[Possible application of lectins in diagnostics and therapy. Part I. Diagnostic application].

Lectins are proteins or glyco-proteins binding selectively and without the involvement of enzymes specific for carbohydrate ligands. Lectins are present in organisms on different levels of evolutionary development and play very important roles in life processes of these organisms. Lectins' functioning mechanism is based on the reaction of glycolysation. In vertebrates, functions of lectins are connected with cell recognition, proliferation control, adhesion, cell differentiation, mechanisms of organ creation, and defense mechanisms. Due to their ability to bind reversibly with specific carbohydrate structures, Lectins have commonly been used as a perfect molecular tool in various disciplines of biology and medicine. With the use of modern methods of lectin affinity chromatography (LAC) and various histochemistry methods, lectins provide practical application during observation of changes occurring in the cell membrane in different stages of physiological and pathological development of human or animal organisms. What is particularly important is lectins' contribution to studies on the isolation and structure of glycoconjugates in clinical pathology (including processes of tumor transformation). Serology was the first discipline of medicine relying on the specific activity of lectins. It had been based on the discoveries (by Rekonen in 1948 and Nowell in 1960) that proved that some lectins are able to bind with human and animal blood group antigens. Another discovery (by Nowell in 1960s) of mitogenic effect of PHA on human lymphocytes made lectins helpful and commonly used in the diagnosis of genetic conditions in several diseases. Proving that lectins bind differently with glycoconjugates of normal and tumor cells and are able to detect subtle neoplastic changes was a clue that lectins can be precious and useful in cancer treatment and diagnostics. For many years lectins inducing apoptosis, with immuno-modulatory or antiproliferative activity and toxic lectins belonging to II-RIP class (Ribosome Inactivating Proteins like viscumin, ricin) have been intensively examined in therapy of various diseases, esp. in cancer. Currently the use of lectins in drug targeting is being examined (lectins as drug-carriers, the preparation of bioadhesive "Second Generation" drug-delivery systems). Paper presents below is an attempt at collecting the latest information on diagnostic and therapeutic application possibilities of lectins.