THE TRAPPING OF INTRAVENOUSLY INJECTED EXTRACELLULAR PRODUCTS FROM AEROMONAS-SALMONICIDA IN HEAD KIDNEY AND SPLEEN OF VACCINATED AND NONVACCINATED ATLANTIC SALMON, SALMO-SALAR L

Trapping of intravenously injected crude extracellular products from A eromonas salmonicida was studied in Atlantic salmon, Salmo salar L. Fr ozen tissue from head kidney and spleen was collected 1 h and 8 h afte r the injection and localisation of A. salmonicida antigens, complemen t factor 3 and immunoglobulin was investigated in vaccinated and nonva ccinated fish using a double immunofluorescence staining technique. In the head kidney of vaccinated fish, A. salmonicida antigens was coloc alised with complement factor 3 and immunoglobulin in sinusoidal cells . A weaker reactivity to A. salmonicida antigens was detected in coloc alisation with complement factor 3 alone in nonvaccinated fish. In the spleen, ellipsoidal sheaths showed reactivity to A. salmonicida antig ens in fish from both groups. In addition, the ellipsoids that trapped A. salmonicida antigens were stained for complement factor 3 and immu noglobulin in the vaccinated fish but stained for complement factor 3 alone in nonvaccinated fish. Computer-assisted morphometric analysis w as further used to provide semi-quantitative estimates of A. salmonici da antigens and complement factor 3 in the head kidney. The estimated stained areas were significantly larger for the two antigens in vaccin ated fish compared with nonvaccinated fish. (C) 1996 Academic Press Li mited