Specific Antibody Formation Research Articles

Testing of the Biocan® B inj. ad us. vet. vaccine and development of the new recombinant vaccine against canine borreliosis

Verification of the efficacy of Biocan B inj. ad us. vet. (Bioveta, a.s.) was done by challenge testing. Ticks collected in the nature were used as natural vectors of the infection. Six beagles and two control ones were used in the test. Formation of outer surface protein A specific antibodies (OspA antibodies) and borrelia specific immonoglobulins (IgG) was measured by Western blot and EIA in the sera samples. The tissue samples were used for detection of borreliae by cultivation method and dark field microscopy (DFM). Formation of IgG antibodies and OspA antibodies after vaccination was observed. The maximum titer level of antibodies was reached between 21. and 49. day after vaccination and then slowly decreased. Presence of borreliae was detected only in skin biopsies of non-vaccinated dogs. The post mortem tissue samples showed presence of borreliae in all of the samples of the non-vaccinated dogs. The tissues of the vaccinated dogs were not infected with borreliae, except for two samples of dog with low titer levels of OspA antibodies. The development of the new vaccine is based on preparation of recombinant outer surface proteins (e.g. rOspA and rOspC) of B. afzelii, B. burgdorferi and B. garinii origin. Chosen recombinant proteins were successfully expressed in E. coli. The obtained purified proteins are currently being tested on laboratory BALB/c mice. Formation of specific antibodies against some recombinant proteins has been confirmed. These proteins are suitable candidates for preparation of a vaccine prototype and they will be subsequently used in challenge tests.

Protease-Activated Receptor-2 (PAR-2) as a Novel Target for Modulating Immune Responses to Neo Antigens Following In Vivo Gene Transfer.

The safety of several strategies using novel adeno-associated viral (AAV) vectors (serotypes-1,-5,-7,and -8) to skeletal muscle of large animals have been hampered by the immune response to the transgene ( Blood 103: 85, 3303, and 3330). Dendritic cells (DC) are potent antigen-presenting cells that govern the immune responses. The involvement of proteases is critical to DC antigen processing and presentation. Proteases' effects on cells are mediated by protease-activated receptor (PAR) a group of four G-protein-coupled receptors. Bone marrow-derived DC from PAR-2 knockout mice do not spontaneously develop to mature state and only do so upon stimulations of inflammatory signals, therefore, PAR-2 proved critical for DC activation. Work with selective PAR-2 agonists and knockout animals suggests a in vivo contribution of this receptor to several chronic inflammatory diseases and tumor development. In fact, small peptides functioning as PAR-2 antagonists are now being tested as anti-angiogenic agents. We sought to determine whether inhibiting specific targets on the T-cell activation cascade would provide a strategy to prevent the development of antibody following IM injection of AAV. To do this we evaluated the risk of inhibitior formation to clotting factor IX (FIX) in PAR-2 deficient mice compared with heterozygous (+/−) or normal (+/+) genotypes. Mice received IM injection of AAV-1 encoding human FIX (hFIX) at two different doses (low and high cohorts). FIX and antibody levels were monitored weekly. PAR-2(−/ −) mice(n=4) given the low dose exhibited circulating FIX levels of 500± 99ng/ml which remained stable for the duration of the experiment(10 weeks), and no antibody for FIX was detected. In three PAR-2(+/+) mice, FIX expression was transiently detected at week 2 followed by a period of 4 weeks with undetectable levels. This was due to the formation of FIX specific IgG-1 antibody, which results from activation of CD4+ T-cell mainly of Th2 subset, that peaked at week 6. These antibodies inhibit FIX clotting activity as determined by a functional assay at titre of 3–5.5BU (Bethesda Unit) in all 3 mice. High dose AAV-1 treated PAR-2(−/ −) mice(n=6) resulted in continuous expression of FIX(1,500±353ng/ml) in the absence of FIX antibody. In contrast, inhibitors of FIX were detected in all mice(5 per group) PAR-2(+/−) or PAR-2(+/+). All animals develop IgG-1 antibodies to FIX through 10 weeks of observation. At week 6 post-injection, FIX inhibitors were detected in 3/10 mice at levels of ~1 BU. Continuous follow-up showed that a decrease in antibody titers to FIX was associated with slowly increasing FIX antigen. In addition, splenocytes from PAR-2 (+/+) mice exhibit significant increase (p<0.05) in antigen-specific IFN-γ secretion detected by ELISpot whereas in PAR-2 (−/ −) mice no response was detected. Furthermore, in PAR-1(−/ −) and PAR-1(+/+) mice IM injected with AAV-1, FIX inhibitor was detected in all animals (n=4/group). This demonstrates a PAR-2-specific immunomodulatory mechanism. In summary, these data suggest that pharmacological inhibition of PAR-2 may provide a novel strategy to evade the immune response to the transgene in a variety of gene-based strategies.

Xenogeneic Human Tyrosinase DNA Vaccination Induces Specific Immune Response in Dogs with Advanced Malignant Melanoma

Introduction: Xenogeneic melanosomal differentiation antigens, delivered in the form of a plasmid DNA vaccine, can overcome host immune ignorance/tolerance in preclinical animals to melanoma by: 1) generating humoral and cytotoxic T cell responses and 2) inducing protection from tumor challenge. Initial trials of human tyrosinase (huTyr) DNA vaccination of dogs with advanced malignant melanoma (Bergman et al, 2003) demonstrated safety and prolongation of survival with this therapeutic modality. We investigated antigen‐specific immunity in dogs receiving huTyr DNA vaccination.Methods: Three cohorts of three dogs each with advanced (WHO stage II‐IV) canine malignant melanoma (CMM) received four biweekly IM injections (dose levels 100, 500, or 1,500 ug, respectively/vaccination) of huTyr plasmid DNA via the Biojector2000 jet delivery device. Sera samples were taken before and after vaccination to detect specific antibody formation to huTyr by Enzyme‐Linked ImmunoSorbent Assays (ELISAs) and flow‐cytometry.Results: Three dogs have measurable, 2 to 4 fold huTyr‐specific antibody titers. Preliminary studies by flow‐cytometry have confirmed antibody response to huTyr by positive binding to endogenous human tyrosinase in SK‐Mel188 cells using post‐vaccinate serum.Conclusions: Xenogeneic (huTyr) DNA vaccination generates antigen‐specific humoral responses, which may partially explain the previously reported clinical efficacy and anti‐tumor responses. Ongoing studies include: 1) a comprehensive analysis by flow‐cytometry to detect huTyr‐specific antibodies and 2) a quantitative measure of potential cytotoxic T‐cell responses in these dogs by the DNA vaccination.

Anaphylactic reaction after rocuronium

Anaphylactic reaction after rocuronium

Organic dusts and disease: a continuous research challenge.

Research on organic dust during recent years has revealed major clinical effects and some causative agents. Many of the symptoms reported are caused by an inflammation in the airways, characterized by a neutrophil response. This condition can cause a non-allergic asthma. There are also reactions characterized by lymphocyte accumulation and by specific IgE antibody formation. Causative agents identified as bacterial endotoxins, molds, and different allergens.

Exposure to Burkholderia pseudomallei induces cell-mediated immunity in healthy individuals

Melioidosis is an emerging tropical infection caused by the intracellular bacterium Burkholderia pseudomallei, and is associated with high mortality rates. Previous studies investigating the prevalence of melioidosis have based conclusions on serological evidence. However, cell-mediated immunity is more relevant for protection against an intracellular pathogen such as B. pseudomallei. This is the first demonstration that exposure to B. pseudomallei may lead to the formation of specific antibodies and the development of cell-mediated immunity in a healthy individual.

Antigen presentation by common variable immunodeficiency (CVID) B cells and monocytes is unimpaired.

CVID is a primary immunodeficiency syndrome comprising a heterogeneous group of patients with hypogammaglobulinaemia and defective formation of specific antibodies. Previous studies demonstrated defective T cell responsiveness to antigen in a major subgroup of patients. In the present study we investigated the capacity of peripheral blood monocytes and Epstein-Barr virus (EBV)-transformed B cell lines from seven patients with CVID, including two patients expressing an extended MHC haplotype described to be associated with CVID, to present antigen (Tet. Tox.) to CD4+ antigen-specific T cell lines from healthy controls. The results presented show an unimpaired capacity of peripheral blood monocytes to present antigen in all patients studied. In addition, the present study demonstrates for the first time that CVID B cells function normally as antigen-presenting cells (APC). These findings indicate that expression of a certain MHC phenotype in CVID is not associated with a defect in the presentation of recall antigen by monocytes and B cells. Based on these studies, uptake, processing and re-expression of recall antigen in association with MHC class II molecules on the APC surface are functional and there is no indication for structural abnormalities of the MHC class II molecules expressed by the patients studied that could be essential for their function in antigen binding and presentation.

Antibodies to oxidized low-density lipoproteins and angiographically assessed coronary artery disease in white patients.

Low-density lipoprotein (LDL) can be oxidatively modified by reactive oxygen species, thus generating oxLDL. The latter induce formation of specific antibodies (oxLDLAb), which are detectable in patients with atherosclerosis, in which they might play a pathogenic or a protective role. Thus, we aimed to investigate the association of antibodies with oxidized LDLs (oxLDL) (oxLDLAbs) with coronary artery disease (CAD) and acute coronary syndromes. In a cross-sectional study of 529 consecutive patients undergoing quantitative coronary angiography for suspected CAD, we measured the titer of IgG oxLDLAbs by ELISA. With regression analysis techniques, we also investigated the determinants of oxLDLAb titer and the association of oxLDLAbs with CAD severity. We found no significant differences of oxLDLAb titer between groups of patients without and with different CAD severity. The oxLDLAb titer was 18.6 enzyme units (EU) (11.5 to 25.7 EU/mL) (mean, 95% CI) in patients without CAD; 16.8 EU (9.6 to 24.2 EU) in patients with stenosis <50%; and 19.9 EU (15 to 24.8 EU), 17.2 (13.8 to 20.6 EU), and 14.7 EU (12.1 to 17.3 EU) in those with in 1-, 2-, or 3-vessel > or =50% stenosis, respectively. Similarly, no differences of oxLDLAb titer between patients without and with acute coronary syndrome were found. The oxLDLAb titer correlated weakly with aging and with serum total, LDL, and HDL cholesterol and plasma homocysteine levels; however, only age and HDL cholesterol remained significant predictors of the oxLDLAb titer at a stepwise regression analysis. The results of this study, which was adequately powered from the statistical standpoint, provided no evidence for an association of IgG oxLDLAb titer with angiographically assessed CAD in whites.

APC0576: a novel small molecule, immunosuppressive agent effective in primate models.

APC0576, 5-(((S)-2,2-dimethylcyclopropanecarbonyl)amino)-2-(4-(((S)-2,2-dimethylcyclopropanecarbonyl)amino)phenoxy)pyridine is a novel synthetic compound with an inhibitory activity on NF-kappaB-dependent gene activation and chemokine synthesis in human endothelial cells. This article describes the effect of APC0576 on T-cell-dependent immune functions in vitro and in vivo in primate models, because NF-kappaB is known to be one of the potent mediators in T-cell activation. The effects of APC0576 on interleukin-2 production and proliferative responses in human peripheral blood mononuclear cells were studied under various stimuli with in vitro culture assay. Next, female rhesus monkeys were immunized with tetanus toxoid (TTx), and APC0576 was orally administered for 4 weeks. Serum-specific antibody for TTx was monitored weekly using an enzyme-linked immunosorbent assay, and delayed-type hypersensitivity reaction was examined after 4 weeks of APC0576 treatment. To evaluate the immunosuppressive activity, APC0576 was orally administered for 32 days to rhesus monkeys that received transplants of allogeneic kidney. APC0576 effectively suppressed interleukin-2 production and proliferation in activated human peripheral blood mononuclear cells. Both delayed-type hypersensitivity reaction and specific antibody formation evoked by TTx was significantly and dose-dependently attenuated by 4 weeks treatment of APC0576 without any serious toxicologic signs. Allogeneic kidneys grafted in rhesus monkeys were not rejected and fully functioned during the 32 days of APC0576 treatment, although they were rapidly rejected after the withdrawal of the drug. A novel, orally available immunosuppressive agent, APC0576, effectively inhibited T-cell-based immune responses both in vitro and in vivo. APC0576 may have potential for a therapeutic agent in clinical organ transplantation and various cytokine-mediated diseases.

Potential implications of ABO blood group for vascular rejection in pig to human kidney xenotransplantation.

A substantial hurdle for successful xenotransplantation is to negate the effect of xenoreactive natural antibodies [mainly Galalpha1-3Galbeta1-4GlcNAc (alpha-Gal) specific] that cause hyperacute xenograft rejection. Galalpha1-3Gal molecules (alpha-Gal) have close structural homology with human ABO blood groups and therefore an individual's blood group might influence the formation of alpha-Gal specific antibodies. Genetic heterogeneity controlling alpha-Gal specific antibody formation could have important implications for future pig to human xenotransplantation clinical trials. We have investigated the relationship between ABO blood group and immunoglobulin M (IgM) and immunoglobulin G (IgG) alpha-Gal specific antibody titres in sera obtained from renal dialysis patients and healthy blood donors. Serially diluted sera (n = 166) obtained from renal dialysis patients awaiting kidney transplantation (n = 116) and healthy blood donors (n = 50) were tested for IgM and IgG alpha-Gal antibodies using an enzyme-linked immunosorbent assay (ELISA) specific for alpha-Gal. The study cohort comprised 62, 48, 36 and 20 sera obtained from blood group O, A, B and AB individuals, respectively. Reciprocal alpha-Gal specific antibody titres were calculated from ELISA titration curves and stratified by individual blood group. No significant heterogeneity was found in IgM alpha-Gal specific antibody titres across ABO blood groups. In contrast, marked heterogeneity was observed in IgG alpha-Gal specific antibody titres when stratified by blood group. IgG alpha-Gal specific antibody titres were higher in sera obtained from blood group O renal dialysis patients [median titre 40, interquartile range (IQR) 14 to 72], compared with blood group A (median titre 18, IQR 7 to 54, P = 0.05), blood group B (median titre 6, IQR 0 to 15, P < 0.001) and blood group AB patients (median titre 3.5, IQR 0 to 16, P = 0.002). A similar correlation was found for IgG alpha-Gal specific antibody titres in sera obtained from healthy blood donors with median titres of 20 (IQR 12 to 34), 37 (10 to 91), 9 (0 to 20), and 5.5 (0 to 12) in blood groups O, A, B and AB individuals, respectively. There was a strong interrelationship between alpha-Gal specific antibody class and blood group, with both IgM and IgG alpha-Gal specific antibodies found in 84% of the blood group O sera, 73% of blood group A sera, 50% of blood group B sera and 40% of blood group AB sera (P < 0.001). In a subgroup of 39 renal dialysis patients, IgM and IgG alpha-Gal specific antibody titres were measured in two serum samples obtained at different time-points (median time interval 581 days, range 42 to 4414), and showed a high degree of stability (correlation coefficient 0.88 and 0.90 for IgM and IgG, respectively). IgG alpha-Gal specific antibody titres are significantly higher in the sera of blood group O and A renal dialysis patients and healthy individuals compared with blood groups B and AB. These data indicate that future clinical trials of pig to human xenotransplantation may be more problematic for non-blood group B patients who are likely to have high levels of IgG alpha-Gal specific antibodies that are associated with acute vascular rejection.

Reduction of blood loss using aprotonin during spinal surgery in children for non‐idiopathic scoliosis.

Background Aprotinin, a serine protease inhibitor, reduces surgical blood loss by mechanisms including antifibrinolysis and preservation of platelet function. Its effectiveness has been reported in adult patients undergoing cardiac, major orthopaedic surgery (1) and liver surgery, as well as in paediatric cardiac surgery.Spinal surgery in children with scoliotic deformities involves major blood loss. This may often be more than one circulatory blood volume and therefore results in exposure to blood products and the accompanying risks and problems. Patients with Duchenne muscular dystrophy or other neuromuscular conditions presenting for correction of a spinal deformity pose a particular problem because of their propensity to bleed during surgery.Aprotinin was introduced into the RMCH for the purpose of reducing blood loss in this group of patients in 1999. Administration of aprotinin carries the risk of the formation of aprotinin specific antibodies and anaphylaxis. Re‐exposure carries a greater risk.The aim of this study was to investigate the effect of aprotinin on blood loss during corrective spinal surgery in the neuromuscular patients.Methods We have performed a retrospective review of 33 ASA III cases operated on in period June 1998–September 2000. All notes were studied and data recorded on the intraoperative blood loss and the length of surgical procedure. Aprotinin was used only in children where it was felt that they would be unlikely to be re‐exposed because of their initial presenting diagnosis. Our regimen for aprotinin administration was: test dose 5 ml (50 000 KIU) over 20 min, loading dose 2 ml·kg−1 (20 000 KIU·kg−1) infused over 30 min, then maintenance at 0.5 ml·kg−1·hr−1 (5 000 KIU·kg−1·h−1).Results In the group that had not received aprotinin were 15 patients aged 7–17 years (mean age 13 ± 2 years), measured blood loss was 2849 ± 1802 ml, length of surgery 343 ± 78 min. In the aprotinin group we had 18 patients aged 7–15 years (mean age 12 ± 2 years) with recorded mean blood loss of 1380 ± 1000 ml and duration of procedure 389 ± 142 min. The blood loss in the group that had received aprotinin was significantly reduced (P &lt; 0.01).Discussion Our two groups of patients were similar regarding the age of patients, pathology and clinical presentation. We believe that the use of aprotinin resulted in significant reduction of blood loss and requirements for blood products.

Diagnosis of lyme borreliosis by polymerase chain reaction

Diagnosis of lyme borreliosis by polymerase chain reaction

Circumvention of MHC class II restriction by genetic immunization

The fate of T cell responses to peptide-based vaccination is subject to constraints by the major histocompatibility complex (MHC), MHC restriction. Using as a model system of T and B cell epitopes from the circumsporozoite protein of Plasmodium falciparum malaria parasite, we show that vaccination by somatic transgene immunization readily primes Balb/c mice (H-2 d) a strain previously reported to be non-responder to immunization with a synthetic peptide vaccine encompassing these epitopes. Following genetic vaccination Balb/c mice developed a primary T cell response comparable to that of the responder strain C57Bl/6 (H-2 b). Following booster immunization on day 45 Balb/c mice responded with a typical T cell memory response. Priming induced the formation of specific antibodies, which rose sharply after booster immunization. These findings suggests that genetic immunization can circumvent MHC class II restriction.

Down-regulation of inducible nitric-oxide synthase (NOS-2) during parasite-induced gut inflammation: a path to identify a selective NOS-2 inhibitor.

Nitric oxide (NO) possesses potent anti-inflammatory properties; however, an over-production of NO will promote inflammation and induce cell and tissue dysfunction. Thus, the ability to precisely regulate NO production could prove beneficial in controlling damage. In this study, advantage was taken of the well characterized inflammatory response caused by an intestinal parasite, Trichinella spiralis, to study the relationship between intestinal inflammation and the regulation of nitric oxide synthase-type 2 (NOS-2) expression. Our study revealed that a specific gut inflammatory reaction results in inhibition of NOS-2 expression. Characteristics of this inhibition are: 1) local jejunal inflammation induced by T. spiralis systemically inhibits NOS-2 gene transcription, protein expression, and enzyme activity; 2) the inhibition blunts endotoxin-stimulated NOS-2 expression; 3) the inhibition does not extend to the expression of other isoforms of NOS, to paxillin, a housekeeper protein, or to cyclooxygenase-2, another protein induced by proinflammatory cytokines; 4) the inhibition is unlikely related to the formation of specific anti-parasite antibodies; and 5) the inhibition may involve substances other than stress-induced corticosteroids. Elucidation of such potent endogenous NOS-2 down-regulatory mechanisms could lead to the development of new strategies for the therapy of inflammatory conditions characterized by the overproduction of NO.

Stabilization of serum antibody responses triggered by initial mucosal contact with the antigen independently of oral tolerance induction.

Initial contacts with a T-dependent antigen by mucosal routes may result in oral tolerance, defined as the inhibition of specific antibody formation after subsequent parenteral immunizations with the same antigen. We describe here an additional and permanent consequence of these initial contacts, namely, the blockade of secondary-type responsiveness to subsequent parenteral contacts with the antigen. When repeatedly boosted ip with small doses (3 microg) of ovalbumin (OVA) (or lysozyme), primed B6D2F1 mice showed progressively higher antibody responses. In contrast, mice primed after a single oral exposure to the antigen, although repeatedly boosted, maintained their secondary antibody titers on a level which was inversely proportional to the dose of antigen in the oral pretreatment. This phenomenon also occurred in situations in which oral tolerance was not induced. For example, senile 70-week-old B6D2F1 mice pretreated with a single gavage of 20 mg OVA did not become tolerant, i.e., they formed the same secondary levels of anti-OVA antibodies as non-pretreated mice. However, after 4 weekly challenges with 3 microg OVA ip, orally pretreated mice maintained the same anti-OVA serum levels, whereas the levels of control mice increased sequentially. This "stabilizing" effect of mucosal exposure was dose dependent, occurred with different proteins and was triggered by single or multiple oral or nasal exposures to the antigen.

MULTIPLE IMMUNE FUNCTIONS IN RATS FED ECHINACEA EXTRACTS

This study evaluated acquired-immune functions representing the three major branches of the immune system in male rats fed a commercially available echinacea product. An additional comparison of effects on antibody formation in male and female rats was done using the commercial echinacea product and two echinacea tinctures marketed by local herbalists. In initial testing, we found no evidence of altered natural killer cell activity, T cell-mediated delayed-type hypersensitivity, or specific antibody formation in male rats given either a 225 mg/kg or 50 mg/kg of the commercial echinacea for 6 weeks. Antibody formation was significantly suppressed in female but not male rats given 250 mg/kg for 2 weeks of the commercial echinacea. The local products tested had no effect on antibody formation. We concluded that our study provided no supporting evidence for immunostimulatory activity by the echinacea preparations we examined and, in fact, may be immunosuppressive under some conditions.

Immunomodulating Components From Chinese Medicines

Modern scientific studies have shown that several components from Chinese herbal medicines are immunologically active. Astragalus mongholicus polysaccharide APS, a polymer of glucose and arabinose, increases specific antibody formation as well as synthesis of RNA, DNA and protein in mouse spleen. The polysaccharide PES isolated from Acanthopanax senticosus used as a tonic and sedative agent also induces interferon production. An oligosaccharide AbPS isolated from Achyranthes bidentata with a mw of only 1360 Da significantly enhances the humoral immune response and antagonizes the immunosuppressive effects of cyclosporin A. AbPS increases the production of TNF and the activity of NK cells. In tumor patients treated by chemotherapy or radiotherapy, AbPS maintained their peripheral white blood cell count and improved the quality of life. PSP, the protein bound polysaccharide extracted from Coriolus versicolor , has been developed as an anticancer drug in China. It promoted T cell proliferation, increased NK and LAK cell activities as well as anticancer cytokines IL-2, IL-6, IFN-? and TNF-a production so as to induce tumor cell apoptosis. Celastrol, a triterpene compound isolated from Tripterygium wilfordii was proven to be an equally-strong immunosuppressor and inhibited free radical damage in experimental arthritis. Ginkgo biloba extract improves cognitive functions. Ginkgolide A and B inhibited IL-1, TNF-a and nitric oxide production in rat microglia and prevented the chronic inflammatory process in neurodegenerative diseases.

An In Vitro Approach to Drug Photoallergy: Use of Drug-directed Antibodies to Assess Photobinding of Non-steroidal Anti-inflammatories to Skin Cells

Photobinding of drugs to biomolecules constitutes the early key event in the onset of photoallergy. This process generally involves excitation of the drug to an excited triplet state, which in turn can interact with cell constituents leading, in the case of proteins, to the formation of covalent photoadducts. The resulting photoantigens may trigger an immune response. In the present communication, we report the use of drug-directed antibodies to detect photoadduct formation in skin cells. This has been exemplified with tiaprofenic acid and suprofen as model compounds (two well known photoallergens) and human fibroblasts as representative skin cells. Upon irradiation of cells in the presence of these non-steroidal anti-inflammatories, time-dependent photoadduct formation was observed. This occurred predominantly at the cell membrane level. Most interestingly, the immunogenicity of cell photoadducts could be demonstrated by injection of Balb/c mouse fibroblasts into immunologically identical syngenic animals, where they triggered an immune response, as evidenced by the formation of specific antibodies and sensitized T-cells.

Experience with a Mouse Intranasal Test for the Predictive Identification of Respiratory Sensitization Potential of Proteins

The predictive identification of respiratory allergenic potential is an important primary step in the safety evaluation of (novel) proteins, such as the enzymes used in a range of consumer laundry products. In the past this has been achieved by assessing the relative ability of proteins to give rise to the formation of anaphylactic antibody in the guinea pig. Recently, an alternative model has been proposed which assesses the formation of specific IgG1 antibody in a mouse intranasal test (MINT), the assumption being that specific IgG1 antibody is a surrogate for anaphylactic antibody in the mouse. This procedure has undergone successful initial intralaboratory and interlaboratory assessment. In the present work, the MINT has been evaluated in a more thorough intralaboratory study using eight enzymes plus ovalbumin. While the data generated with a reference enzyme protein, Alcalase, showed good reproducibility, results with the remaining eight proteins led to estimates of their relative antigenic or sensitization potential several of which were at variance from those derived from the guinea pig/human experience. In consequence, it is concluded that the MINT requires substantial further investigation before it can be adopted as a model for the assessment of the relative ability of proteins to behave as respiratory allergens.

Suppression of induction of experimental immune mediated blepharoconjunctivitis by tolerogenic conjugates of the antigen and monomethoxypolyethylene glycol

AIMCovalent conjugates consisting of diverse antigens coupled to optimal numbers of monomethoxypolyethylene glycol (mPEG) molecules have been shown to suppress antigen specific antibody formation. In this study, the possibility was...