Immunoregulatory pathways in pregnancy.

Murine pregnancy is characterized by transient thymic atrophy and splenomegally. Several laboratories are investigating the immunoregulatory mechanisms during pregnancy, and the majority of these studies are primarily focused on the immunological changes either in the uterus or the thymus and not much information is available on the immunological changes in the spleen that result in transient splenomegally. An attempt has been made in this review to understand the significance of thymic atrophy, splenomegally and local immune changes in the uterus to understand the overall immunomodulatory mechanisms in pregnant mother. The most significant change which occurs soon after mating is the infiltration of immune cells such as macrophages and gammadelta-T cells into the uterus indicating that the mother's immune system detects the presence of foreign antigens in the reproductive tract. The sensitized cells appear to migrate to the secondary lymphoid organs including the spleen. The microenvironment in the spleen is conducive for the cell-cell contact and generation of immune response. The major changes that occur in the spleen are, the induction of T-cell dependent B-cell response on day-1 post-coitum (P.C.), generation of antibody producing B-cells on day-3 and also proliferation of CD8+ T-cells that peaks on day-3 of pregnancy. The weight of the spleen reaches a peak on day-10 in mice. Thereafter, on day-15 of pregnancy, lymphocyte apoptosis is seen in the spleen indicating the deletion of peripheral sensitized cells. This results in decrease in spleen weight to that of normal non-pregnant mice. The decrease in thymic weight after day-5 pregnancy was associated with the increased apoptosis of cortical thymocytes. This perhaps is due to negative selection of self-reactive thymocytes. Our studies have demonstrated that the pregnancy associated monoclonal antibodies react with antigens of sperm indicating that the mother's immune system recognizes and responds to the constituents of the semen to produce non-precipitating asymmetric auto antibodies (NPAA) or blocking antibodies which have favourable effects on pregnancy. It is postulated that the mother's immune response could be directed to some antigens of sperm along with some conserved antigens such as heat shock proteins (HSP) that are present both in sperm and in the mother. It may be speculated that after the initial priming to some conserved antigens of sperm and due to the presence of similar antigens in the mother, these activated clones are eliminated both in the primary and secondary lymphoid organs to prevent autoimmunity in the mother during pregnancy.

The role of LFA-1, Mac-1, ICAM-1 and Ia in the induction of Th-2 type of immune response in spleen during murine syngeneic pregnancy.

Murine syngeneic pregnancy is characterized by the transient splenomegaly at mid gestation. Recent studies from our laboratory have indicated the initiation of T-cell dependent B-cell response in the spleen during early pregnancy (Hegde and Nainan 1998). Present studies were carried out to understand the role of cell adhesion and MHC class II (Ia) molecules in the induction of Th-2 type of response in the spleen of pregnant mouse. Immunochemical localization of ICAM-1, LFA-1, Mac-1 and Ia in spleen have been carried out at different stages of pregnancy and formation of cell clusters and natural cell adhesion assay with splenocytes were carried out on day 1 (D1) pregnancy and compared with control. Upregulation of ICAM-1, LFA-1, Mac-1 and Ia was observed during early pregnancy. This coincided with the formation of germinal centers (GC) and Th2 type of interleukins in spleen as reported earlier. Increased expression of cell adhesion and Ia molecules during early pregnancy provides additional evidence for the systemic shift to Th2 type of immune response in syngeneic murine pregnancy.

Immunochemical characterization and antifertility effect of an androgen independent antigen of spermatozoa identified by a monoclonal antibody (D7G3).

Monoclonal antibody, (mAb) D7G3, directed to human spermatozoa and cross-reactive with mouse and rat spermatozoa was found to be a sperm agglutinating antibody. It reacted with antigen present on the post acrosomal region of human spermatozoa and acrosomal region of mouse spermatozoa. The antigen reacting with mAb D7G3 was localized in mouse testicular germ cells and Sertoli cells. It was also localized in the epithelium and spermatozoa of the caput, corpus and cauda epididymides. In addition, the antigen was detected in the epithelial cells and secretions of the prostate and seminal vesicle. The mAb D7G3 reacted with a band of molecular mass 16 kDa in testicular and epididymal sperm and protein preparations of ventral prostate. In the seminal vesicle, an additional band of molecular mass 36 kDa was also identified. The effect of castration on the expression of proteins was studied in the rat. Immunohistochemical localization and Western blotting experiments showed that the antigens identified by the mAb D7G3 was detectable in the epididymis, ventral prostate and seminal vesicle after two weeks of castration. In the seminal vesicle, three additional bands were identified by mAb D7G3 following castration. The expression of this antigen throughout spermatogenesis and sperm maturation indicated that it may have an important biological function. A polyclonal antiserum directed to the 16 kDa mouse epididymal sperm protein was raised in rabbits. Passive immunization of female mice with this antibody caused a significant reduction in fertility only if administered 24 hours prior to mating, indicating that the antibody inhibited a pre-fertilization event by inhibiting sperm function.

Epididymal sperm maturation proteins.

Mammalian spermatozoa are not motile when they leave the testis. They have to undergo a complex maturation process to be able to fertilize in vivo. The maturation changes of mammalian sperm membrane have been extensively studied using lectins and antibodies. Some of these antigens have been purified and cloned. The interaction of secreted proteins with sperm membranes and acquisition of sperm motility as essential steps for spermatozoa to be fertile are well documented. The role of these epididymal maturation proteins in infertility and the possibility of using these antigens for immunocontraception are discussed in this review.

Prognostic significance of myeloperoxidase containing blast cells in acute myelogenous leukaemia.

Fifty three newly diagnosed patients of de novo acute myelogenous leukaemia (AML) received treatment consisting of remission induction with daunorubicin 60 mg/m2 on day one and continuous infusion of cytosine arabinoside 200 mg/m2/day over 24 h from day one to 7. Thereafter patients in complete remission received consolidation chemotherapy with two identical courses. Complete remission (CR) could be achieved in 40 patients (75.5%). Seven patients (13.2%) died with complications during aplasia phase following remission induction therapy while six patients (11.3%) had resistant disease. Twenty seven patients (67.5%) developed relapse while eight patients (15.1%) continue to remain in complete remission ranging from 51 to 68 months (median 62.5). The projected event free survival and disease free survival at 60 months is 15 per cent (SE + 11.9%) and 21 per cent (+6%) respectively. Evaluation of the prognostic significance of pretherapy characteristics showed that infection at presentation and low number of myeloperoxidase (MPO) containing blasts affected the achievement of complete remission adversely on univariate analysis. Similarly age at diagnosis, of more than 45 yr, total leucocyte count of 50,000/cumm or more and low number of MPO containing blasts affected the remission duration (disease free survival) adversely on univariate analysis. On multivariate analysis, MPO positivity of blast cells, remained the only significant independent characteristic. High MPO positivity affected the remission duration favourably (P < 0.01). Patients with high MPO positivity also achieved CR with one induction cycle in 32 out of 40 instances while only 2 out of 5 patients with low MPO positivity, achieved CR with one chemotherapy cycle (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Localization and detection of ovarian follicular fluid protein in follicles of human ovaries.

Human ovarian follicular fluid protein has been partially purified and the active fraction designated as hGF2. Using specific polyclonal antiserum to hGF2, it was observed to be localized immunohistochemically in the granulosa cells of medium but not large follicles of human ovary. The hGF2 levels were estimated by ELISA in serum and follicular fluid of 10 gonadotropin-stimulated women recruited for IVF-ET programme. The results revealed a 3-fold increase in the concentration of hGF2 in follicular fluid compared to that in serum of these patients. These data indicate that the protein is secreted by granulosa cells and plays an important role in the regulation of follicular maturation and ovulation.

Production and characterisation of a monoclonal antibody to progesterone and its effect on fertility.

A monoclonal antibody reacting with progesterone has been raised by fusion of mouse myeloma cells (SP20) and splenocytes of BALB/c mice hyperimmunized with 4-pregnane 3,20 dione conjugated to bovine serum albumin. Association constant of this antibody for binding with progesterone was 0.22 x 10(9) l/mole. The antibody was highly specific for progesterone. A single ip injection of this antibody brought about an antifertility effect which is influenced by genotype. Antibody treatment brought about a significant decrease in the fetal weight and a slight decrease in the plasma progesterone levels. The antifertility effect could be reversed only up to day 3 by exogenous administration of progesterone.

Chemical probes for water oxidation cycle of photosystem II: Part 2--Effect of histidine modifying reagent on thermoluminescence peaks of spinach chloroplasts.

A modification of water oxidation complex in spinach chloroplasts by rose bengal (RB), a known histidine modifying agent, has been studied using thermoluminescence (TL) technique. The changes in the TL profiles at low concentrations of the dye are explained on the basis of alterations in the protein dynamics while those at higher concentrations of the dye are related to the oxidation of histidine residues.

Immune response to syngeneic spermatozoa & its effect on target organs in mice.

Two groups of adult Swiss mice were immunised with washed syngeneic spermatozoa without any adjuvant for a period of two months or four months respectively. The presence of antibodies to spermatozoa was measured by micro sperm-agglutination and micro sperm-immobilization tests. The development of cell mediated immune response (CMIR) was measured by leucocyte migration inhibition test (LMIT) using spermatozoal antigens solubilized by 3M KCl, Nonidet P-40 or by subjecting the cells to ultrasonication. SDS-PAGE analysis of these proteins indicated that extraction of spermatozoa with 3 M KCl was a better method for solubilization of antigens present on sperm membrane. Almost all immunized mice had varying titers of sperm agglutinating antibodies. Nearly 40-50 per cent of the mice had a titre of 1:128 in both groups whereas only 33 per cent had sperm immobilizing antibodies. CMIR, as assessed by LMIT, was detected in immunized mice. However, this had not resulted in the infiltration of immune cells into the target organs perhaps due to the lower magnitude of immune response.

Effect of metal chelators on thermoluminescence peaks of spinach chloroplasts and photosystem II particles: probing the water oxidation cycle with 8-hydroxyquinoline.

Inhibition of photosystem II (PS II) activity by 8-hydroxyquinoline (8-HQ) has been investigated in case of spinach chloroplasts and isolated photosystem II particles using the thermoluminescence technique. In presence of 8-HQ, water to methylviologen (MV) photoreduction in isolated chloroplasts is inhibited while the reduction of dichlorophenol indophenol is inhibited in both chloroplasts as well as in photosystem II particles. The activity can be restored fully by addition of diphenylcarbazide (DPC), suggesting that the donor side of water oxidation complex is affected. The changes in the thermoluminescence peaks indicate that the charge recombination processes involving S2 or S3 states of the Kok's cycle are probably affected by 8-HQ treatment.