Recognition of human polymorphonuclear leukocyte receptors for leukotriene B4 by rabbit anti-idiotypic antibodies to a mouse monoclonal antileukotriene B4

Rabbit anti-idiotypic IgG antibodies to the combining site of a mouse monoclonal IgG2b antibody to leukotriene B4 (LTB4) cross-reacted with human polymorphonuclear (PMN) leukocyte receptors for LTB4. Anti-idiotypic IgG and Fab both inhibited the binding of [3H]LTB4, but not [3H]N-formylmethionyl-leucylphenylalanine (fMLP), to PMN leukocytes with similar concentration-effect relationships, whereas neither nonimmune rabbit IgG nor Fab had any inhibitory activity. At a concentration of anti-idiotypic IgG that inhibited by 50% the binding of [3H] LTB4 to PMN leukocytes, the antibodies preferentially recognized high affinity receptors. Anti-idiotypic IgG and Fab inhibited PMN leukocyte chemotactic responses to LTB4, but not fMLP, with concentration-effect relationships resembling those characteristic of the inhibition of binding of [3H] LTB4, without altering the LTB4-induced release of beta-glucuronidase. Chemotaxis and increases in the cytoplasmic concentration of calcium equal in magnitude to those elicited by optimal concentrations of LTB4 were attained at respective concentrations of anti-idiotypic IgG equal to and 1/25 the level required for inhibition of binding of [3H]LTB4 by approximately 50%. Thus, the anti-idiotypic antibodies bound to PMN leukocyte receptors for LTB4 with a specificity, preference for high affinity sites, and capacity to alter PMN leukocyte functions that were similar to LTB4.