Interactions of complement with an extract of airborne spring wheat dust.

The inhalation, by grain elevator workers, of airborne grain dusts can lead to pulmonary problems. Complement, which is present in human airways, can interact with various grain dusts, producing activation products that have been shown to participate in the inflammatory reaction. Because of this apparent connection between grain-dust inhalation, complement activation, and respiratory difficulties, we are studying the reaction of an aqueous extract of spring wheat dust (swd) with human complement. The swd extract activates both the classical and alternative pathways; it acts on purified C2 to inhibit it, and it reacts with undiluted serum to consume C4 with kinetics significantly different from those shown by a "typical" antigen-antibody complex (sensitized sheep erythrocytes). Enzyme susceptibility experiments suggest that the alternative and classical pathway activators of swd extract are neither protein nor nucleic acid; periodate oxidation indicates these substances are carbohydrate, and gel filtration suggests they are macromolecular. Enzyme vulnerability also indicates that the C2 inhibitor of swd extract is ribonucleic acid. Although endotoxin is present in swd extract, a gel-filtration experiment showed that a major fraction of the complement reactivity was not associated with this substance.

Reactivity of vitamin A derivatives and analogues with vitamin A antibodies.

Vitamin A antibodies were obtained using retinoic acid conjugated to human serum albumin as an immunogen. The following constraints governed the reactivity of vitamin A analogues with such an anti-serum. The stereochemistry of the side chain is relatively unimportant, and 9- and 13-cis retinal react almost as well as all-trans retinal. The nature of the ring is important; all of the compounds that react readily carry a beta-ionic ring; all of the compounds bearing an aromatic ring react poorly; the two compounds that display intermediate reactivity have non-aromatic 6- and 5-membered rings, respectively.

Terminal stages of complement hemolysis: technical comment.

In studying terminal lytic events of sensitized erythrocytes which have reacted with all 9 components of complement, we agree in general with the conclusions of Boyle and Borsos [1] that the cellular intermediate passes through the stages E*bound, E*inserted, and E*doomed. However, we differ with these workers on the influence of 3 variables on the terminal reactions. These variables are: time of hemolysis; temperature of E* preparation; and the use of EDTA to manipulate E*.

Vitamin A antibodies: application to radioimmunoassay.

A radioimmunoassay for serum vitamin A is described which can detect as little as 1 ng of retinol. The statistical characteristics of this assay are presented and its use in a nutritional experiment is discussed.