Fractionation and biological characterization of Olea europea pollen extract

Preliminary fractionation of Olea european pollen extract has been performed. At least 10 antigenic fractions have been found by crossed electrophoresis. After Sephadex gel filtration, two fractions with a molecular weight of 160,000 and 65,000 have been obtained. The fractions were evaluated for allergenic activity by two in vitro techniques: polystyrene tube radioimmunoassay (PTRIA) and basophil degranulation test (BDT), and by skin tests. All tests indicated that the most reactive fractions were those in the 65,000 molecular weight peak. BDT has been shown to be a very reliable method as compared with histamine release and other parameters. Although common antigenic fractions have been found for Lollium perenne and O. europea, no cross-allergenicity has been shown by PTRIA inhibition.

IgG antibodies: in vitro blocking activity of IgE mediated reactions

Sera from 177 atopic patients treated by immunotherapy were screened in order to detect IgD antibodies against a purified fraction of Lollium perenne (fractions C). IgD antibodies were found in 23% of the subjects. Eight of these sera were selected and their IgD isolated by means of immunoabsorption. The in vitro biological activity of the IgD antibodies against fraction C was tested by three methods: basophil degranulation, histamine release and RAST inhibition test. In all these assays, the data obtained indicated a possible blocking effect of the IgD antibodies upon the IgE in vitro mediated reactions.

Role of T gamma cells in the in vitro IgE response after antigenic stimulation

Fifteen patients with seasonal allergic pollenosis and five controls were investigated to elucidate the role of the T gamma-cell population in the in vitro IgE response by peripheral blood lymphocytes (PBL). In vitro IgE production by PBL of atopic patients after antigenic stimulation was measured in culture supernatants. The optimal dose for antigenic stimulation was found to be 0.16 micrograms/20 X 10(6) cells of purified antigen. No difference was found when comparing the percentages of T cells (E rosettes) between the two groups: mean per cent for controls was 69.2 +/- 5.76 versus 69.54 +/- 4.42 for the allergic group. With regard to the T gamma-cell population, the values obtained by rosetting with ox erythrocytes sensitized with IgG antibody were 12 +/- 0.71% in normals and 9.8 +/- 1.32% in those with allergic pollenosis. This difference, although significant, may not be enough to explain the different pattern when the in vitro IgE production of both groups investigated was compared. In order to detect the role of T gamma cells in this system, lymphocyte cultures, depleted of T gamma cells, were performed and compared with unfractionated cultures from the same donors. Our results show no differences in the in vitro IgE production when T gamma cells were depleted as compared with the unfractionated cultures.

In vitro production of IgE and IgG by sensitized human peripheral lymphocytes

Antigenic stimulation of peripheral lymphocytes was made in two different groups of atopic patients, testing their capabilities to produce IgE and IgG in vitro. For this purpose, Marbrook's technique was used in the cultures. The immunoglobulins produced were measured in the supernatants by a sensitive double-antibody method. Results demonstrate that it is possible to produce enough IgE and IgG to be detected. Some important parameters had to be considered: appropriate selection of the patients and the antigens used in the antigenic stimulation, as well as the number of cells and the duration of the culture.