... immobilizes them near entry site, not allowing them to move about the host's body, which makes it harder for them to acquire nutrients by diffusion. All animals have agglutinins, which is something they have in common with plants. Wound closure is another type of molecular defence that prevents loss of body fluids and entrance of more pathogens. Examples of this are phyla like Annelida, Arthropoda and Echinodermata that contain specialized cells that congregate in wounds producing coagulants that cause body fluids to gel and block wounds. In vertebrates, the main cascade reaction of innate immunity is complement cascade which has a final molecule called membrane attack complex that makes pores in pathogens, allowing access for other defensive mechanisms. In invertebrates, the cascade reaction is the PpO cascade that converts proplenoloxidase (PpO) to plenoloxidase, enzyme that destroys microbial pathogens. Animals have evolved specialized defensive cells, called leukocytes in addition to their ...

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