Human reagins to grass pollens and moulds: their purification and physico-chemical characterization.

Abstract

Chromatography of reaginic sera (to grass pollens and to moulds) on DEAE-cellulose leads to the concentration of reagins in three well separated fractions. They emerge (a) together with siderophilin, (b) with the early albumin-containing fractions, and (c) in association with strongly adsorbed proteins that require a comparatively high ionic strength buffer for their elution. The proportion of reagins in each of these fractions varies with different sera and with small alterations in the experimental procedure. All three reaginic fractions contain small amounts of γ globulins (referred to as R globulins) of mobilities slightly less than that of siderophilin; (c) contains much α(2M) globulin and there are traces of α(2M) in (a) and (b). Yet the bulk of the γ globulins are shown to be free from reaginic activity, and the same is true of the α(2M) and the β(2M) globulins, of siderophilin and of albumin. The purer the reaginic fractions are the smaller is the portion of the reagins that can be precipitated with the γ globulins by half saturation with ammonium sulphate. In contrast to the bulk of the γ globulins, R globulins and reagins appear to associate readily with other serum proteins, particularly with α(2M) globulins. Fractionation with sodium sulphate produces three fractions of similar potency although they have little in common; one consists of the bulk of the γ globulins (0–15 per cent w/v), the most active fraction of the remaining globulins (15–18 per cent) and the third fraction (supernatant from the 18 per cent precipitate) of albumin containing some α globulins, but only a trace of γ globulin. Ultracentrifugation studies on three main reaginic DEAE-fractions show that the bulk of the reagins are not macroglobulins although misinterpretation can arise from complex formation with α(2M) globulin. High agglutination titres (Stavitsky's method, Stavitsky and Arquilla, 1958) for pollen proteins are associated only with the unretarded non-reaginic γ globulins of post-treatment sera (which contain the blocking antibodies) although traces of agglutinating antibodies can be demonstrated in many fractions, including the reaginic fractions derived from the sera of untreated hay fever subjects.