Metabolism of 4-14C-dehydroepiandrosterone and 4-14C-4-androstene -3, 17-dione by isolated cells of early human placenta.

The preparation of isolated cells was used for the study of the metabolism of 4-14C-dehydroepiandrosterone and 4-14C-4-androstene-3,17-dione in early human placenta. Free cells suspension converted dehydroepiandrosterone and 4-androstene-3,17-dione into estrone, estradiol-17beta and into C1[neutral steroids 4-androstene-3,17-dione and testosterone.

The effect of antibody on the migratory pattern of peritoneal macrophages.

51Cr-labeled peritoneal macrophages which interiorized sheep erythrocytes (SRBC) injected i.p. into syngeneic recipients accumulate in a typical fashion in different organs. The pattern of distribution can be altered by two maneuvers--when animals at the time of macrophages transfer are injected i.v. with cytophilic antibody, or when macrophages are fed with IgG-SRBC complexes instead of native SRBC. The possible role of modified migratory pattern of macrophages in antibody-induced suppression of the immune response is discussed.

Inhibitory effect of alpha-globulins of different origin on the cell-mediated immune responses in mice.

alpha-Globulins prepared from different biological sources (human and bovine sera, mouse ascitic fluid, human ovarian cyst fluid) were separated by ion exchange chromatography on DEAE-cellulose into fractions A, B and C. Whereas fractions A and B had no immunosuppressive activity, fraction C injected into mice shortly before antigen administration, but not after, significantly inhibited the contact sensitivity to oxazolone. Single high doses were preferential over divided doses given on several occasions. In transfer experiments when cells of animals sensitized to oxazolone were injected into recipients treated previously with fraction C, the response was also inhibited. Fraction C, when administered into F1 hybrid mice before injection of parental splenocytes, prevented the development of GVH reaction. The authors point out that the critical concentration of alpha-globulins at the time of antigen administration is necessary to make T-lymphocytes hyporesponsive, and when once triggered by antigen they become refractory to alpha-globulins action.

Primary immune response to sheep red blood cells in mice treated with immunoregulatory alpha-globulins (IRA).

Alpha-Globulins from human and bovine sera or from mouse ascitic fluid were separated by ion-exchange chromatography on DEAE-cellulose into fractions A, B, and C. Fractions A and B had no immunosuppressive activity; fraction C injected into mice at the time of antigen administration, but not later, significantly reduced the number of anti-SRBC plaque-forming cells in the spleens of experimental animals. Single high dose inhibited the response better than the same doses given on 4 consecutive days. It is concluded that a critical level of alpha-globulins is necessary to render lymphocytes hyporesponsive, and when once stimulated by antigen they become less susceptible to alpha-globulin action.

Contact sensitivity in alloxan-diabetic mice.

Alloxan-diabetic mice of Swiss, CBA and DBA/2 strains show a significant depression of contact sensitivity to oxazolone, as compared with normoglycaemic control animals, which is accompanied by the involution of the thymus and spleen. Insulin treatment partially restores the contact sensitivity in diabetic animals and also increases the weight of lymphatic organs. In contrast, the non-specific inflammatory response to oxazolone is not impaired in insulin-deficient mice. Further experiments have shown that neither sensitized lymphocytes of control animals given to diabetic mice, nor sensitized lymphocytes of diabetic mice injected into normoglycaemic recipients, were able to transfer passively any significant contact sensitivity. It is suggested that in alloxan-diabetic mice the function of T lymphocytes is affected.

Non-specific decrease of cell-mediated immunity in female mice during syngeneic and allogeneic pregnancy.

Cell-mediated immunity is non-specifically reduced in the second half of H-2 incompatible pregnancy compared with syngeneic mating. Significant difference between syngeneic and allogeneic mated female mice was obtained using two independent tests: contact sensitivity to oxazolone (P smaller than 0.001) and local graft-versus-host reaction (P smaller than 0.01).

Demonstration of cells with igg receptor in human placenta.

The presence of two types of cells with IgG surface receptors was demonstrated in mature and immature human placentas. One type corresponded morphologically to the Hofbauer cells and the second to the blood monocytes. Transitional forms between monocytes and Hofbauer cells were also observed.