Role of secretory phospholipases A2 in the pathobiology of disease.
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Biomedical subjects
Publications and source records attributed to W Pruzanski.
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Phospholipase A2 (PLA2) activity has now been identified in rheumatoid synovial fluids. This PLA2 is a calcium-requiring protein of MW 11,000 with a neutral pH optimum. Its activity was inhibited by high concentrations of Mg2+, and by the active site-directed histidine reagent p-bromophenacyl bromide. Ionic and nonionic detergents, or the sulfhydryl reagent dithiothreitol caused loss of enzyme activity. Synovial fluid PLA2 did not interact with sulphated mucopolysaccharides such as heparin or chondroitin sulphate. Release and sequestration of PLA2 in the joint space may contribute to the characteristic rheumatoid inflammatory changes.
Fulminant gangrene of the fingers, toes and nose developed in a 57-year-old woman with Escherichia coli pneumonia. Cryoglobulinemia was noted, and the cryoglobulin was identified as IgM-IgG with anti-I cold agglutinin activity. The cold agglutinins possessed potent lymphocytotoxic and monocytotoxic activity and weaker granulocytotoxic activity. Treatment with plasmapheresis, steroids and antibiotics led to complete clinical recovery, although amputation of several toes was necessary. The patient died 1 1/2 years later; the main findings at autopsy were chronic and acute pyelonephritis and acute bacterial endocarditis. This seems to be the first case of IgM-IgG cold agglutinemia occurring during the course of E. coli infection and the third case of fulminant gangrene complicating transient cold agglutinemia.
Seven cationic substances--human and egg-white lysozyme, RNase, protamine, histone, poly-L-lysine and poly-L-arginine; five cationic lysosomal fractions from human polymorphonuclears (PMNs); RNA; poly-L-glutamic acid; DNA; heparin; endotoxin; mastocytotropic agent compound 48/80; and cytochalasin B were tested for the influence on chemotaxis and random migration of human PMNs using under-agarose migration and Boyden chambers with two filters and [51Cr]PMNs. The above substances were either preincubated with PMNs, added to chemoattractants, or used instead of chemoattractants. In under-agarose migration method chemotaxis was inhibited by 11-35% when egg-white lysozyme, protamine, heparin, endotoxin, or compound 48/80 was added to the cells. High concentration of cytochalasin B inhibited chemotaxis by 73%. Cationic fractions I and V and low concentration of cytochalasin B enhanced chemotaxis by 11%, 41%, and 30%, respectively. When human and egg-white lysozyme, DNA, or cytochalasin B was added to the chemoattractants, motility of PMNs was inhibited. Cationic fractions II and V from human PMNs, when used as chemoattractants, enhanced cellular motility by 143-167%. Random migration was enhanced by heparin and inhibited by cytochalasin B and by cationic fractions from human PMNs. These findings suggest that various cationic and anionic substances and cationic fractions from human PMNs have heterogeneous influence on random migration and chemotactic activity of human PMN. Analysis relating chemotaxis to phagocytosis and to intracellular bactericidal activity (ICBA) has shown several patterns. Protamine, poly-L-lysine, poly-L-arginine, and agent compound 40/80 all inhibit chemotaxis and enhance phagocytosis and ICBA; cationic fractions II and V enhanced all three functions, whereas cytochalasin B suppressed phagocytosis and ICBA and had concentration-dependent modulatory influence on chemotaxis. It implies diverse mechanisms of action and possible impact on inflammatory reactions.
95 of 1,019 (9.3%) sera with monoclonal immunoglobulins (MIg) were found to have cold-reacting lymphocytotoxins (LCT). There was no difference in the prevalence of LCT in multiple myeloma, macroglobulinemia, cancer, lymphoma or benign monoclonal gammopathy. Prevalence of LCT was similar in various classes and types of MIg with the exception of the IgG/lambda group in which LCT were more common than in IgG/K (p = 0.013). IgMs had the most potent whereas IgAs had the weakest LCT activity. MIg were purified from 61 LCT-positive sera. 25 pure MIg (41%) had LCT activity. In the rest, LCT activity resided in other fractions. 64 sera with LCT were tested against B and T cells; 56% were equally cytotoxic to B and T cells, 39% killed more B cells and 5% killed more T cells. 18 purified lymphocytotoxic MIg killed both B and T cells. When serial dilutions of sera, and of purified MIg were tested, in all but one instance the reactivity with the T cells weakened more than that with the B cells. Lymphocytotoxins absorbed to and eluted from the peripheral blood lymphocytes or separately from B or from T cells retained LCT activity against B and T lymphocytes. It may be concluded that about one tenth of sera with M components have lymphocytotoxic activity and that in about 40% of these positive sera, this activity is related to the monoclonal immunoglobulins. LCT react with both B and T cells. Antilymphocyte activity of MIgs may play a role in immunoregulatory abnormalities in plasmalymphocytic diseases.
Chemotherapeutic agents (CTAs) used for treatment of neoplastic and other diseases may influence defense mechanisms of the patient, altering various humoral and cellular immunologic functions. Herein we report the influence of 16 CTAs on random migration and chemotaxis of human polymorphonuclear cells (PMNCs), using two methods, under-agarose migration and double-filter Boyden chambers with 51Cr-PMNCs. Random migration was inhibited by vinblastine only (P less than .01). BCNU and daunorubicin inhibited random migration only when used in high concentrations. In under-agarose migration, only BCNU and vinblastine inhibited chemotaxis (P less than .01) in therapeutic concentrations. Inhibition was also observed when higher concentrations of vincristine were tested. In the Boyden method, marked inhibition of chemotaxis (P less than .01) was caused by BCNU, vinblastine, vincristine, daunorubicin, and doxorubicin. Inhibition of chemotaxis could not be reversed by washing the cells after preincubation. CTAs per se did not have chemoattractant activity. This study shows that some chemotherapeutic agents inhibit random and directed migration of human PMNCs. It also supports the evidence that Boyden chamber method may detect chemotactic abnormalities that escape recognition by the under-agarose migration method. Suppression of locomotion of PMNCs should be taken into consideration in patients treated with CTAs.
Phospholipase A2 (PLA2) activity was found in the sera and synovial fluids (SF) in rheumatoid arthritis (RA) and osteoarthritis (OA). PLA2 activity in RA SF was 6158 +/- 549 (SEM) U/ml (n = 48) and in RA sera 554 +/- 175 U/ml (normal sera-115 +/- 12 U/ml). In OA SF PLA2 activity was 5069 +/- 542 U/ml (n = 28), and in OA sera 268 +/- 55 U/ml. There was no significant difference between SF PLA2 activity in RA and OA. PLA2 activity in SF did not correlate with muramidase (lysozyme), beta-glucuronidase, total protein or white cell count, which were all significantly higher in RA SF than OA. A positive correlation between PLA2 in SF and matched sera was found in both RA and OA. It may be concluded that significant elevation of extracellular PLA2 occurs in both RA and OA, especially in the SF. The fact that high PLA2 did not correlate with other enzymes such as lysozyme and beta-glucuronidase, which are usually high in RA and low in OA SF, may mean that the handling of PLA2 in the joint space is different from other enzymes.
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A case of invasive aspergillosis complicated by the formation of an aspergilloma is described. The patient, a 48-year-old man, was apparently healthy except for mild alcoholic steatosis of the liver. A review of the literature revealed that 5 of the 14 previously reported cases of invasive aspergillosis in seemingly immunocompetent hosts were associated with liver disease. Immunologic investigation in this case revealed transient cutaneous anergy during the acute illness and normal lymphocyte function. Assessment of polymorphonuclear leukocyte function, however, showed abnormalities of phagocytosis as well as impairment of intracellular bactericidal activity. These abnormalities may have contributed to a relative immunodeficiency. Impairment of immune function may play a role in the pathogenesis of invasive aspergillosis in some apparently healthy patients.
Nine patients (2.2%) in a group of 415 who were followed in a longitudinal prospective study of systemic lupus erythematosus (SLE) were found to have various monoclonal (M) proteins in their blood (IgG [6 patients], IgA [2 patients], IgM [1 patient]). No other findings compatible with plasmacytic dyscrasia were found. Bence Jones proteinuria was absent. Bone marrow aspirates and skeletal radiographs did not reveal any associated features of malignancy. Four of the 9 patients were under the age of 50. From the point of view of the M components, 3 groups emerged: transient (2 patients), persistently stable (6 patients), and increasing serum concentrations (1 patient). Using current measures of disease status, no correlation was apparent between the presence, type, and concentration of the M protein and the clinical and laboratory variables of lupus activity. Thus, M proteins were found in 2% of our SLE patients, but their relationship to the polyclonal B cell activation seen in this disorder, or perhaps to therapeutic modalities used in its treatment, remains to be elucidated.
Cationic lysosomal proteins from human polymorphonuclears (PMN) were isolated by column chromatography and divided into five fractions. On acrylamide gel electrophoresis, fraction I had four bands slower than lysozyme (LZM) mobility; fraction II had five or six bands slower than LZM; fraction III had at least seven bands slower and two bands faster than LZM; fraction IV contained LZM, two bands faster and a few faint bands slower than LZM; fraction V was composed of almost pure LZM. Partial characterization of the fractions showed presence of neutral protease in fractions I-IV, chymotrypsin in fraction III, lysozyme in fractions IV and V, and phospholipase A2 mainly in fractions II and III. Modulatory activity of fractions I-V were tested at concentrations up to 50 micrograms/ml. Enhancement of phagocytosis of Staphylococcus aureus was observed by fractions I, IV, and V, whereas phagocytic index was enhanced by all but the fraction II. Intracellular bactericidal activity (ICBA) was markedly enhanced by fractions I, II, and V. Addition of DNA or cytochalasine B inhibited or abolished phagocytosis-enhancing activity of cationic fractions. Their influence on ICBA was much less pronounced. Fraction III enhanced phagocytic index and phagocytosis of E. coli, whereas fractions I and II enhanced intracellular bactericidal activity against this bacteria. Enhancement of phagocytic activity of monocytes has also been observed. The data suggest that some cationic lysosomal fractions from human PMNs enhance phagocytosis and phagocytic index by human PMNs and monocytes and intracellular bactericidal activity of human PMNs. This alternative pathway of phagocytic enhancement is unrelated to the previously described enhancers of phagocytosis and may play a role in defense mechanisms against infection.
Sera of 48 patients with Graves' disease (GD) and 23 with Hashimoto's thyroiditis (HT) were tested for lymphocytotoxic (LCT), granulocytotoxic (GCT) and monocytotoxic (MCT) activity. In GD, 12 patients (25%) had cold-reacting LCT and 13 patients (27%) had warm-reacting LCT. LCT were cytotoxic to both B and T cells but the majority of sera with cold-reacting LCT and eluates from lymphocytes were more cytotoxic to B lymphocytes. Warm-reacting LCT were directed exclusively against B cells. LCT did not correlate with peripheral lymphocyte counts, antithyroglobulin or antimicrosomal antibodies, sex, age, pregnancies, thyroid status or medication. However the mean duration of the disease was 15 months in LCT positive group and 55 months in LCT negative group (p less than 0.01). Weak GCT were found in 8 of 35 sera (23%). Six of 33 sera (18%) contained cold-reacting MCT and 9 (27%) had warm-reacting MCT. Some cytotoxins were directed against several types of cells as evidenced by cytotoxicity of eluates from lymphocytes against PMN and/or monocytes. Of 23 patients with HT, 11 (48%) had cold-reacting LCT. None had warm-reacting LCT. Sera and eluates from lymphocytes showed predominant cytotoxicity toward B cells. No correlation to the presence of antibodies, sex, age, pregnancies, thyroid status or medication was detected. Four of 23 sera had weak cold-reacting GCT, 5 had cold-reacting MCT which killed on average 31% of monocytes and 4 had weak warm-reacting MCT. Twelve of 22 sera from GD and HT had cytotoxic activity against thyroid cells (TCT). TCT correlated with LCT at p less than 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)
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Thirteen chemotherapeutic agents were tested for modulatory activity on phagocytosis by human granulocytes and monocytes. Phagocytosis, phagocytic index, and intracellular bactericidal activity were assessed using Staphylococcus aureus, smooth strain of Escherichia coli, and latex particles. Modulation of phagocytic activity depended on the type of particle used and the presence of serum in the medium. Testing granulocytes, only 1,3-bis(2-chloroethyl)-1-nitrosourea suppressed phagocytosis of all three types of particles used for ingestion. Other drugs suppressed either phagocytosis of E. coli and S. aureus or of one of the bacteria and latex particles. Three drugs enhanced ingestion of latex particles. The most pronounced modulation of phagocytosis was observed in conditions similar to those in vivo, namely, when serum was added to the medium and when the cells were exposed for longer time to the drugs. In the absence of serum, very little modulation of phagocytosis was observed, and only 1,3-bis(2-chloroethyl)-1-nitrosourea retained strong suppressive activity. Intracellular bactericidal activity was markedly suppressed by 7 of 13 drugs tested. Monocytes were less influenced by chemotherapeutic agents, their phagocytic activity being either suppressed or enhanced. The influence of chemotherapeutic agents on phagocytosis must be taken into consideration when assessing defense mechanisms and susceptibility to infection in patients with malignant diseases.
Six immunomodulators were tested for the influence on phagocytosis and intracellular bactericidal activity of human polymorphonuclear cells (PMN). Frentizole, lamprene, intal and levamisole but not dapsone enhanced phagocytosis in the presence of serum. Without serum, frentizole strongly enhanced phagocytosis, whereas lamprene, levamisole and dapsone had weaker enhancing activity. Rifampin suppressed phagocytosis of Staphylococcus aureus whether the serum was present or not. The influence on phagocytosis was time and dose dependent. All drugs but dapsone markedly enhanced intracellular bactericidal activity of PMN in a dose dependent fashion. Dapsone enhanced bactericidal activity without the serum and suppressed it in its presence. It may be concluded that immunomodulators are a heterogeneous group of substances and their influence on phagocytosis and cellular bactericidal activity varies. Enhancing activity of some immunomodulators implies that they may be used in conditions with impaired phagocytosis.
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