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J E Merrill

Publications and source records attributed to J E Merrill.

77 records · Page 5Linked to original sources
PubMed1978

A two-step centrifugation procedure for the purification of sheep erythrocyte antigen-binding cells.

A two-step centrifugation procedure has been developed to isolate greater quantities of highly purified sheep erythrocyte antigen-binding cells (ABC) than previously possible. The first step involves partially separating sheep erythrocyte rosettes from unrosetted lymphocytes by their difference in buoyant density on Ficoll-Hypaque. Subsequent passage through a linear 5 to 10% Ficoll gradient produces further purification of rosettes by sedimentation velocity. Approximately 4.5 X 10(6) ABC can be obtained at 50 to 100% purity from 10(9) immune spleen cells (5 days post-immunization) and 1 X 10(5) ABC at 20 to 40% purity from 10(9) nonimmune spleen cells. The purified ABC from 5-day immune animals are 80 to 90% B cells and 10 to 20% T cells, and represent between 30 and 40% of the original ABC in the spleen cell population. Less than 0.2% of the purified ABC are plaque-forming cells (PFC) and less than 2% have intracellular immunoglobulin (Ig) or J chain. The quantities of ABC obtained are sufficient for investigating biochemical parameters of antigen-induced lymphocyte activation and for direct analysis of the surface isotypes found on antigen-binding cells after immunization.

Animals↗
PubMedDate not supplied

Stimulation of oligodendroglial proliferation and maturation by interleukin-2.

There exists considerable evidence that the growth of glial cells can be influenced by T-cell-derived lymphokines and monokines. Astrocytes proliferate in the presence of mitogen- or antigen-stimulated T-cell supernatants, supernatants from human T-lymphotropic virus (HTLV)-transformed T cells, and purified human interleukin-1 (IL-1; ref. 4). Oligodendrocytes proliferate and differentiate when incubated with supernatants from mitogen-activated or HTLV-transformed T cells. In addition, we have recently purified a T-cell-derived lymphokine of relative molecular mass 30,000, termed glial growth promoting factor (GGPF), which specifically stimulates the proliferation of oligodendrocytes. The traditional role of interleukins 1 and 2 is in the initiation, propagation and regulation of the immune response. IL-1, released by a variety of cells including monocytes, stimulates T cells to produce IL-2; IL-2 in turn induces the expansion of T cells that is critical for immune responsiveness. Recently, IL-2 has been shown to induce B-cell proliferation and immunoglobulin secretion, indicating that its action is not restricted to T cells. We now report that recombinant human IL-2 influences the growth of glial cells--specifically, the proliferation and differentiation of oligodendrocytes. IL-2 may have a role in the inflammatory neural lesions of multiple sclerosis patients and in the growth of brain glia during injury or disease.

Animals↗
PubMedDate not supplied

Production of and response to interleukin 1 by cloned human oligodendroglioma cell lines.

Clones and subclones of the human oligodendroglioma line TC620 were characterized with respect to surface and cytoplasmic markers as well as for ability to produce and respond to immunoregulators of inflammation such as products of arachidonic acid metabolism, interleukin 1(IL1) and tumor necrosis factor (TNF). Clone 1.0 and its subclone 1.3 both resembled immature oligodendroglia or precursor-type cells. Both clones were 100% positive for surface galactocerebroside (Gal C), though distinct with respect to predominance of surface gangliosides and lectin receptors. Both clones responded to IL1 beta and IL1b by proliferation and both constitutively released IL1 alpha. The parental line also produced some IL1 but did not proliferate in response to IL1. The IL1 alpha produced could be detected in supernatants as well as cell lysates of TC620 1.0 and 1.3. Neither clone produced prostaglandin E (PGE), leukotriene B4 (LTB4), or tumor necrosis factor (TNF) but IL1 alpha production by 1.3 could be influenced by exogenous PGE and TNF. Response to IL1 beta and IL1 alpha could be specifically inhibited by anti IL1 alpha or beta respectively. The clones also responded to autologous conditioned supernatants. This response was partially inhibited by anti IL1 alpha but not anti IL1 beta, indicating that the factor in the supernatant was IL1 alpha-like.

Arachidonic Acid↗