Page 99 - Veterinary Immunology, 10th Edition

occurs by three different pathways, referred to as the alternative,
VetBooks.ir the lectin, and the classical pathways (Fig. 4.2). The alternative and

lectin pathways are activated by microbial carbohydrates and are
thus typical pattern-recognition pathways that trigger innate

responses. The classical pathway, in contrast, is activated by
antibodies and thus works in association with adaptive immune
responses.

FIG. 4.2 The three pathways by which the complement system
can be activated. The alternate and lectin pathways are innate, the
classical pathway is adaptive since it is triggered by antibodies. All
three activate C3, which in turn initiates the amplification pathway
and generates the terminal complement complex.

99