Histamine release and local responses of rat and human skin to substance P and other mammalian tachykinins.

Substance P and two recently identified neurokinins, substance K and neuromedin K as well as the nonmammalian tachykinin kassinin were compared for histamine-releasing abilities from rat mast cells, plasma extravasation effects on rat skin, and wheal and flare responses on human skin. Among the four tachykinins, a significantly dose-dependent histamine release from rat mast cells and a flare response in human skin was observed only with substance P, indicating the possible implication of histamine in this response. On the other hand, the four peptides were similarly active on the wheal response (plasma extravasation produced by increased permeability of capillaries and venules) in human skin and on the plasma extravasation in the rat skin, suggesting a dissociation of effects and possibly of receptors.

Interaction of Vicia graminea anti-N lectin with cell surface glycoproteins from erythrocytes with rare blood group antigens.

The erythrocyte receptors for Vicia graminea (Vg) anti-N lectin have been investigated after 125I-labelling of the purified lectin and binding to membrane components separated by dodecyl sulphate polyacrylamide gel electrophoresis. GP alpha (synonym glycophorin A or MN glycoprotein) and GP delta (synonym glycophorin B or Ss glycoprotein) are the main Vg receptors of native human blood group NN and MN erythrocytes whereas Vg lectin only binds to GP delta from MM red cells. The glycoprotein of 28 kDa present in Mi III erythrocytes (a presumed variant of GP delta) carries Vg receptors.

Miltenberger Class I and II erythrocytes carry a variant of glycophorin A.

The membranes from Miltenberger Class I (Mi I) and II (Mi II) erythrocytes, two rare variants at the blood group MNSs locus, exhibited an abnormal glycoprotein of 32 kDa apparent molecular mass sharply stained by the periodic acid/Schiff procedure and a decreased content of glycoprotein alpha (synonym glycophorin A, glycoprotein MN) as seen on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Purified 125I-labelled Vicia graminea lectin binds to the unusual 32 kDa glycoprotein separated from Mi I and Mi II erythrocyte membrane of blood group NN or MN, but no significant labelling of this band was observed with Mi samples typed MM. On the basis of such lectin-labelling experiments we have described two heterozygous MN, Mi I individuals that carry one copy of an M gene producing a normal alpha-glycoprotein with M-specificity and one copy of a MiI gene producing a 32 kDa glycoprotein with N-specificity.