Pre-treatment with Concanavalin-A increases resistance of mice to peritoneal infection by Serratia marcescens.
Mice pre-treated with Concanavalin-A largely survived an intra-peritoneal inoculum of 2 x 10(7) Serratia marcescens, whereas all control mice died within 15 h of inoculation. A subpopulation of peritoneal macrophages from Con-A pre-treated mice was able to phagocytose the bacteria in vitro (6.7 SEM 1.2% phagocytosing cells) and in vivo (16.9 SEM 2.1%), whereas control phagocytes did not phagocytose S. marcescens. The survival of Con-A pre-treated mice allowed their immunisation with living bacteria, and the antiserum thus produced increased the phagocytosis of S. marcescens in vitro. Control mice largely survived an inoculum of S. marcescens suspended in 50% immune serum, although the bacteria were resistant to the bactericidal activity of that serum. These results suggest that, in contrast to the delayed humoral protection afforded by immunisation, phagocytosis by phagocytes activated by Con-A conferred early protection to mice against experimental infection by S. marcescens.
Arraes
S M
SM
Laboratory of Clinical Immunology, Universidade Estadual de Maringá, Brazil.
Gaziri
L C
LC
Vidotto
M C
MC
Saridakis
H O
HO
Felipe
I
I
D000818:Animals; D001770:Blood Bactericidal Activity; D003208:Concanavalin A / Q000494:pharmacology* / Q000627:therapeutic use; D007106:Immune Sera / Q000032:analysis / Q000276:immunology; D007111:Immunity, Cellular / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology; D051379:Mice; D010532:Peritoneal Diseases / Q000276:immunology* / Q000517:prevention & control; D010587:Phagocytosis / Q000187:drug effects; D016868:Serratia Infections / Q000276:immunology* / Q000517:prevention & control; D012706:Serratia marcescens / Q000276:immunology* / Q000472:pathogenicity; D014774:Virulence
D007106:Immune Sera; D003208:Concanavalin A