Detection of interleukin-1, interleukin-6, and tumor necrosis factor-alpha in the uterus during the second half of pregnancy in the mouse

This study demonstrated interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF alpha) in the mouse uterus during the second half of pregnancy (days 9-18). High concentrations of IL-1 alpha mRNA and bioactive IL-1 were detected between days 12-17. IL-1 bioactivity decreased to very low levels as pregnancy approached parturition. IL-6 mRNA was detected from days 9-18, and IL-6 bioactivity approximately paralleled IL-1 bioactivity. High levels of IL-1 and IL-6 bioactivity, but not IL-1 or IL-6 mRNA, were detected in the placenta between days 12-17. Placental IL-1 and IL-6 also decreased to low levels near parturition. TNF alpha was expressed from days 9-17, and a peak of TNF alpha bioactivity was detected during the period immediately before parturition. TNF alpha mRNA and TNF alpha bioactivity were not detected in the placenta. On day 18, the day of parturition, the concentrations of IL-1, IL-6, and TNF alpha mRNA were very low relative to those on other pregnancy days. Immunocytochemistry with antibodies to IL-1, IL-6, and TNF alpha was used to confirm the presence of all three cytokines in uterine cells throughout the second half of pregnancy. Those data showing the kinetics of cytokine production during fetal development raise the possibility that cytokines and cytokine-induced mediators modulate cellular events during the late stages of pregnancy in the mouse.

Characterization of cells comprising murine thymocyte multicellular complexes

Characterization of complexes between thymocytes and thymic stromal cells was facilitated in the present study by demonstrating that complexes would reform if cells were incubated for 1.5 to 2 h in vitro at ambient temperature. Several immunologic approaches were used to determine the phenotype of complexed cells. Bound T cells were 97% double-positive (CD4 and CD8), 3% double-negative and greater than 99% CD3 positive by using immunoperoxidase immunohistology on cytospins. Five percent expressed the TCR beta-chain and 1 to 2% were IL-2R positive. The percentages were the same whether complexes were preformed in vivo or formed in vitro. Despite the apparent absence of single positive cells in complexes, when isolated CD4 or CD8 positive cells were tested for their ability to bind to adherent thymic macrophages, each subpopulation contained some cells which were capable of complex formation. When thymocytes were fractionated by density, steroid sensitivity or peanut agglutinin positivity then allowed to form complexes, cells with an immature phenotype had a greater propensity for complex formation. Central stromal cells all were class II MHC gene product (I-A and I-E) positive, expressed macrophage-associated Ag (B23.1 and MAC-1), were negative for cytokeratin but positive for vimentin, were reactive with a polyclonal antimacrophage serum, but did not express dendritic cell Ag (33D1). The data demonstrate that immature thymocytes bind exclusively to class II MHC gene product positive thymic macrophages. This binding step may play a role in the acquisition of T cell function in the thymus.

Characterization of cells comprising murine thymocyte multicellular complexes

Characterization of complexes between thymocytes and thymic stromal cells was facilitated in the present study by demonstrating that complexes would reform if cells were incubated for 1.5 to 2 h in vitro at ambient temperature. Several immunologic approaches were used to determine the phenotype of complexed cells. Bound T cells were 97% double-positive (CD4 and CD8), 3% double-negative and greater than 99% CD3 positive by using immunoperoxidase immunohistology on cytospins. Five percent expressed the TCR beta-chain and 1 to 2% were IL-2R positive. The percentages were the same whether complexes were preformed in vivo or formed in vitro. Despite the apparent absence of single positive cells in complexes, when isolated CD4 or CD8 positive cells were tested for their ability to bind to adherent thymic macrophages, each subpopulation contained some cells which were capable of complex formation. When thymocytes were fractionated by density, steroid sensitivity or peanut agglutinin positivity then allowed to form complexes, cells with an immature phenotype had a greater propensity for complex formation. Central stromal cells all were class II MHC gene product (I-A and I-E) positive, expressed macrophage-associated Ag (B23.1 and MAC-1), were negative for cytokeratin but positive for vimentin, were reactive with a polyclonal antimacrophage serum, but did not express dendritic cell Ag (33D1). The data demonstrate that immature thymocytes bind exclusively to class II MHC gene product positive thymic macrophages. This binding step may play a role in the acquisition of T cell function in the thymus.