Cell-mediated Immune Response
Immunity is divided into a humoral immune response,
in which the immunoglobulins play an essential role,
and a cell-mediated immune (CMI) response based on
antibody-independent components. However, immunity
cannot be distinctly separated into these two parts,
because many mechanisms are closely linked and
dependent on each other. Generally, CMI is identified
with cytotoxic T cells, natural killer (NK) cells, activated
macrophages, and cells mediating antibodydependent
cytotoxicity. The CMI response not only is
particularly important in viral infections, such as influenza,
porcine reproductive and respiratory syndrome
(PRRS), porcine circovirus type 2 (PCV2) infection, and pseudorabies virus (PRV, Aujeszky’s disease), but is
also assumed to play an important role in Mycoplasma
hyopneumoniae infection .