P. Šíma

Role of the leukemia-inhibitory factor gene mutations in infertile women: The embryo-endometrial cytokine cross talk during implantation — a delicate homeostatic equilibrium

Locally secreted cytokines of both the embryonic and the endometrial origin control the implantation process. The defects in their signaling that lead to unfavorable environment within the uterus may cause embryo implantation failure. The leukemia inhibitory factor (LIF), interleukin-11 (IL-11) as well as IL-12/IL-15/IL-18 system are regarded to be important signaling vectors. LIF plays an essential role in the preimplantation embryo development and the blastocyst implantation and its gene mutations in women contribute to the implantation failure and subsequent infertility. IL-11 signaling has been shown to be required for the uterine decidualization response as well as for the hatching and attachment of blastocysts. The IL-12/IL-15/IL-18 system interacts with endometrial leukocytes, particularly with NK cells, and influences directly the local angiogenesis and tissue remodeling. Differences in the levels of endometrial leukocytic subpopulations and in the patterns of intra-uterine cytokine concentrations that are observed between fertile and infertile women contribute to infertility probably by affecting the embryonic maternal dialogue during the implantation and early placentation period. Focusing on this cross talk promises to open new era in assisted reproduction techniques that will be based on diagnostics of missing signaling molecules and impairments of uterine receptivity as well as on therapeutic applications of individualized embryo culture and transfer media.

Altered distribution of NK and NKT cells in follicular fluid is associated with IVF outcome

The aim of this study was to investigate differences in the relative distributions of subsets of natural killer (NK) cells, including immunoregulatory NK cells (CD56(+)CD16(-)), cytotoxic NK cells (CD56(+)CD16(+)), as well as total NK cells (CD56(+)CD3(-)), and NKT cells (CD56(+)CD3(+)) in peripheral blood and follicular fluid in subjects with successful or unsuccessful IVF treatment. The immunoregulatory NK cell population in follicular fluid of women who failed to achieve pregnancy after IVF treatment was significantly decreased compared to women who became pregnant after IVF. Conversely, the NKT cell population in the follicular fluid of women with unsuccessful treatment was significantly elevated compared with those with successful IVF. Understanding the changes in the distribution of NK and NKT cell populations in follicular fluid might serve as the basis for a more detailed study to determine whether NK cell parameters have prognostic value in guiding the selection of individual ova for use in IVF procedures.

Nonmammalian vertebrate antibiotic peptides.

With the exception of cyclostomes, all vertebrates share the common immune strategy of adaptive, highly specific immunity, based on the products of recombination-activating genes and recombined noninherited receptors for antigens. In addition, they have retained ancient vectors of innate immunity, such as antimicrobial peptides, which are widespread in all eukaryotic organisms and show a high degree of structural homology across most animal taxa. Recently, these substances have become the objects of intensive study for their outstanding bioactive properties with the aim to be applied as very efficient antibiotics, antimicrobials, and even cancerostatics in clinical practice.

DIFFERENCES IN THERMOREGULATION BETWEEN IMMUNOCOMPETENT AND IMMUNODEFICIENT HAIRLESS MICE EXPOSED TO MILD COLD

Cold-induced thermogenesis in brown adipose tissue (BAT) represents in adult mice the most important thermoregulatory mechanism which is further potentiated in hairless strains (Weihe 1984; Holub 1989; Hou~trk et al. 1989), mainly due to a diminished insulating capacity of the hairless skin. The role of a profound immunodeficiency in the thymic system of the hairless nude mutant (Holub 1989) is of principal interest. We therefore studied the effect of mild cold acclimation (22 vs. 28 ~ of nu/nu and of immunologically normal hairless BFU mice (Ho~ek and Chlumeck~ 1965; Heldmaier 1974). We tried to explain the conspicuous increase of the thermogenic potential of BAT in mild-coldexposed nudes and their inability to sustain a constant body (dorsal skin) temperature, in contrast to BFU mice.

Association of the leukemia inhibitory factor gene mutation and the antiphospholipid antibodies in the peripheral blood of infertile women

To characterize the impact of the potentially functional mutation — the G to A transition at the position 3400 of the leukemia inhibitory factor (LIF; a pluripotent cytokine that plays a central role in the control of the embryo implantation) gene that leads to the exchange of valine with methionine at codon 64 we evaluated the association of the LIF gene mutation and the levels of antiphospolipid antibodies (aPLs) in the peripheral blood of infertile women (the aPLs examination was part of our routine immunological test during the infertility check-up). Eight infertile mutation-positive women were diagnosed with idiopathic infertility (n=5) and endometriosis (n=3) and their levels of aPLs in serum were compared with 115 infertile women without any LIF gene mutation. Enzyme-linked immunosorbent assay was used for the detection of seven antiphospholipid antibodies; the results were statistically assessed by the Fisher’s 2 by 2 exact test to evaluate the association of the LIF gene mutations and aPLs in serum of infertile patients. The presence of aPLs was significantly higher in our study group (100 %) than in 30 % of aPLs-positives in control infertile patients (p=0.0035) which indicates that the aPLs are elevated in women with LIF gene mutations.

Enhancement by mild cold stress of the antibody forming capacity in euthymic and athymic hairless mice

Temperature over 28 ~ is recommended as an optimum for the maintenance of immunodeficient hairless (athymic) mice, and about 21-23 ~ for immunocompetent hairless (euthymic) mice to sustain their heat balances (Ediger and Giovanella 1978; Weihe 1984). In contrast to immunocompetent mice, immunodeficient ones develop a higher stimulation of their thermogenic apparatus if they are held at an ambient temperature decreased to 22 ~ and prevented from mutual social thermogenesis for at least 2 weeks. The up regulation of thermogenesis of athymic hairless mice under mild cold stress is accompanied with significant changes of their immune status (for review see Holub 1989). Here we describe the mild-cold-induced differences in the numbers of IgM and IgG antibody-forming cells, and in the relative distribution of cell subpopulations bearing surface IgM and IgG receptors, and CD4 and CD8 markers in immunodeficient mice.

Changes in proliferation activity and relative distributions of lymphoid cell subpopulations in congenitally athymic nu/nu mice and lurcher mice with spontaneous olivopontocerebellar degeneration

Changes observed in mice with congenital damage of some part of the CNS-neuroendocrine-immune regulatory system are described. nu/nu mice with congenital absence of thymus and Lurcher mice with spontaneous olivopontocerebellar degeneration displayed changes in the histoarchitecture of adrenal gland, immune organs (thymus, spleen, axillar lymph nodes) and intestine. Changes were also observed in IgM+, IgG+, CD4+ and CD8+ lymphoid cell subpopulations in the main lymphoid organs — the spleen and axillar lymph nodes and in the proliferative ability of whole lymphoid cell populations. The extreme decrease of lymphoid T-cell subpopulations in athymic nu/nu mice is the consequence of the absence of thymus, the organ of their maturation. On the other hand, a relative increase of B-cell subpopulations was found in this mouse strain. A relative decrease of CD4+ lymphocytes and a different influence of immunization on B-cell subpopulations were found in the spleen in neurodeficient Lurcher mice. The high percentage of apoptotic cells, cells in the S-phase of cell cycle and increased proliferation index in nu/nu mice suggest that the turnover and renewal of lymphoid cells in the spleen in nu/nu mice is more rapid than in control immunocompetent BALB/c mice.

Shifts of lymphoid and phagocytic cell populations during mild cold acclimation in hairless mice

Changes in some cellular populations in the central and peripheral tissues of mild-cold-exposed immunodeficient and immunocompetent hairless mice have been noticed (Holub et al. 1996). Since we have established (Funda et al. 1997) that the exposure has different effects on skin temperature of immunocompetent (BFU) and immunodeficient (athymic, nu/nu) mice, leading to progressive hypothermia in the latter model, the changes of cellular populations in the skin and superficial lymph nodes of both models must be attributed to the effect of hypothermia complicated by differences in the key immune defenses the two hairless, temperature-sensitive models.