T cells in the brain

Persistence of T cells in the brain is a rare event and is associated wdth chronic pathology forming tertiary lymphoid structure that provides support and activation signals by DCs and macrophages. These structures are present in perivascular spaces, meninges and choroid plexus, and w ere studied mostly in multiple sclerosis (see Chapter 18). 

Marcondes MC, Burudi EM, Huitron-Resendiz S, Sanchez-Alavez M, Watry D, Zandonatti M, Henriksen SJ, Pox HS (2001) Highly activated CD8(+) T cells in the brain correlate with early central neiwous system dysfunction in simian immunodeficiency virus infection. J Immunol 167 5429—5438. 

Aharoni R, Kayhan B, Eilam R, Sela M, Amon R (2003) Glatiramer acetate-specific T cells in the brain express T helper 2/3 cytokines and brain-derived neurotrophic factors in situ. Proc Natl Acad Sci USA 100 14157-14162. 

Glatiramer acetate-specific T cells in the brain express T... 

Cyclophilin C was first characterized in the rat, where it was observed to be expressed in a smaller subset of tissues than was CyPA or CyPB.22 In humans CyPC is abundant in the kidney, pancreas, skeletal muscle, heart, lung, and liver, but is almost absent from T-cells and the brain.56 CyPC binds CsA with an affinity comparable to that of CyPA. It also binds a 77 kDa glycoprotein, called cyclophilin-C-associated-protein (CypCAP) in the absence of CsA, which is a competitive inhibitor of this interaction.22,99 The physiological relevance of the CyPC-CypCAP interaction is not known. 

Thy-1 is a cell-surface glycoprotein which is mostly found on cells in the brain and on T cells. Whilst expression in the brain is phylogeneticallv conserved, expression on T cells is not. Thus in the mouse, Thy-1 is found on both thymocytes and peripheral T cells, in the rat it is essentially only found on thymocytes and in man it is found on neither [186]. 

The adult human brain has a power output of about 40 W (see Problem 4.15, p. 415). Suppose that 25 W are utilized to pump Na" ions out of the n we cells, the concentration within the cell being 12 mM, that outside being 150 mM. (a) If the pump works with 50% efficiency, calculate the flux of Na ions out of the nerve cells (T 37 C) (b) If there are 10 nerve cells in the brain, and each nerve impulse causes 10 mol Na to leave a cell, what is the average frequency of impulses in... 

In the complex context of the brain, the mechanisms that remove connections can be as important as the mechanisms that make them. Immune cells in the brain called microglia don t attack pathogens, but attack their neighbors the neurons, plucking off stray neuron branches and removing weak connections. This strengthens the connections left behind, so that a well-primed brain is a strong brain. 

Immune cells in the brain called microglia don t attack pathogens,. Y. Zhan et al. Deficient neuron-microglia signaling results in impaired functional brain connectivity and social behavior. 2014. NatNeurosci. 17(3),p. 400. DOl 10.1038/nn.3641. 

Voluntary muscle contraction is initiated in the brain-eliciting action potentials which are transmitted via motor nerves to the neuromuscular junction where acetylcholine is released causing a depolarization of the muscle cell membrane. An action potential is formed which is spread over the surface membrane and into the transverse (T) tubular system. The action potential in the T-tubular system triggers Ca " release from the sarcoplasmic reticulum (SR) into the myoplasm where Ca " binds to troponin C and activates actin. This results in crossbridge formation between actin and myosin and muscle contraction. 

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