Vaccination of Domestic and Wild Animals Against Tuberculosis 209
mycobacteria, in a study where BCG vaccine was
shown to be ineffective (Buddle et al., 2002;
Parlane and Buddle, 2015). Vaccination with a
leucine auxotroph of M. bovis was shown to sig-
nificantly reduce the bacterial burden and histo-
pathology in calves following challenge with
virulent M. bovis, compared to non-vaccinated
controls (Khare et al., 2007). A comparison with
BCG was not undertaken in this study. A double
deletion mutant of M. tuberculosis, a region of
difference 1 (RD1) knockout and pantothenate
auxotroph, failed to protect calves from an aero-
solised M. bovis challenge (Waters et al., 2007),
while vaccination with a RD1 deletion mutant
of M. bovis provided protection comparable to
BCG (Waters et al., 2009). For cattle, an attenu-
ated M. tuberculosis mutant may be less immu-
nogenic as compared to those produced on a
M. bovis or BCG background strain as cattle are
not a natural host for M. tuberculosis. An attenu-
ated M. bovis strain with a double deletion in the
mce2 gene was shown to induce significant pro-
tection against an M. bovis challenge in cattle
and significantly lower histopathological lesion
scores in the lungs and pulmonary lymph nodes
than those vaccinated with BCG (Blanco et al.,
2013).
No subunit TB vaccine has been able to
induce better protection in cattle than that
induced by BCG, although they can produce a
synergistic effect when used in combination
with BCG. DNA vaccines have induced minimal
protection against TB when used alone, although
some protection has been observed when myco-
bacterial DNA was combined with DNA encod-
ing co-stimulatory molecules CD80 and CD86
(Maue et al., 2004) or combined with an adju-
vant (Cai et al., 2005). More encouraging results
have been reported when DNA vaccines have
been used in heterologous prime-boost regimes
with BCG, and priming or boosting with myco-
bacterial DNA vaccines induced greater protec-
tion than with BCG vaccine alone (Skinner et al.,
2003, 2005; Maue et al., 2007). Similarly, TB
protein vaccines have induced little protection in
cattle when used alone, whereas when co-
administered at adjacent sites with BCG have
induced protection that was better than that
observed with BCG alone (Wedlock et al., 2005a,
2008). The major problem encountered usingTable 14.1. Types of new TB vaccines tested in cattle.
Type of Vaccine Vaccine
Protection against
TB compared to
BCG ReferenceModified BCG BCG over-expressing Ag85B
BCG ∆ zmp1
BCG mutants (BCGDleuCD,
BCGDfdr8, BCGDmmA4,
BCGDpks16)+
+=Rizzi et al., 2012
Khatri et al., 2014, and B. Khatri,
unpublished data
Waters et al., 2015Attenuated M.
tuberculosis
strain
M. tuberculosis ∆RD1 ∆panCD - Waters et al., 2007Attenuated
M. bovis strain
UV-irradiated M. bovis
M. bovis ∆ leuD
M. bovis ∆ RD1
M. bovis ∆ mce2+
NTb
=
+Buddle et al., 2002
Khare et al., 2007
Waters et al., 2009
Blanco et al., 2013DNA vaccine Mycobacterial DNA
Heterologous prime boost:
mycobacterial DNA + BCG
=
+Maue et al., 2004; Cai et al., 2005
Skinner et al., 2003, 2005; Maue
et al., 2007
Adjuvanted
protein vaccine
Simultaneous protein + BCG + Wedlock et al., 2005a, 2008Virus-vectored
vaccine
Heterologous prime boost:
BCG + Ad85A+ Vordermeier et al., 2009; Dean
et al., 2014a