Coupling to proteins

There are a number of practical problems involved with using polysaccharides as vaccines as there are frequently too many different chemotypes for it to be practicable to prepare a vaccine. In some cases a limited number of serotypes are the dominant cause of infection and it may then be possible to produce vaccines. A major problem is the poor immune response elicited by polysaccharide antigens, which may in some cases be improved by chemical modification. This is (fie case for vaccines for Haemophilus influenzae type b (a causative agent of meningitis), where the antigenicity of the polysaccharide can be increased by coupling to proteins. 

The following protocol for mPEG activation using TsT and its coupling to proteins is based on the protocols of Abuchowski et al. (1977b) and Gotoh et al. (1993). 

Miron, T., and Wilchek, M. (1993) A simplified method for the preparation of succinimidyl carbonate polyethylene glycol for coupling to proteins. Bioconjugate Ghent. 4, 568-569. 

This chapter deals with fluorine-containing molecules that are currently clinically used as pharmaceuticals or are at an advanced stage of their development (i.e., registered by the administration or under clinical trials I, II, or III). These compounds are found in almost all therapeutic classes and stem from very diverse chemical families. In most cases, they are inhibitors of enzymes (anti-infectious, antitumor, antiviral drugs) or are ligands of various receptors (membraneous receptors coupled to protein G, ionic channels, or nuclear receptors). 

SASD (Chapter 5, Section 3.2) behaves in a similar manner, except it contains an amine-reactive end that can be coupled to proteins and other molecules. Its photoreactive end can be iodinated using any of the radioiodination reagents discussed previously. Just as in the case of APDP, SASD cross-links can be cleaved by a disulfide reductant to transfer the radioactive component to a second molecule. 

Queiroz G, Quintas C, Talaia C et al (2004) Coupling to protein kinases A and C of adenosine A2b receptors involved in the facilitation of noradrenaline release in the prostatic portion of rat vas deferens. Neuropharmacology 47 216-24... 

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