IGG ASYMMETRIC ANTI-OVALBUMIN ANTIBODIES SYNTHESIZED BY VIRGIN AND PREGNANT RATS

A study on the synthesis of asymmetrical IgG molecules 'with no specif ic activity' and with anti-ovalbumin activity was carried out both in virgin rats and in rats inoculated with ovalbumin and made pregnant by syngeneic and allogeneic males. Before pregnancy, female rats synthes ize about 23% of asymmetrical IgG molecules, when the level of these m olecules is assessed in total IgG, in anti-ovalbumin IgG and in the su pernatant from the adsorption of anti-ovalbumin antibodies. On the oth er hand, anti-ovalbumin antibodies isolated are predominantly of the s ymmetrical IgG type; they are also precipitants and effecters of the b iological mechanisms that the host operates to preserve pathogenic ant igens (bacteria, parasites). In rats pregnant by syngeneic and allogen eic males, the ratio asymmetric/symmetric IgG molecules increases, and the anti-ovalbumin antibodies are mainly of the asymmetrical IgG type , which aid antigen-blocking. Similar results are found in virgin rats , immunized with ovalbumin and intraperitoneally transferred simultane ously with supernatants of placental cultures. These results suggest t hat, during pregnancy, there is an increase of the IgG asymmetric/symm etric molecule ratio, produced by placental factors, whatever the immu nogen specificity may be. Speculations about this fact are presented.