Alain J. Duclos

Decidual Infiltration and Activation of Macrophages Leads to Early Embryo Loss

PROBLEM: There is considerable controversy concerning the root cause and mechanisms of early embryo loss. It has been suggested that most pregnancy losses occur due to morphogenetic anomalies of the embryo. It has also been suggested that the maternal specific immune system rejects the embryo.

Immunological Prevention of Spontaneous Early Embryo Resorption Is Mediated by Non-Specific Immunosimulation

PROBLEM: Spontaneous early embryo resorption following implantation occurs in many species, but little is known regarding the causes or the prevention of early pregnancy failure. Embryo and fetal loss have widely been assumed to be due to maternal allospecific immune rejection. Alloimmunization therapy with paternal tissues has been successfully used in human and murine pregnancies to prevent early embryo demise. The mechanisms of this treatment have been assumed to be the induction of antigen specific, fetal “graft” enhancing antibodies and suppressor cells. The purpose of this study was to investigate the validity of this assumption.

Presence of Activated Macrophages in a Murine Model of Early Embryo Loss

PROBLEM: Even though our knowledge of the phenomenon at play at the fetoplacental interface has greatly advanced during the past years, a complete understanding of the reasons why the developing embryo is not rejected by maternal immune effector cells remains largely unknown.

Evaluation of the role of exogenous pathogens on the incidence of embryo loss during early pregnancy in mice

Abstract The mating of CBA/j♀ mice (H2k) by DBA/2j♂ mice (H2d) typically results in an elevated incidence of spontaneous embryo loss thus providing an ideal genetically controlled laboratory model for the study of the factors causing early embryo loss during pregnancy. There is now considerable data on the cells and factors involved in fetal resorption but little is known about the events which activate this process. While the activation of the maternal response to the fetal implant could have endogenous or genetic origins, a role for exogenous factors including microbial pathogens could also be involved. In order to investigate these possibilities, the reproductive success of CBA/j♀ × DBA/2j♂ matings in a conventional animal care facility were compared with matings in a specific pathogen free (SPF) animal facility. All animals housed under these conditions were routinely screened by immunoassay and culture, for the presence of a number of viral and bacterial pathogens of mice. The incidence of spontaneous embryo loss in specific pathogen free CBA female mice mated by DBA and other male strains was found to be virtually identical to that of CBA female mice infected with multiple viral pathogens and housed under otherwise identical conditions (non-SPF). However, the numbers of implantation per pregnancy was significantly greater in an SPF facility. Therefore, exposure of mating mice to exogenous viral and bacterial pathogens did not appear to alter the overall incidence of spontaneous embryo resorption. It was concluded that the immunomodulatory effects of infection by common murine pathogens neither augmented nor reduced post-implantation embryo losses.

Transforming growth factor-β levels in aqueous humor during experimentally induced uveitis

The anterior chamber of the eye is known to be a site of immune privilege. Particularly, the aqueous humor (AqH) appears to possess unique immunoregulatory properties. The authors have previously shown that human AqH (HAqH) may increase or decrease the proliferation of different cell types. Although no single factor has been established as solely responsible for these effects, much attention has been given to the 24-30 kD fraction of AqH, where transforming growth factor-beta (TGF-β) is found. The purpose of this study was to determine the changes occurring in the rabbit AqH (RAqH) in relation to intraocular inflammation. Heterologous lens or human serum albumin (HSA) immunization-induced uveitis models were used in two groups of New Zealand albino rabbits to study the relationship between uveitis and TGF-β. AqH and serum samples were obtained serially before, during and after the induction of ocular inflammation. Systemic humoral immunity to HSA or lens antigens was monitored using enzyme-linked immunosorbent assay (ELISA). A mink lung epithelial cell (CCL-64) bioassay for TGF-β was used to quantify the amount of this cytokine in RAqH. TGF-β levels in RAqH increased fourfold after the first immunization. A sharp decrease in RAqH TGF-β levels was found in association with the development of acute intraocular inflammation. The implications of this finding to the etiology of uveitis are discussed.

Quantification of transforming growth factor-β in aqueous humor

The use of biological assays in research often creates complex Problems of data analysis. Due to the nature of bioassays which respond to the intricate interplay between multiple factors that may either increase or decrease the readout, simple arithmetic or standard linear regression analysis often fails to provide accurate values when extrapolation from a standard curve is employed. Non-linear polynomial analysis could provide a better way for expressing such complex relationships. Using a bioassay for transforming growth factor-beta (TGF-β) employing the mink lung epithelium cell line CCL-64, the authors present a new way to analyze experimental data based on non-linear polynomial statistics to provide accurate quantitative results when other simpler techniques have failed. This technique for data analysis provided accurate consistent results with acceptably small experimental variance. Using this approach, the bioactive concentration of TGF-β in normal rabbit aqueous humor was found to be 2.72 ± 0.61 ng/ml, that is, corresponding to 2. 72 ng of PURE TGF-β2, when referring to a standard curve.