Thymosin β₄ is a shared antigen between lymphoid cells and oligodendrocytes of normal human brain

Abstract

In the normal human brain, immunoreactive thymosin beta 4, a well-characterized thymic extract, was demonstrated specifically in the cell bodies and processes of a subset of interfascicular and satellite oligodendrocytes with their stained processes terminating around myelin sheaths. Antisera directed against two other thymic polypeptides, thymosin alpha 1 and alpha 7, did not react. In lymphoid tissues, thymosin beta 4 was present in macrophages, Langerhans' cells of the skin, and the interdigitating cells of the thymus. Thus, a subset of oligodendrocytes shares a common antigen of thymic origin with the reticular-dendritic and phagocytic lymphoid cells--all Ia+ immunocompetent cells that participate in the presentation of antigens to T cells. The subset of thymosin beta 4-positive oligodendrocytes is antigenically distinct and may play a role in the immune surveillance of the central nervous system or the demyelinating processes induced by antigen-presenting activated macrophages.

Neuromuscular diseases associated with human immunodeficiency virus infection

“…It is not surprising that the skin is also affected in HIV-positive patients with neurological diseases, because Langerhans' cells of the skin, tissue, or circulating macrophages, inter- digitating cells of the lymphoid organs, and oligodendrocytes of normal brain share common antigenic determinants and appear to be cells of the same lineage, presenting antigens to T cells [30].…”

The interaction of actin with thymosin β4

“…Even allowing for the fact that these data are drawn from different species, and that the concentrations of these proteins also vary with age, most of the pool of unpolymerized actin in brain must be sequestered by proteins other than TI34. Further, histochemical studies suggest that much of the T]34 in brain is located in oligodendrocytes rather than neurons (Dalakas & Trapp, 1986), suggesting that neurons in particular must rely on other sequestering proteins. Studies now in progress on retinal pigment epithelial cells also show low levels of T[~4 relative to the concentration of unpolymerized actin (Philp & Safer, unpublished data).…”

Migration and Proliferation of Motile Immature Glial Cells in the Developing Cerebral Cortex of Infantile Rat.

“…At the second postnatal week (P7 to P12), oligodendroblasts are differentiated from glioblasts [16,33]. Dalakas et al [11] have observed that a certain subset of oligodendrocytes, positive with galactocerebroside, of corpus callosum in newborn and 15-day-old rats are stained positively with anti-Tb4 antibody. They interpreted this finding to mean that these oligodendrocytes are actively myelinating.…”

“…Most immunoreactivity of Tb4 disappears as the development proceeds, but it persists in microglial cells all over the adult brain [11]. Yasuda et al have confirmed that microglia in the adult rat cerebral cortex are rather specifically stained by immunohistochemistry using anti Tb4 antibody, while other cell types in the cortex become virtually negative [40].…”