Table 1.

Host immunity and parasite immune escape strategies.

Host immunity	Parasite stage	Parasite evasion strategy	Outcome
Complement	AS, S	Bind complement regulatory factor, factor H Disrupt c-Jun kinase pathway	Prevent complement activation system Avoid recognition by complement
Monocytes/macrophages	AS	Subvert or kill phagocytes by (1)inhibiting phagocytosis and (2)inducing apoptosis	Prevent parasite elimination by (1)inhibiting phagocyte function and (2)reducing phagocyte numbers
Dendritic cells (DC)	AS	Subvert or kill DC by (1)inhibiting DC maturation and (2)engaging apoptosis receptor, Fas	Decrease DC functions by (1)preventing T cell priming and expansion and (2)inducing immunosuppression through decreased pro-inflammatory (IL12) cytokine production and increased immunosuppressive (IL10) cytokine production
Antibodies/B cells	Spz, AS, S Spz, AS, S AS AS AS AS AS Spz, AS, S AS AS	Antibody enhancement invasion and/or growth Antigen polymorphism Antigenic variation Antigenic diversion Epitope masking Smoke-screen strategy B cell dysregulation Homology with host proteins B cell apoptosis Redundancy in cell invasion pathways	Expansion of parasite in host Avoid recognition by antibody Avoid recognition by antibody Prevent the action of neutralizing antibodies Prevent the action of neutralizing antibodies Avoid antibody recognition by diverting neutralizing antibody from their target Poor or limited B cell memory Poor or no antibody response by inducing immunological tolerance Poor antibody response Allow continued invasion and expansion of parasite even when one invasion pathway is inhibited by antibody
T cells	LS AS AS AS	T cell epitope polymorphism Apoptosis Induction of expression of check-point inhibitors Regulatory T cells	Avoid T cell recognition prevent T cell priming and activity, and interfere with memory T cell development Poor T cell response Anergy and/or T cell exhaustion Negative regulation of immune responses
Hepatocytes	LS	Cellular shelter	Avoid immune surveillance due to intracellular niche

Spz, sporozoite; LS, liver stage; AS, asexual blood stage; S, sexual stage.