ANTIBODIES DIRECTED TO THE CHEMOTACTIC FACTOR RECEPTOR DETECT DIFFERENCES BETWEEN CHEMOTACTICALLY NORMAL AND DEFECTIVE NEUTROPHILS FROM LJP PATIENTS

Localized juvenile periodontitis (LJP) is a progressively destructive infection of the supporting tissues of the teeth, primarily affecting adolescents. In this disease, patients' polymorphonuclear leukocytes (PMN) exhibit decreased chemotaxis (CTX) and decreased binding of the chemotactic peptide N-formyl-l-methionyl-l-leucyl-l-phenyl-alanine (FMLP) to specific receptors on the PMN surface. Since the FMLP receptor is involved in the activation of the PMN, and its subsequent response to chemotactic stimuli, a decrease in the chemotactic peptide receptor, as seen in LJP patients, is suspected to be a predisposing factor for this disease. To define differences in the FMLP receptor between CTX defective LJP patients and CTX normal donors, a battery of monoclonal antibodies reactive against the FMLP receptor was prepared. The FMLP receptor was affinity-purified, and was found to be comprised of two components, one of 68 kDa, and the other of 94 kDa. Only the 68 kDa component specifically bound a radioiodinated FMLP analogue in a photoaffinity experiment. Seven monoclonal antibodies were selected on the basis of their reactivity with the 68 kDa receptor component, and of these, 5 showed reduced binding against PMN from CTX defective LJP donors when compared to their reactivity against PMN from CTX normal subjects. Two of the 7 anti-68 kDa antibodies reacted with PMN from both sets of subjects at a comparable extent. Furthermore, the presence of 20 nmol of FMLP inhibited the binding of 5 of the anti-receptor antibodies to whole PMN, including one that showed no difference in binding between CTX normal and defective PMN, and 4 of the 5 that did show such difference.(ABSTRACT TRUNCATED AT 250 WORDS)