Immunogenicity Testing of Food Proteins: in vitro and in vivo Trials in Rats

Abstract

The immunogenicity of an industrially produced bacterial food protein (single cell protein, SCP) was analyzed in a comparative study. SCP, casein and ovalbumin were injected into or fed to rats. The systemic response was tested in vitro with a lymphocyte transformation test and in vivo with a footpad swelling assay. Feeding of casein induced cell-mediated reactivity against casein, while feeding of SCP or ovalbumin had no effect. One injection of casein led to sensitization compared with three injections of SCP. Prior feeding of SCP did not abrogate the response to injected SCP. The footpad swelling test is suggested as a particularly effective model for helping to determine the immunological risk of foodstuffs to man.