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HUMAN ENDOGENOUS RETROVIRUSES. "Two ERV genes, termed Syncytin-1 and Syncytin-2, which encode former envelope (Env) proteins, trigger fusion events between villous cytotrophoblasts and the peripheral multinucleated syncytiotrophoblast layer." https://lnkd.in/eNxap6v View in LinkedIn

BREACHING THE WALL. "The modulation of apoptosis by protozoan parasites is an important component of their pathogenic profile. Pathogen decisions on how to manipulate apoptosis represents a continuum from its complete inhibition to its promotion." http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2958.2007.05714.x/full View in LinkedIn

SYNCYTINS. "Retroviruses appear to have a particular ‘affinity’ for placentas. Retroviral particles and mRNAs are often observed in placentas and several genes use retroviral promoters to produce placenta-specific transcripts. Domesticated retroviral envelope proteins (‘syncytins’) promote the fusion of mononucleate trophoblast cells to form a syncytial layer at the maternal–fetal interface of primates and rodents." https://lnkd.in/edp9HQZ View in LinkedIn

APOPTOTIC DEFENSIVE WALL. "Apoptosis, induced in infected cells by cytotoxic immune effector cells, is a critical defence against intracellular pathogens. Despite this cell-mediated immunity, many viral, bacterial and protozoan pathogens have developed mechanisms to invade and multiply within host cells without inducing apoptosis." http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2958.2007.05714.x/full View in LinkedIn

MONUMENTAL ACCIDENT. "An accidental infection of a mammalian ancestor by a retrovirus was responsible for the evolution of a novel mechanism of reproduction, one that launched the entire lineage of placental mammals no less." https://lnkd.in/e6q2jTP View in LinkedIn

IMMEDIATE HOST DEFENSIVE RESPONSE. "Infection by protozoan parasites is often accompanied by the production and secretion of cytokines and other immune effectors that can induce apoptosis in host cells. This response creates a hostile environment characterized by increased levels of FasL, TNF-α, IFN-γ, various other cytokines which induce apoptosis, and the activities of immune effector cells." http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2958.2007.05714.x/full View in LinkedIn

IMMUNOSUPPRESSION. "Due to the presence of their ISD domain, early identification of both Syncytin-1 and-2 suggested that these proteins could be involved in the fetomaternal tolerance state prevailing during pregnancy. It is indeed known that exogenous retroviruses frequently induce severe immunosuppression in both human and animals." https://lnkd.in/eNxap6v View in LinkedIn

"APOPTOSIS, a regulated programmed cell death, is a process whereby cells are culled from healthy tissue. It is important during tissue development, the regulation and termination of an immune response, and the removal of damaged or infected cells. Biochemically, apoptosis is the orderly, immunologically silent dismantling of a cell following the activation of a family of cysteine proteases known as caspases." https://lnkd.in/eg2G-GY View in LinkedIn

REJECTION SUPPRESSION. "As an additional interesting feature of Syncytin proteins, again shared with a certain number of exogenous retroviruses, the presence of an immunosuppressive domain (ISD) has also been demonstrated in these ERV proteins." https://lnkd.in/eNxap6v View in LinkedIn

CELL SUICIDE is called apoptosis. It is normal and widespread. "The cells of a multicellular organism are members of a highly organized community. The number of cells in this community is tightly regulated—not simply by controlling the rate of cell division, but also by controlling the rate of cell death. If cells are no longer needed, they commit suicide by activating an intracellular death program." https://lnkd.in/eaj7Brc View in LinkedIn