New fetoproteins, as presumptive antigenic inducers of abortions and congenital anomalies. Temporal forking of immunological abortions. A working hypothesis.

In a previous experimental study soluble alloantigens and soluble foreign (not recognized by the dam's immune system) transitory antigens in chick embryo have been detected. When a chick embryo extract was injected in hens and their eggs were incubated, the death or a delay in chick embryo development or congenital anomalies were observed. Based on the foregoing, the following working hypothesis is established: any fetoprotein not coming into contact with the fetal immune system during the central clonal selection period becomes a foreign antigen. If it is a female fetus that becomes pregnant at adult age, then passage to the maternal circulation or to the decidua of the same foreign fetoprotein from her fetus is a candidate to induce a humoral or cell-mediated response. If specific IgG or toxic factors of the different cells activated by cell-mediated immunity in the mother access the inductive antigen (e.g., an enzyme) in the conceptus, there functions may be cancelled or the antigen-carrier cell may undergo lysis. This will result in damage to tissues leading to abortion or to a viable but morphologically or functionally abnormal offspring. This can occurs with some of soluble foreign transitory antigens existents. The soluble alloantigens are foreign for the mother because are coded by paternal genes and act of similar way.