Detection of Chlorella-specific IgE in mould-sensitized children

The content of IgE, specific to the unicellular green alga Chlorella sp., was analysed in sera from 46 atopic children sensitized to moulds, using radioallergosorbent test (RAST), immunoblotting and crossed immunoelectrophoresis/crossed radioimmunoelectrophoresis (CIE/CRIE). Chlorella-specific IgE was found in 23/46 sera by RAST, in 28/41 sera by immunoblotting and in 6/30 sera by CIE/CRIE. The Chlorella components most frequently binding IgE as analysed by gradient gel electrophoresis and immunoblotting were of molecular weights of approximately 13, 17, 19, 26 and 49 kD. Twenty-nine precipitating antigens, including seven IgE-binding precipitates were detected by CIE/CRIE. The study shows that low concentrations of specific IgE are formed to the green alga Chlorella in sera from atopic individuals sensitized to moulds.

Preparation of allergen extracts from the green alga Chlorella. Studies of growth variation, batch variation, and partial purification

Allergen extracts were prepared from different raw materials of three strains of the unicellular green alga Chlorella (C. vulgaris, C. homosphaera and C. saccharophila). Growth variation, batch variation and composition of partially purified extracts were studied by analyzing total protein and carbohydrate content, protein and IgE-binding patterns and allergenic potency. Chlorella allergens were produced in the same proportions in early and late exponential growth phases but appeared partly degraded in the stationary phase. Uniform growth and extraction from Chlorella cells in the late exponential phase were demonstrated. Partially purified extracts from cells in late exponential phase contained 50% protein of the dry weight compared to 20% in crude extracts. The carbohydrate content was 20-30% of the dry weight of both crude and purified extracts. The allergenic potency of the purified extracts was 150-340% of the crude extracts, as assayed by RAST inhibition. The purified C. vulgaris extract showed a reduced IgE binding compared to crude extracts, while C. homosphaera and C. saccharophila extracts exhibited consistent IgE binding and are therefore suitable for in vivo and in vitro studies of allergenic properties of Chlorella.

Variability of allergenicity in eight strains of the green algal genus Chlorella

Biochemical and immunological properties of allergen extracts from eight strains within four species of the unicellular green alga Chlorella were compared. The total protein and carbohydrate contents ranged from 13 to 29 and 18 to 47% of the dry weight, respectively. It was shown, both with RAST inhibition and immunoblotting, that Chlorella contain components which specifically bind to patient IgE antibodies. The relative allergen potency as assayed by RAST inhibition varied fivefold. Between seven and twenty IgE-binding components were identified in the various strains with molecular weights from 13 to 80 kD. Thus, the use of thoroughly characterized Chlorella strains is mandatory for preparation of relevant allergen extracts.

Immuno-gold localization of glutamine synthetase in a nitrogen-fixing cyanobacterium (Anabaena cylindrica)

Localization of glutamine synthetase in thin sections of nitrogen-fixing Anabaena cylindrica was performed using immuno-gold/transmission electronmicroscopy. The enzyme was present in all of the three cell types possible; vegetative cells, heterocysts and akinetes. The specific gold label was always more pronounced in heterocysts compared with vegetative cells, and showed a uniform distribution in all three types. No specific label was associated with subcellular inclusions such as carboxysomes, cyanophycin granules and polyphosphate granules. When anti-glutamine synthetase antiserum was omitted, no label was observed.