Reaction of antibodies to Campylobacter jejuni and cytolethal distending toxin B with tissues and food antigens

BACKGROUND

The bacteria Campylobacter jejuni (C. jejuni) is commonly associated with Guillane-Barré syndrome (GBS) and irritable bowel syndrome (IBS), but studies have also linked it with Miller Fisher syndrome, reactive arthritis and other disorders, some of which are autoimmune. It is possible that C. jejuni and its toxins may be cross-reactive with some human tissues and food antigens, potentially leading to autoimmune responses.

AIM

To measure the immune reactivity of C. jejuni and C. jejuni cytolethal distending toxin (Cdt) antibodies with tissue and food antigens to examine their role in autoimmunities.

METHODS

Using enzyme-linked immunosorbent assay (ELISA) methodology, specific antibodies made against C. jejuni and C. jejuni Cdt were applied to a variety of microwell plates coated with 45 tissues and 180 food antigens. The resulting immunoreactivities were compared to reactions with control wells coated with human serum albumin (HSA) which were used as negative controls and with wells coated with C. jejuni lysate or C. jejuni Cdt which served as positive controls.

RESULTS

At 3 SD above the mean of control wells coated with HSA or 0.41 OD, the mouse monoclonal antibody made against C. jejuni showed moderate to high reactions with zonulin, somatotropin, acetylcholine receptor, β-amyloid and presenilin. This immune reaction was low with an additional 25 tissue antigens including asialoganglioside, and the same antibody did not react at all with another 15 tissue antigens. Examining the reaction between C. jejuni antibody and 180 food antigens, we found insignificant reactions with 163 foods but low to high immune reactions with 17 food antigens. Similarly, we examined the reaction of C. jejuni Cdt with the same tissues and food antigens. The strongest reactions were observed with zonulin, intrinsic factor and somatotropin. The reaction was moderate with 9 different tissue antigens including thyroid peroxidase, and reaction was low with another 10 different antigens, including neuronal antigens. The reaction of C. jejuni Cdt antibody with an additional 23 tissue antigens was insignificant. Regarding the reaction of C. jejuni Cdt antibody with different food antigens, 160 out of 180 foods showed insignificant reactions, while 20 foods showed reactions ranging from low to high.

CONCLUSION

Our findings indicate that C. jejuni and its Cdt may play a role in inflammation and autoimmunities beyond the gut.

Multi-centre phase IV trial to investigate the immunogenicity of a new liquid formulation of recombinant human growth hormone in adults with growth hormone deficiency

PURPOSE

To investigate whether a new liquid formulation of recombinant human growth hormone (r-hGH) induces the production of binding antibodies (BAbs) in adults with congenital or adult-onset growth hormone deficiency (GHD).

METHODS

Men or women aged 19-65 years with adult growth hormone deficiency who were r-hGH-naïve or had stopped treatment ≥ 1 month before screening were treated with between 0.15 and 0.30 mg/day r-hGH liquid formulation for 39 weeks. The primary endpoint was the proportion of patients who developed BAbs at any time. Secondary endpoints were the proportion of patients with BAbs who became positive for neutralising antibodies, the effects on biomarkers of r-hGH exposure, safety, and adherence to treatment downloaded from the easypod™ connect software.

RESULTS

Seventy-eight patients (61.5% men) with mean age 44.5 years (range 21-65) started and 68 (87.2%) completed the 39-week treatment period. 82.1% were treatment naïve; all were negative for BAbs to r-hGH at baseline. The median (interquartile range) duration of treatment [273 (267.0-277.0) days] was consistent with patients receiving the required doses, and mean treatment adherence measured using easypod™ connect was 89.3%. The proportion of patients who developed BAbs was 0% (95% confidence interval 0-4.68%) and biomarker profiles were consistent with exposure to r-hGH. 92.3% of patients reported ≥ 1 adverse event during treatment. Most events were mild or moderate and no new safety concerns were detected.

CONCLUSIONS

The low immunogenicity profile of the liquid formulation was consistent with that for the freeze-dried formulation, and no new safety concerns were reported.

Therapeutic effect of human ghrelin and growth hormone: Attenuation of immunosuppression in septic aged rats

Sepsis is a leading cause of mortality in intensive care units, and is more common in the geriatric population. The control of hyperinflammation has been suggested as a therapeutic approach in sepsis, but to date clinical trials utilizing this strategy have not lead to an effective treatment. In addition to hyperinflammation, patients with sepsis often experience a state of immunosuppression, which serves as an important determinant for increased morbidity and mortality. We previously used aged animals to demonstrate the effectiveness of combined treatment with human ghrelin (Ghr) and human growth hormone (GH) in improving organ injury and survival in septic animals. Here, we hypothesized that combined treatment with Ghr and GH could improve immune function in septic aged animals. Male 24-month-old rats were subjected to cecal ligation and puncture (CLP) for sepsis induction. Human Ghr (80nmol/kg BW) plus GH (50μg/kg BW) or vehicle (normal saline) was administrated subcutaneously at 5h after CLP. The ex vivo production of TNF-α, IL-6 and IL-10 to LPS-stimulation, as well as TNF-α, IL-6, IL-10 and IFN-γ production to anti-CD3/anti-CD28 antibody-stimulation, in splenocytes isolated 20h after CLP, was significantly decreased compared to production of these cytokines in splenocytes from sham animals. The production of cytokines from splenocytes isolated from septic animals that received the combined treatment, however, was significantly higher than from those isolated from vehicle-treated septic animals. Combined treatment prevented the loss of splenic CD4⁺ and CD8⁺ T cells in septic aged rats, and reduced lymphocyte apoptosis. Combined treatment also inhibited an increase in the regulatory T cell (T_reg) population and expression of the immune co-inhibitory molecule PD-1 in the spleens of septic aged rats. In contrast, expression of HLA-DR was increased after combined treatment with Ghr and GH. Based on these findings, we conclude that co-administration of Ghr and GH is a promising therapeutic tool for reversing immunosuppression caused by sepsis in the geriatric population. This article is part of a Special Issue entitled: Immune and Metabolic Alterations in Trauma and Sepsis edited by Dr. Raghavan Raju.

Growth Hormone Antibodies Formation in Patients Treated with Recombinant Human Growth Hormone

Human growth hormone (hGH) is normally produced by acidophilic cells of the anterior lobe of the pituitary gland. Recombinant DNA technology has made it possible to produce rhGH. There have been reports of immunological reactions in patients treated with rhGH. For this reason, it is necessary to check sera of patients for presence of antibody against rhGH. Forty-seven children were treated for up to 6 months with recombinant human growth hormone (rhGH-Novo), 0.1 IU/Kg body weight, subcutaneously, three times weekly. The magnitude of growth response was similar to those expected from clinical experience with pituitary growth hormone. We examined sera for specific antibodies against rhGH by ELISA methods. Four patients developed serum antibodies against growth hormone. The analysis of these four sera by Dot blotting method also showed presence of antibodies against rhGH. In the sera of treated patients, pre-incubated with different concentration of rhGH, specific antibodies were detected by neutralizing assay. This finding was confirmed by ELISA technique. In conclusion, the main concern with anti-GH antibodies could be their ability to neutralize circulating growth hormone and inhibition its growth promoting effect.

Hormonal control of T-cell development in health and disease

The physiology of the thymus, the primary lymphoid organ in which T cells are generated, is controlled by hormones. Data from animal models indicate that several peptide and nonpeptide hormones act pleiotropically within the thymus to modulate the proliferation, differentiation, migration and death by apoptosis of developing thymocytes. For example, growth hormone and prolactin can enhance thymocyte proliferation and migration, whereas glucocorticoids lead to the apoptosis of these developing cells. The thymus undergoes progressive age-dependent atrophy with a loss of cells being generated and exported, therefore, hormone-based therapies are being developed as an alternative strategy to rejuvenate the organ, as well as to augment thymocyte proliferation and the export of mature T cells to peripheral lymphoid organs. Some hormones (such as growth hormone and progonadoliberin-1) are also being used as therapeutic agents to treat immunodeficiency disorders associated with thymic atrophy, such as HIV infection. In this Review, we discuss the accumulating data that shows the thymus gland is under complex and multifaceted hormonal control that affects the process of T-cell development in health and disease.

Acute resistance exercise stimulates sex-specific dimeric immunoreactive growth hormone responses

PURPOSE

We sought to determine if an acute heavy resistance exercise test (AHRET) would elicit sex-specific responses in circulating growth hormone (GH), with untreated serum and serum treated with a reducing agent to break disulfide-bindings between GH dimers.

METHODS

19 untrained participants (nine men and ten women) participated in an acute heavy resistance exercise test using the back squat. Blood samples were drawn before exercise (Pre), immediate post (IP), +15 min (+15), and +30 min (+30) afterwards. Serum samples were chemically reduced using glutathione (GSH). ELISAs were then used to compare immunoreactive GH concentrations in reduced (+GSH) and non-reduced (-GSH) samples. Data were analyzed using a three-way (2 sex × 2 treatment × 4 time) mixed methods ANOVA, with significance set at p ≤ 0.05.

RESULTS

GSH reduction resulted in increased immunoreactive GH concentrations when compared to non-reduced samples at Pre (1.68 ± 0.33 μg/L vs 1.25 ± 0.25 μg/L), IP (7.69 ± 1.08 μg/L vs 5.76 ± 0.80 μg/L), +15 min (4.39 ± 0.58 μg/L vs 3.24 ± 0.43 μg/L), and +30 min (2.35 ± 0.49 μg/L vs 1.45 ± 0.23 μg/L). Also, women demonstrated greater GH responses compared to men, and this was not affected by reduction.

CONCLUSIONS

Heavy resistance exercise increases immunoreactive GH dimer concentrations in men and women, with larger increases in women and more sustained response in men. The physiological significance of a sexually dimorphic GH response adds to the growing literature on aggregate GH and may be explained by differences in sex hormones and the structure of the GH cell network.

Generation and characterization of nanobodies against rhGH expressed as sfGFP fusion protein

Growth hormone (GH) deficiencies are diagnosed in most children with short stature and treated with a long course of administrating expensive and daily doses of recombinant human GH (rhGH or Somatropin®). This work describes for the first time the production of several GH specific nanobodies with great potential in the field of GH production and detection. Nanobodies are the smallest intact antigen binders derived from heavy chain-only antibodies (HCAbs) of camelids. They are very stable, highly soluble and are produced as recombinant proteins in Escherichiacoli at an affordable cost for various biotechnological applications. To increase its solubility and immunogenicity, GH was produced as fusion with superfolder green fluorescent protein (sfGFP) and was used in this form to successfully immunize an adult camel. The active involvement of HCAbs in the specific camel immune response encouraged the preparation of large nanobody "immune" library. Phage display biopanning of this library against GH resulted in the isolation of five interesting and different nanobodies, referred to as NbGH01, 02, 03, 04 and 06. All nanobodies were able to recognize GH in its fusion and free formats and the detection sensitivity ranged from 0.5 to 10 ng/ml in sandwich ELISA. Pure rhGH was successfully purified by affinity chromatography, using immobilized NbGH06, from the cleavage reaction of fusion proteins with the tobaccos etch virus (TEV) protease. These specific molecular binders, especially NbGH06, provide valuable tools for rhGH diagnostic as well as for production purposes.

Late primary autoimmune hypothyroidism in a patient with postdelivery autoimmune hypopituitarism associated with antibodies to growth hormone and prolactin-secreting cells

BACKGROUND

Pituitary and thyroid autoimmunity can be triggered by pregnancy. We report the first association of combined growth hormone (GH) and prolactin secretion deficiency due to autoimmune damage to GH- and prolactin-secreting cells in a patient with postdelivery lactation failure, presenting subsequently with primary autoimmune hypothyroidism.

PATIENT FINDINGS

A 34-year-old woman presented with lactation failure following the delivery of her first child. She had a family history of hypothyroidism without a history of pituitary dysfunction. Physical examination did not show any abnormal findings. Laboratory investigations showed normal gonadotropin levels after the restoration of normal menstrual cycles following pregnancy, normal basal and stimulated cortisol levels, but an impaired GH response to insulin-induced hypoglycemia, and low basal prolactin and insulin-like growth factor-1 concentrations. Thyroid function was normal when initially investigated three months after delivery, but five months later, marked primary hypothyroidism (thyrotropin levels >100 mIU/L) occurred. Immunological investigation revealed the presence of antipituitary antibodies, identified by double immunofluorescence and targeting GH- and prolactin-secreting cells. Antithyroid antibodies, in the normal range three months postpartum, became significantly elevated when the hypothyroidism appeared. Autoimmune hypophysitis is responsible for selective or multiple pituitary-hormone deficiencies, sometimes involving thyrotropin secretion and causing secondary hypothyroidism, but usually associated with hyperprolactinemia. To our knowledge, this is the first observation of autoimmune hypopituitarism involving deficient growth hormone and prolactin secretion in a patient with lactation failure after delivery, subsequently followed by severe primary autoimmune hypothyroidism, thus falling into an unusual constellation of autoimmune polyendocrine syndrome type 3.

CONCLUSIONS

Considering the well-known relationship between pregnancy and autoimmunity, an early postdelivery immunological and functional investigation in women presenting with disorders of lactation may be useful to detect potential pituitary and thyroid dysfunction even at a subclinical stage.

Development of antibodies against growth hormone (GH) during rhGH therapy in a girl with idiopathic GH deficiency: a case report

A 12.5-year-old Italian girl was referred to our institute for progressive growth failure from the age of 6 years, with a height of 128.2 cm (-3.37 SDS) and a bone age of 9 years. Endocrinological evaluation revealed a partial growth hormone deficiency (GHD) and GH therapy was started at a dosage of 0.25 mg/kg/week. During the first 3 years, she showed an increase in growth rate and experienced pubertal development onset. Then a poor growth rate (2 cm/year=0.43 SDS) was observed, notwithstanding an increase in GH dosage (0.35 mg/kg/week) and good compliance. We found a positive anti-GH antibody titre (1:1850, cutoff 1/100), confirmed 6 months later (1:2035); the antibodies had low binding capacity (0.63 μg/mL) and were only partially capable of inhibiting the GH effect. However, GH treatment was discontinued, and after 3 months the antibody titre decreased (1:950). In conclusion, we suggest evaluation of anti-GH antibodies in GH-treated idiopathic GHD children in whom growth response decreases after some years of therapy.

Growth hormone and proopiomelanocortin are targeted by autoantibodies in a patient with biopsy-proven IgG4-related hypophysitis

Hypophysitis is a chronic inflammation of the pituitary gland often caused by autoimmunity. Among the autoimmune diseases it is one of the few where the autoantigens remain to be identified. The goal of the paper was to characterize the antigenic profile in a previously reported patient with IgG4-related hypophysitis. Immunofluorescence and immunoblotting were performed to detect antibodies to human pituitary proteins. The proteins recognized by western blotting were then submitted to mass spectrometry for sequencing. The patient's autoantibodies recognized two unique bands around 40 and 30 kDa on immunoblotting. Sequencing revealed one peptide from proopiomelanocortin in the 40 kDa band and four peptides from growth hormone in the 30 kDa band. This work represents the first antigenic profile in IgG4-related hypophysitis, and the first recognition of proopiomelanocortin as a possible pituitary autoantigen. In addition, the work supports previous suggestions of growth hormone as a pituitary autoantigen. Further studies are needed to prove the pathogenicity and diagnostic utility of these two pituitary proteins.

Genetics of GHRH, GHRH-receptor, GH and GH-receptor: its impact on pharmacogenetics

When a child is not following the normal, predicted growth curve, an evaluation for underlying illnesses and central nervous system abnormalities is required and, appropriate consideration should be given to genetic defects causing GH deficiency (GHD). Because Insulin-like-Growth Factor-I (IGF-I) plays a pivotal role, GHD could also be considered as a form of IGF-I deficiency (IGFD). Although IGFD can develop at any level of the GHRH-GH-IGF axis, a differentiation should be made between GHD (absent to low GH in circulation) and IGFD (normal to high GH in circulation). The main focus of this review is on the GH-gene, the various gene alterations and their possible impact on the pituitary gland. However, although transcription factors regulating the pituitary gland development may cause multiple pituitary hormone deficiency they may present initially as GHD. These defects are discussed in various different chapters within this book, whereas, the impact of alterations of the GHRH-, GHRH-receptor- --as well as the GH-receptor (GHR) gene--will be discussed here.

Specific monoclonal antibodies and ultrasensitive immunoassays for 20K and 22K human growth hormone

OBJECTIVE

Generation of specific monoclonal antibodies (mAbs) against 20K and 22K human growth hormone (hGH) and development of ultrasensitive immunoassays to quantify 20K and 22K hGH.

DESIGN

Mice were immunized with recombinant 20K or 22K hGH. Hybridoma cells were screened with biotinylated 20K and 22K hGH simultaneously. The specific mAbs were further characterized and used for construction of isoform specific assays. The ultrasensitive chemiluminescent assays were developed with AMDEX streptavidin-HRP and a sensitive substrate.

RESULTS

The 20K hGH specific mAb 1G12 and the 22K hGH specific mAb 5E1 showed less than 0.1% cross-reactivity to 22K or 20K hGH by competitive binding assay, respectively. Western blot analysis also confirmed the specificity of mAb 1G12 and mAb 5E1. Using mAb 1G12 and mAb 5E1, 20K and 22K specific assays with working range of 2-2000 pg/mL were constructed. The 22K hGH concentrations in 103 serum samples from different healthy subjects in the basal GH state were 343.7+/-421.5 pg/mL (18.6-1820 pg/mL). The 20K hGH concentrations were 30.7+/-37.5 pg/mL (2.4-205pg/mL). The ratios of 20K to 20K plus 22K hGH were 9.8+/-4.4% (3.3-28.3%). Both 22K hGH and 20K hGH concentrations in women (465.9+/-476.3 pg/mL and 43.7+/-46.1 pg/mL, n=47) were significantly higher than those (241.1+/-337.0 pg/mL and 20K hGH 19.8+/-23.0 pg/mL, n=56, P<0.01) in men. However, there was no difference in the proportion of 20K to 20K plus 22K between men and women (P>0.05). The strong correlation between 20K and 22K hGH (R=0.914, P<0.01) indicated the constant proportion between 20K and 22K hGH in the basal GH state of healthy subjects.

CONCLUSIONS

Specific monoclonal antibodies and ultrasensitive chemiluminescent immunoassays for 20K and 22K hGH were generated. The ultrasensitive immunoassays are essential for the determination of 20K and 22K hGH in the basal GH state. This universal ultrasensitive immunoassay form can be adapted to other immunoassays for broad application.

Effects of recombinant human growth hormone (rhGH) replacement therapy on detailed immunologic parameters in somatotropine--deficient paediatrics patients prior and after 6 months of rhGH treatment

OBJECTIVE

This study aims at assessing how recombinant human growth hormone treatment of children and young people suffering from isolated growth hormone deficiency affects some selected parameters of the immune system: a percentage of lymphocytes, granulocytes, monocytes, concentrations of A, G, and M immunoglobulins, a percentage of T lymphocytes divided into subpopulations CD4 and CD8, a percentage of NK and B lymphocytes, and phagocytic activity of granulocytes and monocytes.

MATERIALS AND METHODS

The study comprised 30 children and young people aged 4.2-18 years with isolated growth hormone deficiency both prior to and 6 months after rhGH (recombinant human growth hormone) treatment with a dose of 0.093 IU/kg every 24 hr. The control group comprised 25 healthy children with normal height in the respective age bracket. Labelling was conducted by flow cytometry FACS manufactured by Becton-Dickinson using both labelled antibodies and PHAGOTEST® commercial kit (Orpegen). Concentrations of A, G and M immunoglobulins in blood serum were assessed by means of immunoturbidimetric method using COBAS (manufactured by Roche).

RESULTS

The lowest percentage of active granulocytes in PHAGOTEST® was found in a group examined prior to treatment compared to the control group. The percentage increased after 6 months of rhGH treatment to values comparable with the control group. Although mean concentrations of IgM and IgA after 6 months of treatment with rhGH significantly decreased in comparison with those determined prior to treatment, they still remained within the baseline norm. No significant differences in the phagocytic activity of monocytes, IgG concentration, % of NK lymphocytes, T lymphocytes divided into CD4 and CD8 lymphocytes, B lymphocytes and CD4/CD8 lymphocytic index were found. None of the patients exhibited any clinical symptoms of immune disorders.

CONCLUSION

rhGH treatment of patients with isolated growth hormone deficiency can have positive influence on the phagocytic activity of scavenger cells, mainly granulocytes, which in children with isolated growth hormone deficiency seems to be lower than in their health peers. Growth hormone treatment of children with isolated growth hormone deficiency does not significantly affect the activity of the immune system expressed by the phagocytic activity of monocytes, the percentage of B, T and NK lymphocytes and IgG concentration in blood serum.

TLR7 stimulation augments T effector-mediated rejection of skin expressing neo-self antigen in keratinocytes

Immunotherapy generally fails to induce tumour regression in spontaneously arising tumours. Failure is attributed to both tumour-related factors and an ineffective immune response. As a model of tumour immunotherapy, without the confounding effects of potential tumour-determined mechanisms of immune evasion, we studied the requirements for rejection of skin grafts expressing a neo-self antigen in somatic cells and not in antigen-presenting cells. When antigen expression was restricted to somatic cells, both CD4(+) and CD8(+) effector cells were required for graft rejection. Although freshly placed grafts were spontaneously rejected, healed grafts established under the cover of T cell depletion were not rejected even after T cell numbers recovered to a level where freshly placed grafts on the same animal were rejected, suggesting that healed skin grafts expressing a neo-self antigen only in somatic cells could not be rejected by primed recipients with functional effector T cells. Local TLR7 ligation induced inflammatory responses and rejection of healed grafts exposed to the TLR agonist but did not induce rejection of untreated healed grafts on the same animal. Thus, local pro-inflammatory signalling via TLR7 can promote effector T cell function against skin cells displaying their nominal antigen.

[Prospective study of early application of immune-enhanced enteral nutrition and recombined human growth hormone on patients with gastric neoplasms after total gastrectomy]

OBJECTIVE

To explore the effect of immune-enhanced enteral nutrition (IEN) together with recombined human growth hormone (rhGH) on patients after total gastrectomy.

METHODS

Forty-eight patients after total gastrectomy were randomly divided into EN group (n=16), IEN group (n=16) and IEN+ rhGH(n=16) group. Nitrogen balance, nutritional status, immune function and lassitude degree were compared among 3 groups.

RESULTS

IEN+rhGH group had better efficacy as compared to EN and IEN group in improving postoperative nutritional status, immune function, nitrogen balance and lassitude degree, and recovered to normal level after 7 days. All the indexes of IEN+rhGH group except CD8 were improved significantly on the 10th day after operation as compared to those of EN group[total protein(66.8 +/- 2.0)g/L vs (65.8 +/- 0.9)g/L, CD3(66.1 +/- 6.3)% vs (60.5 +/- 5.6)%, Christensen score (4.6 +/- 0.9) vs (6.3 +/- 0.9), all P<0.05].

CONCLUSION

Early application of IEN combined with rhGH plays an effective role in improving protein metabolism and immune function for patients after total gastrectomy in short period.

Properties of cryptic epitopes and their corresponding antibodies as indicated by the study of human and ovine growth hormones

Antibodies (Ab) directed to hidden antigenic determinants (cryptotopes) are undesirable because they are not neutralizing. Additionally, we have previously demonstrated a close association between the extent of Ab to cryptic determinants and the expression of autoantibodies (autoAb) under some experimental conditions. Thus, the first objective of this work was to establish the physicochemical characteristics of Ab to cryptotopes and the second one was to examine the structural features of cryptic epitopes themselves. Using human and ovine growth hormones (hGH and oGH) as antigenic models and competition ELISA under different conditions of temperature, pH or ionic strength, we did not find any difference between the binding properties of anti-cryptic epitope antibodies (Ab) and anti-native epitope Ab. Then, using synthetic peptides and tryptic digests and direct and competition ELISAs we studied the structures of cryptic hGH and oGH epitopes. Isolated peptides either in solution or adsorbed on microplates failed to react. Partially digested hGH was recognized only when insolubilized on microplates, and anti-oGH Ab only reacted with a large fragment of the hormone either in solution or insolubilized. These results indicate that, at least in the case of hGH and oGH, cryptic epitopes are not simple linear sequences, as commonly referred without any evidence, but new exposed conformational structures different from those found in the native antigen.

Co-expression of interleukin-6 and human growth hormone in apparently normal prostate biopsies that ultimately progress to prostate cancer using low pH, high temperature antigen retrieval

Prostate cancer is the most common cancer in American men and the second leading cause of cancer deaths in this group. Both growth hormone (GH) and the inflammatory cytokine interleukin 6 (IL-6) have been implicated in prostate cancer progression. Studies in other systems have shown that an increase in GH results in an increase in IL-6 also. The current study demonstrated a parallel spatial and temporal expression of GH and IL-6 in cells in prostate cancer glandular acina cells. This study cannot determine if this expression is coincidental or causative, but it seems likely that the increase in GH could induce the expression of IL-6, since this is the case in other tissues. Optimal labelling for IL-6 in our study was achieved with low pH, high temperature antigen retrieval.

Effects of central infusion and immunoneutralization of growth hormone on the timing of puberty and plasma leptin levels in the female rat

Growth hormone (GH) levels increase during puberty though its role in puberty onset is still unclear. An interaction is suggested between GH and leptin, as triggering factor of puberty. To evaluate the role of GH on the timing of puberty and its relation with leptin, we centrally administered recombinant human GH (rhGH; 1 microg/day) to normally fed or food-restricted (FR) prepubertal female rats, and monitored time of vaginal opening (VO). Median time of VO was equally postponed in FR animals and in normally fed rhGH-infused rats: median time of VO was respectively 35 and 34 vs. 27 d. Central infusion of rhGH in FR rats partially restored the delay in VO. Plasma leptin levels were increased in rhGH-infused animals, normally fed or FR. Centrally infused anti-rat GH (0.6 microg/day) did not affect plasma leptin levels, but advanced median time of VO (25 vs. 28 d) in pair-fed female rats but not in ad lib-fed animals. The effects of the centrally infused compounds appear to depend on the dietary regime imposed on the prepubertal animals. Furthermore, plasma leptin levels show no direct or predictive relation to the time of VO. The data indicate an involvement of GH in puberty onset, but do not explain the mechanism employed.

Effects of growth hormone (GH) and insulin-like growth factor-I therapy in patients with gene defects in the GH axis

We report on four patients (3 F) who were diagnosed as having either a 6.7 kb GH1 gene deletion, a GH1 signalling peptide mutation, or a GH receptor mutation, with particular regard to treatment modalities (GH, rhIGF-I) and final height. Patients with GH1 gene defects developed anti-GH antibodies (GH-Ab) following GH treatment. Surprisingly, growth response to GH was unrestricted in one girl, who reached a final height within her target height range, whereas her cousin with the identical genetic defect responded far less favourably. Variability in the growth inhibiting potency of GH-Ab may therefore depend on genetic disposition, specific epitopes, or induction of immunological tolerance. Growth response during rhIGF-I treatment carried out in three of the patients was moderate, but pubertal development and bone age acceleration occurred in the two patients treated at pubertal age. GH resistance, either caused by GH-Ab or GH receptor mutations, is still difficult to treat and results in a heterogeneous outcome.

Dose dependency of the serum bio/immuno GH ratio in children during pharmacological secretion tests

Dissociation between GH bioactivity (bio-GH) and GH immunoactivity (immuno-GH) is due to the heterogeneity of the molecule: the measurements do not always provide reliable information on the bio-GH. We studied the ratio of bio-GH and immuno-GH during pharmacological secretion tests in 211 sera to study the concentration-response curve of the assay (C1), 16 samples of normally growing subjects with idiopathic short stature (C2), 13 samples from patients with GH deficiency (GHD1) and 6 samples of 3 patients with GHD and normal provocative tests (GHD2). GH bioactivity was determined by the Nb2 cell proliferation assay (bio-GH) and immuno-GH by a time-resolved immunofluorometric assay (IFMA) (immuno-GH). A non-linear negative relationship between the serum bio-GH/immuno-GH ratio and serum immuno-GH was observed in C1. In log-log plotting representation, two cut-off lines were drawn: a vertical cut-off line separating above-below cut-off serum peak immuno-GH values in provocative tests, and a diagonal cut-off line separating normal-abnormal serum bio-GH/immunoGH ratio; four areas were defined. GHD1 had normal ratios, but below cut-off peak immuno-GH responses. P2 and P3 of Group GHD2 had abnormal ratios in samples with low serum immuno-GH but only P2 had autosomal dominant mutation. P1 had the same autosomal dominant isolated GHD as P2 but a low normal ratio. Our data underline the importance of relatively low serum GH concentrations in mediating GH biological actions. An abnormal serum bio-GH/immuno-GH ratio might explain certain cases of GHD and might be useful in detecting abnormal circulating isoforms of GH in patients with growth failure.

Immunogenicity of recombinant human proteins: causes and consequences

Antibodies develop to varying degrees during treatment with human proteins, including insulin, growth hormone, granulocyte-macrophage colony-stimulating factor, factor VIII, erythropoietin, and interferons. These antibodies may reduce the clinical efficacy of these agents by blocking or neutralizing their biologic activity and may have other biologic effects. For example, antibodies develop in 20 % to 40% of patients with severe hemophilia treated with human factor VIII; the presence of these antibodies can result in tolerance to the clotting effects of this agent. Similarly, a proportion of patients treated with interferon alpha develop antibodies, which inhibit its therapeutic effects. Therefore, it is important to test for neutralizing antibodies during treatment with these agents, particularly in patients who are unresponsive to treatment or have breakthrough disease. This article reviews the incidence and clinical impact of antibodies that develop in response to some of the commonly used protein therapeutic agents.

Frequent appearance of autoantibodies against prohormone convertase 1/3 and neuroendocrine protein 7B2 in patients with nonfunctioning pituitary macroadenoma

Among pituitary disorders having mass effect of the pituitary gland, nonfunctioning pituitary macroadenoma and lymphocytic hypophysitis are difficult to differentiate without histological examination. In order to efficiently distinguish lymphocytic hypophysitis and pituitary tumors, we studied the presence of autoantibodies against prohormone-processing enzymes, prohormone convertase (PC) 1/3, PC2, carboxypeptidase E (CPE), and PC2 regulatory protein, 7B2, by radioligand assay using recombinant human 35S-labeled protein in patients with clinically nonfunctioning pituitary macroadenoma, lymphocytic hypophysitis, and other pituitary diseases. The indexes for anti-PC1/3 antibodies (Ab) were significantly higher in patients with nonfunctioning pituitary macroadenoma than in patients with lymphocytic hypophysitis. Patients positive for either anti-PC1/3 or anti-7B2 Ab were significantly frequent among patients with nonfunctioning pituitary macroadenoma than in other pituitary diseases and healthy controls. None of the patients was positive for anti-PC2 Ab or anti-CPE Ab. These results suggest that autoantibodies against PC1/3 and 7B2 are novel tumor-associated autoantibodies and can be helpful in the diagnosis of clinically nonfunctioning pituitary macroadenoma.

Effects of housing on the thymic deficiency in dwarf mice and its reversal by growth hormone administration

Initial studies on T cell development in the Snell Dwarf (dw/dw) strain of mice, which are deficient in the production of anterior pituitary hormones, have been interpreted to indicate a clear dependence of T cell development on endocrine system-derived factors. However, normal thymopoiesis in this strain has also been reported. The aim of the present study was to reconcile these contradictory data in order to define the role of anterior pituitary hormones in the thymus. The results indicated that if female dw/dw mice are housed together with their normal-sized littermates, thymic cellularity and the frequency of CD4(+)CD8(+) thymocytes are markedly reduced. However, administration of growth hormone could reverse these decreases seen in the double-positive T progenitor cells. Taken together, the data indicate that stress is the unifying parameter that can explain the disparate dw/dw mouse literature and suggest that endocrine effects on the T cell development can best be understood by interpreting the literature in this context.

The functional binding epitope of a high affinity variant of human growth hormone mapped by shotgun alanine-scanning mutagenesis: insights into the mechanisms responsible for improved affinity

A high-affinity variant of human growth hormone (hGH(v)) contains 15 mutations within site 1 and binds to the hGH receptor (hGHR) approximately 400-fold tighter than does wild-type (wt) hGH (hGH(wt)). We used shotgun scanning combinatorial mutagenesis to dissect the energetic contributions of individual residues within the hGH(v) binding epitope and placed them in context with previously determined structural information. In all, the effects of alanine substitutions were determined for 35 hGH(v) residues that are directly contained in or closely border the binding interface. We found that the distribution of binding energy in the functional epitope of hGH(v) differs significantly from that of hGH(wt). The residues that contributed the majority of the binding energy in the wt interaction (the so-called binding "hot spot") remain important, but their contributions are attenuated in the hGH(v) interaction, and additional binding energy is acquired from residues on the periphery of the original hotspot. Many interactions that inhibited the binding of hGH(wt) are replaced by interactions that make positive contributions to the binding of hGH(v). These changes produce an expanded and diffused hot spot in which improved affinity results from numerous small contributions distributed broadly over the interface. The mutagenesis results are consistent with previous structural studies, which revealed widespread structural differences between the wt and variant hormone-receptor interfaces. Thus, it appears that the improved binding affinity of hGH(v) site 1 was not achieved through minor adjustments to the wt interface, but rather, results from a wholesale reconfiguration of many of the original binding elements.

The use of an animal immunogenicity model in the development of Protropin somatrem (methionyl human growth hormone)

The clinical development of methionyl human growth hormone, with particular emphasis on immunogenicity and the effects of antibody development, are summarized. In an animal model in rhesus monkeys, the immunogenicity of dinical preparations was reduced by the inclusion of additional purification steps in the manufacturing process. The immunogenic response in patients was also decreased by these improvements. No safety consequences related to antibody formation were observed and the occurrence of growth attenuation due to antibodies was found to be extremely low (<0.1%). The data suggest that the immunogenicity was not due to the N-terminal methionine or E. coli protein impurities: rather it was probably caused by small amounts of growth hormone with subtle structural alterations whose nature remains unknown.

Effects of various adjuvants and a viral infection on the antibody specificity toward native or cryptic epitopes of a protein antigen

An immunization protocol that induces antibodies (Abs) directed to cryptic epitopes of a protein antigen (Ag) reduces the efficacy of vaccines that ideally should induce Abs against native epitopes. We have shown earlier that viral infections concomitant with immunization against a protein tend to shift the Ab specificity toward cryptic epitopes and tend to induce the production of autoantibodies (autoAbs). Here, we show the effects of three adjuvants on the Ab specificity in the absence or presence of a viral infection (lactate dehydrogenase-elevating virus or LDV), with human growth hormone (hGH) being, as before, the protein Ag. Pathogen-free CBA/Ht and BALB/c mice were immunized with hGH in the presence of complete Freund's adjuvant (CFA), monophosphoryl lipid A (MPL) or alum, with the animals being either infected with LDV or not infected with LDV. Conventional and competition enzyme-linked immunosorbent assays (ELISAs) indicated that in noninfected mice, CFA induced higher titres of anti-hGH Ab than did MPL or alum, with the Ab being almost totally directed to cryptic hGH epitopes. Strikingly, CFA plus LDV infection in CBA/Ht mice shifted the specificity of the anti-hGH Ab toward native epitopes, whereas the virus decreased the Ab titre when MPL or alum was used. Our Western blot results showed that 70% of mice immunized with hGH in the presence of any adjuvant produced autoAbs against a variety of tissue Ags. The amount of autoAb and the concentration of Ab to hGH cryptic epitopes did correlate, suggesting a relationship between both kinds of Ab. Significant differences were observed in the various effects of adjuvants and the viral infection between the two mouse strains used in this work.

Detection of autoantibodies against the pituitary-specific proteins in patients with lymphocytic hypophysitis

OBJECTIVE

Several reports have described antipituitary antibodies by immunofluorescent or immunoblotting methods in patients with lymphocytic hypophysitis. However, with the exception of the pituitary hormones, individual antigens specific for the pituitary gland have not been studied. To understand the pathogenesis of lymphocytic hypophysitis and to diagnose this disease efficiently, we studied the presence of autoantibodies against three pituitary-specific proteins, GH and two novel pituitary-specific proteins, namely, pituitary gland specific factor 1a (PGSF1a) and PGSF2.

DESIGN

Seventeen patients with lymphocytic hypophysitis, all of whom had pituitary enlargement (5 with lymphocytic adenohypophysitis and 12 with lymphocytic infundibuloneurohypophysitis, including 3 of the latter group proven by biopsy), and 14 patients with hypopituitarism without pituitary enlargement (10 with isolated ACTH deficiency and 4 with idiopathic TSH deficiency) were studied, and compared with 11 patients with non-functioning pituitary macroadenoma, 31 patients with other autoimmune diseases, and 36 healthy controls.

METHODS

The presence of each antibody was studied by radioligand assay using recombinant human (35)S-labeled protein.

RESULTS

Three (18%) patients with lymphocytic hypophysitis having pituitary enlargement, five (36%) patients with hypopituitarism without pituitary enlargement and three (9.7%) patients with other autoimmune diseases were positive for one or more of the antibodies studied.

CONCLUSIONS

Anti-human GH, anti-PGSF1a, and anti-PGSF2 antibodies were detected in patients with lymphocytic hypophysitis and other hypopituitarism, but were not detected in patients with non-functioning pituitary macroadenoma. Detection of these antibodies may be useful for the diagnosis of lymphocytic hypophysitis.

Antibodies to pituitary surface antigens during various pituitary disease states

Autoantibodies to cell surface antigens of human somatotropinoma (ASAS), human prolactinoma (ASAP) and rat adenohypophysis (ASARA) were assayed in the serum of patients with pituitary diseases associated with GH deficiency (GHD), such as pituitary dwarfism and primary empty sella syndrome (ESS), and in the serum of patients with hyperprolactinaemia of different etiologies: idiopathic hyperprolactinaemia, prolactinoma and ESS. The investigation was carried out with a cellular variant of an ELISA. Among children with GHD, the highest percentage of antibody-positive patients was found in the group with idiopathic isolated GHD (89% of ASAS(+) patients and 30% of ASARA(+) patients vs 33.3% and 0% respectively in the group with idiopathic combined pituitary hormone deficiency, and 33.3% and 9% in patients with pituitary hypoplasia associated with isolated GHD or combined pituitary hormone deficiency). Among hyperprolactinaemic patients, the highest ASAP and ASARA frequency was observed in patients with idiopathic hyperprolactinaemia (67.7% and 41.9% respectively) where it was twice as high as in the group of patients with prolactinoma. The proportion of ASAS(+) and ASARA(+) did not differ significantly between the groups of patients with ess with or without GHD. Similarly, there was no significant difference between the number of ESS ASAP(+) and ASARA(+) patients with or without hyperprolactinaemia. The data obtained suggested that autoimmune disorders may be primary, and responsible, at least in part, for pituitary dysfunction in the cases of idiopathic isolated GHD and idiopathic hyperprolactinaemia. At the same time, the autoimmune disorders in the patients with prolactinoma or ESS are probably secondary to the organic pituitary lesion and their significance in the development of the pituitary dysfunction is obscure.

Resumption of growth after methionyl-free human growth hormone therapy in a patient with neutralizing antibodies to methionyl human growth hormone

A 16-5/12 year-old male was diagnosed with classical growth hormone (GH) deficiency at the age of 8-6/12 years and was treated with recombinant methionyl human growth hormone (m-hGH). Height increased from 104.0 cm to 107.4 cm over the first 6 months. After that, for 1 year, he demonstrated poor growth velocity which was found to be secondary to a high titer of GH antibodies with GH binding capacity >2 mg/l. After a 7-month washout period during which no GH was given, at age 11 years he was placed on recombinant methionyl-free human growth hormone (met-free hGH). His height increased 14.9 cm in 11 months (annualized growth rate of 16.2 cm/year). This report illustrates that evaluation of growth failure during GH therapy should include measurement of anti-GH antibodies so that an appropriate alteration of GH therapy can be made if indicated.

The thymus gland: a target organ for growth hormone

Increasing evidence has placed hormones and neuropeptides among potent immunomodulators, in both health and disease. Herein, we focus on the effects of growth hormone (GH) upon the thymus. Exogenous GH enhances thymic microenvironmental cell-derived secretory products such as cytokines and thymic hormones. Moreover, GH increases thymic epithelial cell (TEC) proliferation in vitro, and exhibits a synergistic effect with anti-CD3 in stimulating thymocyte proliferation, which is in keeping with the data showing that transgenic mice overexpressing GH or GH-releasing hormone exhibit overgrowth of the thymus. GH also influences thymocyte traffic: it increases human T-cell progenitor engraftment into the thymus; augments TEC/thymocyte adhesion and the traffic of thymocytes in the lymphoepithelial complexes, the thymic nurse cells; modulates in vivo the homing of recent thymic emigrants, enhancing the numbers of fluroscein isothiocyanate (FITC)+ cells in the lymph nodes and diminishing them in the spleen. In keeping with the effects of GH upon thymic cells is the detection of GH receptors in both TEC and thymocytes. Additionally, data indicate that insulin-like growth factor (IGF)-1 is involved in several effects of GH in the thymus, including the modulation of thymulin secretion, TEC proliferation as well as thymocyte/TEC adhesion. This is in keeping with the demonstration of IGF-1 production and expression of IGF-1 by TEC and thymocytes. Also, it should be envisioned as an intrathymic circuitry, involving not only IGF-1, but also GH itself, as intrathymic GH expression is seen both in TEC and in thymocytes, and that thymocyte-derived GH could enhance thymocyte proliferation. Finally, the possibility that GH improve thymic functions, including thymocyte proliferation and migration, places this molecule as a potential therapeutic adjuvant in immunodeficiency conditions associated with thymocyte decrease and loss of peripheral T cells.

Systemically administered human growth hormone improves initial implant stability: an experimental study in the rabbit

PURPOSE

This study was an investigation to determine whether human growth hormone (hGH) continuously administered to rabbits may improve implant integration in bone.

MATERIALS AND METHODS

Thirty-two commercially pure titanium (c.p. Ti) implants were inserted in the tibiae of 16 rabbits. Human growth hormone (0.3 U/kg/d) or sodium chloride (NaCl) was administered by subcutaneous pumps. Insulin-like growth factor-1 (IGF-1) levels in blood were measured. Two biomechanical tests were performed: (1) every second week resonance frequency analysis (RFA) was used to investigate implant stability or stiffness at the interface and, after 8 weeks of follow-up, (2) removal torque (a measure of implant integration and stability) was registered. Further evaluation was performed by dual energy x-ray analysis (DEXA), to evaluate bone mineral density, and histomorphometric analysis of tissue-to-implant integration on undecalcified cut and ground sections.

RESULTS

A difference in implant stability was detected with the RFA technique after 2 weeks and 8 weeks in favor of the hGH-treated rabbits. No significant differences were detected with removal torque, DEXA, and histomorphometric measurements. The blood test demonstrated antibody development in the rabbits treated with hGH after 4 weeks.

CONCLUSION

Growth hormone has an initial beneficial effect on implant integration; however, owing to rapid antibody formation, this study did not demonstrate whether this effect remains in the long term.

[The immunogenicity and effect of domestic recombinant human growth hormone: serum GH-antibody determination and evaluation]

OBJECTIVE

To investigate the immunogenicity of a domestic recombinant human growth hormone (rhGH) preparation and assess its influence on the growth-promoting effect.

METHODS

We developed a specific and sensitive radioimmuno-precipitation assay to determine the anti-hGH-antibody (GH-Ab) in serum of GH-deficient (GHD) children treated with rhGH preparation. The study included 61 GHD children (49 boys and 12 girls) who were treated with daily subcutaneous injections of rhGH (0.1 IU/Kg) before sleep for six months. The patients' height, growth velocity and height standard deviation score were measured prior to and after treatment. The binding ratio with 125I-hGH and titer of GH-Abs were measured by radioimmuno-precipitation assay; the binding capacity and affinity (Ka) were analyzed by competitive RIA and Scatchard plot method.

RESULTS

Three months after rhGH therapy, serum GH-Abs were detected in 29 patients (48%), and their GH-Abs were persistently positive till the end of the trial. Serum GH-Ab was not detectable in the other 32 patients (52%) during treatment. The GH-Abs positive samples, according to the 125I-hGH binding ratio (B/T%), were divided into the weakly positive (B/T < 10%, n = 20) and strong positive (B/T > 15%, n = 9) groups; their binding capacity, affinity (Ka) and titer were (0.1-4.8) pmol/L, (1.7 x 10(7)-6.5 x 10(8))L/mol and 1:4-1:8, respectively. They were weak and not available to give negative effect to rhGH activity. The height and growth velocity as well as height standard deviation score of the GH-Ab positive patients presented no decrease during treatment and were not significantly different from that of negative patients.

CONCLUSION

The domestic rhGH preparation certainly had growth-promoting effect on the children with GHD. Nearly forty-eight percent patients showed GH-Ab positive in serum, but due to the lower titer and binding capacity, the GH-Ab had no negative effect on the height velocity of GHD children.

Long-lasting rat growth enhancement by an immunoregulating synthetic peptide

We have studied the long-lasting effects on rat weight gain of an active immunization with a peptide construction consisting of the covalent linkage of the 104-113 GH sequence to the 323-339 sequence of ovalbumin and to adjuvant muramyl dipeptide (MDP). The 104-113 GH sequence has already been identified as a potential epitope capable of enhancing growth hormome (GH) activity when complexed with the specific antibodies. Our results show that: a) 104-113 peptide antibodies after reacting with the endogenous GH produced a weight gain up to 7% higher than that observed in unimmunized rats; and b) the position of the adjuvant sequence in the molecule was critical for the immune response. Antibodies elicited in hypophysectomised rats had no effect on weight gain, thus confirming that the increase in hormonal activity is actually linked to the binding of specific peptide antibodies to endogenous GH.

Treatment with growth hormone in short children born with intrauterine growth retardation

In the past 10 yr, the potential benefits of treatment with growth hormone (GH) in children born with intrauterine growth retardation (IUGR) have been well documented. In this study, 46 children with IUGR received 3 yr of GH treatment (0.2 IU/kg of body wt) followed by a further 3 yr of observation without treatment. Height velocity (HV) increased dramatically during the first year of treatment, and over the 3-yr treatment period there was a 2 standard deviation score (SDS) gain in height (from -3.3+/-0.7 SDS to -1.3+/-0.3 SDS). Bone age (BA) was increased by 4 yr during treatment. A dramatic decrease in HV was observed in the second phase of the study when patients were no longer receiving GH. Similarly, the gain in BA during the observation period was only half that observed during the treatment period. No clinically significant changes were observed in laboratory test results, and no clinical adverse events could be related to treatment. In conclusion, the data provide evidence of a beneficial effect of GH treatment in IUGR children. However, adequate treatment duration is critical, because growth velocity decreases dramatically on discontinuation of GH treatment.

Detection of antipituitary antibodies in patients with autoimmune thyroid disease

The aim of the present study was to investigate the prevalence of antipituitary antibodies (APA) in patients with autoimmune thyroid disease as determined by Western blot analysis and enzyme-linked immunosorbent assay (ELISA). Results by Western blot analysis showed positivity for APA in serum of 22.4% of patients with Graves' disease (n=143, p<0.05) and 18.5% of patients with Hashimoto's thyroiditis (n=54, p<0.05), which were significantly higher than 6.2% in healthy controls (n=97). Similar results were obtained with ELISA. The titers of APA measured by ELISA (APA/ELISA) remained unchanged before and after therapy with antithyroid drug for Graves' disease, while thyrotropin-binding inhibitor immunoglobulins (TBII) decreased significantly. Similarly, no changes in APA by Western blot analysis were observed after therapy. In patients with Graves' disease, APA were not associated with thyroid status. There was no difference in APA between patients with positive and negative thyroid autoantibodies. A significant but weak positive correlation between APA/ELISA and anti-human GH measured by ELISA (anti-hGH/ELISA) was observed in patients with Graves' disease (r=0.601 p<0.001) and Hashimoto's thyroiditis (r=0.428 p<0.005). These findings have demonstrated the existence of APA detected by Western blot analysis and ELISA in some cases of autoimmune thyroid disease. The present results suggest that hGH and other antigens may be involved in APA in patients with Graves' disease and Hashimoto's thyroiditis.

Low peripheral blood levels of the immunosuppressive cytokine interleukin 10 (IL-10) at the start of gonadotrophin stimulation indicates increased risk for development of ovarian hyperstimulation syndrome (OHSS)

Our hypothesis was that patients developing ovarian hyperstimulation syndrome (OHSS) might have a disturbed responsiveness or delayed activation of the immunosuppresive cytokine system. In a prospective cohort study, women (n=428) undergoing in vitro fertilisation (IVF) treatment were subjected to repeated blood sampling and collection of clinical data. Fifteen patients, who developed severe OHSS, were compared with matched (age, follicle numbers, pregnancy) control patients. Samples of serum and plasma were collected throughout the stimulation and up to 7 days after embryo transfer as well as during hospitalisation for OHSS. Levels of IL-4, IL-10, IL-13, oestradiol and progesterone were measured. Significantly lower levels of IL-10 were seen at the start of gonadotrophin stimulation in OHSS patients, with an increase seen after the development of OHSS. In these OHSS patients, a negative correlation between IL-10 levels and number of follicles at time of aspiration existed, but there were no correlations between steroid and IL-10 levels. Levels of IL-13 and IL-4 were low in both groups and did not change during stimulation. The lower levels of IL-10 at start of stimulation in OHSS patients, as compared with controls, may be of pathophysiological importance by allowing for an enhanced Th-1 type immune response during gonadotrophin stimulation and thereby increased and generalised inflammation. The increase in IL-10 after development of OHSS indicates that IL-10 at that time is induced in a systemic attempt to suppress the inflammation of OHSS.

A novel specific bioassay for serum human growth hormone

Human GH receptor (hGHR) was recently expressed on a Ba/F3 cell line, which is a mouse pro-B cell lymphoma that has been induced to become a cloned cell line (Ba/F3-hGHR). Using a Ba/F3-hGHR cell line, we have established a bioassay for serum hGH. hGH stimulated cell proliferation in a dose-dependent manner in concentrations ranging from 1 ng to 100 ng/mL. Cell proliferation was not influenced by other hormones or growth factors in the bioassay, with the exception of insulin-like growth factor I (IGF-I) and GH binding protein. Free IGF-I significantly stimulated the proliferation of Ba/F3-hGHR cells at concentrations over 25.85 ng/mL in this bioassay system, but serum IGF-I did not stimulate cell proliferation because the sensitivity of cell proliferation was insufficient for free IGF-I in serum. GH binding protein, however, did suppress cell proliferation at the highest concentration (100 ng/mL), but did not at the average concentration (20 ng/mL). Human serum stimulated cell proliferation, which was completely suppressed by anti-GH antibody. The GH bioactivity of serum samples from normal children and patients with non-GH deficient short stature correlated strongly with the serum hGH concentration determined by immunoradiometric assay (IRMA) (r = 0.967, r = 0.924, P < 0.0001, respectively). The ratio of bioactivity/IRMA was 1.01+/-0.26 in sera from normal children and 1.18+/-0.24 and 1.00+/-0.29 at basal values and peak values in GH stimulation tests, respectively, in sera from patients with non-GH deficient short stature. The bioactivity/IRMA ratio for the serum GH bioactivity of a patient who had biologically inactive GH caused by an amino acid substitution was 0.333+/-0.056 (mean +/- SD). In conclusion, we established a new sensitive bioassay for hGH that is specific for hGH somatogenic action and is useful for screening of patients with short stature caused by biologically inactive hGH.

Adjuvant effects of various lipopeptides and interferon-gamma on the humoral immune response of chickens

The adjuvant effects of various lipopeptides and recombinant chicken interferon gamma (IFN-gamma) on the humoral immune response of laying hens was investigated in four immunization studies. We used the lipopeptide Pam3Cys-Ser-(Lys)4 (PCSL), the conjugate P-Th1 consisting of the lipopeptide P3CS and the T-helper epitope Th1 (FISEAIIHVLHSRHPG), and the conjugate P-Th2 of the lipopeptide P3CSS and the T-helper epitope Th2, which corresponds to the peptide EWEFVNTPPLV, as adjuvants. Human serum albumin (HSA), recombinant bovine somatotropin (RBST), and human immunoglobulin G (IgG) served as antigens in the different experiments. All tested adjuvants enhanced the humoral immune response with various intensities. Chickens showed high antibody titers after the immunization with HSA even without adjuvant, but the adjuvant effects of PCSL and the combination of PCSL and recombinant chicken interferon-gamma (IFN-gamma) were much more pronounced using the antigens RBST and IgG. Especially after the third immunization, higher titers of antibodies were induced by the coadministration of P-Th1 and, to a greater extent, by the combination of PCSL and P-Th1 compared with the use of PCSL. Also, chickens that had received PCSL and P-Th2 showed the highest immune response, even after the second booster. The average concentrations of chicken immunoglobulin Y were significantly higher in 5-mo-old chickens (9.4 mg/mL serum and 10.1 mg/mL egg yolk) compared with 9-mo-old chickens (5.9 mg/mL serum and 5.1 mg/mL egg yolk). The specific serum antibody response was higher in the older chickens than in the younger chickens. Because chicken antibodies are likely to be used increasingly for diagnostic and therapy in the future, lipopeptides and recombinant chicken IFN-gamma may find many applications as adjuvants, thus contributing to the welfare of experimental animals.

Treatment of acromegaly with the growth hormone-receptor antagonist pegvisomant

BACKGROUND

Patients with acromegaly are currently treated with surgery, radiation therapy, and drugs to reduce hypersecretion of growth hormone, but the treatments may be ineffective and have adverse effects. Pegvisomant is a genetically engineered growth hormone-receptor antagonist that blocks the action of growth hormone.

METHODS

We conducted a 12-week, randomized, double-blind study of three daily doses of pegvisomant (10 mg, 15 mg, and 20 mg) and placebo, given subcutaneously, in 112 patients with acromegaly.

RESULTS

The mean (+/-SD) serum concentration of insulin-like growth factor I (IGF-I) decreased from base line by 4.0+/-16.8 percent in the placebo group, 26.7+/-27.9 percent in the group that received 10 mg of pegvisomant per day, 50.1+/-26.7 percent in the group that received 15 mg of pegvisomant per day, and 62.5+/-21.3 percent in the group that received 20 mg of pegvisomant per day (P<0.001 for the comparison of each pegvisomant group with placebo), and the concentrations became normal in 10 percent, 54 percent, 81 percent, and 89 percent of patients, respectively (P<0.001 for each comparison with placebo). Among patients treated with 15 mg or 20 mg of pegvisomant per day, there were significant decreases in ring size, soft-tissue swelling, the degree of excessive perspiration, and fatigue. The score fortotal symptoms and signs of acromegaly decreased significantly in all groups receiving pegvisomant (P< or =0.05). The incidence of adverse effects was similar in all groups.

CONCLUSIONS

On the basis of these preliminary results, treatment of patients who have acromegaly with a growth hormone-receptor antagonist results in a reduction in serum IGF-I concentrations and in clinical improvement.

Altered plasma cytokines and total glutathione levels in parenterally fed critically ill trauma patients with adjuvant recombinant human growth hormone (rhGH) therapy

OBJECTIVES

Glutathione (GSH) is a potent endogenous antioxidant that serves as one of the body's most important defenses against oxygen metabolites. Plasma levels of GSH are maintained primarily by a balance between secretion from the liver and degradation in the kidney. The ability to maintain and enhance tissue GSH may be of particular importance in controlling cytokine production in response to a stimulus like injury. The interaction after severe trauma between GSH and cytokines, tumor necrosis factor (TNF) -alpha, and interleukin (IL)-6, are not known. The purpose of the study was to investigate the levels of plasma GSH and cytokines TNF-alpha and IL-6 in adult patients admitted to the intensive care unit of our level I trauma center who were treated with recombinant human growth hormone (rhGH) for > or =7 days.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Trauma intensive care unit.

PATIENTS

Twenty-eight patients with multiple injuries and 14 normal postabsorptive controls.

INTERVENTIONS

From 48-60 hrs after injury, when resuscitation was complete, a stable hemodynamic status was achieved and the patients were receiving maintenance fluid without nitrogen or calories, a blood sample was drawn for basal, plasma GSH, TNF-alpha, and IL-6 measurement. Intravenous feeding was then started and continued for 7 days. The patients were randomized to receive or not to receive daily intramuscular doses of recombinant human growth hormone (0.15 mg rhGH/kg/day). Daily morning plasma was obtained for analysis of GSH, TNF-alpha, and IL-6 levels.

RESULTS

In the early catabolic "flow phase" of severe injury, the plasma levels of GSH were not altered but plasma TNF-alpha and IL-6 levels were increased significantly, compared with uninjured controls. Seven days of total parenteral nutrition alone enhanced plasma GSH levels (76%), but no change in TNF-alpha was observed. Supplementation with rhGH enhanced GSH (180%), and TNF (65%) with no changes in IL-6 levels. There is a significant linear relationship between plasma GSH and TNF-alpha levels in our rhGH-supplemented trauma patients.

CONCLUSION

Modification of plasma GSH and TNF-alpha levels by adequate nutritional support with adjuvant rhGH during the postinjury period demonstrates the beneficial role of GSH in enhancing antioxidant defenses.

DeltahGHR, a novel biosafe cell surface-labeling molecule for analysis and selection of genetically transduced human cells

We describe a new selectable marker for retroviral transduction and selection of human and murine cells. The molecule expressed on the cell surface of the transduced population is a truncated version of human growth hormone receptor (deltahGHR), capable of ligand (hGH) binding, but devoid of the domains involved in signal triggering. We demonstrate that the engineered molecule is stably expressed in the target cells as an inert protein unable to trigger proliferation or to rescue the cells from apoptosis after ligand binding. This new marker will probably have a wide application spectrum, since hGHR in the human adult is highly expressed only in liver cells, and lower levels have been reported in certain lymphocyte cell populations. The deltahGHR label has high biosafety potential, as it belongs to a well-characterized hormonal system that is nonessential in adults, and there is extensive clinical experience with hGH administration in humans. This record allows us to hypothesize the lack of relevant clinical consequences resulting from massive transgene expression caused by successful replacement of a large tissue with genetically transduced cells. We take advantage of the differential binding properties of several monoclonal antibodies (MAbs) in describing a cell rescue method in which the antibody used to select deltahGHR-transduced cells is eluted by competition with hGH or, alternatively biotinylated hGH is used to capture tagged cells. In the latter system, the final purified population would be recovered free of attached antibodies in hGH (a substance approved for human use)-containing medium, providing additional biosafety relative to currently existing methods that rely on the use of murine MAb to rescue genetically labeled cells.

Development and evaluation of a direct immunofluorimetric assay for urinary growth hormone

We describe a two-site immunofluorimetric assay for urinary growth hormone that is resistant to interference from a wide range of urinary constituents and therefore eliminates the need for sample pre-treatment. A microtitre plate format is used with specific orientation of capture antibody on a polystyrene surface carrying a hydrazide group. Europium-labelled F(ab)2 is the fluorophore and time-resolved fluorimetry with co-fluorescence enhancement the signal detection system. Inter-assay precision was 11.3% at 5.2 ng/L and 10.3% at 44.3 ng/L, minimum detection limit (22% coefficient of variation, CV) was < 1.0 ng/L, working range (< 10% CV) was 0-100 ng/L and quantitative recovery and good parallelism were demonstrated. This convenient and sensitive assay is suitable for the routine measurement of human growth hormone (hGH) in urine.

Prophylactic treatment with growth hormone and insulin-like growth factor I improve systemic bacterial clearance and survival in a murine model of burn-induced gut-derived sepsis

The purpose of this investigation was to evaluate the effects of GH and IGF-I administration in a murine model of burn-induced gut-derived sepsis. BALB/C mice were treated with 4.8 mg/kg/day of GH, 24 mg/kg/day of IGF-I or saline for 4 days. They were then administered 10(10) E. coli by gavage and subjected to 20% full thickness flame burn. All mice received allogeneic blood transfusion 5 days before burn injury to induce mild immunosuppression. Seventy-three mice were observed for survival and 51 mice were sacrificed at 4 and 20 h postburn. Blood, mesenteric lymph nodes (MLN), spleen and liver were harvested aseptically, and viable bacterial counts in the organs were determined. The small intestine was harvested for the evaluation of villus height and mitoses in the crypts. GH and IGF-I groups showed a significantly better survival than the control group. GH and IGF-I groups had significantly greater villus height and mitoses/crypt than the control group. Translocation of bacteria was not significantly different among groups, however, the relation between the numbers of viable bacteria in MLN and blood suggests that both GH and IGF-I reduced systemic spread of translocated bacteria. It is concluded that GH and IGF-I had positive effects on outcome in this model of burn-induced gut-derived sepsis. It appears that GH and IGF-I may have immune-enhancing effects and that administration of these agents may be useful for burn injury.

Insulin-like growth factor-I treatment in two children with growth hormone gene deletions

Two unrelated Brazilian patients had homozygous 6.7 kb deletions in the GH-1 gene (girl and boy, 1.8 and 3.3 yr, heights -7.9 and -6.0 SDS, respectively). Desensitization using small amounts of exogenous GH (0.033 IU/kg body weight/week, divided into daily s.c. injections) was attempted, but anti-GH antibodies appeared. Replacement with usual doses of hGH induced only transient increase in growth. IGF-I therapy with increasing doses resulted in catch-up growth without side-effects. Growth velocity was 7.5 cm/yr in the first year and 8.4 cm/yr in the next 6 months in patient 1, and 6.7 cm/yr in the first year, 5.9 cm/yr in the second year and 7.9 cm/yr in the third year of IGF-I treatment in patient 2, when the daily dose of 240 micrograms/kg was divided into three injections. IGFBP-3 levels were low (0.55 and 0.40 mg/I) and did not increase after IGF-I treatment, suggesting that this GH effect is not mediated by IGF-I, and injected IGF-I had a rapid disappearance rate. We conclude that IGF-I promotes growth by endocrine mechanisms and constitutes an effective treatment for patients with GH insensitivity secondary to GH antibodies.

Synergistic effect of formulated plasmid and needle-free injection for genetic vaccines

PURPOSE

A plasmid-based gene expression system was complexed with protective, interactive, and non-condensing (PINC) polymer system and administered with Medi-Jector, a needle-free injection device (NFID), to achieve high and sustained levels of antigen-specific antibodies in blood circulation.

METHODS

Human growth hormone (hGH) or bacterial beta-galactosidase gene expression plasmids driven by a cytomegalovirus (CMV) promoter were formulated in saline or complexed with a PINC polymer, polyvinylpyrrolidone (PVP), and intramuscularly or subcutaneously administered into dogs and pigs using a 22-gauge needle or a NFID. The hGH-specific IgG titers in serum were measured by an ELISA. Beta-galactosidase expression was measured in injected muscles by an enzymatic assay or immunohistochemistry. The effect of NFID on DNA stability and topology was assessed by gel electrophoresis.

RESULTS

Intramuscular (i.m.) or subcutaneous (s.c.) injection of a hGH expression plasmid pCMV-hGH (0.05-0.5 mg/kg) in dogs and pigs elicited antigen-specific IgG antibody titers to expressed hGH. With both routes of injection, pDNA delivery by a NFID was superior to pDNA injection by needle. The magnitude of hGH-specific IgG titers with NFID was 15-20-fold higher than needle injection when pDNA was complexed with PVP, and only 3-4-fold higher with pDNA in saline. The transfection efficiency in the injected muscle, as measured by beta-galactosidase expression, following i.m. injection of pCMV-betagalactosidase/PVP, was not significantly different between needle and NFID-injected groups.

CONCLUSIONS

These data demonstrate that the combination of pDNA/ PVP complexes and a NFID act synergistically to achieve high and sustained levels of antigen-specific IgG response to expressed antigen. This gene delivery approach may offer advantage over needle injection of naked DNA for the development of genetic vaccines.

DNA-based non-invasive vaccination onto the skin

Non-invasive vaccination onto the skin (NIVS) could improve vaccination programs because the procedure requires no specially trained personnel and may eliminate many problems associated with needle injections. There is also evidence that the efficacy of a skin-targeted vaccine may be optimal when the antigen is expressed within the outer layer that is in constant contact with potential pathogens. We report here that non-invasive gene delivery by pipetting adenovirus- or liposome-complexed plasmid DNA onto the outer layer of skin could achieve localized transgene expression within a restricted subset of skin in mice and the elicitation of an immune response against the protein encoded by the DNA. These results provide a proof of principle that NIVS may appear as a novel method for the administration of DNA-based vaccines.