Thymocytes double-negative

S100A9 Knock-out No functional abnormalities. Absence of S100A8 protein. Myeloid cells with reduced density. No functional abnormalities in vivo. Absence of S100A8 protein. Reduced response to chemoattractant stimuli in vitro. Stimulation of myeloid cells with ATP results in a stronger increase of intracellular free Ca2+. No emigration of CD4-CD8 double-negative thymocytes upon tetrachlorodibenzo-p-dioxin exposure. 

Biotin deficiency in mice changes the subpopnlations of spleen lymphocytes and decreases the proliferative response of spleenocytes to concanavalin A (17). They have also shown that in experimental biotin deficiency the involution of the thymus is accelerated and thymocyte maturation is arrested in the double negative (DN-4) substage. A specific stage in the T cell maturation process is thus sensitive to biotin deficiency (18). 

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