Characterization of monoclonal nonspecific suppressor factor (MNSF) with the use of a monoclonal antibody

The secretion of immunoglobulin (Ig) from cultured mononuclear cells by lipopolysaccharide (LPS) stimulation is inhibited by monoclonal nonspecific suppressor factor (MNSF), a lymphokine produced by murine T cell hybridoma. In an attempt to develop a murine monoclonal antibody (MAb) with specific reactivity against MNSF, a cell fusion technique that incorporated immune murine splenocytes and HAT-sensitive murine myeloma cells was used. Cross-reactivity experiments confirmed that the MAb (MO6) does not bind to unrelated proteins such as bovine serum albumin, mouse IgG, and murine interferon-gamma (IFN-gamma). There are no effects when anti-IFN-gamma antibodies are used with MNSF. As far as biological activity is concerned, MO6 inhibits in vitro the activity of MNSF in terms of the Ig secretion from cultured lymphocytes. By using MO6, affinity chromatography and immunoblotting were performed. The MNSF on the SDS-PAGE showed a band with m.w. of approximately 70,000, indicating the formation of an aggregate in saline; but after treatment with 0.4 M pyridine-acetic acid buffer, separate bands of 24,000 and 16,000 daltons were evident. Therefore MO6 recognizes 70,000 and both 24,000 and 16,000 daltons. Thus we confirmed by using this MAb and affinity chromatography, the existence of human counterpart, human nonspecific suppressor factor (hNSF), in supernatant from concanavalin A-stimulated T cells. When hNSF was fractionated by high pressure liquid chromatography (HPLC), the activity was found in a region corresponding to 70,000 daltons. However, when fractionated in pyridine-acetic acid buffer, hNSF activity was distributed in a slightly wider range of 15,000 to 30,000 daltons. Physicochemical analysis showed that the purified hNSF is resistant to either heating at 56 degrees C or to 2-mercaptoethanol treatment; however, it is labile to acidification at pH 2.0 and is also sensitive to protease treatment, the characteristics of which were similar to those of murine MNSF. Thus MO6 was confirmed to be a pertinent tool for isolation of hNSF, as well as for murine MNSF.

Transfer of spleen cells expanded by T cell growth factor suppresses arthritis induced in rats

The effects of transfer of T cell growth factor (TCGF)-expanded spleen cells after concanavalin A (Con A) stimulation into syngeneic Lewis rats were studied. The recipient rats were immunized with complete Freund's adjuvant for induction of adjuvant arthritis (AA) or chick type II collagen in incomplete Freund's adjuvant for induction of collagen-induced arthritis (CIA) on day 0. Each of 5 X 10(7) cultured cells without mitogenic stimulation, 2 X 10(7) Con A-stimulated cells, or 1 X 10(7) TCGF-expanded cells cultured for 8 days (4 days X 2 culture cycles) after Con A stimulation was given on days 0 and 7. Both transfers of the cultured cells without stimulation and TCGF-expanded cells markedly diminished the severity of AA and CIA. On the contrary, transfer of Con A-stimulated cells led to no suppressive activity. In addition, transfer to TCGF-expanded cells significantly lowered the titre of anti-type II collagen antibody compared to that of control rats. The transfer of 1 X 10(7) TCGF-expanded cells was optimal for suppressing AA, in terms of cell number. This observation suggests that these cells were much more effective than were the unstimulated cultured cells, for which more than five times the number was required for the same suppressive activity. As far as the phenotypic proportion of helper (W3/13) and suppressor (OX-8) cells is concerned, we found no significant differences between the cultured cell groups and the freshly separated spleen cell group. The precise mechanism of these suppressive effects is the subject of further study. The transfer of TCGF-expanded cells appears to have a potent immunomodulatory effect.

Self-rating depression scales correlated with regional cerebral blood flow in normal volunteers

In order to investigate possible influences of satisfaction with life on regional cerebral blood flow (rCBF), we studied the relationship between the self-rating depression scale and rCBF in normal middle-aged volunteers. A significant inverse correlation between SDS scores and the rCBF was observed. This result was independent of the influences of risk factors for stroke and age. Our findings suggest that satisfaction in daily life is important in maintaining active levels of brain metabolism.

Isolation and characterization of a monoclonal nonspecific suppressor factor (MNSF) produced by a T cell hybridoma

By fusing Con A-activated BALB/c mice spleen cells with AKR thymoma BW5147 cells, we prepared a hybridoma producing a monoclonal nonspecific suppressor factor (MNSF). This factor inhibits a generation of LPS-induced immunoglobulin-secreting cells. We used ELISA for the bioassay of MNSF activity. With this method, a stable E17 hybridoma clone was selected, and its product in culture medium was isolated and characterized. MNSF fractionated on Sephadex G-100 in saline buffer shows a form with multiple m.w., but fractionated in 0.4 M pyridine-acetic buffer, it is limited to two species of approximately 24Kd and 16Kd. The MNSF was purified by hydroxyapatite chromatography, with marked effectiveness. MNSF activity was found exclusively in the 0.35 M sodium phosphate elution, and the content was further fractionated on subsequent gel filtration in the high ionic strength buffer described above. The purified factor exhibited two forms, of 24Kd and 16Kd, and showed peaks of pI 5.3 and 5.7, respectively, on isoelectric focusing. The MNSF preparation described here is stable at 56 degrees C and unaffected by 2-mercaptoethanol, but is unstable at pH 2.0 and is sensitive to tryptic proteolysis. We injected the hybridoma cells into the peritoneal cavity of pristane-primed F1 (AKR/J X BALB/c) mice, and a large amount of pure MNSF was obtained from the ascites, the characteristics of which were similar to those in the culture supernatant. Thus, the MNSF obtained from the E17 hybridoma consists of functionally identical but physicochemically different discrete proteins. This simple method of purification can serve as a probe for further characterization of MNSF and its application in in vivo experiments.

Isolation and characterization of a monoclonal nonspecific suppressor factor (MNSF) produced by a T cell hybridoma

By fusing Con A-activated BALB/c mice spleen cells with AKR thymoma BW5147 cells, we prepared a hybridoma producing a monoclonal nonspecific suppressor factor (MNSF). This factor inhibits a generation of LPS-induced immunoglobulin-secreting cells. We used ELISA for the bioassay of MNSF activity. With this method, a stable E17 hybridoma clone was selected, and its product in culture medium was isolated and characterized. MNSF fractionated on Sephadex G-100 in saline buffer shows a form with multiple m.w., but fractionated in 0.4 M pyridine-acetic buffer, it is limited to two species of approximately 24Kd and 16Kd. The MNSF was purified by hydroxyapatite chromatography, with marked effectiveness. MNSF activity was found exclusively in the 0.35 M sodium phosphate elution, and the content was further fractionated on subsequent gel filtration in the high ionic strength buffer described above. The purified factor exhibited two forms, of 24Kd and 16Kd, and showed peaks of pI 5.3 and 5.7, respectively, on isoelectric focusing. The MNSF preparation described here is stable at 56 degrees C and unaffected by 2-mercaptoethanol, but is unstable at pH 2.0 and is sensitive to tryptic proteolysis. We injected the hybridoma cells into the peritoneal cavity of pristane-primed F1 (AKR/J X BALB/c) mice, and a large amount of pure MNSF was obtained from the ascites, the characteristics of which were similar to those in the culture supernatant. Thus, the MNSF obtained from the E17 hybridoma consists of functionally identical but physicochemically different discrete proteins. This simple method of purification can serve as a probe for further characterization of MNSF and its application in in vivo experiments.

Suppression of adjuvant arthritis in rats by transfer of cultured spleen cells

We studied the in vivo effect of transfer of nonspecific suppressor spleen cells into syngeneic Lewis rats. The rats were immunized with Freund's adjuvant on day 0, and then given 5 X 10(7) cells on days--7, 0 and 7. These cells had been incubated for 3 days, with or without mitogenic stimulation. Transfer of the cultured cells markedly diminished the severity of adjuvant arthritis (AA). On the contrary, transfer of concanavalin A (Con A)-stimulated cells led to no suppressive activity. These results differed from findings in a prior in vitro experiment, in which the suppressive influence of previously cultured cells on T and B lymphocytes proliferation rates was examined and significant suppressive activity was detected in Con A-stimulated cells but not in cultured cells. Suppressor activity by transfer of solely cultured cells was identified in T cell fractions. Transfer of 5 X 10(7) spleen cells proved to be the optimal dose for suppressing AA, and transfer of less than 2 X 10(7) cells had no significant effect. The number and time of transfer were also important factors in the suppression. Each group of transfer on days--7, 0 and 7, days--7 and 0, and days 0 and 7 led to a similar reduction in the severity of AA, and was less prominent in the group injected on days 7 and 14. A single injection on days--7, 0, or 7 revealed minimal or no effects. These observations indicate that the transfer of in vitro cultured spleen cells nonspecifically modified the course of rat AA in vivo, thereby differing from the results of the suppressor activity seen in vitro. The transfer of cultured cells, as a potential tool for the treatment of clinical diseases warrants further attention.

Analysis of interleukin-2 activity in patients with Behçet's disease. Ability of T cells to produce and respond to interleukin-2

We examined interleukin-2 (IL-2) activity in patients with Behçet's disease. T cells from all patients with Behçet's disease were able to produce normal levels of IL-2 in response to phytohemagglutinin; however, responsiveness to IL-2 was impaired in their concanavalin A-activated lymphoblasts. This defect was due to decreased numbers of cells bearing IL-2 receptors in patients with early active disease; in patients with chronic active or with inactive disease, there was a decrease in density of IL-2 receptors on T cells bearing these receptors. Unresponsiveness of T cells to IL-2 may thus contribute to immunologic aberrations in Behçet's disease.

Abnormal B cell function in patients with Behçet's disease

We evaluated B lymphocyte function in 23 patients with Behçet's disease at various stages. The patients with active disease, but not those with inactive disease, were found to have elevated numbers of cells spontaneously secreting immunoglobulin and a decreased B cell response to the T cell-independent B cell mitogen, Staphylococcus aureus Cowan 1. Moreover, B cells from almost all patients with Behçet's disease were unresponsive to the T cell-dependent polyclonal activator, pokeweed mitogen. These results indicate that B cell abnormalities, including some which are associated with disease activity, could be involved in the pathogenesis of Behçet's disease.

Implications for the role of cognate interactions in in vitro human B cell activation by Staphylococcus aureus Cowan I and pokeweed mitogen

Human B cell-triggering mechanisms were investigated using the polyclonal activators Staphylococcus aureus Cowan I (SAC) and pokeweed mitogen (PWM). When the cultures of B cells, T cells, and monocytes were stimulated for 5 d by SAC or PWM, B cells could be activated by both mitogens to proliferate and secrete Ig. Even when T cells were substituted by T cell-derived soluble factors, SAC-stimulated B cells could differentiate into Ig-secreting cells. In contrast, interactions of B and T cells for at least the first 6 h of culture were necessary for the B cell triggering by PWM. Experiments that allow a more precise delineation of the B cell-triggering mechanisms by PWM demonstrated that interactions of B cells with T4+ but not T8+ cells are required for the B cell triggering; anti-Ia or anti-T4 antibody can block this triggering; in contrast, anti-T3 or anti-T8 antibody do not exert any effects on the B cell triggering. However, all these monoclonal antibodies could not modulate the ability of B cells that had been already activated by PWM to respond to T cell-derived factors. These data suggest that SAC can directly activate B cells, while cognate interactions between Ia-like antigens on B cells and T4+ cells are essential for B cell triggering by PWM. Furthermore, once B cells are triggered, they will proliferate, differentiate, and secrete Ig in response to T cell-derived factors; Ia-like antigens or T cell differentiation antigens may not be involved in the processes in this cascade.

OKT4+ and OKT8+ T lymphocytes produce soluble factors that can modulate growth and differentiation of human B cells

The human T cell subset(s) responsible for the production of soluble factors that can modulate B cell growth and B cell differentiation was investigated in the present study. For this purpose, highly purified OKT4+ and OKT8+ lymphocytes were stimulated with phytohaemagglutinin and phorbol myristate acetate. Subsequently, culture supernatants were analysed for B cell growth factor (BCGF) activity and B cell differentiation factor (BCDF) activity in the following systems: 1) maintenance of a proliferative state of Staphylococcus aureus of strain Cowan I (SAC)-stimulated B cells and 2) induction of plaque-forming cell responses of SAC-stimulated B cells. Mitogenic stimulation led to production of equivalent amounts of either BCGF activity or BCDF activity from both of the OKT4+ and OKT8+ subsets. These findings may provide a basis for further studies of the molecular mechanisms as well as cellular interactions involved in human B cell activation, proliferation and differentiation.

Application, to Japanese patients, of the 1982 American Rheumatism Association revised criteria for the classification of systemic lupus erythematosus

The 1982 American Rheumatism Association revised criteria for the classification of systemic lupus erythematosus were tested on Japanese patients. Sensitivity and specificity data were comparable with those presented in the development of the revised criteria by the American Rheumatism Association. Complement determinations were evaluated for their ability to improve the criteria for the diagnosis of early systemic lupus erythematosus.