Definition for View source for Contact-Dependent Signalling

Not all signalling molecules can readily diffuse from one cell to another. Some molecules are bound to the surface of cells and provide a signal to other cells that possess an appropriate receptor. Contact-dependent signalling is exemplified by antibody producing cells, which coordinate antibody production by interacting with one another. Interestingly, the same receptor that permits this interaction is also a target of the capsid protein of the [[human immunodeficiency virus]] (HIV), responsible for the disease called [[acquired immune deficiency syndrome]] (AIDS). This allows the AIDS virus to select such cells for infection, often culminating in the demise of that cell type and the loss of immunological protection.