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The Requirements for Transferrin‐Dependent Adherence of Human Granulocytes to Pollen Grains
Author(s) -
Mackay J. A.,
SassKuhn S.,
Moqbel R.,
Walsh G. M.,
Kay A. B.
Publication year - 1986
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.1986.tb00297.x
Subject(s) - transferrin , pollen , lactoferrin , transferrin receptor , sephadex , ovalbumin , granulocyte , albumin , receptor , immunology , biochemistry , biology , chemistry , antigen , botany , enzyme
Human granulocyte/pollen binding protein (GPBP), previously identified as serum transferrin, promoted prolonged firm adherence of neutrophils to Timothy grass pollen. Some characteristics of this adherence reaction are reported. GPBP‐induced binding was time‐, temperature‐ and concentration‐dependent. Maximal adherence was observed by 2 h and was only slightly decreased at 18 h. The optimal temperature for adherence was 37° C. Concentrations of GPBP as low as 1.25 μ g/ml gave significantly greater binding than the albumin or lactoferrin control. Eosinophils, monocytes and lymphocytes did not appear to participate in GPBP‐induced pollen binding reactions at concentrations up to 300 μg/ml. In the presence of GPBP, neutrophils adhered to a range of grass, weed and tree pollens. These included timothy, meadow, false oat, rye, giant and short ragweed, plantain, silver birch and ash. GPBP did not facilitate the adherence of granulocytes to inert particles of similar size such as Sephadex beads and agarose. The adherence was Mg ++ ‐ but not Ca ++ ‐ dependent and was not inhibited by a monoclonal antibody to the transferrin receptor (OKT9). Transferrin/GPBP did not bind to either neutrophils or pollen grains. A purified commercial transferrin reacted in all respects like GPBP in these pollen binding studies. These observations indicate that GPBP/transferrin‐induced adherence of granulocytes to pollen grains is a hitherto unrecognized property of transferrin which appears unrelated to iron transport or the conventional transferrin receptor.