Studies on leukocyte adherence inhibition test. Part I. Studies on mechanisms of leukocyte adherence inhibition.

Mechanisms of leukocyte adherence inhibition (LAI) phenomenon were investigated by utilizing Halliday's hemacytometer method. When guinea pig were immunized with dinitrophenyl conjugated bovine serum albumin (DNP BSA) with Freund's complete adjuvant, the adherence of their leukocytes to glass surface is markedly inhibited by the presence of BSA or PPD, but not by bovine gammaglobulin (BGG). Percent leukocyte adherence inhibition (% LAI Mean •} S.D.) is 46.6 •} 1.9, 42.7 •} 1.7 and 3.2 •} 8.2, respectively. When immunized with DNP-BGG, % LAI is 34.5 •} 5.8, 42.9 •} 2.6 and 6.9 •} 3.9 by incubated with BGG, PPD and BSA, respectively. Thus LAI phe nomenon is carrier specific reaction. While the whole blood leukocytes react with the specific antigen and showed positive LAI, but not polymorphonuclear leukocytes. This result indicates that mononuclear leukocytes (MNL), that is lymphocytes and monocytes, are effector and indicator cells. Adherence of leukocytes from guinea pigs producing antibody are not inhibited by antigen. Sera containing antibody or antigen-antibody complex did not sensitize normal cells to antigen. Lymphokine can perform LAI phenomenon to normal leuko cytes, but a half to twelve hours culture supernatant of MNL with the specific antigen can not. These findings indicate that LAI psenomenon is the expres sion of cell-mediated immunity, and partly mediated by soluble substances other than lymphokine.