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Small quantities of very pure polyclonal antibodies can be produced in rats and

mice in ascitic fluid. Ascites is a mammalian response to a tumour within the

peritoneum (cavity containing the intestines). Fluid similar to plasma is secreted into

the cavity of the animal and contains very high levels of the antibodies that the

animal is currently secreting in its blood. Animals are immunised with the antigen of

interest and once a high serum level is detected then ascitic fluid production is

induced. Non-secretory myeloma cells such as NS-0 are introduced into the peritoneal

cavity of the animal by injection and allowed to grow there. The presence of the

tumour cells causes the animal to produce ascitic fluid which contains high levels of

immunoglobulins to the original antigen. The fluid is removed by aspiration with a

syringe and needle usually on three or four occasions over a month or so.

7.2.2 Monoclonal antibody production

Mice are usually the donor animal of choice for monoclonal antibody production

although rats and other rodent species may be used. They are cheap to buy and

house, and easy to manage and handle. The limitation on using other species is the

availability of a suitable tumour partner for performing fusions. Balb/C is the usual

mouse strain used for monoclonal antibody production and most of the tumour cell

lines used for fusion are derived from this mouse. Females are usually used as they can

be housed together without too much aggression.

Pre-immunisation bleed

Immunisation 1 day 0

Immunisation 2 day 14

Immunisation 3 day 44

Test bleed day 55

Immunisation 4 Day 65 If poor, immunise again

Test quality of serum by ELISA

Test by ELISA to establish

basic immunity

If good,

collect donations

Fig. 7.4Immunisation schedule.

274 Immunochemical techniques