Induction of Immune Suppression in the Chick by an Optimal Dose of an Immunizing Antigen in Presence of Its Specific Maternal Antibody

抄録

Prolonged interference or suppression of maternal antibodies on humoral immune response of the newly hatched chicks to active immunization has been documented, while the immunological mechanisms responsible for such suppression still unclear. Laying hens were immunized with dinitrophenyl-keyhole limpet hemocyanin (DNP-KLH). Purified maternal anti-DNP or non-specific IgY antibodies were transferred by yolk sac inoculation to newly hatched chicks, and they were immunized with DNP-KLH or rabbit serum albumen (RSA) at 1 and 4 weeks of age. Concentration of anti-DNP and anti-RSA antibodies in serum samples of these chicks was measured by using Enzyme-linked immunosorbent assay (ELISA). The immune response of the chick received high dose of maternal anti-DNP antibodies and immunized with appropriated dose of DNP-KLH was suppressed. However, those of the chicks received the same high dose of maternal non-specific IgY antibodies and immunized with appropriated dose of DNP-KLH, or those of the chicks received high dose of maternal anti-DNP antibodies and immunized with RSA were not suppressed. On the other hand, suppression of anti-DNP antibody production would not be induced if the chicks received high dose of antigen specific maternal antibodies and immunized with high dose of the same antigen. These results revealed that the immune suppressive effect of maternal antibodies on the immune response of the newly hatched chicks was antigen specific and depends mainly on the ratio of antigen/maternal antibody at the time of immunization.