symbiont-mediated perturbation of host cellular process symbiont-mediated perturbation of host defense response symbiont-mediated activation of blood coagulation, intrinsic pathway https://github.com/geneontology/go-ontology/issues/31937 GO:0140424 pg biological_process 2026-05-05T13:33:45Z A process in which a symbiont initiates, promotes, or enhances blood coagulation in another organism by activation of the intrinsic pathway. A common mechanism is the triggering the activity of host coagulation Factor XIIa (F12), one of the contact activation system (CAS) components, which consists of factor XII (FXII), prekallikrein (PK), and high molecular weight kininogen (HK). FXIIa instigates the coagulation cascade by cutting factor XI (FXI).