T cell

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Related to T lymphocytes: MHC, B lymphocytes, Cytotoxic T lymphocytes

T lym·pho·cyte

a lymphocyte formed in the bone marrow from which it migrates to the thymic cortex to become an immunologically competent cell; T lymphocytes have long lifespans (months to years) and are responsible for cell-mediated immunity; T lymphocytes form rosettes with sheep erythrocytes and differentiate and divide in the presence of transforming agents (mitogens); T lymphocytes have characteristic T cell receptor-CD3 complexes as surface markers and may be further categorized by function, such as helper and cytotoxic.
See also: B lymphocyte.
Synonym(s): T cell

T cell

n.
Any of the lymphocytes that mature in the thymus and have the ability to recognize specific peptide antigens through the receptors on their cell surface. Also called T lymphocyte.

T cell

Cardiology
A specialised myocyte found in clusters in the sinus node, which is intermediate in size, structure, and organisation between P cells and normal atrial myocytes, and connect swith either of these cells; perinodal T cells surround the sinus tract and are thought to “bundle” impulses leaving the sinus node and to filter premature ectopic atrial impulses.

Immunology
A thymus-derived white cell responsible for cell-mediated immunity and immunoregulation which is the most complex cell of the immune system, given:
(1) The diversity of T-cell types, including T cells with activator, cytotoxic, delayed hypersensitivity and suppressor activities;
(2) The wide range of cytokines, growth factors and immune modulators produced by activated T cells;
(3) The complexity of T-cell interaction with exogenous and endogenous antigens (e.g., mediation of delayed hypersensitivity, graft-versus-host disease);
(4) The complexity of T-cell maturation in the thymus.

50 to 70% of circulating WBCs are granulocytes (neutrophils); the rest are lymphocytes, of which T cells (defined as having “pan T cell” markers), CD2 and CD7 and other T-cell markers (e.g., CD1, CD3, and CD5) comprise 70 to 85%; B cells comprise 15 to 30%.

T lym·pho·cyte

(lim'fŏ-sīt)
A thymocyte-derived lymphocyte of immunologic importance that is responsible for cell-mediated immunity. These cells have the characteristic T3 surface marker and may be further divided into subsets according to function, such as helper, suppressor, and cytotoxic.
See also: B lymphocyte
Synonym(s): T cell.

T cell

One of the two broad categories of LYMPHOCYTE, the other being the B cell group. Subsets of T cells with different functions include cytotoxic T cells (CD8+ T cells) which destroy tumour cells and cells infected with viruses; helper T cells (CD4+ T cells) which assist the immune response, and are a target of HIV infection; REGULATORY T CELLS, formerly called suppressor T cells, which are essential for the maintenance of immunological tolerance; and natural Killer T cells (NKT cells).

T cell

A type of white blood cell produced in the thymus gland that regulates the immune system's response to diseased or malignant cells. It is possible that a subcategory of T cells known as CD4 cells plays a role in Ménière's disease.

T lym·pho·cyte

(lim'fŏ-sīt)
Lymphocyte formed in bone marrow from which it migrates to thymic cortex to become an immunologically competent cell.

Patient discussion about T cell

Q. How are cancer cells similar to normal cells, and how are they different? I know that a similarity would be cells regenerate, and a difference would be cancer cells grow uncontrollably. Is there anything else?

A. I learned a lot of new things from the answers. Thanks.

Q. what is difference between normal cell and a cell infected with cancer?

A. Malignant cells (cancerous cells, which is the correct term, since cancer isn't transmitted from cell to cell like microbes), are immortalized cells: the life span of each cell in our body is tightly regulated according to the body's needs, so cells don't multiply endlessly and eventually undergo programmed death (called apoptosis). Cancerous cells succeed to overcome this regulation, and therefore become immortalized: either excessive multiplication or avoidance of death.

You may read more here:
http://www.mayoclinic.com/health/cancer/CA99999

Q. What tests can the doctors do to see if I have cancer cells still in me? Am using my friend user name. I had a mastectomy in October of the 3cms lump. They also removed lymph nodes from armpit. They found that 2 nodes were slightly infected and 2 blood vessels leading away were the same. My oncologist says I should start chemo for 5 months followed by 5 wks of radiotherapy. I am awaiting the results from bone, heart, lungs and blood tests. What tests can the doctors do to see if I have cancer cells still in me?

A. You need to have your own self examination, which you can get guidance from doctor and all the tests which you already had and the tests which you are awaiting. Like you may have clinical examination, mammograms- which you already had, breast biopsy, ultrasonography, post biopsy pathology test, HER-2 gene test to find the speed of your tumor growth. Tests to check cancer spread – like lymph, bone, liver and lungs whose results you are waiting for.

More discussions about T cell
References in periodicals archive ?
Indeed, the preincubation of the CD3+CD4+CD25+ T lymphocytes with the anti-FasL antibodies or the preincubation of the K562 cells with the anti-Fas antibodies resulted in a complete disappearance of the cytotoxic activity (Figure 2(a)).
Although the role of activated T lymphocytes is clear in the pathogenesis of preeclampsia, previous studies have been unable to detect alterations in the ratio of CD3/CD69 cells and the rate of CD25-expressing lymphocytes in preeclampsia in comparison with healthy pregnancy [2, 15].
Maturation of T Lymphocytes: An Important Event in the Immune Response
In test-tube experiments, they found that the vpr protein spurs healthy T lymphocytes to initiate programmed cell death.
Given the high expression of CD25 in the membrane of Treg lymphocytes, the latter obtain most of the cytokine, leaving effector T lymphocytes without the supply of this growth factor.
Furthermore, hyperglycemia and ketoacidosis were found to increase the levels of proinflammatory cytokines and the numbers of activated T lymphocytes in diabetic patients [14].
Previous research has shown that killer T lymphocytes produced in the lab using conventional methods are inefficient in killing cancer cells mainly because they have a very short life-span, which limits their use as treatment for cancer.
These results show that at 7 days postinfection, T lymphocytes were developed specifically in response to Listeria infection.
Vaccinia virus-specific CD8+ cytotoxic T lymphocytes in humans.
"In contrast to antibody allergy, allergic contact dermatitis requires memory T lymphocytes," says Weston.
IDDM occurs when T lymphocytes infiltrate the pancreas and destroy the insulin-producing cells.
Rotavirus-specific cytotoxic T lymphocytes appear at the intestinal mucosal surface after rotavirus infection.