Fusidic acid

An antibiotic used to treat bacterial infections

Engineered Monoclonal Antibodies

Diagram of engineered monoclonal antibodies

Engineered monoclonal antibodies are a class of biological therapies that are designed to target specific antigens on the surface of cells. These antibodies are produced using recombinant DNA technologies and are used in the treatment of various diseases, including cancer, autoimmune disorders, and infectious diseases.

Structure and Function

Monoclonal antibodies are composed of two identical heavy chains and two identical light chains, forming a Y-shaped molecule. The tips of the "Y" contain the antigen-binding sites, which are highly specific to the target antigen. This specificity allows monoclonal antibodies to bind to their target with high affinity, blocking or modulating the function of the antigen.

Types of Engineered Monoclonal Antibodies

There are several types of engineered monoclonal antibodies, each designed for specific therapeutic purposes:

• Chimeric antibodies: These antibodies are composed of murine (mouse) variable regions and human constant regions. They are less immunogenic than fully murine antibodies.

• Humanized antibodies: These antibodies are mostly human, with only the antigen-binding sites derived from murine sources. This reduces the risk of immune reactions.

• Fully human antibodies: These are entirely human in origin, produced using transgenic mice or phage display technologies.

• Bispecific antibodies: These antibodies are engineered to bind two different antigens simultaneously, offering unique therapeutic mechanisms.

Applications in Medicine

Engineered monoclonal antibodies have revolutionized the treatment of many diseases:

• Cancer therapy: Monoclonal antibodies can target specific tumor antigens, leading to direct tumor cell killing or recruitment of immune cells to attack the tumor.

• Autoimmune diseases: By targeting specific components of the immune system, monoclonal antibodies can reduce inflammation and tissue damage in diseases such as rheumatoid arthritis and multiple sclerosis.

• Infectious diseases: Monoclonal antibodies can neutralize pathogens or their toxins, providing passive immunity or enhancing the host's immune response.

Production

The production of engineered monoclonal antibodies involves several steps:

1. Antigen identification: The target antigen is identified and characterized. 2. Hybridoma technology: B cells from immunized animals are fused with myeloma cells to create hybridomas that produce the desired antibody. 3. Recombinant DNA technology: Genes encoding the antibody are cloned and expressed in suitable host cells, such as Chinese hamster ovary cells. 4. Purification and formulation: The antibodies are purified and formulated for clinical use.

Challenges and Future Directions

While engineered monoclonal antibodies have shown great promise, there are challenges such as high production costs, potential for immune reactions, and the development of resistance. Ongoing research aims to improve antibody design, reduce immunogenicity, and enhance therapeutic efficacy.

Related Pages

• Monoclonal antibody therapy
• Biopharmaceutical
• Immunotherapy
• Hybridoma technology

Overview

Chemical structure of fusidic acid

Fusidic acid is a steroid antibiotic that is primarily used to treat bacterial infections, particularly those caused by Staphylococcus aureus. It is a member of the fusidane class of antibiotics and is known for its ability to inhibit bacterial protein synthesis.

Mechanism of Action

Fusidic acid works by interfering with the function of elongation factor G (EF-G) in the bacterial ribosome. This inhibition prevents the translocation step in protein synthesis, effectively halting bacterial growth. Unlike many other antibiotics, fusidic acid does not directly kill bacteria but rather inhibits their ability to multiply, making it a bacteriostatic agent.

Clinical Uses

Fusidic acid is commonly used in the treatment of skin infections such as impetigo, cellulitis, and wound infections. It is also used in osteomyelitis and endocarditis caused by susceptible strains of bacteria. The antibiotic is available in various forms, including topical creams, ointments, and oral tablets.

Pharmacokinetics

Fusidic acid is well absorbed when administered orally and is widely distributed throughout the body. It is highly protein-bound and is metabolized in the liver. The drug is primarily excreted in the bile, with a small amount eliminated via the urine.

Side Effects

Common side effects of fusidic acid include gastrointestinal disturbances such as nausea and diarrhea. Topical application may cause local irritation or contact dermatitis. Rarely, systemic use can lead to liver dysfunction or jaundice.

Resistance

Resistance to fusidic acid can develop through mutations in the bacterial ribosomal protein or EF-G. However, it remains an effective treatment option for many methicillin-resistant Staphylococcus aureus (MRSA) infections.

Related pages

• Antibiotic resistance
• Staphylococcus aureus
• Protein synthesis inhibitors