Piscirickettsia salmonis antigen (P. salmonis antigen)

Piscirickettsia salmonis antigens are immunogenic proteins or molecules derived from the Gram-negative, facultative intracellular bacterium Piscirickettsia salmonis, the causative agent of Salmonid Rickettsial Septicemia (SRS) (Rozas-Serri, 2022). These antigens, which include Outer Membrane Proteins (OMPs) such as OmpA, Heat Shock Proteins (HSPs) like Hsp60 and Hsp70, and components of the Type IV Secretion System, are essential for the pathogen's ability to adhere to, invade, and survive within host fish cells, particularly macrophages (Wilhelm et al., 2006; Price et al., 2017). In the aquaculture industry, these antigens serve as the primary targets for the development of vaccines, including inactivated, recombinant subunit, and live-attenuated formulations (Tobar et al., 2015). The therapeutic objective is to prime the fish's immune system to recognize these molecular signatures, thereby inducing protective humoral and cellular responses that can mitigate the high mortality rates associated with SRS outbreaks. Despite the widespread use of antigenic vaccines, SRS remains a significant economic challenge due to the bacterium's intracellular nature and its ability to evade host defenses, necessitating ongoing research into more robust and conserved antigenic targets.

Other names

SRS antigenPiscirickettsiosis antigenP. salmonis surface proteinSalmonid Rickettsial Septicemia antigen

Vaccines containing these antigens stimulate the host adaptive immune system to produce specific IgM antibodies and activate T-cell mediated immunity, thereby neutralizing the pathogen and preventing its entry and replication within host macrophages.