A simple method of blood exchange in mice and its application to immunology.

A new method for blood exchange (up to 97 per cent) in mice was developed and used to carry out three immunological assays. We showed that it was not possible to influence the immune response appreciably by blood exchange immediately after antigen application. The observation that specific 7S antibodies inhibit immune response, even if these 7S antibodies were removed almost completely by blood exchange, and the comparison with other experimental data, gives rise to the belief that this inhibition might be based on the formation of anti-antibodies. In another assay we tested the importance of `natural' antibodies for the immune response. Using mice we could not confirm the results of Murray (1968) that the removal of `natural' antibodies in the blood of rats by adsorption to sheep red cells causes an immune response. The act of adsorption adds antigen to the blood and this antigen is the reason for the immune response.