Per Ivar Gaarder

Diesel exhaust particles and carbon black have adjuvant activity on the local lymph node response and systemic IgE production to ovalbumin

The possible adjuvant effect of diesel exhaust particles (DEP) on the response to the model allergen ovalbumin (OA) was studied in BALB/c mice using the popliteal lymph node (PLN) assay. In addition to changes in PLN weight, cell numbers and cell proliferation, specific serum IgE anti-OA antibody levels were measured. OA inoculated together with DEP into one hind footpad gave a significantly augmented response (increase in weight, cell numbers and cell proliferation) in the draining popliteal lymph node as compared to DEP or OA alone. Also, the local lymph node response was of longer duration when DEP were given with the allergen. Experiments in thymus-deficient nu/nu mice indicated that the lymph node response observed in BALB/c mice was of a specific immunologic character and not an unspecific inflammatory reaction. The OA-specific IgE response was increased in mice receiving OA together with DEP as compared to the response in mice receiving OA without DEP. Carbon black (CB) was given with and without OA in some experiments, as a surrogate for the non-extractable core of DEP. CB was found to resemble DEP in its capacity to increase the local lymph node response and serum specific IgE response to OA, but CB appeared to be slightly less potent than DEP. Thus, both DEP and CB had a significant adjuvant effect on the local immune-mediated inflammatory response and on the systemic specific IgE response to allergen. The results indicate that the non-extractable particle core contributes substantially to the adjuvant activity of DEP.

Fine particles of widely different composition have an adjuvant effect on the production of allergen-specific antibodies

Diesel exhaust particles (DEP) are reported to increase the specific IgE response to allergens, and results from our laboratory suggest that the particle core of DEP contribute to this adjuvant activity. The purpose of the present study was to explore further the adjuvant effect of particles per se, that is particles by themselves. NIH/Ola mice were given two intraperitoneal injections with ovalbumin (OVA; 10 microg) alone or OVA in combination with PSP, polytetrafluoroethylene (teflon), titanium dioxide (TiO(2)) or amorphous silica particles (2.8x10(10)-2.8x10(12)). Blood samples were drawn 7 days after the last injection, and serum levels of allergen-specific and total IgE and IgG2a were measured. All types of particles gave increased levels of allergen-specific IgE and IgG2a. Similar results were obtained after intranasal or intratracheal instillation with OVA plus PSP or silica. Our results indicate that fine particles of widely different composition may have an adjuvant effect on the production of allergen-specific antibodies.

Airborne house dust elicits a local lymph node reaction and has an adjuvant effect on specific IgE production in the mouse

Indoor suspended particulate matter (SPM) consists of many different types of particles, the vast majority of which are less than 2.5 microm in diameter. An important question is how these particles, being inhalable, contribute to asthma and respiratory symptoms. One possibility is that these particles have an adjuvant effect on the immune response and increase the IgE production, or cause a non-specific irritation in the airways, contributing to bronchial hyper-responsiveness. In this study, the adjuvant activity of indoor SPM on the response to the model allergen ovalbumin (OA) in BALB/c mice was investigated, using the popliteal lymph node (PLN) assay. The adjuvant activity on the local lymph node response was determined by measuring the PLN weight, cell numbers and cell proliferation, and the adjuvant activity on the IgE production by measuring the levels of serum IgE specific to OA. SPM was found to give a significant PLN response, both when injected alone and together with OA. SPM was also found to enhance the production of specific IgE to OA when injected together with OA, after reinjection with OA, compared with immunisation with OA alone.

IgE adjuvant effect caused by particles — immediate and delayed effects

Diesel exhaust particles are reported to increase the specific IgE response to ovalbumin (OVA) and pollen. Evidence has been provided that the particle core contributes to this adjuvant activity. The purpose of our study was to investigate the effect of well-defined simple particles, polystyrene particles (PSP), on the production of allergen-specific IgE in a mouse model. The IgE adjuvant effect of PSP was investigated in experiments using intranasal (i.n.) instillation, intratracheal (i.t.) instillation or intraperitoneal (i.p.) injection. Delayed and cumulative adjuvant effects were investigated by giving mice i.p. injections with PSP 1-3 days, or on 4 consecutive days before OVA, respectively. The levels of allergen-specific and total IgE were measured. Irrespectively of immunisation route and protocol, OVA in combination with PSP elicited increased levels of both allergen-specific and total IgE when compared with OVA alone. Therefore, in the experimental model, particles were found to augment the specific IgE response to an allergen even when the allergen was introduced several days after the particles. These findings imply that individuals exposed to particulate air pollution at one point of time may develop an increased reaction towards allergens inhaled later that day or even several days after the particle exposure.

Preserved splenic function after angioembolisation of high grade injury

BACKGROUND After introducing splenic artery embolisation (SAE) in the institutional treatment protocol for splenic injury, we wanted to evaluate the effects of SAE on splenic function and assess the need for immunisation in SAE treated patients. METHODS 15 SAE patients and 14 splenectomised (SPL) patients were included and 29 healthy blood donors volunteered as controls. Clinical examination, medical history, general blood counts, immunoglobulin quantifications and flowcytometric analysis of lymphocyte phenotypes were performed. Peripheral blood smears from all patients and controls were examined for Howell-Jolly (H-J) bodies. Abdominal doppler, gray scale and contrast enhanced ultrasound (CEUS) were performed on all the SAE patients. RESULTS Leukocyte and platelet counts were elevated in both SAE and SPL individuals compared to controls. The proportion of memory B-lymphocytes did not differ significantly from controls in either group. In the SAE group total IgA, IgM and IgG levels as well as pneumococcal serotype specific IgG and IgM antibody levels did not differ from the control group. In the SPL group total IgA and IgG Pneumovax(®) (PPV23) antibody levels were significantly increased, and 5 of 12 pneumococcal serotype specific IgGs and IgMs were significantly elevated. H-J bodies were only detected in the SPL group. CEUS confirmed normal sized and well perfused spleens in all SAE patients. CONCLUSION In our study non-operative management (NOM) of high grade splenic injuries including SAE, was followed by an increase in total leukocyte and platelet counts. Normal levels of immunoglobulins and memory B cells, absence of H-J bodies and preserved splenic size and intraparenchymal blood flow suggest that SAE has only minor impact on splenic function and that immunisation probably is unnecessary.

Scanning electron microscopy of immunogold labeled cat allergens (Fel d 1) on the surface of airborne house dust particles.

This study investigated the ability of an immunogold labeling technique to demonstrate the presence of Fel d 1 (domestic cat) allergens on the surface of particles in samples of airborne house dust. Suspended particulate matter was sampled from ten Norwegian households, five with and five without a domestic cat. The specimens were immunogold labeled and examined in the backscatter electron imaging mode of the scanning electron microscope and in the transmission electron microscope. X-ray microanalysis was also applied to execute element analysis of the suspended particular matter. The gold probe was mainly detected on carbon particles in the suspended particulate matter, both on small (< 1 microns) and larger carbon aggregates (1-10 microns). The present method may be useful in studying the localisation of different allergens on airborne house dust particles of various sizes and composition.

The Adjuvant Effect of Particles – Importance of Genetic Background and Pre-Sensitisation

Background: We have previously reported that simple and well-characterised particles, such as polystyrene particles (PSP), have an IgE adjuvant effect in mice. The purpose of this study was to explore the importance of genetic background concerning the adjuvant effect of PSP in different strains of mice. Methods: Inbred NIH/Ola, BALB/c and C3H/HeJ mice were given two intraperitoneal injections with either PSP plus OVA or OVA alone, and then an intraperitoneal challenge with OVA alone. NIH/Ola mice were also pre-sensitised to develop a weak or strong IgE response to OVA, and then given an intraperitoneal challenge with PSP plus OVA or OVA alone. Serum levels of total and allergen-specific IgE and IgG2a were measured. Results: PSP had a specific IgE and IgG2a adjuvant effect in NIH/Ola mice but not in C3H/HeJ and BALB/c mice. Weakly pre-sensitised NIH/Ola mice showed the same response pattern as the naive NIH/Ola mice. In contrast, strongly pre-sensitised mice showed an antibody response pattern similar to that of high-responder BALB/c mice. Conclusions: Our results indicate that the allergen responder status, either genetic or induced, is of importance for the adjuvant effect from particles. The IgE and IgG2a adjuvant effect may depend on the genetically determined susceptibility of an individual to be influenced by exposure to the adjuvant. Therefore, the allergy-enhancing effect from particle pollution may differ between individuals.

IgE ADJUVANT ACTIVITY OF PARTICLES-WHAT PHYSICAL CHARACTERISTICS ARE IMPORTANT?

Diesel exhaust particles (DEP) are reported to increase the allergic immune response to ovalbumin (OVA) and pollen. There are studies reporting that both the adsorbed chemical substances and the carbon core of DEP may contribute to the immunoglobulin E (IgE) adjuvant effect. The aim of this study was to investigate which physical properties of particles per se, that is, the particles by themselves, might be important for their IgE adjuvant effect, namely, dose weight, size, number, and surface area. Since DEP have a tendency to form aggregates of varying shapes and sizes, evaluation of the relative importance of these characteristics is difficult using DEP. We therefore decided to use well-characterized, spherical polystyrene particles (PSP). We performed four different types of experiments, in which the total dose weight (12.25 mg), size (0.1 μm in diameter), total number (8 x 1010), or total surface area (1300 cm2) of PSP, respectively, was kept constant. NIH/Ola mice were given 2 intraperitoneal injections with PSP plus OVA or OVA alone, over a 16-day period. The mice were exsanguinated at the end of each experiment, and the serum concentration of IgE anti-OVA was measured. The serum levels of IgE anti-OVA increased with both an increasing number and surface area of PSP. We found no clear association between PSP size and the levels of IgE anti-OVA, but because of the relatively small size range of PSP used, no definitive conclusions can be made on whether size is an important factor for the IgE adjuvant effect of PSP. There seemed to be no covariation between the dose weight and the levels of IgE anti-OVA. Our findings indicate that the total number and total surface area of PSP, rather than the dose weight, are important parameters for the IgE adjuvant activity from PSP, and possibly also for particles in general.

Human IgE production in hu-PBL-SCID mice injected with birch pollen and diesel exhaust particles

Mice with severe combined immunodeficiency were transplanted with human peripheral blood lymphocytes (hu-PBL-SCID mice). The response to immunisation with birch pollen was used to study possible effects of diesel exhaust particles (DEP) and aluminium hydroxide (Al(OH)3) on human IgE production in this human in vivo model. The adjuvants were well tolerated, as determined by the number of human cells in the peritoneal cavity at the end of the experiments. Total and birch pollen-specific IgE was detected in 76 and 41% of the mice, respectively. In the present experiments where the mice were stimulated early with birch pollen, a doubling in percentage of hu-PBL-SCID mice with production of specific IgE was observed, as compared to later stimulation used in previous experiments. Although a tendency to higher total IgE levels was observed after treatment with DEP, no statistically significant adjuvant effect of DEP or Al(OH)3 could be demonstrated. Electron microscopy analysis after immunogold labelling showed that the major birch pollen allergen Bet v I was released from the pollen grains and adsorbed to the surface of the DEP. Early stimulation with allergen appears to be important for optimal production of specific IgE in the hu-PBL-SCID model. However, our results show that further improvements are needed in order to demonstrate the expected effects from adjuvants and environmental pollutants.

Total and Birch Pollen-Specific Human IgE in Mice with Severe Combined Immunodeficiency Transplanted with Human Peripheral Blood Lymphocytes: Donor Dependence, Seasonal Variation and in vivo Half-Life

BACKGROUND There is a need for animal in vivo models in the study of human allergy. The aim of the present experiments was to study production and catabolism of human IgE in mice with severe combined immunodeficiency transplanted with human peripheral blood lymphocytes (hu-PBL-SCID mice). METHODS Groups of SCID mice were transplanted intraperitoneally with hu-PBL from the same three donors in five experiments. Subgroups of transplanted mice were immunized with birch pollen. Production of human total and birch pollen-specific IgE in the hu-PBL-SCID mice was analyzed over a 7-week period. RESULTS Human IgE was detected in 93% of the hu-PBL-SCID mice, and the production showed reproducible donor-dependent kinetics. Production of birch pollen-specific human IgE, however, was seen only in mice transplanted with cells from birch pollen-allergic donors. A greater proportion of the mice produced specific IgE when the experiment was started in, or some months after a birch pollen season with high pollen counts. The half-lives of passively transferred human IgE were determined to be 24.0 and 23.4 h for total and birch pollen-specific IgE, respectively. CONCLUSIONS This study demonstrates that human IgE production in hu-PBL-SCID mice is very reproducible when the same donor is used several times. Specific IgE production in recipient mice seems to require the use of cell donors with the actual specific allergy, and is most readily obtained during or after a period of donor allergen exposure. The short half-lives found indicate that hu-PBL-SCID mice have a high ongoing production of human IgE.