R-MC46 monoclonal antibody stimulates adhesion and phagocytosis by rat macrophages.
BACKGROUND
In our previous experiments it was shown that R-MC46 monoclonal antibody (mAb), produced at our Institute, stimulated homotypic aggregation of rat granulocytes and production ofproinflammatory cytokines. The aim of this study was to examine antigen expression and function, recognized by R-MC46 mAb on macrophages.


METHODS
The expression of R-MC46 antigen on thymic and peritoneal macrophages was investigated using immunocytochemistry and flow cytometry methods. Its biochemical characterization was performed by Western blot. The ability of R-MC46 mAb to modulate adhesion and phagocytosis by macrophages was studied by using co-culture experiments with autologous thymocytes.


RESULTS
R-MC46 mAb stained thymic macrophages more strongly than peritoneal macrophages. After in vivo treatment of peritoneal macrophages with Pristane, a significant up-regulation of the R-MC46 antigen expression was observed Western blot analysis showed that the mAb recognized a low molecular weight antigen of about 5.5 kDa. R-MC46 mAb significantly enhanced binding and phagocytosis of thymocytes by both thymic and peritoneal macrophages. These processes were completely blocked by WT.3 (anti-CD18) mAb. The stimulation of binding thymocyte to macrophages was higher with the use of thymic macrophages,while the phagocytosis of these cells was higher in the presence of peritoneal macrophages.


CONCLUSIONS
R-MC46 mAb recognized a new molecule expressed by rat macrophages. The antigen is most probably involved in 82 integrin-mediated adhesion and phagocytosis, as well as proinflammatory functions of macrophages.
Gasić
Sonja
S
Military Medical Academy, Institute for Medical Research, Belgrade. vmaimi@eunet.yu
Vucević
Dragana
D
Popović
Petar
P
Vasilijić
Sasa
S
Colić
Miodrag
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D000954:Antigens, Surface / Q000276:immunology; D018821:CD18 Antigens / Q000276:immunology; D002448:Cell Adhesion; D018920:Coculture Techniques; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology / Q000502:physiology; D010587:Phagocytosis; D051381:Rats; D011919:Rats, Inbred Strains; D013950:Thymus Gland / Q000166:cytology
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D018821:CD18 Antigens