Passive immunization of tilapia, Oreochromis niloticus (L.), with anti-Streptococcus iniae whole sera |
| |
| Authors: | R A Shelby P H Klesius C A Shoemaker & J J Evans |
| |
| Institution: | Aquatic Animal Health Research Laboratories, Agricultural Research Service, US Department of Agriculture, Auburn, AL, USA,;Agricultural Research Service, US Department of Agriculture, Chestertown, MD, USA |
| |
| Abstract: | Passive immunization of tilapia, Oreochromis niloticus, was conducted to determine whether anti- Streptococcus iniae whole sera (ASI), heat inactivated anti- S . iniae whole sera (HIASI) and normal whole sera (NWS) were protective when intraperitoneally (i.p.) injected into tilapia. The ASI was produced in tilapia actively immunized (challenged) with virulent S. iniae by i.p. injection. An antibody response against S. iniae was demonstrated by enzyme linked immunosorbent assay (ELISA) and 18% of the immunized fish died because of the S. iniae infection. The actively immunized tilapia demonstrated a secondary antibody response and immunity to S. iniae after challenge with S. iniae by i.p. injection. Survival was 100% in the actively immunized fish. The NWS was obtained from tilapia free of ASI antibody and susceptible to S. iniae infection (40% mortality). In two separate experiments, significantly higher mortality was noted in tilapia passively immunized with NWS (33 and 53%) and phosphate buffered saline (PBS) (30 and 60%), in comparison with mortalities of 0 and 10% or 3.3 and 6.7% in the fish passively immunized with ASI or HIASI 14 days after S . iniae infection by i.p. injection ( P = 0.0003 and 0.0023). Results suggest that immunity provided by ASI and HIASI was because of antibody against S. iniae . Inactivation of complement in the HIASI treatment further suggests that ASI antibody plays a primary role in immunity against S. iniae infection. |
| |
| Keywords: | antibody response immunization Oreochromis niloticus tilapia Streptococcus iniae |
|
|
