3 ms·

Viable chimeras are fascinating. How does the immune system tolerate two different definitions of self?

by stefantalpalaru 12y ago

adolph 12y ago
Using a test for interface rather than implementation maybe?
pygy_ 12y ago
Self-recognition is the consequence of a selection process that occurs in the thymus at a young age, for T-Cells, and in the bone marrow for B-cells. https://en.wikipedia.org/wiki/Thymus https://en.wikipedia.org/wiki/Thymus First, T cells undergo "Positive Selection" whereby the cell comes in contact with self-MHC expressed by thymic epithelial cells; those with no interaction are destroyed. Second, the T cell undergoes "Negative Selection" by interacting with thymic dendritic cell whereby T cells with high affinity interaction are eliminated through apoptosis (to avoid autoimmunity), and those with intermediate affinity survive. See also https://en.wikipedia.org/wiki/V%28D%29J_recombination https://en.wikipedia.org/wiki/V%28D%29J_recombination V(D)J recombination, also known as somatic recombination, is a mechanism of genetic recombination in the early stages of immunoglobulin (Ig) and T cell receptors (TCR) production of the immune system. V(D)J recombination takes place in the primary lymphoid tissue (the bone marrow for B cells, and Thymus for T cells). V(D)J recombination nearly randomly combines Variable, Diverse, and Joining gene segments in vertebrate lymphocytes, and because of its randomness in choosing different genes, is able to diversely encode proteins to match antigens from bacteria, viruses, parasites, dysfunctional cells such as tumor cells, and pollens.
gizmo686 12y ago
My guess would be that it simply lacks the ability to differentiate between them. Consider that we regularly transplant organs between individuals who are less related than twins, and who have fully grown before the transplant.

3 ms·

Viable chimeras are fascinating. How does the immune system tolerate two different definitions of self?

by stefantalpalaru 12y ago

Viable chimeras are fascinating. How does the immune system tolerate two different definitions of self?

adolph 12y ago
Using a test for interface rather than implementation maybe?
pygy_ 12y ago
Self-recognition is the consequence of a selection process that occurs in the thymus at a young age, for T-Cells, and in the bone marrow for B-cells. https://en.wikipedia.org/wiki/Thymus https://en.wikipedia.org/wiki/Thymus First, T cells undergo "Positive Selection" whereby the cell comes in contact with self-MHC expressed by thymic epithelial cells; those with no interaction are destroyed. Second, the T cell undergoes "Negative Selection" by interacting with thymic dendritic cell whereby T cells with high affinity interaction are eliminated through apoptosis (to avoid autoimmunity), and those with intermediate affinity survive. See also https://en.wikipedia.org/wiki/V%28D%29J_recombination https://en.wikipedia.org/wiki/V%28D%29J_recombination V(D)J recombination, also known as somatic recombination, is a mechanism of genetic recombination in the early stages of immunoglobulin (Ig) and T cell receptors (TCR) production of the immune system. V(D)J recombination takes place in the primary lymphoid tissue (the bone marrow for B cells, and Thymus for T cells). V(D)J recombination nearly randomly combines Variable, Diverse, and Joining gene segments in vertebrate lymphocytes, and because of its randomness in choosing different genes, is able to diversely encode proteins to match antigens from bacteria, viruses, parasites, dysfunctional cells such as tumor cells, and pollens.
gizmo686 12y ago
My guess would be that it simply lacks the ability to differentiate between them. Consider that we regularly transplant organs between individuals who are less related than twins, and who have fully grown before the transplant.