Many viruses and bacteria use carbohydrate chains of host cell both for recognition and as receptors for primary adhesion. The carbohydrate-binding sites of microbial proteins as lectins (adhesins, pilins, hemagglutinins) and toxins are very conservative since changes in this part should abolish the receptor-binding properties. Knowledge of the carbohydrate receptors permits to solve several important practical tasks, particularly the following:

• to study receptor specificity of the known yet poorly characterized viruses and bacteria, as well as artificially designed microorganisms

• to detect microorganisms rapidly and specifically (in monitoring and screening mode)

• to reveal soluble bacterial toxins, many of which bind carbohydrates

• to develop rationally a potent blockers for the microorganisms, both for therapy and prevention

• to perform HTPS of blockers-mimetics.