Superantigenicity of helper T-cell mitogen (SPM-2) isolated from culture supernatants of Streptococcus pyogenes

A superantigen (Streptococcus pyogenes mitogen-2; SPM-2) that stimulates human helper T cells bearing unique types of variable domains of T-cell receptor beta-chain (TCR V beta) was isolated from the culture supernatant of S. pyogenes strain T12. The active molecule isolated by diethylaminoethyl (DEAE)-cellulose chromatography and isoelectric focusing was a protein with a molecular weight (MW) of 29,000 and isoelectric point (pl) of 6.0. This new superantigen was found to activate preferentially V beta 4+, 7+, and 8+ T cells, whereas recombinant streptococcal pyrogenic exotoxin A and C activated V beta 12+ and V beta 2+ T cells, respectively, as determined by flow cytometry and reverse transcriptase-polymerase chain reaction (RT-PCR) methods. This proliferative response was significantly inhibited by anti-HLA-DR monoclonal antibody, and required paraformaldehyde-fixed antigen-presenting cells (APC), indicating that this action is dependent on major histocompatibility complex (MHC) class II molecules without processing. Analysis of the amino-terminal amino acid sequence of the molecule failed to find any identical or significantly homologous proteins. We have previously reported that cytoplasmic membrane-associated protein (CAP), a streptococcal superantigen isolated from the cell membranes of S. pyogenes T12 strain, stimulated mainly V beta 8+ T cells. Both SPM-2 and CAP preferentially stimulated helper T cells, and rabbit antiserum against SPM-2 completely neutralized the T-cell-stimulating activities of CAP, suggesting that SPM-2 and CAP belong to a family of streptococcal mitogenic proteins. The SPM-2 activity with stimulation of V beta 8+ T cells was detected extensively in the culture fluids of group A streptococci, but not in those of other streptococcal species, including groups B and D streptococci, and most of the activities detected were completely inhibited by anti-SPM-2 serum. These results indicate that SPM-2 may be a newly discovered superantigen molecule, which can be commonly synthesized by group A streptococci.

Accessory cell function of a human colonic epithelial cell line HT-29 for bacterial superantigens

The expression and up-regulation of cell adhesion molecules on a human colonic epithelial cell line HT-29, and the peripheral blood T lymphocyte proliferation responses to bacterial superantigens presented by this cell line were investigated, compared with peripheral blood monocytes. In HT-29 cells, there was constitutive expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-3 (LFA-3) at a low level, but no constitutive expression of HLA-DR, LFA-1, B7-1 and B7-2 molecules. After stimulation with the supernatants of staphylococcal enterotoxin B (SEB)-stimulated peripheral blood mononuclear cells for 48 h, there was significant up-regulation of HLA-DR and ICAM-1 molecules (both > 90% positive). However, this stimulation had no effect on the expression of LFA-1, B7-1, B7-2 and LFA-3 molecules. In the presence of all tested superantigens SEB, toxic shock syndrome toxin-1, and streptococcal pyogenic exotoxin A, stimulated HT-29 cells caused significant T cell proliferation. When monocytes were used as antigen-presenting cells (APC), the MoAbs against HLA-DR, B7-2 and LFA-3 showed a significant inhibition of SEB-induced T cell proliferation. Anti-ICAM-1 MoAb had no effect on this response. On the other hand, when stimulated HT-29 cells were used as APC, the MoAbs against HLA-DR and ICAM-1 significantly inhibited SEB-induced T cell proliferation. In contrast to monocytes, anti-B7-2 and anti-LFA-3 had no effect on this response. SEB could not induce HT-29 cells to produce IL-8 directly; however, SEB significantly induced the stimulated HT-29 cells to produce IL-8 in the presence of T cells. Thus these data demonstrate that the products of superantigen-stimulated T cell activation can increase the expression of HLA-DR and ICAM-1 molecules on HT-29 cells significantly. Stimulated HT-29 cells can serve as APC to bacterial superantigens. This response is an HLA-DR- and ICAM-1-dependent, but B7-2- and LFA-3-independent process, which was different from professional APC monocytes.

Monocyte aggregation and multinucleated giant-cell formation in vitro in Crohn's disease. The effect of cell adhesion molecules

BACKGROUND

Multinucleated giant-cell (MGC) formation is a common histopathologic feature of various granulomatous diseases, including Crohn's disease (CD).

METHODS

We have investigated monocyte aggregation and subsequent MGC formation by in vitro culturing peripheral monocytes from 25 CD patients, 15 ulcerative colitis (UC) patients, and 10 healthy controls. The effect of cell adhesion molecules on the monocyte aggregation and MGC formation in CD patients was investigated by using anti-beta 2 integrin and anti-ICAM-1 antibodies.

RESULTS

The monocyte aggregation and MGC formation were significantly higher in CD than those seen in UC and controls (p < 0.05). In CD, antibody to beta 2 integrin could inhibit not only the monocyte aggregation but also the subsequent MGC formation. In contrast, the antibody to ICAM-1 could inhibit the monocyte aggregation; however, it could not inhibit the MGC formation.

CONCLUSIONS

Monocyte aggregation and MGC formation are increased in CD. beta 2 Integrin may play an important role in the monocyte aggregation and MGC formation of CD patients.

Negative chemotaxis in Cytophaga johnsonae

Chemotaxis, both positive and negative, has been extensively studied in flagellated bacteria, such as Escherichia coli and Salmonella typhimurium, but not in gliding bacteria. The rapidly motile gliding bacterium Cytophaga johnsonae has been seen to be repelled by H2O2, OCl-, and N-chlorotaurine, as well as by low pH. Its response to H2O2 was eliminated by catalase. Nalidixic acid at 200 microM, which inhibits the growth but not the motility of C. johnsonae, did not interfere with its negative chemotactic response to H2O2, whereas sodium phosphate at 10 mM, which inhibits motility, did so. Cytophaga johnsonae was not repelled by taurine, n-octanol, phenol, L-valine, or high pH. Chemotaxis can be conveniently studied in gliding bacteria such as C. johnsonae.

Preparation and characterization of Mn-salophen complex with superoxide scavenging activity

Mn(III)-salophen complex with superoxide scavenging activity was prepared from manganese(III) acetate dihydrate and salophen in ethanol. Visible absorption spectrum of the red-brown complex exhibits a shoulder at 430 nm which was absent with either salophen or manganic acetate alone. Titration of salophen with manganese(III) is consistent with a 1:1 Mn to salophen stoichiometry of the complex based on changes in the absorbance at 500 nm or of superoxide scavenging activity. The superoxide dismutase (SOD)-like activity of the complex in the xanthine-xanthine oxidase/cytochrome c assay was 1450 units/mg salophen. The SOD activity of the complex was suppressed 50% in the presence of EDTA (1 mM), but was not altered in the presence of bovine serum albumin (1 mg/ml) or crude protein extract of Escherichia coli QC779 sodA-sodB- (1 mg/ml). E. coli QC779 sodA-sodB- grew scantily after an 8-h lag phase in aerobic M63 glucose minimal medium. The aerobic growth of the E. coli SOD double mutant in glucose minimal medium was greatly enhanced in the presence of 5 or 10 microM Mn-salophen complex compared to that of control after 24 h incubation. Mn-desferal green complex (10 microM) and pink complex (5 microM) also increased growth rate of E. coli QC779 sodA-sodB- but to a lesser extent than Mn-salophen complex. However, the growth was completely inhibited by 50 microM Mn-salophen complex, 100 microM Mn-desferal green complex, or 10 microM Mn-desferal pink complex.

Effect of berberine alone or in combination with argon ion laser treatment on 9L rat glioma cell line

The cell-killing effect and its possible mechanism of berberine used alone or in combination with argon ion laser treatment on 9L rat glioma cells were studied. The survival fraction of 9L cells after single treatment of berberine has been investigated using both colony formation and microtitration (MTT) method, the half lethal dose of berberine (LD50) has been estimated to be 60 micrograms/ml. After the addition of low energy laser treatment, the LD50 of berberine markedly decreased to 10 micrograms/ml. The inhibitory effect of berberine on biosynthesis for DNA, RNA, and protein of 9L cells was enhanced by argon ion laser. Moreover, when morphologic change was examined, the 9L cells showed lysis, encystation, and degeneration after berberine treatment; the laser treatment enhanced the cell-killing effect. The study proves the cell-killing effect of berberine combined with laser treatment on 9L rat glioma cell line, hence introducing the possibility of berberine as a photosensitive agent.

[Relaxation of coronary arterial smooth muscle and depolarization of cell membrane potential by selenium]

Selenium (Se) is an important trace element to the human being. The effects of selenium on contraction and cell membrane potential of coronary arterial smooth muscle were studied in guinea pig by isometric force development of strips and intracellular recording method. It was showed that Se caused vascular smooth muscle relaxation and depolarization of the cells in a dose dependent manner. Inhibitory effect of Se on KCl- or ACh-induced contraction could be quantitatively assessed by a rightward shift of the concentration-response curve. Furthermore, Se increased KCl-induced depolarization and decreased ACh-induced hyperpolarization.

[A clinical and follow-up study in 33 cases of rapid cyclic affective psychosis]

Three hundred and fifty one cases of manic-depressive psychosis in our hospital were reviewed. Of these, 33 cases were rapid cyclothymic type (9.4%). Their clinical features, including sex, age, personality characteristics, phenomena and clinical types were analysed. The results suggested that: the major precipitating factors are psychosocial factors and antidepressants; the better therapy is the administration of the lithium combined with carbamazepine or neuroleptics; and more ideal prognosis occurs in any patient persisting in receiving the therapy.

[Pattern recognition on the trace element spectrum in gastric cancer and peptic ulcer]

The trace element spectrum of gastric tissue and whole blood specimens from gastric cancer and peptic ulcer patients was recognized with pattern recognition technique in order to obtain the chemical information of gastric cancer. Thirty specimens were obtained from cancer patients in each of the 58 gastric tissues and 54 whole blood specimens. Five pathological types were divided into two groups: peptic ulcer and dysplasia as the ulcer group; well-differentiated, undifferentiated and mucinous carcinoma as the cancer group. The accuracy of recognizing the several spectra was 90%: nine trace element spectra (Cu, Zn, Ni, Co, Cr, Cd, Mn, Fe and Mg) for the tissue specimens from the cancer and ulcer groups; six (Cu, Zn, Mn, Co, Cr and Cd) for dysplasia and well-differentiated adenocarcinoma tissues; five (Cu, Ni, Cr, Cd and Fe) for the whole blood specimens from these two groups and six (Cu, Zn, Cr, Cd, Fe and Ni) for the whole blood specimens from dysplasia and peptic ulcer (including 10 normal individuals). The data were treated by non-linear mapping method and calculated by TRS-80 III type microcomputer.

Intrafascicular decompression in the treatment of causalgia with special reference to the mechanism

A new concept of the pathogenesis of causalgia is suggested in accordance with experimental and clinical work. Endoneural hypertension secondary to nerve trunk disruption is incriminated and intrafascicular decompression is used as the key therapeutic measure. In 14 patients with causalgia thus treated, all except 1 were cured. No symptomatic recurrence was noted in a 4- to 6-year follow-up study.