White blood cells & the immune system What does it mean to be immune to something? Leucocyte (WBC) Phagocytes (engulf & destroy) = Inflammation Lymphocytes (B cells & T cells) B-lymphocytes secrete antibodies into the blood stream

Bacterial antigens – end up on the surface of the phagocytes that have destroyed them These are then called ‘antigen presenting cells’ or APC

Antibody structure Antibody = a protein called an immunoglobulin ( Ig )

8C Immunity

Immunity – memory cells remain in the body following previous exposure to an antigen

The immune response

1.20 Describe Edward Jenner’s contribution to the development of vaccines 1.21 Explain the process of immunisation, including: a harmless pathogen or antigenic material introduced b the antigens trigger an immune response which causes the production of antibodies c the antigens also trigger production of memory lymphocytes 1.22 Demonstrate an understanding of the advantages and risks associated with immunisation 1.23 Describe the role of memory lymphocytes in secondary responses to antigen; interpret data showing variation in blood antibody levels in response to first and subsequent infections

1.24 Describe the production of monoclonal antibodies, including: a use of B lymphocytes which produce desired antibodies but do not divide b production of hybridoma cells c hybridoma cells produce antibodies and they divide

Monoclonal antibodies

Making monoclonal antibodies

1.25 Use of monoclonal antibodies: a pregnancy testing b diagnosis - locating blood clots and cancer cells treatment - cancer c advantages of using monoclonal antibodies to target specific cells (compared to drug and radiotherapy treatments)

Monoclonal antibodies to hCG are used in pregnancy tests Highly specific = no false positives Very sensitive = can be used early in pregnancy when hCG levels are low (first day of missed period) Cheap & easy to produce – cell biology & tissue culture of hybridoma cells

Monoclonal antibodies as an anti-cancer therapy

£39,000 for one individual to receive a twelve month course of treatment.

Herceptin: a new cancer treatment

How does Herceptin ® work? It is an antibody that binds to a receptor that is over- expressed in breast cancer cells, in 25-30% of patients (the HER2 receptor for human epidermal growth factor) Patients with this characteristic (late stage metastatic breast cancer) tend to respond poorly to conventional chemotherapy (cytotoxic drugs) or hormonal therapy (anti- oestrogen) By binding to the receptors, the drug can ‘switch off’ the signal that tells the cells to keep dividing Approximately 175,000 women develop breast cancer every year in Europe. 20% of all deaths in women are caused by breast cancer (1:5)