Extracellular Cell Communication

Extracellular Communication describes the communication between components which are either nearby or distributed over the whole human body. For this communication, normally substances like cytokines, hormones, etc. are used in order to send some messages. These substances have receptors in order to select the receiver-components, guarantee the right routing and that only allowed receiver have access to the information. Furthermore, in cooperation with the blood stream and other components of the human body, it is guaranteed that the information reaches the destination quickly and reliably.

In the artificial immune system, extracellular communication describes the communication between components – artificial Cells, Lymph-Nodes, CNTS, etc. – using substances. These substances are a message and a set of receptors (only public-key is required for each receptor). The receptors describe the components which are allowed to receive the information. The node where the component and the substance meet supervises the identification of the component against the substance. If and only if the component identifies to the given receptors, it receives the information. Furthermore, the information can be encrypted and the component also needs for the decryption the private-keys of the receptors.

Workflow of an Extracellular Communication

Component A wants to send a message to all components of type B which have the receptors R.

1. Then, component A initialises a substance with the right parameters (hop-to-go, time-to-live), inserts the message – encrypted or not – and the set of receptors.
2. Thereafter, component A releases the pheromone and the network routes the substance to all destinations within the distribution-area; this area is defined using the parameters hop-to-go and time-to-live in the substance S.
3. In each node, the node presents the receptors R to the components in this node. If and only if one component identifies correct with the private-/public-keys, the information is given to this component.

Point-to-Point Communication

If two components want to exchange several messages, the nodes where the components reside are known and do not change, the communication can be done using substances with a certain node as destination. For this, the substance is not routed over every node or distributed in an area, it is send to the specific node and the node presents the substance only to all components in this node. Hence, the overhead is minimized against the communication without destination-node. Unfortunately, the sending-component must know the node where the destination resides and, while routing, this should not change.

Advantages of the Extracellular Communication

• No Central Center needed
• No Tracking of the moving Components needed
• Multicast without specification which node is a receiver-node

Disadvantages of the Extracellular Communication

• If two Components want to communicate, there is a overhead against point-to-point communication or in the point-to-point communication, the destination-node must be known

"Extracellular Cell Communication" is mentioned on: Artificial Cell | artificial Lymph Nodes