CAB International 2018. Bovine Tuberculosis
154 (eds M. Chambers, S. Gordon, F. Olea-Popelka, P. Barrow)- Email: [email protected]
Immunity to mycobacterial infections is an
interplay between innate and adaptive immune
responses; both cellular and humoral mecha-
nisms are involved. While it is clear that the
response to mycobacterial infection is driven and
shaped by the initial innate immune response,
defining the mechanisms of adaptive immunity
underpins on-going efforts to develop effective
tuberculosis (TB) vaccines for humans and
cattle. Importantly, definition of correlates of
protective immunity that can be measured read-
ily will facilitate the development and screening
of vaccine candidates and assessment of their
success. However, it must also be stressed that in
the case of mycobacterial infection, these corre-
lates of protective immunity must be defined
carefully. They not only include an ‘absence of
clinical symptoms’, a definition used for many
other veterinary vaccines, but must be defined
as ‘protection to infection’, given the socio-
economic importance of infection with Myco-
bacterium bovis. In addition, since measurement
of the adaptive immune response through
tuberculin skin testing or assessment of antigen-
specific IFN-γ release forms the basis of currently
used diagnostic tests (Waters et al 2011; Pai
et al., 2014), increased knowledge of the
immune response associated with infection or
induced by vaccination is required for improved
surveillance.
11.1 Cell-Mediated Immune
ResponsesStudies in cattle have demonstrated that the cell-
mediated adaptive immune response of adult
cattle is similar to that observed in humans
( Goddeeris, 1998), although the presence of dis-
tinct disease-associated Th1-Th2 bias is less clear
in the bovine immune response. There is also a
significant similarity in the primary mechanisms
of anti-mycobacterial immunity between
humans and cattle (Pollock et al., 2001;
Ottenhoff et al., 2005), including those responses
induced by bacillus Calmette–Guérin (BCG)
vaccination (Semple et al., 2011; Siddiqui et al.,
2012). These include roles for CD4+, CD8+ and
γd TCR+ T cells, function and sources of IFN-γ,
roles for IL-17 and IL-22, and antigen-specific
memory T lymphocytes. In addition, there is
growing evidence for involvement of non-
conventional lymphocytes including mucosal-
associated invariant T (MAIT) cells and
lipid-responsive CD1-restricted T cells. While our
understanding of the immune mechanisms
induced by infection of cattle is less advanced
compared to that in humans (or from murine
studies), it is evident that similar responses are
observed across the two species, implying that
bovine models may provide insights relevant to
human medicine and vice versa (reviewed by
Waters et al., 2011).11 Adaptive Immunity
Jayne Hope1,* and Dirk Werling^2
(^1) The Roslin Institute, University of Edinburgh, Edinburgh, UK;
(^2) The Royal Veterinary College, Hatfield, UK