Apmis

Rygaard, Jørgen

doi: 10.1111/j.1699-0463.1994.tb04838.xpmid: N/A

Fleischer, BERNHARD

doi: 10.1111/j.1699-0463.1994.tb04839.xpmid: 8166997

“Superantigens” is the term for a group of molecules that have in common an extremely potent stimulatory activity for T lymphocytes of several species. They stimulate CD4+, CD8+ and gammaφ+ T cells by a unique mechanism: they cross‐link variable parts of the T‐cell receptor (TCR) with MHC class II molecules on accessory or target cells. The interaction site on the class II molecule and on the TCR is different from the peptide binding site; on the TCR it is the variable part of the ß chain (Vß). The prototype superantigen is the staphylococcal enterotoxin B (SEB), member of a family of genetically related proteins produced by Staphylococcus aureus and Streptococcus pyogenes. These are soluble exotoxins of approximately 27 kd molecular mass. It is intriguing that this molecular mechanism of T‐cell stimulation has been independently produced at least three times in evolution. Other pathogens producing superantigens are retroviruses (the Mouse Mammary Tumor Viruses) and a mycoplasma (Mycoplasma arthritidis). Many additional candidate superantigens have been proposed, but in most cases unequivocal evidence for superantigen activity is still missing. There are several reasons why these molecules have aroused such tremendous interest in recent years. First, they have provided key information on tolerance mechanisms, both on the deletion of T cells in the thymus and on the induction of peripheral tolerance by anergy and apoptosis. Second, of all polyclonal T‐cell stimulators they are the ones that most closely mimic the recognition of specific antigen. Finally, they have been recognized as important factors in the pathogenicity of the producing pathogens, inducing shock and immunosuppression. Whilst there is evidence that superantigens could be involved in the pathogenesis of certain human diseases, in most cases this is still very preliminary and indirect.

Berg, KURT

doi: 10.1111/j.1699-0463.1994.tb04840.xpmid: 8166996

A new, specific and sensitive one‐site ELISA for precise quantification of human interferon‐gamma (HuIFN‐γ) at low levels in 50% human serum samples has been developed. The assay is based on the assumption that biologically active HuIFN‐γ is present exclusively as a dimer. Thus, in contrast to previous reports, the ELISA is based on a single monoclonal antibody (MAb) which is used in two ways: as “catching” antibody and as HRPO‐labelled conjugate. The sensitivity could be improved five‐fold by addition of (NH4)2SO4 to the conjugate solution; the lowest detectable amount of HuIFN‐γ is <0.5 u/ml. Non‐specific interactions were not seen in interferon samples taken from cultures, or samples diluted in ordinary media or 1% BSA. However, >30% of the (serum) samples gave non‐specific false‐positive results when the method was applied to samples containing 50–100% human serum from different donors. The false signals were related to the donors but could ‐ at the expense of the sensitivity which was reduced to 1 u/ml ‐ be abolished by PEG treatment of the (donor) serum samples.

Andersen, CLAUS B.; Ladefoged, SØREN D.; Larsen, SVEND

doi: 10.1111/j.1699-0463.1994.tb04841.xpmid: N/A

Serial biopsies from 41 consecutive renal allotransplanted patients were evaluated in order to obtain pretransplant data as well as information on well‐functioning and acutely rejecting grafts. Each patient served as his own control. Thirty‐five patients were followed according to the schedule which included biopsy prior to transplantation, shortly after opening of reanastomosis, at least once postoperatively (days 7–10), and furthermore whenever clinically indicated. The morphological evaluation was in each case combined with immunofluorescence (to detect immunoglobulins and complement fractions) and immunohistochemistry with a wide panel of monoclonal antibodies for T cells (CD2, CD3, CD4, CD8, γφ), B cells (CD20, CD22), macrophages (CD68, MAC387) NK cells (leu‐7, CD 16), activation markers (IL‐2‐R, Ki‐67, transferrin‐R), MHC antigens (HLA‐ABC, HLA‐DR), adhesion molecules (ICAM‐1, VCAM‐1, ELAM‐1, PADGEM, VLA‐4, LFA‐1 α/β), and growth factors (EGF, TGF‐α, EGF‐R). When 132 biopsies and 10 failed allografts were examined, no specific morphological or immunohistological parameter predictive of rejection or graft outcome could be found. Morphology in follow‐up biopsies from non‐rejecting and rejecting patients revealed a continuum of inflammatory changes, and several non‐rejecting cases demonstrated cellular inflammatory infiltrates which could not be discriminated from those seen in acute rejection. Of the patients 44% had acute rejection accompanied by increased infiltration of T cells and macrophages showing enhanced IL‐2‐R expression, increased tubular and endothelial staining for MHC class II, ICAM‐1, and VCAM‐1, and strong leukocytic expression of VLA‐4 and LFA‐1 α/β.

Meyts, EWA RAJPERT‐DE; HØRding, ULLA; Nielsen, HENRIK W.; SkakkebæK, NIELS E.

doi: 10.1111/j.1699-0463.1994.tb04842.xpmid: 8166998

Epidemiological features suggest that the risk of testicular cancer may be related to exposure to unknown infectious agents, including viruses. Therefore a series of twenty specimens of testicular germ cell tumours, including preinvasive carcinoma in‐situ, were tested for the presence of DNA sequences of two viruses with known transforming abilities, human papillomavirus (HPV) and Epstein‐Barr virus (EBV). The polymerase chain reaction (PCR) technique was used. In none of the 19 successfully amplified samples were DNA sequences of HPV type 16 or type 18 detected. In six cases a faint trace of EBV DNA was revealed in one of two experiments. These samples were examined by imrnunohistochemical staining with specific antibodies raised against the EBV protein products and in‐situ hybridization with specific molecular probes, and were confirmed to be negative. The study indicates that a significant direct involvement of HPV and EBV in human testicular germ cell carcinogenesis is unlikely. However, a putative growth‐stimulating role of EBV‐transformed lymphocytes, which are frequently present in the stromal tissues of testicular tumours, cannot be excluded.

Toft, P.; TØNnesen, E.; Helbo‐Hansen, H. S.; Lillevang, S. T.; Rasmussen, J. W.; Christensen, N. J.

doi: 10.1111/j.1699-0463.1994.tb04843.xpmid: 8166999

Major surgery induces a stress response characterized by granulocytosis in peripheral blood, and increased secretion of adrenaline and Cortisol. The purpose of this study was to investigate the redistribution of granulocytes in response to major surgical stress. Granulocytes were isolated from eight surgical patients and eight healthy volunteers, labelled with Indium‐lll‐tropolone, and reinjected. The distribution of granulocytes was imaged with a gamma camera and calculated by an interfaced computer before surgery and at 2, 4 and 6 h after the end of surgery. The volunteers served as a control group. In the hours after surgery the radioactivity of the area around the surgical field increased to 410.7% of initial values, while the radioactivity of the spleen decreased to 77.5%. In conclusion, the spleen constitutes a readily mobilizable source of granulocytes. This in vivo model demonstrates pronounced postoperative efflux of granulocytes to the area around the surgical field within hours.

WadstrÖM, T.; Rydberg, J.; Rozalska, B.; Lelwala‐Guruge, J.

doi: 10.1111/j.1699-0463.1994.tb04844.xpmid: N/A

A murine model for testing cytokine production stimulated by Helicobacter pylori is described. H. pylori induced significantly lower levels of TNF‐a and IL‐la compared to Escherichia coli or Pseudo‐monas aeruginosa when injected intravenously. The mean TNF‐a concentration in serum during 6 h after stimulation with H. pylori was 0.2 ng/ml, whereas E. coli induced 4.7 ng/ml and P. aeruginosa 6.0 ng/ml. This was not explained by rapid elimination of H. pylori as bacteria were present for at least 3 h in the blood. The difference in cytokine induction may be a reflection of the bacteria's different biological qualities. E. coli and P. aeruginosa are both capable of causing systemic disease, whereas H. pylori causes only a local, often low grade, inflammation in the gastric mucosa.

Jakobsen, P. H.; Hundt, E.; Hansen, M. B.; Knapp, B.

doi: 10.1111/j.1699-0463.1994.tb04845.xpmid: 8167001

A mixture of Plasmodium falciparum exoantigens inducing lymphocyte activation and cytokine production was shown to contain the malaria vaccine candidate, the serine‐stretch protein. This protein was shown serologically to correspond to Ag2, an exoantigen recognized by antibodies linked with protection against malaria. The glycophorin‐binding protein, the histidine‐rich protein II, the S‐antigen, the heat shock protein 70, the ring‐infected erythrocyte surface antigen, and the apical membrane antigen‐1 were also shown serologically to be present in the mixture of exoantigens.

Nyengaard, JENS R.; Bendtsen, THOMAS F.; Christensen, STEN; Ottosen, PETER D.

doi: 10.1111/j.1699-0463.1994.tb04846.xpmid: 8167002

Chronic renal failure was induced in 10 Wistar rats using a lithium‐containing (40 mmol/kg) diet from time of birth until an age of 55–65 weeks. Nine Wistar rats served as controls. The plasma lithium, the plasma urea, and the inulin clearance were measured, and one kidney was fixed by vascular perfusion with glutaraldehyde. The number of glomeruli was estimated stereologically by the fractionator method. The total number of glomeruli per kidney was 23.9 × 103±3.65 × 103 (±SD) in controls and 22.0 × 103±1.48 × 103 in the lithium‐treated group, showing no statistically significant difference. The mean glomerular volume was also estimated using stereological methods. The number‐weighted mean volume was reduced by 42% in the lithium‐treated group, whereas the volume‐weighted mean volume was unchanged. This can be attributed to the occurrence of many small glomeruli and a few very large glomeruli in the lithium‐treated group. The many small glomeruli have in a previous study been shown to be atubular. The present study showed that the glomerular population is quite resistant to the deleterious effect of lithium; thus glomerular atrophy was seen, but no loss of glomeruli occurred.

Nyberg, PETER W.; Nordman, SUSANN A. S.; Linko, LINNÉA

doi: 10.1111/j.1699-0463.1994.tb04847.xpmid: 8167003

Bacillus Calmette‐Guerin (BCG) was added simultaneously with known NADPH oxidase stimulants to suspensions of human mononuclear leukocytes, and the subsequent production of reactive oxygen metabolites (ROMs) was studied by luminol‐dependent chemiluminescence. BCG significantly amplified the ROM responses induced by zymosan, phorbol myristate acetate (PMA), and quartz, but not by concanavalin A and asbestos fibers. The stimulatory effect occurred rapidly when BCG was added to cells already phagocytosing zymosan, and vanished rapidly when extracellular BCG was removed from adherent monocyte cultures by washing prior to the addition of zymosan. The stimulatory effect of BCG could not be reproduced with recombinant interferon‐γ, tuberculin PPD, muramyl dipeptide, nor with the apathogenic Mycobacterium tuberculosis strain RV37. BCG and zymosan or PMA that had been incubated together prior to addition to the mononuclear cell suspensions caused ROM production with faster kinetics than if the reagents were added separately without preincubation. In conclusion, the synergy between BCG and some of the NADPH oxidase stimulants seems to be due to an interaction between BCG and the NADPH oxidase stimulants rather than to an interaction between BCG and the ROM‐producing cells. Such interactions between mycobacteria and NADPH oxidase stimulants may be of importance as a factor affecting the individual susceptibility to tissue damage in tuberculosis, for example in silicotuberculosis.