ABSTRACT
It was found that inoculation of several strains of mice with several types of tumor cells resulted, within 24 hr, in a significant decrease in the serum leucogenenol levels of the mice. Serum leucogenenol levels of the mice inoculated with tumors that are rejected become normal or temporarily above normal at approximately the time the tumor is observed to be rejected. Contrariwise, serum leucogenenol levels of mice inoculated with tumors that are not rejected remain at significantly lower than normal levels during the life of the mice. Unlike tumors, skin allografts increase serum leucogenenol levels. When tumors are rejected because of the previous immunization of the mice, serum leucogenenol levels become normal at approximately the time the tumor is observed to be rejected. Excision of the tumor after 1 week of growth, with the consequent recovery of the mice, is accompanied by a recovery of normal serum leucogenenol levels. Also, it was found that injection of mice with a cell-free 0.9% NaCl solution extract of a tumor results in a temporary decrease in serum leucogenenol levels comparable to that observed with the inoculation of a viable tumor which lasts from 24 to 96 hr. It is suggested that the suppression of serum leucogenenol levels is one of the factors responsible for the immunosuppression associated with a growing tumor.
Subject(s)
Leucogenenol/blood , Neoplasms, Experimental/blood , Spiro Compounds/blood , Animals , Immunization , Mice , Mice, Inbred Strains , Neoplasms, Experimental/immunology , Time FactorsABSTRACT
Maternal immunological unresponsiveness has usually been demonstrated with adult tissue allografts. Experiments were first directed to the question of whether maternal reactivity to allogeneic conceptuses parallels that of implants of allogeneic tumor. BALB/c female mice parous by C3H males for one to eight litters and challenged with Tumor 70429 of C3h origin showed increasing unresponsiveness with multiparity. A high percentage of progressively growing tumors in highly multiparous females indicates that unresponsiveness does not give way to sensitization. The effects of multiparity on placental and fetal weights in BALB/c females pregnant by C3H males resulted in a continuing decrease in placental weight (indicative of unresponsiveness) through the third pregnancy, but this was followed by a contrasting progressive weight increase indicating sensitization with four or more pregnancises. Syngeneic placentas displayed a similar pattern suggesting that weight changes were not entirely alloantigen dependent and that fetus-specific antigens also alter maternal reactivity. The effects of specific and nonspecific maternal preimmunization and specific parity on placental weights were tested as follows. One group of BALB/c females was immunized against C3H (specific), a second was immunized against DBA/2 (nonspecific), and a third was not immunized. Each of these groups was divided in half and mated to either C3H or DBA/2 males for a first litter; then all were mated to C3H for a second pregnancy. Placental weights were significantly smaller in females that had their first litter by C3H males. A similar experiment with BALB/c X C57BL F1 females resulted in fewer changes in placental weights. In all instances, maternal reactivity had its major effect upon placental rather than fetal weight. The effect of maternal unresponsiveness upon reproductive capacity was tested by mating BALB/c females to either DBA/2 POR C3H males for a first litter and then mating all females ot C3H males for a second litter. Second litters were significantly larger when first litters were also sired by C3H males.
Subject(s)
Fetus/immunology , Maternal-Fetal Exchange , Neoplasms, Experimental/immunology , Pregnancy, Animal , Animals , Female , Fetus/anatomy & histology , Immune Tolerance , Immunization , Litter Size , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C3H , Mice, Inbred DBA , Organ Size , Parity , Placenta/anatomy & histology , Placenta/immunology , Pregnancy , Transplantation Immunology , Transplantation, HomologousSubject(s)
Maternal-Fetal Exchange , Pregnancy, Animal , Transplantation Immunology , Animals , Antigens, Neoplasm , Female , Male , Mice , Mice, Inbred BALB C , Mice, Inbred DBA , Pregnancy , Transplantation, HomologousSubject(s)
Skin Transplantation , Animals , Graft Rejection , Histocompatibility , Methods , Mice , Mice, Inbred Strains , Transplantation, HomologousABSTRACT
Transplacental hemorrhage is reportedly detectable by erythrocytes containing fetal hemoglobin-F in the maternal circulation. The procedure in the present study is based on the premise that fetal hemoglobin is not eluted from red cells in blood smears by an acid buffer, whereas adult hemoglobin is removed. Erythrocytes containing hemoglobin-F were observed in blood smears of both virgin and pregnant BALB/c mice, but the relative number of these cells in the maternal blood increased during pregnancy, reached a peak around the time of parturition, and decreased thereafter. In BALB/c females pregnant by DBA/2 males, the relatively large numbers of acid-resistant erythrocytes in maternal blood were related to the maternal unresponsiveness to DBA/2 allografts. The fetal derivation of at least a fraction of these cells was suggested by the apparent activity of fetal immunogens in the maternal circulation. The blood of peripartum BALB/c mice multiparous by DBA/2 males was injected into normal, nonimmune BALB/c mice. The blood recipients were later challenged with an allotransplantable DBA/2 tumor. A low degree of immunity was indicated by a decreased size of tumor implants. Attempts to demonstrate vertical transmission of immune suppression from mothers to progeny were negative. These findings indicate that transplacental hemorrhage is a potential source of antigens involved in the induction of specific maternal unresponsiveness.
