Monoclonal Antibody

PRODUCTIONS:
  • Phage display library: construction of VH and VL gene libaries and expression of them on a filamentous bacterophage. The phage expressing an antigen-bonding domain specific for a particular antigen to screen the mAbs.
  • Transgenic plants: transgenic tobacco plants to produce IgA.
  • Transgenic animals: transgenic mouse to make humanized IgG. (Abgenix,CA)
  • The hybridoma technology: spleen cells from immunized mice are fused with the murine myeloma cells
  • In monoclonal antibody production, monoclonal cells are differentiated from Myeloma cell lines
THE TYPES OF MAB DESIGNED: 
  • Murine source mAbs: rodent mAbs with excellent affinities and specificities
  • Clinical efficacy compromised by HAMA(human anti murine antibody) response, which lead to allergic or immune complex herpersensitivities.
  • Chimeric mAbs: chimers combine the human constant regions with the intact rodent variable regions.
  • Affinity and specificity unchanged. Also cause human antichimeric antibody response (30% murine resource)
  • Humanized mAbs: contained only the CDRs of the rodent variable region grafted onto human variable region framework

MOA: 
  • Three mechanisms that could be responsible for the cancer treatment.
  • MAbs act directly when binding to a cancer specific antigens and induce immunological response to cancer cells. Such as inducing cancer cell apoptosis, inhibiting growth, or interfering with a key function.
  • MAbs was modified for delivery of a toxin, radioisotope, cytokine or other active conjugates.
  • It is also possible to design bispecific antibodies that can bind with their Fab regions both to target antigen and to a conjugate or effector cell


NAKED’ MONOCLONAL ANTIBODIES:
  • Naked’ means these antibodies are not fused to a toxin.
  • Naked Monoclonal antibodies can kill cells via a variety of mechanisms, including: 
  • Antibody-Dependent Cellular Cytotoxicity (ADCC),
  • Complement-Dependent Cytotoxicity (CDC), and 
  • direct induction of apoptosis.
  • Antibody-Dependant Cellular Cytotoxicity
ADCC is the least understood of the three mechanisms, it is mediated by either NK cells or CTL.
  • The action of ADCC is dependant on the recognition of the objective cell by antibodies attached on the surface of the effector cell (terminally differentiated leukocyte). This process is part of the adaptive immune response due to the dependence on antibodies and therefore a former anti-body response is required for this mechanism to take effect and be effective against an invading pathogen.
RITUXIMAB (RITUXAN):
  • Rituximab is a chimeric monoclonal antibody that targets the CD20 B-cell antigen.
  • This antigen is expressed on 90% of B-cell neoplasms
  • The precise biological functions of CD20 are uncertain, but the antibody is believed to function by flagging the B-cells for destruction by the body’s own immune system, including ADCC, CDC, and apoptosis.
  • This antibody thus leads to the elimination of all B-cells from the body (including cancerous ones), allowing new, healthy B-cells to be produced from lymphoid stem cells. Most common side effect of Ritumixab is infusion reaction
TRASTUZUMAB (HERCEPTIN):
  • Herceptin is an anti-cancer antibody that acts on HER2/neu (erbB2) receptor, which is overexpressed in breast cancer. Only cells overexpressing this receptor are susceptible. Such cells, when treated with Herceptin, undergo arrest in the G1 phase of the cell cycle and experience a reduction in proliferation.
  • This can reduce the rate of relapse of breast cancer by 50% during the first year.
  • Gemtuzumab ozogamicin (Mylotarg):
  • This monoclonal antibody is conjugated to the cytotoxic agent calicheamycin
  • It is used to treat acute myelogenous leukemia (AML).
  • This monoclonal antibody attacks the CD33 receptor.
  • Once bound to CD33, the antibody-calicheamycin complex is transported inside of the AML cells by lysosomes.
ECULIZUMAB:
  • By blocking the complement cascade downstream of C5, eculizumab abolishes complement-dependent intravascular hemolysis in all PNH patients, and significantly improves their quality of life.
  • Anti-C5 monoclonal antibody 
BEVACIZUMAB:
  • Bevacizumab (AVASTIN) targets the vascular-endothelial growth factor (VEGF) and inhibits its interaction with the VEGFR1 and VEGFR2 receptors. 
  • VEGF is an angiogenic growth factor that regulates vascular proliferation and permeability and inhibits apoptosis of new blood vessels. 
  • Use: Bevacizumab is FDA approved for metastatic colorectal cancer in combination with 5-FU. 
  • Side effects: Hypertension, pulmonary hemorrhage, gastrointestinal perforation, proteinuria, congestive heart failure
Strategy of a direct or indirect induction of apoptosis in targeted cancer cells:
  • mAbs target growth factor receptors to exert a direct effect on the growth and survival of the cancer cells by antagonizing ligand-receptor signaling.
  • mAbs can target to cell surface antigens and directly elicit apoptotic signaling.
Antibody
Type
Indication
Abciximab chimeric Cardiovascular disease
Adalimumab human Several auto-immune disorders
Alemtuzumab humanized Chronic lymphocytic leukemia
Basiliximab chimeric Transplant rejection
Belimumab human Systemic lupus erythematosus
Bevacizumab humanized Colorectal cancer, Age related macular degeneration
BrentuximabVedot in chimeric Hodgkin lymphoma
Cetuximab chimeric Colorectal cancer, Head and neck cancer
Certolizumabpeg ol humanized Crohn's disease
Daclizumab humanized Transplant rejection
Denosumab human Postmenopausal osteoporosis
Eculizumab humanized Paroxysmal nocturnal hemoglobinuria
Efalizumab humanized Psoriasis
Palivizumab humanized Respiratory Syncytial Virus
Panitumumab human Colorectal cancer
Ranibizumab humanized Macular degeneration
Rituximab chimeric Non-Hodgkin lymphoma
Tocilizumab humanized Rheumatoid arthritis
Tositumomab murine Non-Hodgkin lymphoma
Trastuzumab humanized Breast cancer

SIDE EFFECTS:
Common :
  • Allergic reactions
  • Chills
  • Weakness
  • Diarrhea
  • Nausea
  • Vomiting
  • Rash
  • Itching
  • High blood glucose levels
  • Cough
  • Constipation
Other side effects :
  • Shortness of breath
  • Peripheral edema
  • Headache
  • Fever
  • Muscle aches and pain
  • Decreased appetite
  • Increased triglyceride levels
  • Insomnia
  • Abdominal pain
  • Back pain
  • Dizziness
Serious :
  • Low blood pressure
  • Anaphylaxis
  • Serious infections
  • Cancer
  • Serum sickness
  • Autoimmune thyroiditis
  • Arterial and venous blood clots
  • Cardiomyopathy(Trastuzumab)
  • Bleeding
  • Interstitial lung disease
  • Hepatitis
  • Generation of antibodies
  • Enterocolitis
  • Gastrointestinal perforation
  • Mucositis
  • Stomatitis
  • Anemia
  • Reduced white blood cell counts
  • Hypothyroidism
Exam Question
  • In monoclonal antibody production, monoclonal cells are differentiated from Myeloma cell lines
  • Bevacizumab is Monoclonal antibody against VEGF
  • Herceptin (trastuzumab) prescribed in breast cancer is a monoclonal antibody produced by injecting her-2 antigen
  • Monoclonal antibody against VEGF is Bevacizumab 
  • The monoclonal antibody useful in the treatment of PNH is Eculizumab
  • Monoclonal antibody Produced by hybridoma technology
  • Monoclonal antibody Used for blood grouping
  • Monoclonal antibody Requires in small quantity
  • Cetuximab and rituximab are Chimeric monoclonal antibodies
  • Cardiomyopathy is caused by Trastuzumab
  • DENOSUMAB a monoclonal antibody against RANKL receptor is used in the treatment of Osteoporosis
  • HER2/neu overexpression in Ca breast Responds well to monoclonal antibodies
  • Ritumixab is an anti-cancer drug comes under monoclonal antibodies
  • Ritumixab is a Chimeric monoclonal antibody against CD-20 B cell antigen
  • Most common side effect of Ritumixab is infusion reaction
  • Ritumixab is First FDA drug approved for resistant lymphomas
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