Enrique García-Olivares

Decreased levels of circulating CD4 ÷ T lymphocytes during normal human pregnancy

Peripheral blood mononuclear cell (PBMC) populations during human pregnancy have been investigated by many authors, although the different results obtained, principally in relation to T cells, are very discrepant. In this study we aimed to exclude all the possible causes of these discrepancies: small sample size; diurnal rhythm of CD4+ T cells; smoking habits; haemodilution which occurs during pregnancy and inappropriate statistical analysis; in order to determine whether gestation has a definite effect on PBMC populations. We found that the percentage of CD4+ T lymphocytes decreases in the first and second trimesters, returns to the non-pregnant level in the third trimester and remains there in the postpartum period. The percentages of CD3+ T lymphocytes run parallel to those of CD4+ while CD8+ T lymphocytes do not vary. The proportion of CD16+ cells, which include mature NK cells, diminishes in the second trimester and this reduction is maintained in the third trimester and the puerperium. No variation was found in the other PBMC studied (CD20+ lymphocytes, CD14+ monocytes and D/DR+ cells). When parity was considered no difference was seen between primiparous and multiparous women in any of the cell populations tested.

Comparison of the Proportions of Leukocytes in Early and Term Human Decidua

The percentages of cells expressing immune markers were determined with immunohistochemistry and flow cytometry in early and term human decidua. Although we found no variation in the proportion of cells of bone marrow origin (CD45 +), the percentages of T cells and CD 16 + lymphocytes were significantly higher in term decidua. On the contrary, CD56+ lymphocytes, the most abundant leukocyte type in early decidua, decreased at term. These variations may reflex the immunological adaptations of decidua during pregnancy.

1-aminocyclopropane-1-carboxylate oxidase from embryonic axes of germinating chick-pea ( Cicer arietinum L.) seeds: cellular immunolocalization and alterations in its expression by indole-3-acetic acid, abscisic acid and spermine

A recombinant protein (approximately 38 kDa by SDS/PAGE), induced by expression in Escherichia coli of a cDNA encoding a 1-aminocyclopropane-1-carboxylate oxidase (ACO) isolated from embryonic axes of Cicer arietinum , was recognized by an antibody raised against an apple ACO. A monoclonal antibody, obtained from recombinant ACO of chick-peas, was used for immunolocalization experiments in the embryonic axes of chick-pea seeds. The results indicate that most of the ACO was present in the apoplast of the cell wall. No evidence of this protein in the vacuole was detected. During germination of C. arietinum seeds, the production of ethylene was induced in the embryonic axis; its highest value was reached when radicle emergence occurred. At this moment there was an accumulation of 1-aminocyclopropane-1-carboxylate (ACC), transcription of ACO mRNA, as well as maximal ACO activity. In the post-germinative period the activity of the last step of ethylene biosynthesis decreased. This decrease was eliminated by indole-3-acetic acid (IAA), which caused significant transcription of ACO mRNA. It is suggested that gene expression of ACO may be induced by auxins and spermine (Spm) and inhibited by abscisic acid (ABA).

Cultured human decidual stromal cells express antigens associated with hematopoietic cells

Although decidual stromal cells (DSC) have classically been considered to play a nutritional role during pregnancy, several reports have demonstrated that they can also exert different immune activities. Furthermore, some authors have occasionally found antigens on DSC normally expressed by immune cells. In this study, we isolated and cultured 12 human DSC lines and studied them with immunocytochemistry and flow cytometry using monoclonal antibodies against antigens associated with hematopoietic cells. Decidual stromal cells exhibited a constant phenotype: they were CALLA (CD10)-positive and DR-positive, although the expression of CD45, the leukocyte common antigen, was found to be very weak or negative. We also detected myelomonocytic antigens CD11b (CR3), CD13, CD16 (Fc gamma RIII) and CD36, although DSC lacked CD14, CD15 and CD33. B cell antigens CD20, CD21 (CR3), CD23 (Fc epsilon RII) and CD24 were expressed. DRC-1, an antigen detected on follicular dendritic cells (FDC), was also observed on DSC. When these cells were cultured in the presence of progesterone, they expressed desmin and prolactin (PRL), findings that confirmed their identity as DSC. The phenotype described, together with the immune activities reportedly carried out by DSC, suggest that DSC may play a role in the maternal-fetal immune relationship.

Spanish late Pliocene and early Pleistocene hominid, palaeolithic and faunal finds from Orce (Granada) and Cueva Victoria (Murcia)

In SE Spain, recent excavations in the Orce basin and at Cueva Victoria indicate presence of both hominids and hominid activity from the Plio-Pleistocene boundary and early Lower Pleistocene.

Species-specific albumin in fossil bones from Orce, Granada, Spain

A skull fragment (VM-0) from Orce, Granada, Spain, dated palaeomagnetically at about 1.6 Myr, is thought by some palaeontologist to be hominid, while others maintain it is equid. If hominid, it would be by far the oldest evidence ofHomo in Europe. Immunological studies on residual albumin in this fossil were carried out independently, and with different immunological methods, at the University of California, San Francisco (radioimmunoassay), and at the University of Granada, Spain (enzyme immunoassay). Other fossils attributed to hominids also studied wereVM1960 from Venta Micena, andCV-1 from Cueva Victoria, Murcia, Spain. Undisputed equid and bovid fossils from the same deposits and dated to a similar period as the Orce skull were also analyzed. Our results showed that species-specific albumin can be detected in 1.6 Myr-old hominid, equid and bovid fossils. The albumin from the Orce skull fragment and fromVM-1960 was immunologically closer to human albumin. These findings support the contention that theVM-0 andVM-1960 are hominid and that members of the genusHomo occupied southern Spain 1.6 Myr ago.

Detection of immunoregulatory lipid-like factors in human amniotic fluid.

ABSTRACT: The immunosuppressive activity of amniotic fluid (AF) is extensively documented in the mouse. Although this property is due in part to the presence of alpha‐fetoprotein (α‐FP), other immunosuppressive factors are suspected. In this article, we demonstrate that human amniotic fluid lipid extract (AFLE) is inhibitory of, although not cytotoxic to, PHA‐activated human lymphocytes, of mouse bone marrow cells, and of different established cell lines of human and mouse source. This effect is shown to be reversible. Under preparative thin layer chromatography (TLC) using chloroform:methanol:water (60:38:8) as solvents, the activity of AFLE migrates to two peaks of inhibition with Rf values of 0.46‐0.62 and 0.84‐1, respectively. These lipid‐like factors may play a role as a nonspecific immunoregulatory mechanism which prevents maternally mediated immune rejection of the conceptus.

Short-lived suppressor cell activity during normal human pregnancy.

Short-lived suppressor cell (SLSC) activity was determined in normal pregnant women. This activity was significantly increased in all three trimesters of pregnancy and during the first week postpartum. When pregnant women were divided into primiparous and multiparous groups, no significant differences were found between the two groups in any of the periods studied. These results suggest that increased SLSC activity may play a role in the materno-fetal tolerance and that parity has no influence on this activity.

Expression of class II HLA molecules by endothelial cells of human decidua

Many authors have documented a high level of expression of class II HLA molecules by decidua. Although macrophages appear to be responsible for this, we show in this article that endothelial cells (EC) of the venules and capillaries of human decidua also strongly express class II molecules, whereas EC of chorionic villi do not. We discuss this finding in the context of the maternal-fetal immune interaction.