Carbohydrates within antibody molecules

Immunocytochemical methods have been widely applied to visualize proteins, carbohydrates, or lipids in sectioned material. The advantage of using immunocytochemistry is to be able to localize the molecules of interest within the tissue. Several procedures have been described. Basically, these procedures can be split into four main steps that are described in subheadings (1) tissue preparation, (2) the primary antibodies, (3) the visualization of the target, and (4) enhancement of signals with antibody complexes. In addition, a protocol for alkaline phosphatase will be presented in detail in Subheading 5. The terms primary and secondary antibodies refer to the order in which they are applied to the target. The immunocytochemical procedures are not limited to sectioned... 

Heterobifunctional cross-linking reagents also may be used to site-direct a conjugation reaction toward particular parts of target molecules. Amines may be coupled on one molecule while sulfhydryls or carbohydrates are targeted on another molecule. Directed coupling often is important in preserving critical epitopes or active sites within macromolecules. For instance, antibodies may be coupled to other proteins... 

In addition, humans produce large quantities of antibodies, mainly of the IgM type, without previous immunization. These antibodies are termed natural antibodies, and the archetypical example is the IgM antibodies we have in our blood against the carbohydrate molecules that make up the antigens within the ABO blood group system [2],... 

Molecular interactions where carbohydrates are involved are usually weak interactions. Proteins usually recognize and bind to just a few carbohydrate residues within an oligosaccharide, whether it is an antibody or a lectin. Nature adopts to the needs of higher affinity requirements by the multimerization of either protein or carbohydrate or both units in order to reaeh avidities that can hold molecules and cells under physiological conditions [2, 66]. 

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