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Notes: The purpose of this review-hypothesis is to discuss the literature which had proposed the concept that the mechanisms by which infectious and inflammatory processes induce cell and tissue injury, in vivo, might paradoxically involve a deleterious synergistic ‘cross-talk’, among microbial- and host-derived pro-inflammatory agonists. This argument is based on studies of the mechanisms of tissue damage caused by catalase-negative group A hemolytic streptococci and also on a large body of evidence describing synergistic interactions among a multiplicity of agonists leading to cell and tissue damage in inflammatory and infectious processes. A very rapid cell damage (necrosis), accompanied by the release of large amounts of arachidonic acid and metabolites, could be induced when subtoxic amounts of oxidants (superoxide, oxidants generated by xanthine-xanthine oxidase, HOCl, NO), synergized with subtoxic amounts of a large series of membrane-perforating agents (streptococcal and other bacterial-derived hemolysins, phospholipases A2 and C, lysophosphatides, cationic proteins, fatty acids, xenobiotics, the attack complex of complement and certain cytokines). Subtoxic amounts of proteinases (elastase, cathepsin G, plasmin, trypsin) very dramatically further enhanced cell damage induced by combinations between oxidants and the membrane perforators. Thus, irrespective of the source of agonists, whether derived from microorganisms or from the hosts, a triad comprised of an oxidant, a membrane perforator, and a proteinase constitutes a potent cytolytic cocktail the activity of which may be further enhanced by certain cytokines. The role played by non-biodegradable microbial cell wall components (lipopolysaccharide, lipoteichoic acid, peptidoglycan) released following polycation- and antibiotic-induced bacteriolysis in the activation of macrophages to release oxidants, cytolytic cytokines and NO is also discussed in relation to the pathophysiology of granulomatous inflammation and sepsis. The recent failures to prevent septic shock by the administration of only single antagonists is disconcerting. It suggests, however, that since tissue damage in post-infectious syndromes is caused by synergistic interactions among a multiplicity of agents, only cocktails of appropriate antagonists, if administered at the early phase of infection and to patients at high risk, might prevent the development of post-infectious syndromes.

Notes: An in vitro model was employed to study the potential role of streptococcal extra-cellular products, rich in streptolysin O, in cellular injury as related to streptococcal infections and post-streptococcal sequelae. Extra-cellular products (EXPA) rich in streptolysin O were isolated from type 4, group A hemolytic streptococci grown in a chemostat, in a synthetic medium. EXPA induced moderate cytopathogenic changes in monkey kidney epithelial cells and in rat heart cells pre-labeled with 3H-arachidonate. However very strong toxic effects were induced when EXP was combined with oxidants (glucose oxides generated H2O2, AAPH-induced peroxyl radical (ROO⋅), NO generated by sodium nitroprusside) and proteinases (plasmin, trypsin). Cell killing was distinctly synergistic in nature. Cell damage induced by the multi-component cocktails was strongly inhibited either by micromolar amounts of gamma globulin, and Evan's blue which neutralized SLO activity, by tetracycline, trasylol (aprotinin), epsilon amino caproic acid and by soybean trypsin inhibitor, all proteinase inhibitors as well as by a non-penetrating PLA2 inhibitor A. The results suggest that fasciitis, myositis and sepsis resulting from infections with hemolytic streptococci might be caused by a coordinated ‘cross-talk’ among microbial, leukocyte and additional host-derived pro-inflammatory agents. Since attempts to prolong lives of septic patients by the exclusive administration of single antagonists invariably failed, it is proposed that the administration of ‘cocktails’ of putative inhibitors against major pro-inflammatory agonizes generated in inflammation and infection might protect against the deleterious effects caused by the biochemical and pharmacological cascades which are known to be activated in sepsis.

Notes: Abstract In contrast to former findings lysozyme was able to attack the cell walls ofStaphylococcus aureus under acid conditions. However, experiments with14C-labelled cell walls and ribonuclease indicated that, under these conditions, lysozyme acted less as an muralytic enzyme but more as an activator of pre-existing autolytic wall enzymes. Electron microscopic studies showed that under these acid conditions the cell walls were degraded by a new mechanism (i.e. “attack from the inside”). This attack on the cell wall started asymmetrically within the region of the cross wall and induced the formation of periodically arranged lytic sites between the cytoplasmic membrane and the cell wall proper. Subsequently, a gap between the cell wall and the cytoplasmic membrane resulted and large cell wall segments became detached and suspended in the medium. The sequence of lytic events corresponded to processes known to take place during wall regeneration and wall formation. In the final stage of lysozyme action at pH 5 no cell debris but “stabilized protoplasts” were to be seen without detectable alterations of the primary shape of the cells. At the same time long extended ribbon-like structures appeared outside the bacteria. The origin as well as the chemical nature of this material is discussed. Furthermore, immunological implications are considered.

Notes: Abstract Recent evidence indicates that under in vitro conditions, superoxide anion and hydrogen peroxide (H2O2) are unstable in the presence of manganese ion (Mn2+). The current studies snow that in the presence of Mn2+, H2O2-mediated injury of endothelial cells is greatly attenuated. A source of bicarbonate ion and amino acid is required for Mn2+ to exert its protective effects. Injury by phorbol ester-activated neutrophils is also attenuated under the same conditions. EDTA reverses the protective effects. Acute lung injury produced in vivo in rats by intratracheal instillation of glucose-glucose oxidase is almost completely blocked in rats treated with Mn2+ and glycine. Conversely, treatment of rats with EDTA, a chelator of Mn2+, markedly accentuates lung injury caused by glucose-glucose oxidase. These data are consistent with the findings of others that Mn2+ can facilitate direct oxidation of amino acids with concomitant H2O2 disproportionation. This could form the basis of a new therapeutic approach against oxygen radical-mediated tissue injury.

Notes: Abstract Human neutrophils (PMNs) suspended in Hanks' balanced salt solution (HBSS), which are stimulated either by polycation-opsonized streptococci or by phorbol myristate acetate (PMA), generate nonamplified (CL), luminol-dependent (LDCL), and lucigenin-dependent chemiluminescence (LUCDCL). Treatment of activated PMNs with azide yielded a very intense CL response, but only a small LDCL or LUCDCL responses, when horse radish peroxidase (HRP) was added. Both CL and LDCL depend on the generation of Superoxide and on myeloperoxidase (MPO). Treatment of PMNs with azide followed either by dimethylthiourea (DMTU), deferoxamine, EDTA, or detapac generated very little CL upon addition of HRP, suggesting that CL is the: result of the interaction among H2O2, a peroxidase, and trace metals. In a cell-free system practically no CL was generated when H2O2 was mixed with HRP in distilled water (DW). On the other hand significant CL was generated when either HBSS or RPMI media was employed. In both cases CL was markedly depressed either by deferoxamine or by EDTA, suggesting that these media might be contaminated by trace metals, which catalyzed a Fenton-driven reaction. Both HEPES and Tris buffers, when added to DW, failed to support significant HRP-induced CL. Nitrilotriacetate (NTA) chelates of Mn2+, Fe2+, Cu2+, and Co2+ very markedly enhanced CL induced by mixtures of H2O2 and HRP when distilled water was the supporting medium. Both HEPES and Tris buffer when added to DW strongly quenced NTA-metal-catalyzed CL. None of the NTA-metal chelates could boost CL generation by activated PMNs, because the salts in HBSS and RPMI interfered with the activity of the added metals. CL and LDCL of activated PMNs was enhanced by aminotriazole, but strongly inhibited by diphenylene iodonium (an inhibitor of NADPH oxidase) by azide, sodium cyanide (CN), cimetidine, histidine, benzoate, DMTU and moderately by Superoxide dismutase (SOD) and by deferoxamine. LUCDCL was markedly inhibited only by SOD but was boosted by CN. Taken together, it is suggested that CL generated by stimulated PMNs might be the result of the interactions among, NADPH oxidase, (inhibitable by diphenylene iodonium), MPO (inhibitable by sodium azide), H2O2 probably of intracellular origin (inhibitable by DMTU but not by catalase), and trace metals that contaminate salt solutions. The nature of the salt solutions employed to measure CL in activated PMNs is critical.

Notes: Abstract Poly-l-histidine (PHSTD) of molecular weight 26,000 induced the generation of large amounts of Superoxide (O 2 − ) and hydrogen peroxide (H2O2) in human neutrophils (PMNs). Despite its low solubility at neutral pH, PHSTD was bound very rapidly to the PMN surfaces. Maximal generation of O 2 − took place with 4–5 ×10−6 M of PHSTD, starting after a lag of about 25 sec and proceeding for 15–17 min at a rate of 150 nmol/107 PMNs/min, suggesting that this polycation is one of the most potent stimulators of O 2 − generation known, PHSTD was found to be non-toxic for PMNs even at millimolar concentrations. Generation of O 2 − by PHSTD depended on extracellular calcium; it was inhibited by calcium channel blockers and by trifluoperazine, and it triggered a sharp rise in intracellular calcium as determined by the Quin 2 fluorescence technique. The generation of both O 2 − and H2O2 by PHSTD was partially inhibited by cytochalasin B or (CYB, CYE). On the other hand, CYB markedly enhanced the generation of both O 2 − and H2O2 following stimulation of PMNs either by PHSTD, polyarginine, histone, or by antibody-opsonized group A streptococci. Electron microscopic analysis and NBT reduction tests revealed that both PHSTD and PHSTD-opsonized streptococci were avidly phagocytosed by PMNs. Since CYB totally inhibited internalization of both PHSTD and the PHSTD-opsonized streptococci, it was suggested that these agents stimulated oxygen radical generation mainly on the leukocyte surfaces. Complexes (CX) formed between PHSTD and polyanethole sulfonate (a strong polyanion) or between histone and the polyanion mimicked immune CX in their ability to trigger the generation of large amounts of O 2 − which were inhibited by CYB. Generation of O 2 − and chemiluminescence either by PHSTD or by PHSTD-opsonized streptococci were markedly inhibited by poly-l-glutamate, suggesting that PHSTD acted as a cationic agent which interacted via electrostatic forces with some negatively charged sites in the leukocyte membrane. Generation of H2O2 by PHSTD was also markedly inhibited by deoxyglucose, KCN, DASA, as well as by the lipoxygenase inhibitors nordihydroguaiaretic acid, phenidone, and propylgallate. On the other hand, cyclooxygenase inhibitors such as aspirin, indomethacin, and piroxicam were inactive, suggesting that arachidonic acid metabolism via lipoxygenase pathway might have been involved in the activation by PHSTD of the NADPH oxidase in PMNs. PHSTD may mimic the effects of antibodies both as an opsonin and as a potent stimulator of the respiratory burst in PMNs and may thus serve as a model for further study of leukocyte-bacteria interactions in infectious and inflammatory sites and of the pathogenicity of immune complexes.

Notes: Abstract A heat-stable factor present in extracts of human blood leukocytes is capable of lysing youngStaphylococcus aureus at pH 5.O. Lysis is characterized by breakdown of cell-wall components as judged by electron microscopic and biochemical analysis. The leukocyte extracts can be replaced by a variety of agents known to injure cell membranes, e.g., leukocyte cationic protein histone, polymyxin B, colimycin, phospholipase A, and lysolecithin. The mechanisms by which all these agents bring about the degradation of the staphylococcal walls was studied. By using14C-labeled cell walls devoid of cytoplasmic structures, it was demonstrated that none of the above-mentioned agents had a direct lytic effect on purified cell walls. On the other hand, when any of these agents first interacted with intact staphylococci, a factor (presumably an autolysin) was generated that directly lysed the cell walls. Lysis of cell walls in the presence of intact staphylococci used as a source of autolysin was strongly inhibited by a variety of anionic polyelectrolytes such as heparine and liquoid. The possible role played by bacterial autolysins in the generation of microbial cell-wall components capable of triggering chronic inflammation is discussed.

Notes: Abstract In comparative clinical studies of auranofin (AF, oral gold) and parenteral gold in the treatment of rheumatoid arthritis, no difference in efficacy was detected. Since the pharmacologic profiles of these compounds are different, we studied their combined effect on adjuvant arthritis (AA). The effect of AF alone and combined with gold sodium thiomalate (GTM) or gold sodium thiosulfate (GTS) on the excretion of urinary hydroxyproline (UHP) and urinary calcium (UCa), and the articular index of arthritic rats was followed during five weeks of treatment. The excretion of UHP and UCa was significantly inhibited (P〈0.005) in rats treated with AF combined with GTM or GTS as compared with animals treated with the individual gold compounds. However, the articular index only decreased significantly (P〈0.02) in the group of rats treated with AF + GTS. The present studies open the possibility that combined treatment with oral and injectable gold provide a new approach for chrysotherapy with an increased antiarthritic potency.

Notes: Abstract A variety of cationic polyelectrolytes opsonized group A streptococci andCandida albicans to phagocytosis by human polymorphonuclear leukocytes and by mouse peritoneal macrophages. The most potent opsonins for streptococci were specific antibodies supplemented with complement, nuclear histone, polylysine, polyarginine, ribonuclease, leukocyte lysates, leukocyte cationic protein and, to a lesser extent, lysozyme and myeloperoxidase. Histone, RNAse, leukocyte extracts, and platelet extracts also functioned as opsonins for phagocytosis of streptococci in the peritoneal cavity, where phagocytic indices, higher than those obtained for the in vitro phagocytosis, were obtained. Fresh serum, polylysine, polyarginine, and nuclear histone acted as good opsonins forCandida, but none of the other factors tested were active. In order for the cationic proteins and leukocyte extracts to function as opsonins, they must be present on the particle surface. These agents were poor opsonins when applied on the macrophages. Nuclear histone, polylysine, polyarginine, and fresh human serum also functioned as good opsonins for the uptake ofCandida by mouse fibroblasts. On the other hand, none of the other substances which opsonized streptococci were effective withCandida. The phagocytic capabilities of fibroblast polykaryons were much higher than those of ordinary spindle-shaped mouse fibroblasts. Histone also functioned as a good opsonic agent for the uptake ofCandida by human fibroblasts, HeLa cells, epithelial cells, monkey kidney cells, and rat heart cells. On the other hand, neither leukocyte extracts nor ribonuclease LCP or MPO functioned as opsonins for these mammalian cells.Candida, taken up by fibroblasts, were present within tight phagosomes, but no fusion of lysosomes with the phagosome occurred. A small proportion of the internalized yeast cells underwent partial plasmolysis, but little damage to the rigid cell walls was observed within 24–48 h of internalization. Phagocytosis of streptococci andCandida by macrophages and the uptake ofCandida by fibroblasts were both strongly inhibited by liquoid (polyanethole sulfonic acid sodium salt). This anionic polyelectrolyte also markedly inhibited the release ofN-acetylglucosaminidase from macrophages without affecting cell viability (LDH release). Hyaluronic acid, DNA, and dextran sulfate markedly inhibited the uptake of histone-coated particles by macrophages. On the other hand, hyaluronic acid and DNA enhanced the uptake ofCandida by fibroblasts. The effect of these anionic polyelectrolytes on phagocytosis of serum-opsonized particles by macrophages was not consistent. While in some experiments it blocked phagocytosis, in others it either had no effect or even enhanced the uptake of the particles. Phagocytosis of microorganisms by “nonprofessional” phagocytes like fibroblasts and the paucity in these cells of hydrolases capable of breaking down microbial cell wall components may contribute to the persistence of non-biodegradable components of bacteria in tissues and to the perpetuation of chronic inflammatory sequellae. Cationic polyelectrolytes may also prove important as “helper” opsonins and as agents capable of enhancing the penetration into cells of both viable and nonviable particles, genetic material, and drugs.