Function interaction with antibodies

Viruses are made up of molecules of nucleic acids that are encased in an envelope of proteins called capsid proteins. When they are part of the outermost shell, envelope proteins are referred to as coat proteins. These proteins usually exist as a noncovalent association of protein subunits and are responsible for an array of functions, including cell attachment, cell entry, and RNA release. The study of viruses can shed light on their molecular biology and pathology and on their possible interactions with antibodies. Similar to mass spectrometry identihcation of bacteria, viruses are characterized on the basis of unique marker ions [39-45]. Because capsid proteins are unique to each virus, they are good candidate as biomarkers. 

Not all antigen-antibody reactions are of benefit to the body, as sometimes the complexes (or their subsequent interaction with body tissues) may result in tissue damage. This must be regarded as a malfunction of the immune system and is known as a hypersensitive reaction. These reactions can be categorized into five main types. The first three involve the interaction between antigen and humoral antibody, and as the onset of the reaction is rapid, the condition is termed immediate hypersensitivity. The fourth type (delayed hypersensitivity) involves T cells and the symptoms of the reaction appear after 24 hours. The fifth type is where antibody stimulates cell function. 

Yoon, H.C., Lee, D., and Kim, H.-S. (2002) Reversible affinity interactions of antibody molecules at functionalized dendrimer monolayer affinity-sensing surface with reusability. Anal. Chim. Acta 456, 209-218. 

For a complete functional study of a biological pathway, it is often necessary to confirm the important protein interactions by in vivo experiments. This can be done by demonstrating protein localizations on a microscopic level, for instance, by tagging proteins with the green fluorescent protein or localizing them with antibodies and colloidal gold particles using an electron microscope. Additional, very specific biochemical experiments are often required to confirm the putative protein function. 

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