Regulatory role for the immune complex in modulation of phagocytosis by 3-deazaadenosine.
The S-adenosyl-L-homocysteine hydrolase inhibitor 3-deazaadenosine (3-DAA) modulates antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent phagocytosis (AD phi) by mouse spleen effector cells and antibody-coated erythrocyte target cells. Concentrations of this compound inhibiting ADCC caused augmentation of phagocytosis. In a modified version of these assays referred to as complement-independent cellular cytotoxicity (CICC) and complement-independent phagocytosis (CI phi), specifically immune spleen cells were the source of effector cells and antitarget antibodies. CICC and CI phi were assayed with antiserum-untreated erythrocyte target cells. Although CICC was inhibited, 3-DAA failed to induce augmentation of phagocytosis in CI phi assays. Augmentation was restored by the presence of antibody-coated targets. If 3-DAA was present before the initiation of the assay by the addition of antibody-coated targets, it also failed to augment conventional AD phi. Varying dilutions of the antiserum, used for the preparation of antibody-coated target cells, induced differential effects of 3-DAA on phagocytosis. A regulatory interaction between the target cell antigen-antibody complex and the action of 3-DAA on phagocytosis has been suggested.
D043383:Adenosylhomocysteinase; D000818:Animals; D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects; D000936:Antigen-Antibody Complex / Q000502:physiology*; D003165:Complement System Proteins / Q000378:metabolism; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D006867:Hydrolases / Q000378:metabolism; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D010587:Phagocytosis / Q000187:drug effects*; D012263:Ribonucleosides / Q000494:pharmacology*; D013154:Spleen / Q000166:cytology; D014372:Tubercidin / Q000494:pharmacology*
D000936:Antigen-Antibody Complex; D012263:Ribonucleosides; C018258:3-deazaadenosine; D003165:Complement System Proteins; D006867:Hydrolases; D043383:Adenosylhomocysteinase; D014372:Tubercidin