Combining site specificities of rabbit antibodies to platelet-activating factor (PAF).
Anti-PAF sera from six different rabbits, immunized with C12- or C6-PAF as immunogen, were examined in hapten inhibition experiments in an attempt to define the fine structural recognition specificities of the antibody combining sites. Using a selection of naturally occurring lipids and PAF analogues, no significant cross-reactivity was observed with the lipids or with the inactive metabolite, lyso-PAF. Comparison of the structural specificity requirements of the antibodies from each rabbit showed some heterogeneity, with one antiserum demonstrating a different recognition specificity at position 1 on the glycerol backbone of the PAF molecule. A second rabbit antiserum showed a large degree of tolerance for analogues with increasing acyl chain length at position 2. In general, an ether group at position 1 and an acetyl at position 2 were required for inhibitory activity and a degree of tolerance was demonstrated at position 3, where the main structural requirement was for one or more methyl groups on the nitrogen atom of the phosphocholine moiety.
Cooney
S J
SJ
Kolling Institute of Medical Research, Royal North Shore Hospital, Sydney, St Leonards, NSW.
Smal
M A
MA
Harle
D G
DG
Baldo
B A
BA
D000818:Animals; D000918:Antibody Specificity; D003429:Cross Reactions; D006241:Haptens / Q000276:immunology; D008055:Lipids / Q000276:immunology; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000276:immunology*; D011817:Rabbits; D011863:Radioimmunoassay
D006241:Haptens; D008055:Lipids; D010972:Platelet Activating Factor