Differential responses of CD4+CD45RA+ and CD4+CD29+ subsets to activated CD8+ cells: enhanced stimulation of the CD4+CD45RA+ subset by cells from patients with multiple sclerosis

Immune parameters associated with early treatment effects of high-dose intravenous methylprednisolone in multiple sclerosis

To determine the immunological effects of high-dose intravenous methylprednisolone (IVMP) and elucidate immune measurements used for evaluation of its therapeutic effect, we analyzed lymphocyte subsets and humoral immune parameters in peripheral blood and cerebrospinal fluid (CSF) samples, before and within 2 weeks of treatment during 19 acute exacerbations in 16 relapsing-remitting multiple sclerosis (MS) patients. In addition to decreases in CSF albumin and IgG levels, treatment resulted in an increase of CD8(+)CXCR3(+) cells as well as a decrease in CD4(+) subsets expressing CD25, CD29, and CCR4 in the CSF. Further, the percentage of circulating CD4(+)CXCR3(+) Th1 cells also decreased. Clinical improvement was achieved following 15 of the 19 treatment occasions. Early (<2 weeks of treatment) clinical improvement was significantly associated with a decrease in CSF CD4(+)CD29(+) helper inducer T cells, whereas they were nearly unchanged in four patients who showed no improvement. Changes in other parameters following IVMP treatment were not different between the responder and non-responder groups.

T cells with a quiescent phenotype (CD45RA+) are overabundant in the blood and involuted lymphoid tissues in wasting protein and energy deficiencies

The objective of this investigation was to determine the influence of distinct forms of acute weight loss on the expression of the quiescence marker, CD45RA, by T cells in several lymphoid compartments including the blood. Male and female weanling mice, CBA/J and C57BL/6J strains, were allocated to the following groups: ad libitum intake of a complete purified diet; restricted intake of the complete diet; and ad libitum intake of an isocaloric low-protein diet. The restricted intake protocol produced weight loss through energy deficiency (marasmic-type malnutrition), whereas the low-protein diet caused wasting through inadequate protein nitrogen and induced a condition mimicking incipient kwashiorkor. In one experiment, weanling mice of both strains were maintained for 14 days according to each of these dietary protocols and, in a supplementary study, C57BL/6J weanlings consumed either the complete diet or the low-protein diet ad libitum for 21 days. Zero-time control groups (19-days old and 23-days old in C57BL/6J and CBA/J strains, respectively) were included in the first experiment to control for ontogeny-related change. Expression of CD45RA was assessed by two-colour flow cytometry in CD4+ and CD8+ T cells from the spleen, mesenteric lymph nodes and blood. Within 14 days, energy-restricted mice exhibited a high percentage of CD4+ T cells expressing CD45RA in all three lymphoid compartments in both mouse strains (an average of 50% CD45RA+ versus 9% in well-nourished controls), and a similar outcome was apparent in the CD8+ subset (93% CD45RA+ versus 63%). Mice fed the low-protein diet required up to 21 days to exhibit the same imbalance within the CD4+ T-cell subset (33% CD45RA+ versus 4% in well-nourished controls). A shift toward a quiescent phenotype occurs throughout the peripheral T-cell system in acute wasting disease. Consequently, the quiescence-activation phenotype of blood T cells reflects the same index in secondary lymphoid organs in such pathologies. Naive-type quiescence among T cells is implicated as a component of depressed adaptive immunocompetence in the advanced stages of diverse forms of acute weight loss.

CD29 expression on CD4+ gingival lymphocytes supports migration of activated memory T lymphocytes to diseased periodontal tissue

The cell surface phenotypes of CD+ cells extracted from inflammatory periodontal disease tissues were analyzed using two- and three-color immunofluorescence and flow cytometry. Cells extracted from both adult periodontal and localized juvenile periodontitis lesions showed a depressed CD4/CD8 ratio (1.0 +/- 0.1 adult periodontitis and 1.1 +/- 0.1 localized juvenile periodontitis) compared with cells recovered from normal/marginal gingivitis tissue (1.8 +/- 0.2) or with normal peripheral blood cells (2.1 +/- 0.1) or periodontal disease blood cells (2.1 +/- 0.1 and 1.7 +/- 0.1 for adult periodontitis and juvenile periodontitis, respectively). The monoclonal antibodies anti-2H4 and anti-4B4 were used to identify the CD45RA and CD29 antigens respectively on CD4+ T cells from the periodontal disease lesions. In peripheral blood. CD29+ cells accounted for 66-77% of the CD4+ population, and CD45RA+ cells accounted for 22-27% of the CD4+ subset. No differences in expression were found between peripheral blood lymphocytes from normal subjects and from periodontal disease patients. Two-color analyses of lymphocytes from periodontal diseased tissues showed that 87-89% of the CD4+ population were CD29+ and that 70-79% of the CD4+ cells were CD45RA+. Normal tissues contained significantly fewer CD4+CD29+ cells (56 +/- 4%) and CD4+CD45RA+ cells (40 +/- 4%) on average, and few, if any double-labelled cells could be accounted for. These data implied that a significant percentage of the CD4+ cells from the diseased tissues were both CD29+ and CD45RA+ and that these populations are found in quite different proportions in diseased periodontal tissue than in peripheral blood or nondiseased tissue. In further analyses using three-color cytometry the mean percentage of CD4+ CD29+ CD45RA+ lymphocytes extracted from periodontal disease lesions was 43 +/- 9% of the CD4+ population. These results suggest that CD4+ T lymphocytes in periodontal disease not only demonstrate varying levels of maturity but also that the accumulation of CD4+ T cells within the periodontal tissues may be a result of increased adhesion and transendothelial migration.

CD4 subsets (CD45RA/RO) exhibit differences in proliferative responses, IL-2 and gamma-interferon production during intravenous methylprednisolone treatment of multiple sclerosis

Phytohaemagglutinin (PHA)-induced proliferative responses, interleukin 2 (IL-2) and gamma-interferon production were determined in purified CD4CD45RA and CD4CD45RO lymphocytes isolated by immunomagnetic bead separations from normal subjects and multiple sclerosis (MS) patients. Significantly higher proliferative activities were observed for CD4CD45RA cells compared with the corresponding CD4CD45RO cell population in normal subjects and MS patients. CD4CD45RA lymphocyte proliferative responses declined by 50% 3 h following a single dose (500 mg) of intravenous methylprednisolone (IVMP). At 24 h, levels were similar to those determined pre-therapy, as were the levels observed 24 h after a 5-day course (500 mg daily) of IVMP. In contrast, CD4CD45RO cells were unaffected by IVMP. In vitro incorporation of methylprednisolone (10(-6) M) to cell cultures resulted in a modest reduction in proliferative activities of both CD4 subsets. In MS patients subnormal levels of IL-2 and gamma-interferon were observed in PHA-stimulated cultures of CD4CD45RA and CD4CD45RO cells. Following 5 days of IVMP therapy, IL-2 and gamma-interferon production was similar to that observed in CD4CD45RA and CD4CD45RO cells from normal subjects. IVMP therapy causes selective, but transient, inhibition of CD4CD45RA lymphocyte proliferative responses and enhancement of PHA-induced IL-2 and gamma-interferon production by both CD4CD45RA and CD4CD45RO cells.

Production of soluble autocrine inhibitory factors by human glioma cell lines

Gliomas in vitro exhibit density-limited growth upon the attainment of confluency, an effect usually attributed to cell-cell contact inhibition. Since gliomas have been demonstrated to secrete an array of soluble factors which can enhance tumor growth, we undertook this study to ascertain whether production of soluble factors by the tumor may also inhibit growth in an autocrine manner, and whether production of such factors is associated with the growth phase of the glioma. We observed that cell-conditioned medium (supernatants) from non-confluent glioma cultures induced growth, while confluent culture supernatants produced pronounced growth suppression. These latter supernatants enhanced proliferation of non-transformed astrocytes. Supernatants derived from all stages of confluency produced inhibition of lymphocyte proliferation. To characterize these factors, dialyzed supernatant was tested and found to continue to produce lymphocyte suppression but no glioma growth limitation. Growth of tumors in indomethacin or in acetylsalicylic acid to abolish prostanoid synthesis abrogated the inhibitory influence on glioma growth but only partially reversed the lymphocyte suppressive capacity. These studies suggest that gliomas do produce a growth phase dependent autocrine inhibitory factor(s), and that the production of these small molecular weight factors is at least partially under control of the cyclooxygenase pathway.

Gamma-interferon promotes proliferation of adult human astrocytes in vitro and reactive gliosis in the adult mouse brain in vivo

Reactive gliosis is a characteristic response of astrocytes to inflammation and trauma of the central nervous system. To investigate whether soluble factors (cytokines) from inflammatory mononuclear cells that accumulate at lesion sites can provide the cellular signals to initiate gliosis and to identify such cytokines, we have tested and found that supernatants derived from subsets of activated human T lymphocytes (CD8+ or CD4+) are potent mitogens for cultured human adult astrocytes. This effect is blocked by a neutralizing antibody to gamma-interferon (IFN). Recombinant IFN alone can induce proliferation of human adult astrocytes in vitro and increase the extent of trauma-initiated gliosis in the adult mouse brain. The astrocyte proliferation-inducing activity of supernatants of glial cultures treated with IFN can be completely blocked with IFN-neutralizing antibody, suggesting that the proliferative effect does not require intermediary cytokines or cells. These results implicate IFN as an important mediator of the gliosis observed in pathologic conditions of the adult central nervous system associated with infiltrating lymphocytes.