Saponin TQL1055 adjuvant-containing vaccine confers protection upon Mycobacterium tuberculosis challenge in mice

Tuberculosis (TB), caused by the intracellular pathogen Mycobacterium tuberculosis (Mtb), affects the lungs of infected individuals (pulmonary TB) but can also affect other sites (extrapulmonary TB). The only licensed vaccine Mycobacterium bovis bacillus Calmette-Guerin (BCG) protects infants and young children but exhibits variable efficacy in protecting against adult pulmonary TB. Poor compliance and prolonged treatment regimens associated with the use of chemotherapy has contributed to the development of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mtb. Thus, there is an urgent need for the design of more effective vaccines against TB. The development of safe and novel adjuvants for human use is critical. In this study, we demonstrate that saponin-based TQL1055 adjuvant when formulated with a TLR4 agonist (PHAD) and Mtb specific immunodominant antigens (ESAT-6 and Ag85B) and delivered intramuscularly in mice, the SA-TB vaccine induced potent lung immune responses. Additionally, the SA-TB vaccine conferred significant protection against Mtb infection, comparable with levels induced by BCG. These findings support the development of a SA-TB vaccine comprising TQL1055, as a novel, safe and effective TB vaccine for potential use in humans.

Formulation of Chitosan-Zein Nano-in-Microparticles for Oral DNA Delivery

Gene delivery via the oral route offers a promising strategy for improving DNA vaccination and gene-based therapy outcomes. The noninvasive nature of oral delivery lends to ease of dosing, which can facilitate convenience and patient compliance. Moreover, oral administration allows for both local and systemic production of therapeutic genes or, in the case of DNA vaccination, mucosal and systemic immunity. Here, we describe the methods to produce a dual biomaterial, oral DNA delivery system composed of chitosan (CS) and zein (ZN). In this system, CS serves to encapsulate and deliver DNA cargo to intestinal cells in the form of CS-DNA nanoparticles (CS-DNA NPs), while ZN is used to form a protective matrix around the CS-DNA NPs that prevent degradation during gastric transit but then degrades to release the CS-DNA NPs for transfection upon entry into the intestines. These particles have demonstrated the ability to effectively protect cargo DNA from simulated gastric degradation in vitro and mediate transgene production in vivo, making them an effective oral gene delivery system.

1238. The Novel Semisynthetic Saponin Adjuvant TQL1055 Enhances the Antibody Response to Pertussis Vaccine with an Improved Tolerability Profile over QS-21

Background

Acellular pertussis vaccines are better tolerated but less immunogenic than older whole cell vaccines. Novel adjuvants may be useful to enhance their immunogenicity. First-generation natural saponins are potent immuno-enhancers but are highly reactogenic. The novel semisynthetic saponin TQL1055 was evaluated for its potential to enhance the immunogenicity of a commercially available acellular pertussis vaccine as part of a National Institute of Allergy and Infectious Disease (NIAID) funded project.

Methods

Groups of 10 female C57BL/6J mice were immunized subcutaneously (SC) with Adacel® (containing 0.5 mcg pertussis toxin antigen) alone or in combination with QS-21 at 20 mcg/dose or TQL1055 at 50 mcg/dose on Days 0 and 28. Serum antibody titer to pertussis antigen was determined by ELISA (Alpha Diagnostics) at Days 0, 28, and 42 and geometric mean titers (GMT) in IU/mL were determined. Body weights were measured serially for 7 days after dose 1.

Results

At 28 days following dose 1, mice receiving TQL1055 had an anti-pertussis toxin IgG GMT of 8492, compared with 2263 in mice receiving QS-21 (p = 0.005). At Day 42, 14 days after dose 2, the GMTs increased to 18719 in the TQL1055 group and 10851 in the QS-21 group (p = 0.0653 vs TQL1055 dose 2; p = 0.6038 vs TQL1055 dose 1). Mice in the Adacel and TQL1055 groups gained weight steadily after dose 1, while mice in the QS-21 group had an average weight loss of 10% from baseline at 3 days after dose 1 (p < 0.0001).

Figure 1: TQL1055 Enhances the Antibody Response to Adacel® (Commercial Acellular Pertussis Vaccine) in C57BL/6J Female Mice

Figure 2: TQL1055 Shows Enhanced Tolerability (measured by decreased weight loss) Compared to QS-21 Following Subcutaneous Injection in C57BL/6J Female Mice

Conclusion

TQL1055 enhanced the antibody response to a commercial acellular pertussis vaccine to a greater degree than QS-21. Additionally, TQL1055 was better tolerated than QS-21, with no weight loss after vaccination. These findings suggested that TQL1055 may improve the performance of acellular pertussis vaccines without an increase in reactogenicity.

Disclosures

Chloe Buzz, BS, Adjuvance Technologies (Employee) Sean R. Bennett, MD PhD, Adjuvance Technologies (Employee) Phil Livingston, MD, Adjuvance Technologies (Consultant, Shareholder) Eric Farris, PhD, Adjuvance Technologies (Employee) Tyler Martin, MD, Adjuvance Technologies (Employee, Shareholder)

1237. Robust Adjuvant Activity and Dose-sparing Potential of the Novel Semisynthetic Saponin Adjuvant TQL1055 for Seasonal and Pandemic Influenza

Background

Vaccination against both seasonal and pandemic influenza requires effective adjuvants to maximize the utility of limited antigen and to enhance immunogenicity in hyporesponsive at-risk populations. First-generation natural saponins are potent immuno-enhancers but are reactogenic and have supply constraints. As part of a NIH-funded project, the novel semisynthetic saponin TQL1055 was evaluated for its potential to augment the immunogenicity of influenza antigens.

Figure 1: TQL1055 Enhances the Antibody Response to a Recombinant Antigen Influenza Vaccine (Flublok®) and Exhibits Antigen Dose-Sparing Effects

Methods

Groups of 10 C57BL/6J mice were immunized subcutaneously (SC) with Flublok® (H3N2 antigen) alone at either a 4.5 mcg or 1.1 mcg dose, or at a 1.1 mcg dose in combination with 10, 30 or 100 mcg TQL1055 on Days 0 and 21. Sera were analyzed at days 0, 21 and 42 by ELISA for H3N2-specific IgG. Body weights were measured serially.

Results

A 2-dose series of 1.1 mcg Flublok with TQL1055 elicited anti-H3N2 antibodies in all mice. This effect was TQL1055 dose-dependent, with GMTs of 2178 in the 10 mcg group, 13674 in the 30 mcg group and 48959 in the 100 mcg group. The GMT in all TQL1055 groups was higher than the GMT of 176 in the group receiving 4.5 mcg of Flublok alone. Mice receiving TQL1055 gained weight steadily after immunization, compared with a maximum weight loss of &gt;10% in mice receiving 20 mcg of QS-21.

Conclusion

TQL1055 exhibits robust adjuvant activity for influenza antigens, demonstrating a dose-sparing effect and improved systemic tolerability compared with QS-21. Taken together, these finding support further evaluation of its potential as an adjuvant for influenza vaccines.

Disclosures

Chloe Buzz, BS, Adjuvance Technologies (Employee) Eric Farris, PhD, Adjuvance Technologies (Employee) Sean R. Bennett, MD PhD, Adjuvance Technologies (Employee) Pat Frenchick, PhD, Adjuvance Technologies (Consultant) Tyler Martin, MD, Adjuvance Technologies (Employee, Shareholder)

Screening a chemically defined extracellular matrix mimetic substrate library to identify substrates that enhance substrate-mediated transfection

Nonviral gene delivery, though limited by inefficiency, has extensive utility in cell therapy, tissue engineering, and diagnostics. Substrate-mediated gene delivery (SMD) increases efficiency and allows transfection at a cell-biomaterial interface, by immobilizing and concentrating nucleic acid complexes on a surface. Efficient SMD generally requires substrates to be coated with serum or other protein coatings to mediate nucleic acid complex immobilization, as well as cell adhesion and growth; however, this strategy limits reproducibility and may be difficult to translate for clinical applications. As an alternative, we screened a chemically defined combinatorial library of 20 different extracellular matrix mimetic substrates containing combinations of (1) different sulfated polysaccharides that are essential extracellular matrix glycosaminoglycans (GAGs), with (2) mimetic peptides derived from adhesion proteins, growth factors, and cell-penetrating domains, for use as SMD coatings. We identified optimal substrates for DNA lipoplex and polyplex SMD transfection of fibroblasts and human mesenchymal stem cells. Optimal extracellular matrix mimetic substrates varied between cell type, donor source, and transfection reagent, but typically contained Heparin GAG and an adhesion peptide. Multiple substrates significantly increased transgene expression (i.e. 2- to 20-fold) over standard protein coatings. Considering previous research of similar ligands, we hypothesize extracellular matrix mimetic substrates modulate cell adhesion, proliferation, and survival, as well as plasmid internalization and trafficking. Our results demonstrate the utility of screening combinatorial extracellular matrix mimetic substrates for optimal SMD transfection towards application- and patient-specific technologies.

Impact statement

Substrate-mediated gene delivery (SMD) approaches have potential for modification of cells in applications where a cell-material interface exists. Conventional SMD uses ill-defined serum or protein coatings to facilitate immobilization of nucleic acid complexes, cell attachment, and subsequent transfection, which limits reproducibility and clinical utility. As an alternative, we screened a defined library of extracellular matrix mimetic substrates containing combinations of different glycosaminoglycans and bioactive peptides to identify optimal substrates for SMD transfection of fibroblasts and human mesenchymal stem cells. This strategy could be utilized to develop substrates for specific SMD applications in which variability exists between different cell types and patient samples.

Free Polyethylenimine Enhances Substrate-Mediated Gene Delivery on Titanium Substrates Modified With RGD-Functionalized Poly(acrylic acid) Brushes

Substrate mediated gene delivery (SMD) is a method of immobilizing DNA complexes to a substrate via covalent attachment or nonspecific adsorption, which allows for increased transgene expression with less DNA compared to traditional bolus delivery. It may also increase cells receptivity to transfection via cell-material interactions. Substrate modifications with poly(acrylic) acid (PAA) brushes may improve SMD by enhancing substrate interactions with DNA complexes via tailored surface chemistry and increasing cellular adhesion via moieties covalently bound to the brushes. Previously, we described a simple method to graft PAA brushes to Ti and further demonstrated conjugation of cell adhesion peptides (i.e., RGD) to the PAA brushes to improve biocompatibility. The objective of this work was to investigate the ability of Ti substrates modified with PAA-RGD brushes (PAA-RGD) to immobilize complexes composed of branched polyethyleneimine and DNA plasmids (bPEI-DNA) and support SMD in NIH/3T3 fibroblasts. Transfection in NIH/3T3 cells cultured on bPEI-DNA complexes immobilized onto PAA-RGD substrates was measured and compared to transfection in cells cultured on control surfaces with immobilized complexes including Flat Ti, PAA brushes modified with a control peptide (RGE), and unmodified PAA. Transfection was two-fold higher in cells cultured on PAA-RGD compared to those cultured on all control substrates. While DNA immobilization measured with radiolabeled DNA indicated that all substrates (PAA-RGD, unmodified PAA, Flat Ti) contained nearly equivalent amounts of loaded DNA, ellipsometric measurements showed that more total mass (i.e., DNA and bPEI, both complexed and free) was immobilized to PAA and PAA-RGD compared to Flat Ti. The increase in adsorbed mass may be attributed to free bPEI, which has been shown to improve transfection. Further transfection investigations showed that removing free bPEI from the immobilized complexes decreased SMD transfection and negated any differences in transfection success between cells cultured on PAA-RGD and on control substrates, suggesting that free bPEI may be beneficial for SMD in cells cultured on bPEI-DNA complexes immobilized on PAA-RGD grafted to Ti. This work demonstrates that substrate modification with PAA-RGD is a feasible method to enhance SMD outcomes on Ti and may be used for future applications such as tissue engineering, gene therapy, and diagnostics.

Oral Non-Viral Gene Delivery for Applications in DNA Vaccination and Gene Therapy

Non-viral gene delivery via the oral route is a promising strategy for improving outcomes of DNA vaccination and gene therapy applications. Unlike traditional parenteral administration routes, the oral route is a non-invasive approach that lends itself to high patient compliance and ease of dosing. Moreover, oral administration allows for both local and systemic production of therapeutic genes or, in the case of DNA vaccination, mucosal and systemic immunity. However, the oral route presents distinct challenges and barriers to achieving successful gene delivery. Oral non-viral gene delivery systems must be able to survive the harsh and variable environments (e.g. acidic pH, degrading enzymes, mucus layer) encountered during transit through the gastrointestinal tract, while still allowing for efficient transgene production at sites of interest. These barriers present unique design challenges for researchers in material selection and in improving the transfection efficiency of orally delivered genes. This review provides an overview of advancements in the design of oral non-viral gene delivery systems, and highlights recent and important developments towards improving orally delivered genes for applications in gene therapy and DNA vaccination.

Is population genetic structure of vascular plants shaped more by ecological or geographic factors? A study case on the Mediterranean endemic Centaurea filiformis (Asteraceae)

All known populations of the Sardinian endemic Centaurea filiformis Viv. (Asteraceae) were studied in order to understand the impact of both geographic and ecological factors on the genetic structuring of this species. Fourteen populations and 234 individuals were sampled. The demographic structure of the populations and the reproductive ecology were estimated in 28 plots. Population genetic analyses were based on SSR markers. Genetic structure was investigated by spatial Bayesian methods. Average densities of 0.51 individuals m^-2 were detected, with a prevalence of adults. Ten species of pollinators were identified; C. filiformis ability to self-pollinate and myrmecochory were demonstrated experimentally. The populations displayed an average heterozygosity value of H_e  = 0.576 and high genetic differentiation (overall F_ST  = 0.218). Bayesian analysis suggests that five is the most probable number of gene pools of origin. A strong correlation between geographic distances and genetic distances among populations was highlighted. The demographic population structure of C. filiformis is dominated by adults, suggesting that it is a stable-regressive or senile species, investing more in local persistence than colonisation ability. Despite the scattered distribution, the populations studied do not present evidence of genetic erosion. The analysis of genetic differentiation reveals very high differentiation levels among populations, thus indicating that effective barriers exist against gene flow. A general conclusion is that population distribution results in a clear genetic structure for the populations studied, and that geography and not ecology is shaping the present distribution of this species.

Chitosan nanoparticle delivery of Influenza A Virus DNA vaccine enhances antibody class switching and abrogates weight loss post IAV challenge

DNA vaccination presents a promising new approach for Influenza A Virus (IAV) vaccines, as they can be generated quickly in response to the viral antigenic shift and drift characteristic of IAV pandemic outbreaks. A DNA vaccination approach for IAV was examined using a plasmid encoding PR8 H1N1 hemagglutinin (HA) protein as a potential IAV vaccine. In addition to the HA antigen sequence the plasmid also encoded a sequence that when transcribed, activates the pattern recognition receptor RIG-I, improving innate immune activation. To increase the potential of this IAV DNA vaccine, our study focused on delivery of the plasmid to the respiratory tract using chitosan (CS) nanoparticles. CS, a mucoadhesive/mucopenetrating derivative of chitin, forms complexes with DNA to improve uptake and transfection of the plasmid by immune cells in the lung. In vitro, plasmid/CS complexes containing unbound CS induced bone marrow derived dendritic cell (BMDC) death. BMDC death was accompanied by a robust increase in inflammatory cytokine mRNA. Although BMDC death was abrogated by free CS removal, cytokine expression was also reduced. Alternative complexation methods are being explored to achieve an appropriate balance between cytokine production and cell death. In vivo intranasal prime-boost vaccination with low dose PR8 HA plasmid/CS nanoparticles resulted in PR8 specific IgM and total IgG antibody formation. Although weight loss was abrogated in plasmid/CS vaccinated mice, protection from lethal PR8 infection did not correlate with antibody level. By optimizing this vaccine approach, including dose, regime, and CS nanoparticle modification, critical insights into the development of rapidly deployable IAV vaccines could be gained.

Chitosan-zein nano-in-microparticles capable of mediating in vivo transgene expression following oral delivery

The oral route is an attractive delivery route for the administration of DNA-based therapeutics, specifically for applications in gene therapy and DNA vaccination. However, oral DNA delivery is complicated by the harsh and variable conditions encountered throughout gastrointestinal (GI) transit, leading to degradation of the delivery vector and DNA cargo, and subsequent inefficient delivery to target cells. In this work, we demonstrate the development and optimization of a hybrid-dual particulate delivery system consisting of two natural biomaterials, zein (ZN) and chitosan (CS), to mediate oral DNA delivery. Chitosan-Zein Nano-in-Microparticles (CS-ZN-NIMs), consisting of core Chitosan/DNA nanoparticles (CS/DNA NPs) prepared by ionic gelation with sodium tripolyphosphate (TPP), further encapsulated in ZN microparticles, were formulated using a water-in-oil emulsion (W/O). The resulting particles exhibited high CS/DNA NP loading and encapsulation within ZN microparticles. DNA release profiles in simulated gastric fluid (SGF) were improved compared to un-encapsulated CS/DNA NPs. Further, site-specific degradation of the outer ZN matrix and release of transfection competent CS/DNA NPs occurred in simulated intestinal conditions with CS/DNA NP cores successfully mediating transfection in vitro. Finally, CS-ZN-NIMs encoding GFP delivered by oral gavage in vivo induced the production of anti-GFP IgA antibodies, demonstrating in vivo transfection and expression. Together, these results demonstrate the successful formulation of CS-ZN-NIMs and their potential to improve oral gene delivery through improved protection and controlled release of DNA cargo.

Micro- and nanoparticulates for DNA vaccine delivery

DNA vaccination has emerged as a promising alternative to traditional protein-based vaccines for the induction of protective immune responses. DNA vaccines offer several advantages over traditional vaccines, including increased stability, rapid and inexpensive production, and flexibility to produce vaccines for a wide variety of infectious diseases. However, the immunogenicity of DNA vaccines delivered as naked plasmid DNA is often weak due to degradation of the DNA by nucleases and inefficient delivery to immune cells. Therefore, biomaterial-based delivery systems based on micro- and nanoparticles that encapsulate plasmid DNA represent the most promising strategy for DNA vaccine delivery. Microparticulate delivery systems allow for passive targeting to antigen presenting cells through size exclusion and can allow for sustained presentation of DNA to cells through degradation and release of encapsulated vaccines. In contrast, nanoparticle encapsulation leads to increased internalization, overall greater transfection efficiency, and the ability to increase uptake across mucosal surfaces. Moreover, selection of the appropriate biomaterial can lead to increased immune stimulation and activation through triggering innate immune response receptors and target DNA to professional antigen presenting cells. Finally, the selection of materials with the appropriate properties to achieve efficient delivery through administration routes conducive to high patient compliance and capable of generating systemic and local (i.e. mucosal) immunity can lead to more effective humoral and cellular protective immune responses. In this review, we discuss the development of novel biomaterial-based delivery systems to enhance the delivery of DNA vaccines through various routes of administration and their implications for generating immune responses.

Determination of age and gender differences in biochemical processes affecting the disposition of 2-butoxyethanol and its metabolites in mice and rats to improve PBPK modeling

2-Butoxyethanol (BE) is the most widely used glycol ether solvent. BEs major metabolite, butoxyacetic acid (BAA), causes hemolysis with significant species differences in sensitivity. Several PBPK models have been developed over the past two decades to describe the disposition of BE and BAA in male rats and humans to refine health risk assessments. More recent efforts by Lee et al. [Lee, K.M., Dill, J.A., Chou, B.J., Roycroft, J.H., 1998. Physiologically based pharmacokinetic model for chronic inhalation of 2-butoxyethanol. Toxicol. Appl. Pharmacol. 153, 211-226] to describe the kinetics of BE and BAA in the National Toxicology Program (NTP) chronic inhalation studies required the use of several assumptions to extrapolate model parameters from earlier PBPK models developed for young male rats to include female F344 and both sexes of B6C3F1 mice and the effects of aging. To replace these assumptions, studies were conducted to determine the impact of age, gender and species on the metabolism of BE, and the tissue partitioning, renal acid transport and plasma protein binding of BAA. In the current study, the Lee et al. PBPK model was updated and expanded to include the further metabolism of BAA and the salivary excretion of BE and BAA which may contribute to the forestomach irritation observed in mice in the NTP study. The revised model predicted that peak blood concentrations of BAA achieved following 6 h inhalation exposures are greatest in young adult female rats at concentrations up to 300 ppm. This is not the case predicted for old (> or =18 months) animals, where peak blood concentrations of BAA in male and female mice were similar to or greater than female rats. The revised model serves as a quantitative tool for integrating an extensive pharmacokinetic and mechanistic database into a format that can readily be used to compare internal dosimetry across dose, route of exposure and species.

The effects of biofeedback-assisted relaxation on cell-mediated immunity, cortisol, and white blood cell count in healthy adult subjects

The effect of biofeedback-assisted relaxation on cell-mediated immunity, cortisol, and white blood cell count was investigated in healthy adults under low-stress conditions. Fourteen subjects were trained with biofeedback-assisted relaxation for 4 weeks, while 17 subjects were controls. The group trained in relaxation techniques showed increased blastogenesis, decreased white blood cell count, due to decreased neutrophils, and no change in cortisol in comparison to the control group. Subjects with lower initial anxiety scores and forehead muscle tension levels showed larger increases in blastogenesis and larger decreases in neutrophils than subjects with higher initial anxiety and muscle tension levels.

In vitro gliadin antibody production by peripheral blood mononuclear cells from patients with coeliac disease

In vitro spontaneous IgG gliadin antibody production was shown in peripheral blood mononuclear cell (PBMC) cultures from 12/14 patients with active coeliac disease; in most cases no increase and sometimes a marked reduction of the in vitro synthesis was observed after pokeweed mitogen (PWM) addition. Lower levels of gliadin antibodies were also detected in PBMC cultures from 7/12 coeliac patients in remission; in all the cases the synthesis was increased by PWM. In vitro production was confirmed by higher levels in 7-day culture supernatants than in 0-day frozen-thawed cell pellets and by the inhibitory effect of cycloheximide. Spontaneous release of antibodies occurred within the first 3 days of culture, while PWM-induced antibody production reached a plateau after 7-9 days. The analysis of the in vitro gliadin antibody production is a promising technique to assess the regulatory mechanisms involved in the humoral immune response to gliadin.

An analysis of cereals that react with serum antibodies in patients with coeliac disease

Sera from six children with active coeliac disease, and elevated titres against gliadins and from six age-matched controls, were examined for IgG antibodies against different cereal proteins by a solid-phase radioimmunoassay. Antibodies to the major wheat proteins and the prolamines of other cereals were present in low titre in all control sera. In coeliac sera, significantly higher titres were found against A-gliadin, as well as against hexaploid and tetraploid wheat whole gliadins. Gliadin peptic-tryptic digest retained a significant antigenic activity, completely lost by peptic-tryptic-pancreatic digest. High titres were also found when coeliac sera were tested against wheat glutenins, albumins, and globulins, as well as against barley, oats, and maize prolamines; rice prolamines gave lower titres. Serum from whole gliadins and A-gliadin immunized rabbits showed a similar spectrum of reactivity against prolamines as coeliac sera. Our results indicate a dissociation between immunogenic properties of cereal proteins and toxicity in coeliac disease.

A sandwich enzyme immunoassay for wheat gliadin

A sandwich double antibody solid-phase enzyme immunoassay (EIA) that can detect and quantitate gliadin is described. Quantitative analysis could be carried out in the range of 5-400 ng/ml and the assay was more sensitive than inhibition EIA. Gliadin possessed weak cross-reactivity with oats, maize and rice prolamines. In the presence of anti-gliadin antibody (serum from a patient with active coeliac disease) gliadin could not be detected, but the sensitivity of the assay was restored by heat treatment of the serum. This EIA can therefore be employed to assess the gliadin content of biological fluids where specific antibody may coexist.

Impaired suppressor activity in children affected by coeliac disease

Immunoregulatory cells were enumerated in 19 coeliac disease children on a gluten free diet by means of monoclonal antibodies that define total T lymphocytes (T3), helper/inducer T cells (T4), suppressor/cytotoxic T cells (T8) and monocytes (M1), as well as by means of surface receptors for Fc fragments of IgM and IgG (T mu and T gamma, respectively). In addition, suppressor cell function was assessed in 17 coeliac disease patients by examining the ability of concanavalin-A (Con-A)-activated suppressor cells to inhibit autologous cell response to mitogenic stimulus as compared with age-matched controls. No statistically significant differences were found in the percentages of subsets defined by monoclonal antibodies between coeliac disease patients and age-matched controls, whereas coeliac disease patients had a significant decrease of the subpopulation bearing membrane receptor for Fc fragment of IgG. Mean value was 8.5% in coeliac patients versus 13.4% in age-matched controls. In the functional assay, mononuclear cells from 10 out of 17 coeliac disease patients either totally or partially failed to suppress responder cells after Con-A-activation. This defect is not related to HLA-DR status, because no difference was found between patients-HLA-matched and unmatched normal individuals. In this assay, mononuclear cells of three coeliac disease patients with low suppressor activity were able to inhibit responder cells to the same extent as controls, when indomethacin was used to block prostaglandin production in the induction phase of Con-A-activated suppressor cells. Our results suggest that an abnormality in immunoregulation may play a role in the pathogenesis of coeliac disease.

A solid-phase radioimmunoassay for IgG gliadin antibodies using 125I-labelled staphylococcal protein A

A sensitive radioimmunoassay for IgG gliadin antibodies is described. Serum specimens were added to wells of plastic microtitre plates coated with gliadin. After removal of the unbound material, gliadin antibodies were detected by adding 125I-labelled staphylococcal protein A (125I-SpA). Serum specimens from coeliac patients on a normal diet or on a gluten-free diet were tested, as well as sera from an age-matched control group. Measurements to obtain precise quantitative values were made with gliadin antibody-rich serum as reference standard. High titres of gliadin antibodies were found in 18 out of 19 coeliac patients on a normal diet (95%); in patients on a strict gluten-free diet serum values did not exceed 2 S.D. of the control mean. Due to the high sensitivity of the method a low but detectable amount of gliadin antibody was present in the sera of all controls.

Complexity, extremity, and affect in male and female judgments

Two studies were conducted to elucidate aspects of the interpersonal judement process as it is applied to and by males and females. Measurement of judgments by means of the Role Construct Repertory Test allowed consideration of cognitive complexity scores, as well as the use of extreme ratings and a total affective rating. Consistent findings from both studies suggest that males and females differ in their use of extreme scores and total affective ratings, but not in complexity. Characteristics of the stimulus person affect each of the three dependent measures. Interrelationships among the three judgmental measures provide information about the methodological and conceptual interplay of various factors in interpersonal judgment.