various normal subpopulations within the monocyte/macrophage system, which were also observable in epithelioid cells and U-937 cell line considered as reactive and neoplastic differentiation variants of monocytes, respectively. Alveolar macrophages, in contrast to the other analysed monocyte/macrophage populations, showed a highly activated phenotype comparable to lymphokine stimulated blood monocytes and epithelioid cells. The results underline the concept that the adaptation of monocytes/macrophages to their particular microenvironment is of decisive importance for their definitive differentiation.

Role of alveolar macrophage- and lung T cell-derived mediators in pulmonary sarcoidosis

The process of granuloma formation in the lung is mediated by an intimate interaction between macrophages and T cells, and this interaction provides the appropriate environment for granuloma formation and the development of fibrosis. Much of this process of granuloma formation and fibrosis appears to be triggered by the release of immune mediators by alveolar macrophages and lung T cells.

HLA-DR antigens on human macrophages from bronchoalveolar lavage fluid

The expression of HLA-DR (Ia-like) antigens on human macrophages was investigated by analyses of cells from bronchoalveolar lavage fluid obtained from 12 patients with pulmonary sarcoidosis, six patients with extrinsic allergic alveolitis, nine patients with cryptogenic fibrosing alveolitis, 11 normal non-smokers, and 12 normal smokers. The HLA-DR antigen was demonstrated by the mouse monoclonal antibody OKIa by a peroxidase-antiperoxidase method performed on glass slides. No differences were found in the percentage of alveolar macrophages that expressed DR antigens between the five study groups. OKIa positivity was observed on more than 90% of macrophages in all cases. These observations suggest that the previously reported enhanced antigen presentation by alveolar macrophages in sarcoidosis is not linked with an increase in the percentage of DR+ macrophages in the lung.