Interesting >>>> Lectins

Lectins.

Discovered a hundred years ago, the proteins lectins brought new and unusual knowledge to the science of the world of plants. What interesting scientists have considered in lectins? It turns out that these proteins are involved in the recognition and protection of plants from parasites and harmful microorganisms, transport hormones, RNA, and participate in cell division, growth and differentiation. That is in fact, lectins play the role of immunity factors for plants.

The biotechnological industry began to show particular interest in the protein components of plants. Having set themselves the task of identifying additional sources of biologically active substances, biotechnologists have long been engaged in plant bioscreening to obtain phytopreparations that will help improve plant productivity by adapting them to various weather conditions, aggressive bacterial, viral and fungal environments, as well as to low-fertile biochemical soil composition . The identification and synthesis of beneficial plant proteins has proven to be of great help to genetic engineering, which deals with genetic modification. It is the genes of plants with useful protective and adaptive qualities provided by lectins that are used as genetic material for transplanting the genome into cultivated plant species.

From research in the world of plants, scientists turned to the study of the animal world and learned to isolate lectins from the blood of animals, and then they found these proteins in humans.

Thus, scientists have received evidence that lectins are among the agents of the immune system (they are considered as the evolutionary precursors of antibodies). In particular, they are endowed with a bactericidal effect against certain types of pathogenic bacteria, are able to inactivate the action of some viruses, and are involved in regulating the immune response by activating the complement system.

It is believed that the complement system is an ancient protein system of innate immunity, a system for recognizing foreign proteins. Along with other factors, it relies on the ability of lectins to recognize and bind carbohydrates on the surface of the cell membranes of target cells (that is, cells that are targeted by the immune system).

The types of lectins are diverse, but they all have one property in common - the ability to recognize specific carbohydrates and cause agglutination (adhesion and precipitation of cells). Lectins are considered as carbohydrate-recognizing proteins (multimeric glycoproteins) of a non-immunoglobulin nature (that is, not belonging to the class of immunoglobulins ). But in the molecules of immunoglobulins there is a mechanism of cooperation with lectins, which to some extent puts them on the same level with immunoglobulins. Many cytokines were also assigned to the group of lectins : tumor necrosis factors (alpha), interleukins, some interferons and growth factors, and many others. Moreover, animal lectins exhibit properties similar to those of enzymes, although they are not.

In fact, lectins play the role of some kind of biosensors in the body, capable of recognizing and destroying biofilms of pathogens (foreign and pathologically altered cells).

What is the use of this knowledge for medicine?

For example, the properties of lectins to recognize carbohydrate compounds on the surface of tumor cells open up prospects for effective action on tumor cells and their elimination (excretion from the body).

The ability of lectins to agglutinate certain pathogens enables the pharmaceutical industry to modify many antibacterial, antifungal, and antiviral drugs.

The reaction of agglutination by lectins of other cells in the body promotes the use of lectins to determine blood groups (they have the ability to recognize three types of red blood cells - A, B, O), to identify causative agents of infectious diseases.

Like any discovery, the discovery of lectins also has "side effects." Since humans consume plant-based foods, some unpleasant facts have been identified related to plant lectins. It turned out that the lectins of some plants found in their seeds (peanuts, legumes, wheat) are able to block the activity of digestive enzymes. In addition, having the property of adhering to cell surfaces, lectins disrupt the processes of cell regeneration at the sites of adhesion . In practice, this translates into a violation of digestion and regenerative processes in the gastrointestinal tract.

Plant lectins also increase the penetration of the intestinal wall, which makes the gastrointestinal tract vulnerable to penetration of pathogenic microorganisms.

Therefore, people suffering from diseases of the digestive system (for example, colitis, Crohn's disease and other chronic diseases of the gastrointestinal tract) should not be carried away by foods such as legumes, peanuts, whole grain bread, wheat germ and other similar foods containing seeds or grains of plants. where lectins are found in high concentrations.

But along with this, studies were carried out on the effect of heat treatment of plant lectins on their agglutinating ability, and it turned out that when heated to 100 C o for at least five minutes, lectin proteins denature and lose this ability. This means that eating plants, their seeds and seedlings in their raw form has a detrimental effect on the digestive system, and the above-mentioned products can be safely consumed.

Many scientists today attribute to lectins also the property of causing allergic reactions, that is, making them responsible for food allergies.

To this day, lectins are of increasing interest in the scientific world. But while these studies are at the development stage, science cannot provide all the answers to questions about the positive and negative possibilities of lectins.