Identification of a new oncofoetal antigen associated with several types of human carcinomas.

In experimental animals, oncofoetal antigens1 have been found to be associated with both chemical-2 and virus-induced tumours3. In man the two best known oncofoetal antigens are the α-foetoprotein (AFP) described by both Abelev4 and Tatarinov5 and the carcinoembryonic antigen (CEA) of the human digestive system identified by Gold and Freedman6. We describe here a different human oncofoetal antigen, common to several types of carcinomas and various foetal organs. This antigen has been identified by rabbit antisera raised against semipurified fractions of colon carcinoma soluble extracts. Because of its β-immunoelectrophoretic mobility, this antigen will be referred to as β-oncofoetal antigen (BOFA)

Immunoglobulin E suppression and cytokine modulation in mice orally tolerized to β-lactoglobulin

This study was designed to confirm the tolerogenic properties of β-lactoglobulin in a mouse model and to assess specific oral tolerance induction in humoral and cellular compartments. BALB/c mice were fed β-lactoglobulin (BLG) or whey proteins at different ages and subsequently intraperitoneally challenged 5 days later with both BLG and a non-specific antigen, ovalbumin (OVA). Three weeks later, oral tolerance induction was analysed in CMP-fed, versus saline-fed mice, by measuring specific seric and intestinal antibody responses, delayed-type hypersensitivity (DTH), specific splenocyte proliferation, and cytokine secretion patterns. Three-week-old mice fed high doses of either whey proteins or BLG (respectively 3 mg/g or 5 mg/g of body weight) were found to achieve oral tolerization. At humoral and mucosal levels, anti-BLG immunoglobulin E (IgE) were suppressed in these groups when compared with saline fed mice. With respect to cellular responses, systemic DTH and lymphocyte proliferation to BLG were also inhibited in CMP-fed mice. Weaning time was determined to be the best period for oral tolerance induction. Kinetic analyses showed however, that a minimum of 2 weeks was required for oral tolerance detection. Finally, cytokine profiles indicated a reciprocal decrease of interleukin-2 (IL-2) and interferon-γ (IFN-γ) versus an increase of IL-10 and transforming growth factor-β (TGF-β) secretions in tolerized mice. Taken together, these results clearly showed that oral administration of high doses of cows’ milk proteins can induce significant hyposensitization in mice, in a specific inhibition of T helper 1 (Th1) lymphocytes with the participation of suppressor cytokines