AUGMENTATION OF MOUSE NATURAL KILLER CELL ACTIVITY BY ALLOANTIBODY: A REVERSE ADCC REACTION

Abstract

Publisher Summary This chapter discusses a reverse antibody-dependent cell-mediated cytotoxicity (ADCC) reaction. The human leukemia cell line K562 is only moderately susceptible to lysis by mouse spleen cells but the effector cells treated with specific anti H-2 antiserum have considerably enhanced levels of anti-K562 natural killer (NK) activity. Alloantiserum NK augmentation can be demonstrated either by including the effector-cell reactive alloantiserum in the cytotoxicity incubation medium or by using effector-cell preparations pretreated with the alloantiserum. Anti-K562 NK activity of spleen-cell preparations depleted of T-cells, B-cells, or macrophages can still be augmented by alloantisera, indicating that T-cells, B-cells, and macrophages are not required in the NK activation process and that the alloantibody may exert its effect directly by binding to NK effector cells. Certain other NK-activating agents such as interferon, interferon inducers, and mitogens require a lag period of several hours before optimal NK augmentation takes place and their effects can invariably be blocked by actinomycin-D. A facilitated effector target interaction may be conceived in which the Fc region of effector-cell-bound antibody interacts with Fc receptors on target cells.