A putative serine protease, SpSsp1, from Saprolegnia parasitica is recognised by sera of rainbow trout, Oncorhynchus mykiss

Abstract

Saprolegniosis, the disease caused by Saprolegnia sp., results in considerable economic losses in aquaculture. Current control methods are inadequate, as they are either largely ineffective or present environmental and fish health concerns. Vaccination of fish presents an attractive alternative to these control methods. Therefore we set out to identify suitable antigens that could help generate a fish vaccine against Saprolegnia parasitica. Unexpectedly, antibodies against S. parasitica were found in serum from healthy rainbow trout, Oncorhynchus mykiss. The antibodies detected a single band in secreted proteins that were run on a one-dimensional SDS-polyacrylamide gel, which corresponded to two protein spots on a two-dimensional gel. The proteins were analysed by liquid chromatography tandem mass spectrometry. Mascot and bioinformatic analysis resulted in the identification of a single secreted protein, SpSsp1, of 481 amino acid residues, containing a subtilisin domain. Expression analysis demonstrated that SpSsp1 is highly expressed in all tested mycelial stages of S. parasitica. Investigation of other non-infected trout from several fish farms in the United Kingdom showed similar activity in their sera towards SpSsp1. Several fish that had no visible saprolegniosis showed an antibody response towards SpSsp1 suggesting that SpSsp1 might be a useful candidate for future vaccination trial experiments.

Saprolegnia molecular phylogeny among farmed teleosts in Nova Scotia, Canada

“…Rainbow trout exhibit a much lower incidence of saprolegniosis compared to other salmonids, despite sharing similar physiological stress response characteristics (Pottinger & Carrick, ; Sandoval‐Sierra, Latif‐Eugenin, et al, ). Rainbow trout blood sera are able to recognize the S. parasitica single secreted protein (SpSsp) and respond immunologically, and therefore may refract infection (Minor et al, ). Of the six species of Saprolegnia infecting rainbow trout in the present study, none were S. parasitica .…”

“…Cox2 region, by comparison, failed to reveal strain variations between S1 and S2 as clearly as the ITS, (Pickering, 1994;Pickering & Christie, 1981) which predisposes the fish to being immunocompromised and susceptible to saprolegniosis (Pickering & Duston, 1983;Pickering & Pottinger, 1985 stress response characteristics (Pottinger & Carrick, 1999;Sandoval-Sierra, Latif-Eugenin, et al, 2014). Rainbow trout blood sera are able to recognize the S. parasitica single secreted protein (SpSsp) and respond immunologically, and therefore may refract infection (Minor et al, 2014).…”

A critical review on serine protease: Key immune manipulator and pathology mediator

“…A fish pathogen Saprolegnia parasitica secretes a subtilisin-like domain-containing protein which showed an antibody response. 152 L. donovanisecreted serine protease is used to develop vaccine against visceral leishmaniasis by exploiting its IFN-␥ activity. 153 HtrA family serine proteases in human has been observed to play a protective role in cancer, thus their expression and activation to induce apoptosis of cancerous cell is being pondered.…”

Emerging oomycete threats to plants and animals

“…For animal pathogen oomycetes, limited genomic resources are available at the moment (table 1). More efforts are needed for identifying pathogen proteins that manipulate host immune systems, as these will allow for the selection and testing of suitable antigens, which may result in the development of vaccines [102]. -Genetic manipulation of hosts and pathogens.…”