Immunoglobulins in porcine umbilical cord blood and maternal placenta.

Studies were made of the immunoglobulin (Ig) in serums from umbilical cord of newborn pigs and maternal placenta. The neutralization test for porcine parvovirus and Japanese encephalitis virus was carried out with the serum of the sow and that of the umbilical cord of the newborn pig. Comparative studies of the serums from the dam and the umbilical cord were also done with gel filtration. Of 20 umbilical cord serum samples, IgG was seen in 5 samples (25%), IgA in 1 sample (5%), and IgM in 9 samples (45%). The amount of any 1 of the 3 classes of Ig in the serums was between 13.5 and 28.0 mg/dl. Among the samples examined, 1 had both IgG and IgA and 1 had IgG and IgM, but none had both IgA and IgM and none had 3 classes of immunoglobulins (i.e., IgG, IgA, and IgM). Only 7 samples (35%) did not have any class of Ig. The IgG disappeared from the blood of hysterectomy-produced colostrum-deprived pigs at 3 days of age, and IgM disappeared when pigs were 7 days of age. Neutralization antibodies of porcine parvovirus and Japanese encephalitis virus in maternal serum were not transferred to the fetus through the placenta. Results of immunohistologic surveys indicated that the sow's Ig were not transferred to the fetus through the placenta. Therefore, it is believed that the Ig in the porcine fetus might be synthesized in certain cells in the placental tissue, and the degree of production of the Ig in the placental tissues may differ in each case. The component, which seems to be Ig, was observed as the obscure band of the beta- to gamma-globulin area in serum of the umbilical cord. Comparison was made, with gel filtration, of maternal serum and serum from the umbilical cord of the newborn pig originating from the same sow. Seemingly, the IgG in the umbilical cord serum is mainly in the lower molecular weight fraction, whereas IgG in the sow's serum was distributed in the high to low molecular weight fractions.