Figure 2.

Mechanisms for uptake of pathogens and dead cells. Material from pathogens and dead cells is taken up via the same uptake mechanisms, which include Fc receptor-, complement receptor- and scavenger receptor-mediated uptake. Fc receptor- and complement receptor-mediated uptake require the prior opsonisation of the cargo with antibodies and complement factors, respectively. APC activation is tightly regulated and influenced both by the source of the material and uptake route. Uptake of material from dying uninfected cells induces a number of regulatory pathways which attenuate pro-inflammatory immunogenic antigen-presenting cells (APC) activation. In contrast, uptake of pathogens or pathogen-derived material as associated with infected dying cells leads to pro-inflammatory immunogenic activation of APC.