Ragweed Allergen Research Articles

Reactivity of ragweed allergens with IgE antibodies: Analyses by leukocyte histamine release and the radioallergosorbent test and determination of cross-reactivity

Five distinct proteins with allergenic activity have been isolated from short ragweed pollen. We initially tested three of these, AgE, AgK, and Ra3, for reactivity with IgE antibodies by leukocyte histamine release and by the radioallergosorbent test (RAST). We found highly significant correlations between the reactivities of these allergens by leukocyte histamine release and by the RAST, consistent with the view that both procedures detected comparable allergenic activity. We next tested the allergenic cross-reactivity of all five ragweed allergens, AgE, AgK, Ra3, Ra4, and Ra5, by RAST inhibition. With solid-phase AgE the only nonhomologous inhibitor was AgK, which cross-reacted weakly and required a 140-fold mass excess of AgK compared to AgE. With solid-phase AgK both AgK and AgE produced significant inhibition; AgE was slightly more potent than the homologous AgK. Ra3 and Ra5 were allergenically unique, because only the homologous allergen produced 50% inhibition. Ra4 was weakly inhibited by AgE, Ra3, and Ra5 when these allergens were added in 300- to 500-fold mass excesses: this weak inhibition may represent either cross-reaction or cross-contamination. We found that RAST inhibition could be used as an assay for the individual ragweed allergens and we demonstrated the presence of all of the allergens in a whole ragweed extract. The sensitivity of the RAST inhibition assay ranged from 10 ng to 100 ng for 50% inhibition. Finally, the solid-phase ragweed allergens were used to determine the frequency of elevated IgE antibody levels in 65 patients with ragweed hay fever. Virtually all of the patients reacted with AgE (97%), while 88% reacted with AgK, 51% reacted with Ra3, 28% reacted with Ra4, and 17% reacted with Ra5. These results highlight the usefulness of the RAST as a specific and sensitive tool for immunochemical studies of allergens.

Quantitation of IgE antibody specific for ragweed and grass allergens: Binding of radiolabeled allergens by solid-phase bound IgE

IgE antibody specific for multiple allergens extracted from grass and ragweed pollens was measured by radioimmunoassay. The assay depends on the interaction between IgE antibody bound to a polystyrene solid phase, 125 I-labeled grass allergens (GA), and ragweed allergens (RW). The binding of 125 I RW by serum IgE antibody from 37 allergic patients ranged from 0.2 ng to 75 ng RW protein (P) bound per ml. This binding of 125 I RW by patient's IgE was paralleled by their IgE binding of 125 I antigen E (AgE), a purified allergen from ragweed pollen (r = 0.90, p < 0.001). Inhibition of patient's IgE binding of 125 I RW by highly purified AgE ranged from 25% to 85% indicating individual differences in patient's IgE response to inhaled ragweed pollen. The binding of 125 I GA by serum IgE antibody from 7 grass-sensitive patients ranged from 0.6 ng GA P bound per ml to 15 ng. This assay should be useful in the study of IgE responses to environmental agents containing multiple allergens and has the advantage that other antibody classes cannot interfere with the interaction between IgE antibody and labeled allergens.

Flow-Volume Curves in Patients With Allergic Rhinitis

This study was undertaken in order to determine whether or not the lower airways of men are influenced by ragweed and house dust allergens to a degree comparable to that of dynamic pulmonary function tests. Through a careful analysis of the expiratory spirograms, the maximum expiratory flow-volume curves, and the respiratory resistance among nine patients with ragweed allergic rhinitis and 15 with house dust nasal allergy, it was determined that the ragweed allergic patients maintained a normal pulmonary function throughout the experiments. On the contrary, the house dust allergic patients maintained normal baseline, but their expiratory flow rate at 50 percent and 25 percent levels of the vital capacity showed a tendency to decrease respectively. In addition, after the bronchodilator drug inhalation, the flow-volume curve returned toward the normal pattern for the patients with house dust nasal allergy. The hyperresponsiveness to the bronchodilator drug inhalation is similar to that found in asymptomatic bronchial asthma. It might be suggested that the differences between the two groups of the nasal allergic patients are due to the different types of causative allergens, and especially to the size of the causative allergens particle as it is indicated by several allergologists. The maximum expiratory flow-volume curve is easily obtainable, reproducible, and is more enabling to detect obstructive changes in the lower airways.

Lymphocyte responses to purified ragweed allergens in vitro: I. Proliferative responses in normal, newborn, agammaglobulinemic, and atopic subjects

To evaluate cell-mediated immune responsiveness to pollen allergens in atopic subjects, we studied the deoxyribonucleic acid (DNA) synthetic responses of their cultured lymphocytes to purified ragweed antigens E, K, and Ra-3. Since lymphocytes from some highly ragweed-sensitive subjects gave poor proliferative responses when harvested on day 6, we undertook a series of dose-response and time-course studies in atopic and control subjects. Surprisingly, vigorous DNA synthetic responses to antigen E occurred with lymphocytes from all 45 subjects, including 19 highly ragweed-sensitive atopic adults (8 immunotherapy treated, 11 untreated); 13 nonatopic controls; 4 newborns, and 9 agammaglobulinemic patients. The geometric mean of peak response counts per minute in all 45 subjects was 21,163 and in unstimulated cultures was 2,416 (p = < 0.0001). The mean day on which the maximal responses occurred was 8.7, and the mean dose eliciting the maximum responses was 59 μ/ml. Statistical comparisons of the stimulated culture data revealed no significant intergroup differences. The finding of vigorous responsiveness to these purified pollen allergens by lymphocytes from nonatopic normal, newborn, and agammaglobulinemic subjects suggests that ragweed pollen antigens are either ubiquitous and lead to cell-mediated responsiveness in all subjects with intact cell-mediated inmunity, or that they may have mitogenic properties in addition to their known antigenic properties.

Hyperthermia and Cellular Immunity-Reply

Modification of antigens does improve immunity to ragweed and other allergens. Heating tumor antigen could modify it in a way which stimulates immunity. Immunization of mice with heated Ehrlich carcinoma cells induced greater protection to implantation with viable cells than did immunization with radiation-killed cells. 1 The present work suggests that heated antigen may be a better stimulus in humans.

Non-pollen sources of short ragweed allergens

Non-pollen sources of short ragweed allergens

Physicochemical Properties of Reaginic Antibody

Summary Serum fractions from ragweed sensitive patients were heated at 56°C for 2 to 4 hr and the effect of this treatment on the γG-, γA- and γE-antibodies against purified ragweed allergen (antigen E) was studied. After heating, both γG- and γA-antibodies showed radioactive precipitin bands in radioimmunodiffusion, whereas the γE radioactive band was lost. Disappearance of the radioactive γE band on heating is not due to loss of antigen-binding activity of γE-antibody but to loss of precipitability of the protein with anti-γE-antibody. By the heat-treatment, skinsensitizing γE-antibody was changed to blocking antibody. It was also found that a fraction containing γE-globulin nonspecifically blocked passive sensitization of human skin with reaginic antibody, and that the blocking activity of the preparation was lost by heating. The results indicate that the major reason for inactivation of skin sensitizing activity by heating is the loss of affinity of γE-antibody for human skin tissues rather than to destruction of the antibody-combinding sites of the molecule.

Induction of passive cutaneous anaphylaxis in monkeys by human γE antibody

Serum and serum fractions from ragweed-sensitive patients were tested for their ability to induce passive cutaneous anaphylaxis (PCA) in Macaca irus. When purified ragweed allergen (antigen E) was used, the ability of the samples to induce the PCA reactions paralleled their skin-sensitizing activity in Prausnitz-Küstner reactions in humans and correlated with the concentration of γE antibody as measured by allergen-binding activity. The titer of the samples in the PCA reactions bore no correlation with either γG or γA antibody level. The allergen-binding activity of γE antibody in six different samples containing the minimal amount required to give positive PCA reactions was of the order of 0.00015 to 0.00035 mcg. of antigen E. This dose of the antibody is equivalent to 5×10 −5 mcg.N of rabbit antibody to the same antigen, with respect to allergen-binding activity. One thousand times as much γG antibody and 20 times as much γA antibody were incapable of inducing a positive PCA reaction. The presence of excess γG antibody in the γE antibody-containing samples for sensitization neither prevented nor enhanced the PCA reaction. The skin-sensitizing activity of a patient's serum and its reagin-rich fraction were lost by the precipitation of γE-globulin, whereas the precipitation of γA- and γG-globulins in the fraction did not diminish the activity. These findings indicate that γE antibody is responsible for the PCA reactions in monkeys. It was also found that as much as 1 mcg.N of rabbit γG antibody to antigen E did not give PCA reactions in monkeys, whereas 0.003 mcg.N of the antibody was sufficient to give the reactions in guinea pigs.

The antibody mechanisms of ragweed allergy; electrophoretic and chemical studies. I. The blocking antibody.

Three human serums containing artificially produced blocking antibody against low ragweed allergen were studied for the possibility of relating blocking antibody to electrophoretically definable components. An adaptation of the qualitative passive transfer test to quantitative interpretation is described, methods and procedures are given and uncertainties and possible errors due to lack of precision and accuracy are presented and discussed. At least 65 per cent, but probably more, if not all of the blocking antibody is attributable to gamma globulin. However, no rise of gamma globulin, either its absolute amount or its relative percentage value, paralleled the appearance of blocking antibody. Blocking antibody is not contained in albumin or in alpha-1 globulin. Blocking effect could not be ascertained unequivocally as being connected with alpha-2 or with beta globulin and sizable participation of these two latter electrophoretic components appears improbable. Blocking antibody and sensitizing antibody appear to be chemically different entities.