Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

LECTIN

NFPA

PRODUCT USE

For studying cell surface properties; in cancer research. Lectins are a family of proteins
distributed widely in nature that agglutinate erythrocytes and many other types of cell.
The term " lectin" is now used to describe a sugar- binding protein or protein of non-
immune origin which agglutinates cells and/or precipitates glycoconjugates. Lectins are
isolated from the seeds of plants, roots leaves and bark, are present in invertebrates
such as clams, snails and horseshoe crabs and several vertebrate species.
Phytohaemagglutins are plant lectins such as concanavalin A, abrin, ricin and soybean
agglutinin (SBA) and wheat germ agglutinin (WGA). Molecular weights vary between 17, 000
and 40000 and most lectins contain manganese and calcium ions. Nearly all lectins are
inhibited by free oligo- or mono- saccharides of appropriate specificity. The
physiological function in the species from which the lectins are isolated is largely
unknown; some are specific in their reaction with human blood groups and some induce
mitosis in lymphocytes; WGA agglutinates mouse tumor cells readily whilst SBA and
concanavalin A agglutinate cell lines transformed by chemical or viral carcinogens.
Certain lectins mimic the effects of insulin on nuclear envelope phosphorylation. SBA has
been used in bone- marrow transplants in patients with severe combined immunodeficiency.

SYNONYMS

agglutinins, affinitins, phytoagglutinins, phytohaemeagglutinins, phytohemeagglutinins,
phasins, protectins, abrin, "Pokeweed mitogen", phospholipids

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

None

EMERGENCY OVERVIEW

RISK

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  Although ingestion is not thought to produce harmful effects, the material may still be damaging to the health of the individual following ingestion, especially where pre-  existing organ (e.g. liver, kidney) damage is evident. Present definitions of harmful or toxic substances are generally based on doses producing mortality (death) rather than those producing morbidity (disease, ill-health). Gastrointestinal tract discomfort may produce nausea and vomiting. In an occupational setting however, ingestion of insignificant quantities is not thought to be cause for concern.  Considered an unlikely route of entry in commercial/industrial environments.  The toxic proteins ricin, abrin and phasin (lectins) are resistant to digestive enzymes but are destroyed in cooking. They are amongst the most toxic substances known. The lethal dose after oral consumption by humans is approximately 5 microgram/kilogram. After ingestion of the compounds, the mucosa cells of the gastrointestinal tract are damaged. Severe vomiting and diarrhoea may be fatal due to hypovolaemic-shock. After absorption, various organs, especially the liver and kidney, are damaged. In addition, lectins bid to specific sugar moieties of red blood cell membranes producing agglutination. Some lectin derivatives stimulate mitosis in lymphocytes, acting in a manner similar to antigens. The latency period between ingestion and death is normally two-days. The lectins consist of two protein chains (A and B) connected by a disulfide bridge. The B chain binds covalently to the surface of the cell membrane, whereas the A chain enters the cell and inhibits ribosomal protein synthesis by splitting off adenine from rRNA. It is believed that a single molecule of abrin or ricin is sufficient to kill a cell.  

EYE

  Although the material is not thought to be an irritant, direct contact with the eye may produce transient discomfort characterized by tearing or conjunctival redness (as with windburn).  

SKIN

  The material is not thought to produce adverse health effects or skin irritation following contact (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable gloves be used in an occupational setting.  

INHALED

  The material is not thought to produce adverse health effects or irritation of the respiratory tract (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable control measures be used in an occupational setting.  Persons with impaired respiratory function, airway diseases and conditions such as emphysema or chronic bronchitis, may incur further disability if excessive concentrations of particulate are inhaled.  

CHRONIC HEALTH EFFECTS

  Principal routes of exposure are usually by skin contact/absorption and inhalation of generated dust.  No human exposure data available. For this reason health effects described are based on experience with chemically related materials.  As with any chemical product, contact with unprotected bare skin; inhalation of vapor, mist or dust in work place atmosphere; or ingestion in any form, should be avoided by observing good occupational work practice.