Post-thymectomy murine experimental autoimmune oophoritis is associated with reduced natural killer cell activity

Pathways Involved in Premature Ovarian Failure: A Systematic Review of Experimental Studies

Premature ovarian failure (POF), which may be undetectable for a long time, is associated with impaired fertility. The mechanisms involved in the pathogenesis of POF as well as the concomitant treatments are still unclear. Although many data exist, mainly produced by the study of transgenic animals under various experimental conditions, they remain fragmented. A systematic review of the pathways involved in premature ovarian failure was conducted. Data extraction was performed from experimental studies until 2019. The molecular processes and their correlation with the follicular developmental stage have been described. Furthermore, the effects in other cells, such as oocytes, granulosa and theca cells have been reported. An overall estimation was conducted.

Persistence of CD16+/CD56-/2B4+ natural killer cells: a highly dysfunctional NK subset expanded in ocular myasthenia gravis

We report a case of myasthenia gravis associated with marked expansion of an unusual CD16(+)CD56(-)2B4(+) NK subset. These atypical cells were characterized by poor cytotoxicity against CD48(+) target cells and high proliferation due to 2B4/CD48 interaction. IL18, IFN-gamma and TGF-beta levels were profoundly different in this patient than in healthy donors. Immunosuppressive treatment induced disease remission and decreased the CD16(+)CD56(-)2B4(+)NK cells count. Our data suggest that expansion of this NK subset in myasthenia gravis patients may account for the deleterious NK cell functioning that occurs in this autoimmune disease.

Do NK cells regulate human autoimmunity?

Natural killer cells have been shown to regulate autoimmune responses under experimental conditions in animals. However, a similar role for human NK cells has not been investigated, although NK cells constitute a significant fraction of the infiltrating cells in a range of autoimmune diseases. This review investigates the evidence, both theoretical and experimental, for the involvement of these cells in human immunopathology.

Premature ovarian failure

Premature ovarian failure (POF) causing hypergonadotrophic hypogonadism occurs in 1% of women. In majority of cases the underlying cause is not identified. The known causes include: (a) Genetic aberrations, which could involve the X chromosome or autosomes. A large number of genes have been screened as candidates for causing POF; however, few clear causal mutations have been identified. (b) Autoimmune ovarian damage, as suggested by the observed association of POF with other autoimmune disorders. Anti-ovarian antibodies are reported in POF by several studies, but their specificity and pathogenic role are questionable. (c) Iatrogenic following surgical, radiotherapeutic or chemotherapeutic interventions as in malignancies. (d) Environmental factors like viral infections and toxins for whom no clear mechanism is known. The diagnosis is based on finding of amenorrhoea before age 40 associated with FSH levels in the menopausal range. Screening for associated autoimmune disorders and karyotyping, particularly in early onset disease, constitute part of the diagnostic work-up. There is no role of ovarian biopsy or ultrasound in making the diagnosis. Management essentially involves hormone replacement and infertility treatment, the only proven means for the latter being assisted conception with donated oocytes. Embryo cryopreservation, ovarian tissue cryopreservation and oocyte cryopreservation hold promise in cases where ovarian failure is foreseeable as in women undergoing cancer treatments.

The natural killer cell -- friend or foe in autoimmune disease?

Autoimmune diseases are chronic conditions resulting from a loss of immunological tolerance to self-antigens. Recent observations have supported an ever-broader role for innate immune responses in directing and regulating adaptive immunity, including responses to self. This review summarizes recent findings supporting important functions of natural killer (NK) cells in regulating autoimmunity. A close survey of the current literature reveals multiple steps where NK cells can regulate inflammation and intervene in loss of self-tolerance. Importantly, the findings also caution against inferring a similar role for NK cells in all autoimmune phenomena or during separate stages of the same disease. Indeed, NK cells may have different influences during the priming and the effector phases of disease. Hence, an increased understanding of the involvement of NK cells in inflammation and infection should provide new insights into the pathogenesis of autoimmune disease.

DA rat NK(+)CD3(-) cells inhibit autoreactive T-cell responses

We isolated natural killer (NK) cells from DA rat bone marrow (BM) by staining with PE anti-NKR-P1A and FACS sorting (>98% NK(+)). The purified NK cells inhibit T-cell proliferation in a dosage-dependent fashion and suppressed production of the proinflammatory Th1 cytokine, IFN-gamma. When activated in vitro with Con A supernatant (CAS), the purified NK cells secrete the beta-chemokine monocyte chemoattractant protein-1 (MCP-1) and upregulate MCP-1 mRNA. The activated NK cells also express IFN-gamma mRNA. Sorted NK(+)CD3(-) cells, from which NKT cells have been excluded, also inhibit autoreactive T-cell responses to myelin basic protein (MBP). These findings are consistent with a role for conventional NK cells in maintaining immune homeostasis, by eliminating autoreactive T cells that have inadvertently become activated.

A mouse gene encoding an oocyte antigen associated with autoimmune premature ovarian failure

Autoimmune premature ovarian failure causes young women to develop menopausal symptoms and infertility. A similar syndrome appears in mice with postthymectomy autoimmune premature ovarian failure. We demonstrate that these mice develop antibodies against a 125-kDa protein located in the oocyte cytoplasm (ooplasm). By screening a mouse ovarian complementary DNA expression library with autoimmune serum, we have identified a novel mouse gene with a 3.75-kb ovarian transcript, the expression of which is restricted to the oocyte. The longest open reading frame (3333 bp) encodes an oocyte-specific protein, designated OP1 (ooplasm-specific protein 1). The protein is composed of 1111 amino acids with a predicted molecular mass of 125,502 Da. Based on its primary structure, it appears to be novel and has no motifs to suggest a localization other than in the cytoplasm. The ability of immune serum from mice with ovarian autoimmunity to react specifically with recombinant OP1 raises the possibility that OP1 as an antigen may play a role in murine autoimmune premature ovarian failure.

Inhibition of Autoimmune T Cell Responses in the DA Rat by Bone Marrow-Derived NK Cells In Vitro: Implications for Autoimmunity

Regulation of the immune response is critical to homeostasis. While innate immunity can influence the development of adaptive immune responses, its role in regulation is less well understood. Recently, NK cells have been implicated in the control of experimental autoimmune encephalomyelitis, an animal model for multiple sclerosis. In this report, we show that rat bone marrow-derived NK cells exhibited potent inhibitory effects on T cell proliferation to both Con A as well as the central nervous system Ag myelin basic protein. There was also a significant decrease in both IFN-γ and IL-10 production in vitro, whereas levels of the β-chemokine monocyte chemoattractant protein-1 were significantly elevated. Flow cytometry studies suggest that the NK cells may play an important role in regulating both normal and autoimmune T cell responses by exerting a direct effect on activated, autoantigen-specific T cells.