Recombinant protein vaccines have a number of advantages
over traditional bacterin vaccines, including being inexpensive to
produce and safer to use [25]. One of the other major advantages
is that this method of vaccine preparation avoids the presence of
unwanted antigens from the pathogen in the vaccine, which could
lead to suppression of the host’s immune system. For example,
some of the surface proteins of Renibacterium salmoninarum (i.e.
p22 and p57) have been found to suppress the immune system of
fish, and therefore, aWC preparation of this bacterium is not ideal
to use as a bacterin vaccine [35]. Recombinant protein vaccines, on
the other hand, can induce specific immunity against a particular
antigen which can protect the host from infection [36].