Discrete Association of CD3 and CD4 Molecules in T-Cell Stimulation Acting Through the Autologous Mixed Lymphocyte Reaction and the CD3/T-CelI Receptor Complex in Human Autoreactive T-Cell Clones

To investigate autologous antigen recognition, we developed two autoreactive CD4+ T-cell clones, A2 and A10, maintained with non-T cells and IL-2. Autologous non-T-cell stimulation of the T-cell clones resulted in a decrease in cell surface expression of CD4, whereas the expression of CD2, CD3, and WT31 was unchanged. Activation of the autoreactive T-cell clones by cell surface binding anti-CD3 MoAb, as a specific antigen stimulator of the T-cell receptor complex, induced cell surface antigen comodulation of CD3, CD4, and WT31. These data suggest a discrete association of CD3 and CD4 molecules in T-cell stimulation, acting through the autologous mixed lymphocyte reaction and the CD3/T-cell receptor complex. PMA treatment resulted in concomitant down-regulation of CD3 and CD4 but calcium ionophore treatment did not. Thus, it appears that phosphorylation of CD3 leads to the down-regulation of surface antigens of CD4.     

ISOFLURANE REDUCES MICROTUBULE-ASSOCIATED PROTEIN 2 DEGRADATION COMPARED WITH HALOTHANE DURING FOREBRAIN ISCHAEMIA IN THE RAT

One of the most prominent features of the early phase of cerebralischaemia is the immunohistochemical collapse of cytoskeletalproteins. Among these proteins, microtubule-associated protein2 (MtP2) has been shown to be vulnerable to ischaemic injuries.In order to identify a suitable volatile anaesthetic on thebasis of cytoskeletal protein breakdown during cerebral ischaemia,we have compared the effects of isoflurane and halothane onMtP2 degradation in rats. Under equipotent isoflurane or halothaneanaesthesia, forebrain ischaemia was induced by occlusion ofthe bilateral common carotid artery, combined with a decreasein mean arterial pressure to 50 mm Hg. After 20 min of ischaemia,the frontoparietal cortex, brainstem, hippocampus and cerebellumwere removed separately and homogenized. MtP2 from each regionwas measured using an enzyme-linked immunosorbent assay. MtP2degradation in the frontoparietal cortex and hippocampus wassignificantly (P<0.05 and P<0.01) less with isofluraneanaesthesia (75.6 (SD 10.7)% and 72.3 (12.8)%, respectively)than with halothane (65.0 (13. 1)% and 54.7 (13.9)%, respectively).     

Interleukin-6 inhibits the chemotaxis of human malignant plasma cell lines

The chemotaxis of human malignant plasma cells is promoted by two extracellular matrix proteins (ECMs): fibronectin (FN) and laminin (LN). We examined the effect of the supernatant from a bone marrow stroma cell line, KM-101, on the chemotaxis of human malignant plasma cell lines to assess the chemotaxis-regulatory roles of the bone marrow microenvironment. Five human malignant plasma cell lines, FR4ds, OPM-1ds, U266/B1, RPMI-8226 and ARH-77 showed different profiles of the expression of β1 integrins of FN and LN receptors. FR4ds, OPM-1ds and U266/B1 cells showed chemotaxis promoted by FN (Ch^FN) and LN (Ch^LN). ARH-77 cells showed Ch^FN but not Ch^LN. RPMI-8226 cells did not show either Ch^FN or Ch^LN. The supernatant from KM-101 cells inhibited the chemotaxis of each of these cell lines regardless of whether the chemotaxis was promoted by FN or LN. Among the cytokines produced by KM-101 cells, it was postulated that IL-6 mediated this inhibitory effect because anti-IL-6 monoclonal antibody (MoAb) and anti-IL-6 receptor MoAb significantly reversed the inhibition. Recombinant IL-6 (rIL-6) also exhibited a similar inhibitory effect. Because anti-gp130 MoAb significantly reversed the chemotaxis inhibitory effect of rIL-6, the inhibitory signal is probably transduced via the signal transducing receptor component, gp130. The chemotaxis-regulatory effect is another previously unrecognized function of this pleiotropic cytokine, IL-6. High levels of IL-6 in the bone marrow microenvironment of patients with multiple myeloma appears to be favourable for the localization of myeloma cells there.     

Abnormal Production of and Response to B-Cell Growth Factor and B-Cell Differentiation Factor in Patients with Systemic Lupus Erythematosus

We examined the production of and the response to B-cell growth factor (BCGF) and B-cell differentiation factor (BCDF) in 21 patients with systemic lupus erythematosus (SLE) and 23 normal subjects. T cells, 2.5 × 10⁶/ml, were cultured for 24 or 72 h with 1% phytohaemagglutinin (PHA). After absorption of PHA by chicken erythrocytes (CRBC), they were used for BCGF and BCDF. In inactive SLE, BCGF activity was significantly lower than that in normal subjects. Active SLE contained two separate groups, one showing normal BCGF activity and the other showing lower activity than normal. In contrast. BCDF activity from initial culture in active SLE was elevated. The B-cell response both to BCGF and BCDF was elevated in active SLE without Staphylococcus aureus Cowan I antigen (SAC) preactivation. However, the B-cell response to SAC was markedly disturbed. Thus SLE B cells were shifted to the mature state in vivo. We also demonstrated pivotal abnormalities of monocytes in SLE B-cell growth and differentiation. These results may contribute to the understanding of the abormalities of T-B interactions and the overproduction of antibody in SLE.     

Stimulation of Interleukin 6-Like B-Cell Differentiation Factor Production in Human Adherent Synovial Cells by Recombinant Interleukin 1

Abnormal production of immunoglobulin in the joint space is frequently observed in patients with rheumatoid arthritis (RA). We have previously demonstrated that adherent synovial cells (ASC) from patients with RA are involved in B-cell differentiation by their spontaneous production of B-cell differentiation factor (BCDF). The regulation of the production of this factor, however, has not yet been described. We investigated the effects of recombinant interleukin 1 alpha and beta (rIL-1 alpha and rIL-1 beta) on the production of BCDF in ASC. Increased production of BCDF was observed with increased rIL-1 concentration. Production of BCDF was detected 3 h after exposure of ASC to rIL-1 and increased throughout a 48-h culture. This BCDF, assayed on SKW6-CL4 cells, was found to share a common active site with interleukin 6. The effect of rIL-1 was almost neutralized by anti-IL-1 antibody and the addition of polymyxin B did not diminish the effect of rIL-1, indicating that rIL-1 itself stimulates ASC in vitro. These results suggest that IL-1 may play a regulatory role in the production of BCDF in synovial tissue.     

Decrease in reactivity of basophils by immunotherapy with housedust extract

Changes of basophil reactivity to housedust extract and anti-IgE during immunotherapy was examined in thirteen patients with bronchial asthma sensitive to housedust. (i) A significant decrease in the morphological reactivity of basophils to housedust extract was observed 6 months after the beginning of immunotherapy with the antigen, and a significant decrease after 12 and 18 months’ therapy, accompanied with the decrease of histamine release from the cells. The percent reactive basophils to the antigen decreased from 59.2 ± 2.9% before the therapy to 40.0 ± 1.8% after 18 months’immunotherapy. (ii) A decrease in the morphological reactivity of basophils to anti-IgE was also shown during immunotherapy. The basophil reactivity to anti-IgE decreased significantly at the late stage (18 months) of immunotherapy. (iii) A significant reduction of specific IgE antibody to housedust was observed 12 and 18 months after the beginning of immunotherapy. It was suggested from these results that immunotherapy causes some changes on the surface of basophils and decreased reactivity of the cells, and that a decrease of reactive basophils to anti-IgE in the process of immunotherapy might be due to a decrease in number of IgE receptors essentially or functionally.