Any process that involves recognition of an effector, and by which an organism activates, maintains or increases the frequency, rate or extent of the immune response of the host organism; the immune response is any immune system process that functions in the calibrated response of an organism to a potential internal or invasive threat. The host is defined as the larger of the organisms involved in a symbiotic interaction. Effectors are proteins secreted into the host cell by pathogenic microbes, presumably to alter host immune response signaling. The best characterized effectors are bacterial effectors delivered into the host cell by type III secretion system (TTSS). Effector-triggered immunity (ETI) involves the direct or indirect recognition of an effector protein by the host (for example through plant resistance or R proteins) and subsequent activation of host immune response.