344
However, there was down-regulation of the MHC-II antigen processing pathway
and the markers of CD4(+) T-lymphocyte activation. IgM antibody titres were not
signifi cantly induced following this phase (Yang et al. 2013 ).
Jiao et al. ( 2009 ) described the use of two antigens, Eta6 (= ecotin precursor) and
FliC, (= FliC fl agellin), the former of which was moderately protective in Japanese
fl ounder (RPS = 53 %) when administered in 100 μg amounts by i.p. injection with
Bacillus sp. B187 as an adjuvant with boosters after 20 days. Challenge was only 14
days later. DNA vaccines, centred around Eta6 and FliC, i.e. pEta6 , and pFliC
respectively, gave protection in terms of RPS of 50 % and 33 % respectively, when
injected i.m. as 100 μg amounts in PBS (Jiao et al. 2009 ). A chimeric DNA vaccine,
i.e. eta6 covalently linked to FliC, led to superior protection, i.e. RPS = 72 % (Jiao
et al. 2009 ). A fraction of fl agellin, FliC, termed N163, which is the conserved
N-terminal 163 residues of FliC, has been proposed as an effective adjuvant for use
in Japanese fl ounder (Jiao et al. 2010a ). Sun et al. ( 2010a ) proposed use of a recombinant surface protein, Esa1, of 795 amino acid residues, which led to protection of
Japanese fl ounder when administered orally in alginate microspheres (RPS = 52 %)
and by i.p. injection (RPS = 79 %). Furthermore, Kwon et al. ( 2006 ) used ghost
cells, which were generated by gene E mediated lysis, in tilapia, and demonstrated
high protection.
By multiple passaging through laboratory media, Sun et al. ( 2010b ) isolated a
poorly virulent (= attenuated) strain, TX5RM, which was immunoprotective in
Japanese fl ounder following application by i.p. injection (100 μl containing
10
8 CFU/ml), immersion, (8 h in 10
8 CFU/ml) orally (10
10 cells/g of feed for 5
days), and orally plus immersion. With the exception of injection uptake, the other
groups were administered booster after 3-weeks. Challenge was after 5 or 8 weeks.
Oral administration plus immersion led to the highest RPS of 80.6 % at 5-weeks
after vaccination, which decreased to 69.4 % at 8-weeks (Sun et al. 2010b ). In comparison, the injectable vaccine led to an RPS of 67.7 % at 5-weeks. By the oral route
and immersion alone, the RPS values were 61.3 % and 71 %, respectively at 5-weeks
with a decline in protection at 8-weeks. (Sun et al. 2010b ).
Eta2 is a protein with sequence identity to OMP and was prepared as a recombinant protein in Esch. coli. Eta2 was administered in aluminium hydroxide adjuvant
by i.p. injection as a subunit vaccine to Japanese fl ounder and elicited protection
against challenge at 4-weeks of RPS = 83 % (Sun et al. 2011 ). Meanwhile, using
Eta2 as a DNA vaccine (plasmid pCEta2) was administered by i.m. injection and
also protective (RPS = 67 %) after challenge at 4-weeks (Sun et al. 2011 ). The adhesion gene from Aer. hydrophila , which belonged to the maltoporin group of porins
coding for OMP, Omp48, was cloned and sequenced. The recombinant protein
of ~ 48 kDa molecular weight was administered to rohu and upon challenge with
Edw. tarda resulted in protection (RPS = 60 %). Thus, it was apparent that Aer.
hydrophila conferred broad spectrum protection against Edw. tarda (Khushiramani
et al. 2012 ).
A natural avirulent isolate ATCC 15947 was successful when applied by i.p.
injection [100 μl containing ~4 × 10
8 CFU/ml] [RPS = 79 %] especially with a
booster 3 weeks later [RPS = 100 %] to Japanese fl ounder. High levels of protection
6 Enterobacteriaceae Representatives
However, there was down-regulation of the MHC-II antigen processing pathway
and the markers of CD4(+) T-lymphocyte activation. IgM antibody titres were not
signifi cantly induced following this phase (Yang et al. 2013 ).
Jiao et al. ( 2009 ) described the use of two antigens, Eta6 (= ecotin precursor) and
FliC, (= FliC fl agellin), the former of which was moderately protective in Japanese
fl ounder (RPS = 53 %) when administered in 100 μg amounts by i.p. injection with
Bacillus sp. B187 as an adjuvant with boosters after 20 days. Challenge was only 14
days later. DNA vaccines, centred around Eta6 and FliC, i.e. pEta6 , and pFliC
respectively, gave protection in terms of RPS of 50 % and 33 % respectively, when
injected i.m. as 100 μg amounts in PBS (Jiao et al. 2009 ). A chimeric DNA vaccine,
i.e. eta6 covalently linked to FliC, led to superior protection, i.e. RPS = 72 % (Jiao
et al. 2009 ). A fraction of fl agellin, FliC, termed N163, which is the conserved
N-terminal 163 residues of FliC, has been proposed as an effective adjuvant for use
in Japanese fl ounder (Jiao et al. 2010a ). Sun et al. ( 2010a ) proposed use of a recombinant surface protein, Esa1, of 795 amino acid residues, which led to protection of
Japanese fl ounder when administered orally in alginate microspheres (RPS = 52 %)
and by i.p. injection (RPS = 79 %). Furthermore, Kwon et al. ( 2006 ) used ghost
cells, which were generated by gene E mediated lysis, in tilapia, and demonstrated
high protection.
By multiple passaging through laboratory media, Sun et al. ( 2010b ) isolated a
poorly virulent (= attenuated) strain, TX5RM, which was immunoprotective in
Japanese fl ounder following application by i.p. injection (100 μl containing
10
8 CFU/ml), immersion, (8 h in 10
8 CFU/ml) orally (10
10 cells/g of feed for 5
days), and orally plus immersion. With the exception of injection uptake, the other
groups were administered booster after 3-weeks. Challenge was after 5 or 8 weeks.
Oral administration plus immersion led to the highest RPS of 80.6 % at 5-weeks
after vaccination, which decreased to 69.4 % at 8-weeks (Sun et al. 2010b ). In comparison, the injectable vaccine led to an RPS of 67.7 % at 5-weeks. By the oral route
and immersion alone, the RPS values were 61.3 % and 71 %, respectively at 5-weeks
with a decline in protection at 8-weeks. (Sun et al. 2010b ).
Eta2 is a protein with sequence identity to OMP and was prepared as a recombinant protein in Esch. coli. Eta2 was administered in aluminium hydroxide adjuvant
by i.p. injection as a subunit vaccine to Japanese fl ounder and elicited protection
against challenge at 4-weeks of RPS = 83 % (Sun et al. 2011 ). Meanwhile, using
Eta2 as a DNA vaccine (plasmid pCEta2) was administered by i.m. injection and
also protective (RPS = 67 %) after challenge at 4-weeks (Sun et al. 2011 ). The adhesion gene from Aer. hydrophila , which belonged to the maltoporin group of porins
coding for OMP, Omp48, was cloned and sequenced. The recombinant protein
of ~ 48 kDa molecular weight was administered to rohu and upon challenge with
Edw. tarda resulted in protection (RPS = 60 %). Thus, it was apparent that Aer.
hydrophila conferred broad spectrum protection against Edw. tarda (Khushiramani
et al. 2012 ).
A natural avirulent isolate ATCC 15947 was successful when applied by i.p.
injection [100 μl containing ~4 × 10
8 CFU/ml] [RPS = 79 %] especially with a
booster 3 weeks later [RPS = 100 %] to Japanese fl ounder. High levels of protection
6 Enterobacteriaceae Representatives