Evaluate monoclonal antibodies: advantages & risks
Infection and response • Monoclonal antibodies (biology only) (HT only)
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Definition and production
A monoclonal antibody is an identical antibody produced from a single clone of cells that all recognise the same antigen. Production begins by stimulating an animal’s immune system with a chosen antigen, harvesting antibody-producing spleen cells and fusing them with immortal myeloma cells to create hybridoma cells; hybridomas grow indefinitely and secrete the required identical antibody in large amounts . Limiting factors in production include the time needed to generate and select suitable hybridomas, the requirement for specialised laboratory facilities, and initial reliance on animal cells during the generation process, which creates ethical and logistical constraints .
Advantage - high specificity in diagnostics
Monoclonal antibodies bind very specifically to single antigens, which causes clear binding signals when the target molecule is present. This specificity enables sensitive diagnostic tests such as pregnancy strips and infection detection kits that identify tiny concentrations of hormones or pathogen proteins . Specific binding reduces false positives from unrelated molecules; cause → effect explanation: specific antibody binding causes a detectable signal (colour change or fluorescence), which then reveals the presence of the antigen even at low concentration .
Advantage - targeted treatments
Monoclonal antibodies can target disease cells precisely and therefore deliver toxic drugs or radiation directly to those cells. Cause → effect explanation: antibody binds antigen on a cancer cell surface, so the attached drug or radiation concentrates at the tumour, killing cancer cells while leaving surrounding healthy cells relatively unharmed; this reduces collateral damage compared with non-specific chemotherapy . Targeted therapy examples include antibodies that block growth receptors on cancer cells, slowing tumour growth by preventing growth signals from binding to their receptors .
Disadvantage - side effects and unexpected reactions
Clinical testing of monoclonal antibodies produces unexpected side effects in some patients. Cause → effect explanation: antibody binding or immune activation can trigger adverse immune responses; these reactions produce symptoms that limit the drug’s use and require careful monitoring during trials and treatment . Reported side effects across clinical testing include allergic-type responses and systemic reactions that prevent monoclonal antibodies from being an immediate universal ‘magic bullet’; this reduces their adoption until safety profiles improve .
Disadvantage - cost, production limits and antigen variability
Monoclonal antibody therapies require complex production, purification and testing, which increases cost. Cause → effect explanation: high production complexity causes high prices and limited availability, so treatments may not be accessible or suitable for all patients . Antigen variability provides a further limit: if the target antigen mutates or is absent on some tumour cells, the antibody cannot bind and the treatment loses effectiveness; this causes partial responses or resistance in some patients .
Evaluation framework and practical considerations
Evaluation requires comparison of intended benefit versus likely harm, and consideration of feasibility and ethics. Cause → effect explanation: when specificity and targeted delivery reduce healthy tissue damage, overall patient outcomes improve; however, when side effects or poor antigen coverage occur, risks can outweigh benefits and require alternative treatments . Practical considerations for evaluation include evidence from clinical trials, cost–benefit analysis, patient monitoring for side effects, and the potential need for combination therapies where monoclonal antibodies act alongside other treatments to improve efficacy .
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