Plant-made antibody against miroestrol: a new platform for expression of full-length immunoglobulin G against small-molecule targets in immunoassays

KEY MESSAGE

Plant expression platform is the new source of immunoglobulin G (IgG) toward small low-molecular-weight targets. The plant-made monoclonal antibody-based immunoassay exhibits comparable analytical performance with hybridoma antibody. Immunoassays for small molecules are efficiently applied for monitoring of serum therapeutic drug concentration, food toxins, environmental contamination, etc. Immunoglobulin G (IgG) is usually produced using hybridoma cells, which requires complicated procedures and expensive equipment. Plants can act as alternative and economic hosts for IgG production. However, the production of free hapten (low-molecular-weight target)-recognizing IgG from plants has not been successfully developed yet. The current study aimed at creating a plant platform as an affordable source of IgG for use in immunoassays and diagnostic tools. The functional IgG was expressed in Nicotiana benthamiana leaves infiltrated with Agrobacterium tumefaciens strain GV3101 with recombinant geminiviral vectors (pBY3R) occupying chimeric anti-miroestrol IgG genes. The appropriate assembly between heavy and light chains was achieved, and the yield of expression was 0.57 µg/g fresh N. benthamiana leaves. The binding characteristics of the IgG to miroestrol and binding specificity to related compounds, such as isomiroestrol and deoxymiroestrol, were similar to those of hybridoma-produced IgG (monoclonal antibody, mAb). The plant-based mAbs exhibited high sensitivity for miroestrol (IC50, 23.2 ± 2.1 ng/mL), precision (relative standard deviation ≤ 5.01%), and accuracy (97.8-103% recovery), as determined using quantitative enzyme-linked immunosorbent assay. The validated enzyme-linked immunosorbent assay was applicable to determine miroestrol in plant samples. Overall, the plant-produced functional IgG conserved the binding activity and specificity of the parent IgG derived from mammalian cells. Therefore, the plant expression system may be an efficient and affordable platform for the production of antibodies against low-molecular-weight targets in immunoassays.

Tumors induce de novo steroid biosynthesis in T cells to evade immunity

Tumors subvert immune cell function to evade immune responses, yet the complex mechanisms driving immune evasion remain poorly understood. Here we show that tumors induce de novo steroidogenesis in T lymphocytes to evade anti-tumor immunity. Using a transgenic steroidogenesis-reporter mouse line we identify and characterize de novo steroidogenic immune cells, defining the global gene expression identity of these steroid-producing immune cells and gene regulatory networks by using single-cell transcriptomics. Genetic ablation of T cell steroidogenesis restricts primary tumor growth and metastatic dissemination in mouse models. Steroidogenic T cells dysregulate anti-tumor immunity, and inhibition of the steroidogenesis pathway is sufficient to restore anti-tumor immunity. This study demonstrates T cell de novo steroidogenesis as a mechanism of anti-tumor immunosuppression and a potential druggable target.

Preparation of a highly specific single chain variable fragment antibody targeting miroestrol and its application in quality control of Pueraria candollei by enzyme-linked immunosorbent assay

INTRODUCTION

Miroestrol is the potent phytoestrogen isolated from White Kwao Krua (Pueraria candollei var. mirifica (Airy Shaw & Suvat.) Niyomdham, a Thai traditional medicinal plant. Nowadays, various health supplementary products featuring White Kwao Krua are available worldwide. A sensitive and rapid analytical method for quantification of miroestrol is necessary for quality control of these products.

OBJECTIVES

To prepare a single-chain variable fragment (scFv) antibody specific to miroestrol and develop a scFv-based enzyme-linked immunosorbent assay (ELISA) for quantitative analysis of miroestrol in plant materials and health supplementary products.

METHODS

A gene encoding anti-miroestrol scFv antibody was constructed and expressed in Escherichia coli SHuffle T7 strain. Anti-miroestrol scFv antibody was characterised and applied to ELISA. The developed scFv-based ELISA method was validated for its sensitivity, specificity, accuracy and precision.

RESULTS

Anti-miroestrol scFv antibody was highly specific to miroestrol. The scFv-based ELISA was applied to determine miroestrol in the range 0.06-7.81 μg/mL, with the limit of quantification of 0.06 μg/mL miroestrol. The accuracy of the assay was validated by its 95.08-103.99% recovery from the spiked miroestrol recovery experiment and in good correlation with the results from the monoclonal antibody-based ELISA. The relative standard deviation of the intra- and inter-assay were less than 6.0%.

CONCLUSION

The developed scFv-based ELISA was sensitive, specific, accurate, and precise for determination of miroestrol and useful for quality control of P. candollei plant raw materials and supplementary products.

Model approach for stress induced steroidal hormone cascade changes in severe mental diseases

INTRODUCTION

Stress was described by Cushing and Selye as an adaptation to a foreign stressor by the anterior pituitary increasing ACTH, which stimulates the release of glucocorticoid and mineralocorticoid hormones. The question is raised whether stress can induce additional steroidal hormone cascade changes in severe mental diseases (SMD), since stress is the common denominator.

METHODS

A systematic literature review was conducted in PubMed, where the steroidal hormone cascade of patients with SMD was compared to the impact of increasing stress on the steroidal hormone cascade (a) in healthy amateur marathon runners with no overtraining; (b) in healthy well-trained elite soldiers of a ranger training unit in North Norway, who were under extreme physical and mental stress, sleep deprivation, and insufficient calories for 1 week; and, (c) in soldiers suffering from post traumatic stress disorder (PTSD), schizophrenia (SI), and bipolar disorders (BD).

RESULTS

(a) When physical stress is exposed moderately to healthy men and women for 3-5 days, as in the case of amateur marathon runners, only few steroidal hormones are altered. A mild reduction in testosterone, cholesterol and triglycerides is detected in blood and in saliva, but there was no decrease in estradiol. Conversely, there is an increase of the glucocorticoids, aldosterone and cortisol. Cellular immunity, but not specific immunity, is reduced for a short time in these subjects. (b) These changes are also seen in healthy elite soldiers exposed to extreme physical and mental stress but to a somewhat greater extent. For instance, the aldosterone is increased by a factor of three. (c) In SMD, an irreversible effect on the entire steroidal hormone cascade is detected. Hormones at the top of the cascade, such as cholesterol, dehydroepiandrosterone (DHEA), aldosterone and other glucocorticoids, are increased. However, testosterone and estradiol and their metabolites, and other hormones at the lower end of the cascade, seem to be reduced. 1) The rate and extent of reduction of the androgen metabolites may cause a decrease of cellular and specific immunity which can lead to viral and bacterial infections; joint and stomach inflammation; general pain; and allergic reactions. 2) The decrease in testosterone, and estradiol in SMD may have detrimental effects in cell repair as the estradiol metabolite, 2-methoxy-estradiol (2ME2), helps to transforms stem cells into functional cells. As dopamine and 2ME2 are inversely metabolized via various forms of catechol-O-methyl transferase (COMT), well-being and hypertension may be related. 2ME2 is related to vascular endothelial growth factor (VEGF), which regulates blood capillary growth and O2 supply. As reduced O2 is a key marker of stress, the increase of glucocorticoids in all forms of mental and physical stress cannot counterbalance the reduced 2ME2 in cellular and mental stress. The increased cholesterol and triglycerides are related to stroke and infarction, contributing to a reduced life expectancy in SMD between 14 and 20 years. The increase of aldosterone leads to increases in anxiety, edema, and lung infections.

DISCUSSION

Increasing mental and physical stress is related to systematic deviations in the steroidal hormone cascade in the non-psychotic state, which then may cause life threatening co-morbidities in PTSD, SI, and BD.

[FEMALE STEROID HORMONES - MODULATORS OF IMMUNE RESPONSE TO GENITAL CHLAMYDIA TRACHOMATIS INFECTION.]

In the recent years according to WHO, genital chlamydia is the mos't common sexually transmitted infection. Chlamydia Trachomatis is an intracellular parasite which target are the tubular epithelial cells of the urethra, endocervix, endometrium, endosalpinx, conjunctiva, synovial lining of the joints, Glisson's capsule of the liver Our study, as well as some international researches, shows that in the cases of genital chlamydia there are changes in the ovarian hormones (estradiol and progesterone), their impact on the immune system and their importance for the development and the complications of the infection with Chlamydia trachomatis. The physiological level of the steroid hormones in its turn contributes for the normalization of the local immunity and reduces the possibility of recurrences.

Steroid hormone signaling is essential to regulate innate immune cells and fight bacterial infection in Drosophila

Coupling immunity and development is essential to ensure survival despite changing internal conditions in the organism. Drosophila metamorphosis represents a striking example of drastic and systemic physiological changes that need to be integrated with the innate immune system. However, nothing is known about the mechanisms that coordinate development and immune cell activity in the transition from larva to adult. Here, we reveal that regulation of macrophage-like cells (hemocytes) by the steroid hormone ecdysone is essential for an effective innate immune response over metamorphosis. Although it is generally accepted that steroid hormones impact immunity in mammals, their action on monocytes (e.g. macrophages and neutrophils) is still not well understood. Here in a simpler model system, we used an approach that allows in vivo, cell autonomous analysis of hormonal regulation of innate immune cells, by combining genetic manipulation with flow cytometry, high-resolution time-lapse imaging and tissue-specific transcriptomic analysis. We show that in response to ecdysone, hemocytes rapidly upregulate actin dynamics, motility and phagocytosis of apoptotic corpses, and acquire the ability to chemotax to damaged epithelia. Most importantly, individuals lacking ecdysone-activated hemocytes are defective in bacterial phagocytosis and are fatally susceptible to infection by bacteria ingested at larval stages, despite the normal systemic and local production of antimicrobial peptides. This decrease in survival is comparable to the one observed in pupae lacking immune cells altogether, indicating that ecdysone-regulation is essential for hemocyte immune functions and survival after infection. Microarray analysis of hemocytes revealed a large set of genes regulated at metamorphosis by EcR signaling, among which many are known to function in cell motility, cell shape or phagocytosis. This study demonstrates an important role for steroid hormone regulation of immunity in vivo in Drosophila, and paves the way for genetic dissection of the mechanisms at work behind steroid regulation of innate immune cells.

Electronic anabolic steroid recognition with carbon nanotube field-effect transistors

A proof of concept of the electronic detection of two anabolic steroids, stanozolol (Stz) and methylboldenone (MB), was carried out using two specific antibodies and arrays of carbon nanotube field-effect transistors (CNTFETs). Antibodies specific for Stz and MB were prepared and immobilized on the carbon nanotubes (CNTs) using two different approaches: direct noncovalent bonding of antibodies to the devices and bonding the antibodies covalently to a polymer previously attached to the CNTFETs. The results indicated that CNTFETs bonded to specific antibodies covalently or noncovalently are able to detect the presence of steroids. Statistically significant changes in the threshold voltage and drain current were registered in the transistors, allowing the steroids to be recognized. On the other hand, it was determined that the specific antibodies do not detect other steroids other than Stz and MB, such as nandrolone (ND) because, in this case, statistically significant changes in the transistors were not detected. The polymer prevents the aggregation of antibodies on the electrodes and decreases the transistor hysteresis. Nevertheless, it is not able to avoid the nonspecific adsorption of streptavidin, meaning that nonspecific adsorption on CNTs remains a problem and that this methodology is only useful for purified samples. Regarding the detection mechanism, in addition to charge transfer, Schottky barrier, SB, modification, and scattering potential reported by other authors, an electron/hole trapping mechanism leading to hysteresis modification has been determined. The presence of polymer seems to hinder the modulation of the electrode-CNT contact.

Effects of soluble antigen-induced immune cell activation on steroidogenesis in murine lymphoid organ

The effect of soluble antigenic (bovine serum albumin, BSA) stimulation to induce steroidogenesis in murine lymphoid organs with concomitant changes in proinflammatory or inflammatory cytokine levels and its implication in the alteration of T-cell response was studied in the mice. Male Swiss albino mice (6-8 weeks old) with average body weight (20 +/- 4 g) were randomly assigned to 3 groups and injected with BSA in presence and absence of Freund's complete or incomplete adjuvant, whereas the control group received only saline. After 3 weeks, animals were sacrificed, and serums as well as lymphoid organs were collected. From the lymphoid tissue homogenate, the activities of steroidogenic enzymes and corticosterone and cytokine levels of the serum were estimated. Steroidogenic enzyme activities in murine lymphoid organs, as well as the pro-inflammatory and inflammatory cytokines levels in serum increased after Freund's complete adjuvant-emulsified BSA administration, as compared to control. The serum corticosterone and serum cytokine profile were also elevated. Results suggested that soluble protein antigen (BSA) administration stimulated steroidogenesis in murine lymphoid tissues and rise in the pro-inflammatory or inflammatory cytokine levels might indicate monocyte recruitment as well as TH1 activation.

Steroid binding at sigma receptors: CNS and immunological implications

The sigma receptor has been suggested to be the mediator of the psychomimetic effects induced by certain benzomorphan opioids and phencyclidine. Potent sigma receptor ligands include haloperidol and other 'atypical' potential antipsychotic drugs. The sigma receptor is found in the central nervous system and also in the immune and endocrine systems. Gonadal and adrenal steroids such as progesterone, testosterone, deoxycorticosterone and corticosterone were found to be competitive inhibitors of binding of the sigma receptor ligand [3H] d-SKF-10,047. The sigma receptor is not the traditionally recognized cytosolic progesterone receptor and is found in crude membrane fractions. Results from molecular modelling using geometric fitting and electrostatic potential calculations suggested that the molecular skeleton of steroid hormones shares common features with prototypic sigma ligands such as d-SKF-10,047 and that the oxygen of the C-20 carbonyl group on these steroids may represent a critical 'pharmacophore' for their interactions with sigma receptors. Comparison of the affinities of steroids at sigma receptors with their efficacies is an anti-inflammatory test yielded a striking qualitative correlation. Taken Taken together these results suggest that sigma receptors may mediate certain aspects of steroid-induced mental disturbances and alterations in immune function.

Dissociated steroids

Glucocorticoids (GCs) are some of the most important drugs in clinical use today. They are mainly used to suppress disease-related inflammation and are widely used for the treatment of many inflammatory diseases including asthma and arthritis. However, GCs are also associated with debilitating side effects that place limitations on the long-term use of these drugs. The development of a GC with reduced side effects would allow more effective treatments for patients who require long-term suppression of inflammation. GCs exert their effects by binding and activating the GC receptor (GR). The activated receptor then binds GC response elements (GREs) in the promoter of genes, and activates transcription (transactivation) or interferes with the activation of transcription by inhibiting the transactivating function of other transcription factors, such as AP-1 and NF-ĸB (transrepression). Transrepression is believed to be responsible for the majority of the beneficial anti-inflammatory effects of GCs, whereas transactivation is believed to play a bigger role in the unwanted side effects of GCs. Compounds that can dissociate the transactivation function of GCs from the transrepression function may, therefore, have an improved therapeutic index. A number of these dissociated corticosteroids have been developed. In vitro assays using these compounds appear to show good dissociation. However, in vivo, the dissociation appears to be lost and these compounds still produce many of the side effects associated with conventional GCs. A better understanding of the molecular mechanisms behind GC-induced effects would allow the design of novel selective GR modulators with an improved therapeutic index.

Molecular understanding of cytokine-steroid hormone dialogue: implications for human diseases

Highly sophisticated mechanisms confer upon the immune system the capacity to respond with a certain degree of autonomy. However, the final outcome of an adaptative immune response depends on the interaction with other systems of the organism. The immune-neuroendocrine systems have an intimate cross-communication, making possible a satisfactory response to environmental changes. Part of this interaction occurs through cytokines and steroid hormones. The last step of this crosstalk is at the molecular level. In this article we will focus on the physical and functional interrelationship between cytokine signaling pathway-activated transcription factors (TFs) and steroid receptors in different cell models, where the signals triggered by cytokines and steroid hormones have major roles: (1) the ligand-dependent-activated glucocorticoid receptor (GR) influence the genetic program that specifies lineage commitment in T helper (Th) cell differentiation. How posttranslational modifications of several TFs as well as nuclear hormone receptors could be implicated in the molecular crosstalk between the immune-neuroendocrine messengers is discussed. (2) glucocorticoid (GC) antagonism on the TCR-induced T cell apoptosis. (3) estrogen receptor/TGF-beta family proteins molecular interaction implicated on pituitary prolactinomas pathogenesis. The functional crosstalk at the molecular level between immune and steroids signals is essential to determine an integrative response to both mediators (which in the last instance results in a new gene activation/repression profile) and constitutes the ultimate integrative level of interaction between the immune and neuroendocrine systems.

C4d in pediatric renal allograft biopsies: a marker for negative outcome in steroid-resistant rejection

Recently, deposition of C4d, reflecting complement activation via the classical pathway, has been established as marker of antibody-mediated rejection. As C4d can be detected in paraffin sections, it allows for retrospective analysis in populations with low case loads, such as in pediatric transplantation. In this study we re-evaluated consecutive renal transplant biopsies obtained since 1990 in 36 children (18 boys, 18 girls) who had received their allograft (nine living, 27 cadaveric) at an age of 10.12+/-4.4 yr. Clinical indications for biopsy were 16 acute steroid resistant rejections (ASRs), 11 chronic rejections and nine other diagnoses. Overall, C4d deposition was found in nine cases (25%), eight of them with diagnosed ASR. Six out of these eight allografts were lost during 36 months of clinical follow-up, a significantly higher rate than in C4d-negative biopsies (p<0.05). C4d status therefore turned out to be an excellent predictor for inferior graft survival following ASR. None of the other histopathologic markers were sensitive for humoral rejections. In conclusion, the high prevalence of C4d-positive staining in ASR demonstrates the importance of the humoral part of the immune system in pediatric transplantation. The worse outcome of C4d-positive rejections despite massive immunosuppressive therapy clearly indicates the need for innovative therapies in this high-risk population.

Immunosuppression without steroids in liver transplantation is safe and reduces infection and metabolic complications: results from a prospective multicenter randomized study

BACKGROUND/AIMS

The purpose of this study was to evaluate the efficacy of a steroid-free immunosuppression protocol.

METHODS

From 2001 to 2004, 198 liver-transplant patients were randomized to receive immunosuppression with Basiliximab and cyclosporine, with (St Group) or without (NoSt Group) prednisone. The primary end points were acute rejection, and patient and graft survival. The secondary end points were infection, metabolic complications, and hepatitis C-virus recurrence.

RESULTS

Overall rejection rate was 15%, with no differences (St: 13% vs NoSt: 18%; P=0.33). Infection rate was similar in both groups (St: 51% vs NoSt: 47%; P=0.56), but diabetic patients in the St Group had a significantly higher rate of bacterial infections (St: 54% vs NoSt: 14%; P=0.005). The six-month protocol biopsies showed hepatitis C recurrence in 90% of patients, without differences between groups. Hypertension was more frequent in the St Group (St: 44% vs NoSt: 25%; P=0.006). De novo diabetes rate was higher in the St Group (month 1: St: 29% vs NoSt: 18%; P=0.06), with higher glycatedHb (5.1+/-1.1 vs 4.4+/-0.8; P=0.002). Six-month survival rates were similar (St: 89% vs NoSt: 94%, P=0.62).

CONCLUSIONS

Immunosuppression without steroids is safe and reduces infection and metabolic complications.

Significant improvement in the outcome of HCV-infected transplant recipients by avoiding rapid steroid tapering and potent induction immunosuppression

BACKGROUNDS/AIMS

Recurrent HCV-cirrhosis occurs in a substantial proportion of transplant recipients, with higher rates reported in patients who had recently received a transplant. Over-immunosuppression has been implicated in this more unfavorable outcome. To determine whether the implementation of specific measures aimed at reducing or avoiding negative predictive variables is associated with an improvement in the outcome of recurrent hepatitis C.

METHODS

Comparative study between a cohort of patients who had recently received a transplant (2001-2004) and a historical group of HCV-infected patients transplanted before the implementation of two simple measures (1999-2000): (i) use of dual initial immunosuppression (steroids + cyclosporine neoral or tacrolimus); (ii) slow steroid tapering (>6 months). Yearly biopsies were performed in these recipients, and only those with at least one protocol biopsy and those with cholestatic hepatitis (regardless of follow-up) were included in the study. End-point: rate of HCV-related severe disease (defined as bridging fibrosis, cirrhosis or fibrosing cholestatic hepatitis) within the first year post-transplantation.

RESULTS

Severe disease was significantly lower in this cohort compared to the historical group (26/90, 29% vs 25/52, 48%; p=0.02). While other factors remained unchanged between the two cohorts, the proportion of patients on triple-quadruple regimes and the number of boluses of methyl-prednisolone were lower and the duration of prednisone therapy longer in more patients who had recently received a transplant.

CONCLUSIONS

Improving the outcome of recurrent hepatitis C may be achieved by reducing overall immunosuppression and avoiding abrupt variations in immunosuppression.

[Autoantibodies against structures of the central nervous system in steroid responsive meningitis-arteriitis in dogs]

Steroid-responsive meningitis-arteriitis (SRMA) is a disease of dogs familiar in small animal practice for decades. A combined evaluation of IgA in serum and cerebrospinal fluid (CSF) is an important diagnostic tool. It is suspected that immunpathological mechanisms are involved in the pathogenesis of SRMA because of the marked response to steroids. Excessive production of IgA seems to play a central role and might be caused by an immune reaction to self-antigens of the central nervous system (CNS). To test this hypothesis, we analyzed CSF samples from 55 dogs with SRMA using the western blot method. After blotting canine brain tissue, IgA, IgM and IgG of the CSF samples were tested for their binding to CNS antigens. We also evaluated CSF samples from 45 dogs with other brain diseases, including different encephalitides and intracranial tumors, and from healthy dogs as controls. Positive reactions (mostly IgA) were observed in the CSF samples from dogs with SRMA, different encephalitides and brain tumors (a total of 8% positive samples). The occurrence of autoantibodies against CNS structures was significantly higher in the control group "other brain diseases" than in the SRMA group (p = 0.0135). There was no significant difference in the number of positive samples between dogs with SRMA and the negative control group (healthy dogs, p = 0.1535). Despite the small number of positive samples, only dogs with abnormal findings in the CSF analysis also had autoantibodies in the CSF. There was no significant correlation between the occurrence of autoantibodies and levels of IgA, protein content and cell counts in the cerebrospinal fluid. However, there was a certain trend toward positive reactions in CSF samples with high protein content. The occurrence of autoantibodies in dogs with SRMA thus seems to be an epiphenomenona rather than the cause of the disease.

Ketogenic diet decreases circulating concentrations of neuroactive steroids of female rats

Ketogenic diet (KD) is used to manage intractable epilepsy; however, the mechanisms underlying its therapeutic effects are not known. Steroid hormones, such as progesterone and testosterone, are derived from cholesterol, and are readily 5alpha-reduced to dihydroprogesterone and dihydrotestosterone, which are subsequently converted to 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP) and 3alpha-androstanediol, neuroactive steroids that can influence seizures. The present study examined the effects of the KD on circulating concentrations of these neuroactive steroids, and their precursors, in intact female rats. Thirty-six, 22-day-old female Sprague-Dawley rats (weaned at 21 days) were fasted for 8 hours prior to placement on one of three dietary regimens for 6 weeks: ad libitum chow, calorie-restricted chow, or KD. After 6 weeks of the diet, when six rats in each dietary condition were in diestrus and six were in behavioral estrus, all rats were administered pentylenetetrazole (PTZ, 70 mg/kg, i.p.). The latency and incidence of seizures were recorded by an observer who was uninformed of the estrous cycle and dietary treatment conditions of the rats. Immediately after each test, trunk blood was obtained for later measurement of pregnane (progesterone, dihydroprogesterone, 3alpha,5alpha-THP) and androstane (testosterone, dihydrotestosterone, 3alpha-androstanediol) neuroactive steroid concentrations in plasma by radioimmunoassay. KD tended to lengthen the latency to, and significantly reduced the number of, PTZ-induced barrel roll seizures. KD also significantly reduced plasma levels of the pregnane (dihydroprogesterone, 3alpha,5alpha-THP) and androstane (dihydrotestosterone, 3alpha-androstanediol) 5alpha-reduced metabolites. These data suggest that levels of pregnane and androstane neuroactive steroids, or their precursors, may underlie some of the antiseizure effects of KD.

Steroid-free immunosuppression in organ transplantation

Although steroids have been the cornerstone of immunosuppressive regimens to treat and prevent rejection in organ transplantation, the past decade has seen many successful attempts to minimize or eliminate steroid use. This has been undertaken to decrease the diverse side effects seen with chronic steroid treatment. These efforts have focused on both steroid avoidance and complete elimination, and have been successful across broad patient groups. The key to these efforts has been the adoption of induction protocols with either lymphocyte-depleting agents or anti-interleukin-2 strategies, coupled with the use of the newer maintenance immunosuppressants. In this review, we address the feasibility and benefits of steroid-free and steroid avoidance protocols in kidney, pancreas, liver, and heart transplantation.

Leukocyte apoptosis and its significance in sepsis and shock

Sepsis and multiple organ failure continue to be significant problems among trauma, burn, and the critically ill patient population. Thus, a number of laboratories have focused on understanding the role of altered apoptotic cell death in contributing to immune and organ dysfunction seen in sepsis and shock. Immune cells that undergo altered apoptotic changes include neutrophils, macrophages, dendritic cells, as well as various lymphocyte populations. Evidence of epithelial as well as endothelial cell apoptotic changes has also been reported. Although mediators such as steroids, tumor necrosis factor, nitric oxide, C5a, and Fas ligand (FasL) appear to contribute to the apoptotic changes, their effects are tissue- and cell population-selective. As inhibiting Fas-FasL signaling (e.g., gene deficiency, Fas fusion protein, or Fas short interfering RNA administration), caspase inhibition (caspase mimetic peptides), and/or the overexpression of downstream antiapoptotic molecules (e.g., Bcl-2, Akt) improve survival of septic mice, it not only demonstrates the pathological significance of this process but points to novel targets for the treatment of sepsis.

Can polyclonal intravenous immunoglobulin limit cytokine mediated cerebral damage and chronic lung disease in preterm infants?

Recent evidence suggests that inflammatory cytokines may play an important role in cerebral and pulmonary injury, especially in preterm infants. Immunomodulatory agents may help to limit such injury by reducing inflammation. Immunoglobulin has multiple anti-inflammatory properties and can modulate the inflammatory cytokine response. New evidence is required to test the hypotheses that prophylaxis or treatment with intravenous immunoglobulin may limit such inflammatory damage.

Immunostimulation of the chemical-induced carcinogenesis in the phase of initiation MH-G 0166

It is postulated that the immune reaction on chemical carcinogens can inhibit or stimulate the chemical-induced carcinogenesis depending on the individual peculiarities of the synthesis of antibodies. Critical events take place on the barriers between external and internal media. Antibodies to chemical carcinogens, which are secreted into the digestive or bronchial tract, bind the environmental carcinogens and prevent them from penetrating into the blood through the epithelium and thereby inhibit the beginning of the tumour growth in any organs. On the contrary, the serum antibodies promote the penetration of carcinogens through the digestive and bronchial epithelia and thereby stimulate carcinogenesis in the proper organs. The other events take place in the organs such as breast and prostate where carcinogens are transported from the blood. Secretory antibodies bind carcinogens in the blood and transport them through the epithelium of these glands and thereby stimulate the tumour origin in these organs. Antibodies, which are not secreted into the ducts of breast and prostate, hold carcinogens in the blood and thereby inhibit carcinogenesis in these organs. Antibodies to steroid hormones function in the same way, i.e., secretory antibodies stimulate, while the serum antibodies inhibit the genetoxic action of the hormones on breast and prostate. The stimulation of carcinogenesis in the lymphoid cells is realized owing to hapten-specific binding of carcinogens by the membrane receptors of the corresponding clones. Antibodies to the natural inhibitors of carcinogenesis (retinoids, tocopherole, etc.) stimulate the beginning of the tumour growth. Antibodies to carcinogens and antiidiotypic antibodies to the cytochromes p-450 may act as abzymes, i.e., as cytochromes p-450 and thereby increase the level of the carcinogen metabolites.

Characterisation of antibodies and analytes by surface plasmon resonance for the optimisation of a competitive immunoassay based on energy transfer

The determination of binding constants using surface plasmon resonance (SPR) was introduced to optimise a competitive homogeneous fluorescence energy-transfer immunoassay (ETIA) before labelling. Steroids were chosen as model for the detection of three analytes estrone, estradiol and ethinylestradiol--by taking three polyclonal antibodies (anti estrone-, anti estradiol- and anti estrogen-antibodies) and the corresponding analyte derivatives used for the immunisation. The active concentration of the antibodies was determined before and after labelling. Inhibition curves were recorded using SPR for all possible combinations of analyte, antibody, and analyte derivatives. The experiments revealed that the active antibody concentration can be reduced to 30% whereas the antibody affinity is not affected by the labelling process. Limits of the use of SPR for determination of affinity constants in solution are discussed. All possible ETIA calibration for the quantification of estrone and estradiol was performed. The lower limits of detection for estrone (0.06 microg L(-1)) and estradiol (0.17 microg L(-1)) were reached with the anti-estrogen IgG and its derivative

Immune response to progesterone immobilized on Cu2+-induced amphifilic polyelectrolyte-protein complex: antigen specificity and affinity of hybridoma clones

Cu2+-mediated complex formation between copolymers of acrylic acid with N-isopropyl-acyrlamide (CP1) and negatively charged covalent conjugate of bovine serum albumin with progesterone (BSA.P) was studied in neutral water in the presence of Cu2+. It was shown that under conditions where CP and BSA.P are negatively charged and incapable of binding to one another, the divalent Cu2+ act as "fasteners" promoting the formation of relatively stable water-soluble ternary polycomplexes. The immunogenic properties of ternary mixtures BSA.P-Cu2+-CP1 and BSA.P+IFA were investigated and the production of monoclonal antibodies (MAbs) against progesterone hormone was analyzed. Fusion following the two different immunization procedures resulted in the growth of comparable numbers of progesterone-specific MAbs with apparently similar antigen affinities. Thus, immunizations using antigens in BSA.P-Cu2+-CP1 appear to provide an efficient alternative to incomplete Freund's adjuvant.

Removal of bowel aerobic gram-negative bacteria is more effective than immunosuppression with cyclophosphamide and steroids to decrease natural alpha-galactosyl IgG antibodies

Natural alpha-Galactosyl (Gal) antibodies play an important role in the rejection of pig xenografts by humans and Old World monkeys. In this study we investigate the efficacy of two different strategies to reduce the serum level of natural anti-Gal antibodies. On the one hand, removal of aerobic gram-negative bacteria from the intestinal flora, because anti-Gal antibodies appear to be produced as a result of the continuous sensitization by these microorganisms. On the other hand, we studied the effect on these antibodies of an immunosuppressive regimen of cyclophosphamide and steroids. Ten baboons were treated for three months with norfloxacin (Nor Group; n=6) or cyclophosphamide and steroids (CyP Group; n=4). A further four baboons did not receive any treatment (Control Group). Aerobic gram-negative bacteria became negative in stools of the Nor Group after two weeks of treatment, and remained undetectable until week 7. Thereafter, a gradual increase on the fecal concentration of aerobic gram-negative bacteria was observed despite the norfloxacin treatment. The mean anti-Gal IgG in the Nor Group gradually declined from week 4 to 9 to a mean of 62.7 +/- 18% of the baseline level, and during this period were significantly lower than in the CyP (P<0.02) and the Control (P<0.05) groups. No differences were observed between the three groups during the 16 weeks of follow-up in serum levels of anti-Gal IgM, hemolytic anti-pig antibodies, total IgG, IgM and IgA. In conclusion, removal of normal aerobic gram-negative bacteria from the intestinal flora is more effective than immunosuppression with CyP and steroids in reducing the level of natural anti-Gal antibodies, although there is no discernible effect on IgM antibodies.

Immune response to 17beta-estradiol involved in polymer gels: antigen specificity and affinity of hybridoma clones

The immunogenic properties of 17beta-estradiol, immobilized in negatively charged polymer gels, were investigated, and the specificity of antibodies produced was analyzed. The polymer gels developed were composed of a hydrophobic estradiol core surrounded by hydrophilic polyanions as corona. As an immunogen, it was conceived to function via a dual mode, that is as a hapten-delivery system (prolongation effect) and as a polyelectrolyte adjuvant. Polymer gels containing estradiol appeared to possess a high estradiol-specific immunogenicity even without the addition of traditional adjuvants. A comparative study of estradiol trapped in polymer gels versus estradiol conjugated to bovine serum albumin (BSA.E) + Incomplete Freund's Adjuvant (IFA) mixtures revealed similar immunogenic properties in terms of induction of specific antibodies. Following a short immunization procedure based on the use of 17beta-estradiol immobilized in polymer gels, we developed 10 specific monoclonal antibodies with Kd values ranging between 1.2 X 10(-7) and 8 X 10(-8) M.

N-terminal mutations in the anti-estradiol Fab 57-2 modify its hapten binding properties

Recombinant antibodies often contain N-terminal mutations arising from the use of degenerate cloning primer sets and/or the introduction of restriction sites in the framework 1 regions. We studied the effects of such mutations in a recombinant anti-estradiol Fab fragment derived from the hybridoma cell line 57-2. The 5' ends of the heavy and light chain genes were originally modified to introduce the restriction sites XhoI and SacI, respectively, for cloning purposes. However, the affinity and specificity of the recombinant Fab were lowered compared to the proteolytic Fab' fragment of the parental hybridoma IgG. Replacing the mutated sites with authentic amino acid coding sequences restored the binding properties as well as increased the bacterial production levels fivefold and 10-fold at 30 and 37 degrees C, respectively. Local changes in the antigen binding site were probed by determining the affinity constants (Kd) for estradiol and four related steroids. It was found that the mutated heavy chain amino terminus specifically increased the Kd for testosterone whereas the mutated light chain amino terminus decreased the Kd for all of the steroids to the same extent; the heavy and light chain effects were additive. Analysis of a newly determined crystal structure of the authentic Fab 57-2 in complex with estradiol suggests that mutations in the residue 2 in V(H), and 2 and 4 in the V(L) domain were those responsible for the observed effects. Their general roles as structure-determining residues for the CDR3 loops imply that similar effects can occur with other recombinant antibodies as well.

[Inducing high-specificity anti-cortisol antibodies for use in RIA (radioimmunoassay)]

A method for inducing highly specific cortisol antibodies for measuring plasmatic cortisol by RIA is described. The method is fast, direct (without extraction or separation), with high specificity, due to the high quality of the antibody produced in our laboratory. Reliability was demonstrated by: the sensitivity of the method, with a pattern curve of 50 pg of cortisol; the precision tests showed a variation rate intranalysis of < 9.7% and internalysis of < 17.6%; accuracy was > 87%; and specificity was demonstrated by antiserum characterization with other steroids. Measurings of cortisol in plasma of normal subjects could detect the circadian cycle pattern as well as normal supression with dexametasone. These findings support that our method allows fast measurement of plasmatic cortisol with accuracy and sensitivity, reducing operative cost.

Anti-corpus luteum antibody: a novel serological marker for ovarian dysfunction in systemic lupus erythematosus?

OBJECTIVE

To investigate the presence of autoantibodies directed to corpus luteum (CoL) in systemic lupus erythematosus (SLE) sera and its correlation with menstrual disturbances.

METHODS

We evaluated 87 female patients with SLE, < 40 years old, and 23 women with normal menses as controls. Anti-corpus luteum antibody was detected by immunoblot technique.

RESULTS

Reactivity to a bovine CoL antigen was found in 22% of SLE sera. Characterization of the target antigen revealed a 67 kDa glycoprotein highly enriched in corpus luteum, but nearly absent in total ovary extract. Similarly, target antigen was also weakly detectable in tissues that produce or metabolize steroids, such as testis, adrenal cortex, and liver, and it was absent in adrenal medulla or HEp-2 cells. Anti-CoL antibody was easily distinguished from other frequent reactivities of SLE sera, including anti-RNP, anti-Sm, anti-Ro/La, anti-dsDNA, or anticardiolipin. The observation of anti-67 kDa reactivity to human CoL suggests a possible pathogenic role in gonadal dysfunction. Indeed, we observed an inverse association of anti-CoL antibody with the duration of hypergonadotropic amenorrhea. Supporting this hypothesis, in patients with normal or irregular menses, the presence of this antibody was associated with elevated serum level of follicle stimulating hormone, an early and specific sign of ovarian lesion.

CONCLUSION

Anti-CoL antibody seems to be associated with early stages of ovarian dysfunction in SLE. Moreover, since similar association of antiovarian antibodies has been observed in an experimental model of autoimmune oophoritis, our findings raise the possibility of autoimmune ovarian lesion in patients with SLE.

OKT3 monitoring in the treatment of steroid-resistant acute rejection of hepatotransplant recipients

OKT3 is a monoclonal antibody used as T-specific immunosuppressor agent in the treatment of acute rejection of hepato- or renal-transplanted patients. The immunosuppressor effect is related to the elimination and modulation of T-cells after the binding between OKT3 and the specific antigen CD3+. This drug has been used in the treatment of acute rejection. The more frequent side effects is the immunogenic reaction Human Antibody Mouse Antibody (HAMA). The aim of this study is the evaluation of the dose and the administration route of the OKT3. The results of the antibody monitoring in the plasma of the treated patients and the analysis of the clinical data were evaluated to focus a valid therapeutic protocol as well as a more rational time sampling of the circulating drug to achieve a correct monitoring. The results show a gradual increase of the hematic concentration of the drug, positively correlating the clinical data of hepatic biopsy and lymphocytic screening. These results have permitted to modify the therapeutic protocol previously performed. It has been defined the administration route choosing i.v. infusion (5 mg/die/2 h), moreover it the therapy has been shortened to 6 days. The HAMA were also evaluated and the analysis of the data showed a negative results, suggesting the possibility of the OKT3 retreatment in the cases of rescue.

Avascular necrosis following bone marrow transplantation: a case-control study

The role of specific immunosuppressive agents in the development of avascular necrosis (AVN) following hematopoietic stem cell and solid organ transplantation remains unclear. To further explore this question, we conducted a case-control study of patients who underwent bone marrow transplantation (BMT) at the Fred Hutchinson Cancer Research Center. 96 of 1939 long-term survivors transplanted between May 1976 and October 1993 were identified as having AVN. Eight patients were excluded because AVN developed before transplant and one was excluded due to restrictions on reviewing follow-up records. The remaining 87 patients developed AVN a mean of 26.3 +/- 2 months posttransplant and were matched for age, gender, and date of transplant to other BMT recipients. Records were reviewed for corticosteroid and cyclosporine use, pretransplant conditioning with total body irradiation (TBI), and other information including disease for which the transplant was indicated, type of transplant, the occurrence of acute and chronic graft-vs.-host disease, and steroid use prior to transplant. Adjusted odds ratios (ORs) were obtained from conditional logistic regression for 87 matched pairs. Posttransplant steroid use was a risk factor for the occurrence of AVN (adjusted OR, 14.4; 95% CI, 2.8-73.2), with the greatest risk associated with those receiving steroids at the time of diagnosis of AVN (adjusted OR, 31.9; 95% CI, 4.4-248.9). There was no further increasing risk associated with increasing duration of steroid use. Conditioning with TBI was also associated with the occurrence of AVN (adjusted OR, 3.2; 95% CI, 1.1-9.7); however, cyclosporine was not a risk factor for AVN (adjusted OR, 0.5; 95% CI, 0.1-1.9). Our results support the hypothesis that AVN following BMT has a strong association with the administration of corticosteroids. TBI may be an additional risk factor, and cyclosporine does not appear to contribute to an increased incidence of AVN.

Antibodies to steroids from a small human naive IgM library

Human antibodies specific for digoxigenin, estradiol, testosterone and progesterone have been isolated from a small combinatorial IgM repertoire (4 x 10(7)) of single chain antibodies (scFv). The affinities of both the anti-estradiol and antiprogesterone scFv were approximately 10(8) M(-1). Naive IgM genes appeared to be highly represented, since only the heavy chain variable domain of the anti estradiol antibody contained differences to corresponding germline sequences. The light chain variable domain of the progesterone receptor was also identical to a germline sequence, showing that it is possible for completely naive antibodies to bind steroids with affinities comparable to those obtained after a secondary immune response.

Ovarian and hemolymph ecdysteroids in the terrestrial isopod Armadillidium vulgare (Malacostracan Crustacea)

Ovarian and hemolymph ecdysteroids in Armadillidium vulgare were analyzed at four stages of ovarian maturation through the reproductive molt cycle using high-performance liquid chromatography and radioimmunoassay. The major ecdysteroids in the ovaries and hemolymph of A. vulgare were 20-hydroxyecdysone and ecdysone in free and conjugated forms. The concentration of ovarian ecdysteroids reached a maximal level in maturing ovaries during stage D (premolt period) of the molt cycle. At the end of stage D, a high level of ecdysteroids was detected in fully matured ovaries. On the other hand, hemolymph ecdysteroid titers in reproductive females showed a peak during stage D and declined rapidly to a low level at the end of stage D. No appreciable differences in the amounts of hemolymph ecdysteroids and in molecular species of them were apparent in females in reproductive and nonreproductive molt cycles. The amounts of hemolymph ecdysteroids were about fivefold higher in females than those in males. These ecdysteroids may have a role in controlling ovarian development in female A. vulgare.

Reproductive steroids during maturation in a primitive teleost, the Pacific herring (Clupea harengus pallasi)

Concentrations of reproductive steroids were measured in the plasma of captive Pacific herring, Clupea harengus pallasi, (1) prior to ovulation and milt production, (2) during the periovulatory and newly milt-producing period, (3) during a "ripe" holding period after ovulation and during milt production, and (4) before and after spawning. 17alpha,20beta-Dihydroxyprogesterone (17,20beta-P), despite being present only in low concentrations in the unconjugated (free) form (<10 ng/ml), is likely to be the maturation inducing steroid in females and was associated with the initiation of milt production in males since its levels are elevated coincidentally with these events. Glucuronated 17,20beta-P, free 17alpha-hydroxyprogesterone (17-P), and free and glucuronated 3alpha, 17alpha-dihydroxy-5beta-pregnan-20-one (3alpha,17-P-5beta) were present in high concentrations (140-250 ng/ml) in periovulatory females and newly milt-producing males. This steroid pattern suggests that the low levels of 17,20beta-P are due to glucuronation and competitive conversion of its precursor, 17-P, to free and glucuronated 3alpha, 17-P-5beta. Glucuronated testosterone was the principal steroid in preovulatory and premilt-producing fish (200-350 ng/ml), coincident with similar levels of glucuronated 11-ketotestosterone in males. After ovulation females did not spawn synchronously until 2 months later, which may be partially due to reduced environmental cues in the captive situation, while male fish released milt sporadically throughout the ripe holding period. Steroidal indicators of readiness to spawn in females or males were not detected. Rather, levels of all steroids gradually decreased in ripe holding fish (<30 ng/ml) to reach even lower levels (<1 ng/ml) after spawning. We suggest that "runniness" of gametes is a distinctive characteristic of females that are ready to spawn, but that this may result from relaxation of sphincter muscles rather than being an additional maturational step.

The Ku autoantigen: cast in a new light

With his associates at the University of Ottawa, Dr. Robert Haché has demonstrated that the Ku autoantigen, a protein that plays a role in DNA repair and in immunoglobulin gene recombination, also modifies the action of steroid hormones. This finding has potential implications for the treatment of tumours whose growth is influenced by steroid hormones. The researchers suggest that Ku could be involved in the control of gene expression through a mechanism involving protein phosphorylation. They hope that a better understanding of the role Ku plays in many cellular processes may improve our understanding of autoimmune diseases, diseases of immune deficiency and cancer.

Immunoreactivity of endogenous digitalis-like substances in cord blood sera studied with antidigitoxin monoclonal antibodies

The presence of digitoxin-like immunoreactive substances, whose nature is yet unknown, has been demonstrated in the umbilical cord blood. We selected six antidigitoxin monoclonal antibodies (MAb) having different specificity profiles concerning digitoxin analogs and steroid hormones. These antibodies were tested in a digitoxin radioimmunoassay (RIA). With the help of this technique, we measured the concentrations of apparent digitoxin in the cord blood drawn either at birth or in utero from mothers not undergoing any digitalis treatment. In the cord blood of newborns, the concentrations of apparent digitoxin, measured by the two MAbs that have the highest cross-reactions with dehydroepiandrosterone (DHEA) (123A23 and 145A41), were two or three times higher than with the other antibodies. In the fetal cord blood, where the concentration of DHEA is five to seven times lower than that observed at birth, these antibodies revealed a threefold lower concentration of apparent digitoxin than that observed in blood drawn at birth. Furthermore, MAbs that had similar specificities towards digitoxin analogs and steroids showed different measurements of digitoxin-like concentrations. These observations suggest that digitoxin-like immunoreactive compounds detected by the RIA may constitute a group of different molecules, one of which would be the DHEA.

Structural analysis of antibody specificity. Detailed comparison of five Fab'-steroid complexes

Structures of the Fab' fragment of the anti-progesterone antibody DB3 in complex with five cross-reactive steroids (aetiocholanolone, 5 beta-androstane-3,17-dione, 5 alpha-pregnane-20-one-3 beta-ol-hemisuccinate, progesterone-11 alpha-ol-hemisuccinate and progesterone) have been determined by X-ray crystallography to a maximum resolution of 2.7 A. These different steroids compete with progesterone binding with affinities in the nanomolar range despite substantial differences in their three-dimensional structures. Comparison of the unliganded DB3 Fab' and these five steroid-Fab' complexes reveals that all the steroid ligands bind to an "open" conformation of the Fab' as defined by the orientation of the indole side-chain of TrpH100, whereas in the unliganded or "closed" form the binding site is occluded by TrpH100. Small but significant conformational changes take place in the antibody to maximize the physical and chemical complementarity with each ligand. The various cross-reactive ligands are accommodated in the binding site in two distinct orientations. We term these binding modes syn and anti, as they are defined by the orientation of the steroid beta face relative to TrpH50. In all cases, the steroid D ring is inserted into a hydrophobic cavity formed mainly by TrpH50, TyrH97, TrpH100 and PheH100b; a hydrogen bond interaction with AsnH35 to the keto group at position C17 or C20 orients the steroid in the pocket. The AsnH35 hydrogen bond and the interaction with TrpH50 account for the restricted heavy chain response to immunization with progesterone-like steroids derivatized at the 11 alpha position. Cross-reactivity of the antibody with different steroids is explained by alternative binding pockets for the A ring, which generates different ligand orientations in the binding site. This study suggests which factors are most likely to contribute to the observed antibody specificity, such as linker position and the paucity of functional groups on the immunogenic hapten.

Antisteroid immune complexes and vascular thrombosis during steroid hormone therapy

To test an immunological hypothesis proposed to explain the pathogenesis of cerebrovascular thrombosis in steroid users, circulating immune complexes were assayed in the sera from 6 control subjects, 14 ever users of oral contraceptive having developed a neurological ischaemic accident, and 7 patients with the same clinical history during use of other sex steroid not containing ethinylestradiol. Beaumont's ammonium sulfate and polyethylene glycol precipitation methods, together with a specific method of isolation of circulating immune complexes using affinity chromatography on Protein A, were used. Radioactivity from labeled ethinylestradiol added to the sera before precipitation was monitored in the precipitates to detect anti-ethinylestradiol antibodies. There were no significant differences for these parameters in the three groups. However, protein content and 3H-EE activity in the precipitates were equally and dramatically reduced after affinity chromatography in the three groups. These latter results do not support the presence of antibodies against ethinylestradiol in steroid users with cerebrovascular thrombosis. Moreover, our data suggest a lack of specificity of Beaumont's method for the isolation of immune complexes containing anti-ethinylestradiol antibodies.

Type 1 reactions in leprosy, neuritis and steroid therapy: the impact of the human immunodeficiency virus

The incidence of type 1 reactions and neuritis among HIV seronegative and HIV seropositive leprosy patients was investigated. HIV seropositivity was associated with an increased incidence of type 1 reactions among multibacillary (MB) patients, which were observed in 9 of 12 seropositive MB patients and in 8 of 40 HIV seronegative MB patients (P < 0.0005). Similarly, the incidence of neuritis was significantly increased among the HIV seropositive MB patients, of whom 8 developed acute neuritis compared to 3 of the HIV seronegative patients (P < 0.0005). There was no significant difference between the numbers of paucibacillary HIV seropositive and HIV seronegative patients who developed these complications. Both the HIV seronegative and HIV seropositive patients showed a similar response to steroid therapy for the management of acute neuritis.

Covalent coupling of a steroid to microwell plates for use in a competitive enzyme-linked immunosorbent assay

The covalent coupling of a model steroid, 17 alpha-hydroxypregnenolone, to the wells of the microtiter plate, CovaLink NH, for use in a competitive enzyme-linked immunosorbent assay is described. This plate has secondary amino groups bound to its surface. A carboxylated derivative of the steroid was coupled to the amino group to form an amide bond in a single step using a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (10 mM) as coupling reagent in the presence of N-hydroxysuccinimide (1 mM). After carrying out a competitive immune reaction, antibodies bound to immobilized steroids were estimated by means of a second antibody-enzyme conjugate. The non-specific background was reduced with blocking agents which did not interfere with the immune reaction between antibodies and the steroids coupled to the plastic surface. The following two procedures were effective for this purpose: pretreatment of wells with 0.01% Tween 20 solution followed by 0.5% bovine serum albumin in phosphate buffered saline, and addition of 0.01% Tween 20 to the assay buffer. With this method, the preparation of steroid-enzyme conjugates is unnecessary and optimization of conditions for ELISA procedures can be achieved in a simple manner.

Three-dimensional structure of an anti-steroid Fab' and progesterone-Fab' complex

The monoclonal anti-progesterone antibody DB3 binds progesterone with nanomolar affinity (Ka approximately 10(9) M-1), suggesting high specificity. However, DB3 also cross-reacts with similar affinity with a subgroup of structurally distinct, progesterone-like steroids. Crystals of the unliganded Fab' and various steroid-Fab' complexes are isomorphous and belong to the hexagonal space group, P6(4)22, with unit cell dimensions of a = b = 135 A, c = 124 A. Structures of free and progesterone-bound Fab' have been determined by X-ray crystallography at 2.7 A resolution using molecular replacement techniques. Progesterone is bound in a hydrophobic pocket formed mainly by the interaction of three complementarity determining regions L1, H2 and H3. The orientation of the ligand in the binding site was aided by both crystallographic and biochemical analyses of substituted steroids. The indole side-chain of TrpH100 of the DB3 has two different conformations, inter-converting "open" and "closed" forms of the antibody combining site. The TrpH100 indole thus appears to be acting as an antibody-derived surrogate ligand for its own hydrophobic binding pocket. These structures provide the first atomic view of how a steroid interacts with a protein and offer a structural explanation for the restriction of the anti-progesterone response to the VGAM3.8 family of VH genes.

Production of a monoclonal antibody to cortisol: application to a direct enzyme-linked immunosorbent assay of plasma

Cortisol mouse monoclonal antibodies were produced and characterized. Of the four clones studied, supernatant from one clone (A2), compared with other cortisol monoclonal antibodies, showed minimal cross-reactivity to other C21 steroids and was suitable for the direct determination of cortisol in plasma by enzyme-linked immunosorbent assay using a standard 96-well microtiter plate. The enzyme-linked immunosorbent assay uses the immobilized antigen approach, in which cortisol in plasma samples or standards competes with immobilized steroid for antibody-binding sites. After washing, the cortisol antibody bound to the wells of the microtiter plate is detected with antimouse immunoglobulin conjugated to horseradish peroxidase. Following further washing, o-phenylenediamine substrate is added. The enzyme-linked immunosorbent assay is robust and semiautomated. The mean +/- SD recovery from plasma was 97% +/- 6%. Precision studies on three different plasma pools showed mean coefficients of variation of 7.6% and 8.6% for within- and between-assay variation, respectively. The satisfactory performance criteria allow its use in the routine laboratory.

New steroid haptens for radioimmunoassay: synthesis of steroids substituted with thioether or ester linkages at the 2 alpha-position

Haptens with bridge at the 2-position have not yet been explored. Radioimmunoassays with antibodies directed against 2 alpha-alkyl bridged steroid haptens are expected to be highly specific due to greater topographical exposure and similarity in conformation to the native steroid. The 2 alpha-alkyl bridged haptens were synthesized by first adding a cyclopropane ring to 2-methylene-4-en-3-one. Selective opening of the three-membered ring with trimethyl silyl iodide and transformation of the iodo group gave a carbocyclic acid, the desired analog for conjugation with protein.

A mutation in the ligand binding domain of the androgen receptor of human LNCaP cells affects steroid binding characteristics and response to anti-androgens

LNCaP prostate tumor cells contain an abnormal androgen receptor system. Progestagens, estradiol and anti-androgens can compete with androgens for binding to the androgen receptor and can stimulate both cell growth and excretion of prostate specific acid phosphatase. We have discovered in the LNCaP androgen receptor a single point mutation changing the sense of codon 868 (Thr to Ala) in the ligand binding domain. Expression vectors containing the normal or mutated androgen receptor sequence were transfected into COS or Hela cells. Androgens, progestagens, estrogens and anti-androgens bind the mutated androgen receptor protein and activate the expression of an androgen-regulated reporter gene construct (GRE-tk-CAT). The mutation therefore influences both binding and the induction of gene expression by different steroids and antisteroids.

[Antibiotic and specific immunoglobulin G in the treatment of E. coli sepsis in mice previously given steroids]

Experimental E. coli sepsis was constituted in two groups of mice. One of the groups have been immunosuppressed by steroid therapy of ten days (group A) and the other group was normal (group B). Ceftriaxone and Ig G, prepared by vaccinating rabbits with the same strain of E. coli, were used in therapy. The results of the therapy in both were compared. The mortality rate of mice on Ig G therapy was % 70 in group A and % 80 in group B and that on ceftriaxone therapy % 60 and % 50, respectively. The mortality rate was % 30 in both groups with Ig G + ceftriaxone therapy. There wasn't any significance between these. On this research, the treatment of antibiotic together with Ig G decreased the mortality rate. The statistical value of the mortality rate among the treatment groups was not found significant.

Unexpected loss of immunoreactivity of a glucose oxidase-labeled antigen in a steroid enzyme immunoassay system

Glucose oxidase-labeled 11-deoxycortisol was tested for immunoreactivity in an enzyme immunoassay system using a monoclonal antibody. The antigen was labeled by the N-succinimidyl ester method. It was found that the binding affinity of the label to the anti-steroid antibody markedly decreased during storage; the half-life time was ca. 4.5 d.

Production of highly specific polyclonal and monoclonal antibodies using estradiol-3-O-carboxymethyl ether as hapten

The preparation of high affinity and high specificity polyclonal and monoclonal antibodies to estradiol is described. Monoclonal antibodies were derived from BALB/c mice hyperimmunized with estradiol-3-O-carboxymethyl ether conjugated to bovine serum albumin. Spleen cells were hybridized with mouse myeloma cells. Quite a few monoclonal antibodies showed very good affinity for estradiol. Extended immunization and hyperimmunization were essential for producing a greater number of positive clones secreting high affinity antibodies. Binding constants of the antisera and their cross-reactivities with related steroids were calculated. Both polyclonal and monoclonal antibodies showed very high affinity for estradiol exhibiting little or no cross-reactivities with structurally related steroids indicating that this site of linkage is a good choice for discriminating between differences at the 16-17 position in the D-ring. This monoclonal antibody (44.28.6), having negligible cross-reactivity with estriol and estrone, can be used for diagnostic purposes.