Biomedical subjects

D P Fine

Publications and source records attributed to D P Fine.

7 recordsLinked to original sources

PubMed1978

Evidence for quantitative variability of bacterial opsonic requirements.

We studied human serum opsonins by using combinations of heat inactivation and chelation to inhibit complement, adsorption to remove antibody, and trypan blue to inactivate the C3 receptor of human polymorphonuclear leukocytes. Streptococcus pneumoniae, serotype 25, required both complement and immunoglobulin for opsonization, even though that strain activated the alternative complement pathway. Both strains of Escherichia coli required antibody and complement, but varied in the degree of dependence on the C3 opsonin, since trypan blue moderately inhibited the killing of E. coli-1 and markedly inhibited the killing of E. coli-2. Serratia marcescens was opsonized in heat-inactivated serum (limited complement) or serum absorbed at 0 degrees C with S. marcescens (limited antibody), but depended on the C3 receptor in absorbed serum. S. marcescens activated the alternative pathway. Thus, opsonic requirements varied with the availability of opsonins. Requirements for bacterial opsonization vary with species and strains within species, perhaps reflecting quantitative relationships among alternative and classical pathway activation of C3, efficiency of adsorption of C3 or immunoglobulin G to bacterial surfaces, and efficiency of attachment of these ligands to polymorphonuclear leukocyte receptors. Furthermore, although not always sufficient for opsonization, the C3 opsonin (activated through either the classical or alternative pathway) appears necessary for effective phagocytosis and killing of all strains studied.

Antibodies, Bacterial↗

PubMed1978

Trypan blue inhibits complement-mediated phagocytosis by human polymorphonuclear leukocytes.

Trypan blue completely inhibited attachment of human polymorphonuclear leukocytes (PMN) to Sepharose beads coated with C3 ant to sheep erythrocytes coated with IgM plus C3, but it did not inhibit attachment to erythrocytes coated with IgG. These results suggested that trypan blue inhibited C-mediated attachment to PMN membranes. Corroborative studies were performed with a strain of Staphylococcus aureus that requires C but not antibody, for opsonization and that activates the alternative pathway. Trypan blue was not toxic to PMN or bacteria, did nto interfere with immunoglobulin or C interactions, and did not affect attachment of opsonins to bacteria. However, the dye impaired PMN killing of S. aureus in normal nonimmune serum by inhibiting bacterial attachment to and ingestion by PMN. Further evidence that the inhibition was at the C3 receptor level came from the observations that, 1) once staphylococci were attached to PMN at either 37 degrees C or 0 degrees C, addition of trypan blue did not inhibit killing; and 2) trypan blue inhibited killing of bacteria opsonized with serum sufficient in C but previously absorbed at 0 degrees C with the same strain of organism to deplete specific antibody. Further studies with this agent may elucidate the roles of opsonic receptors on human phagocytes.

Cell Adhesion↗

PubMed1977

Studies of the coagulation and complement systems during experimental Rocky Mountain spotted fever in rhesus monkeys.

We studied the coagulation and complement systems during Rocky Mountain spotted fever in Macaca mulatta experimentally infected with Rickettsia rickettsii. Ninety-one percent of monkeys infected intravenously with a high dose (10(6) plaque-forming units [pfu]) and 56% of monkeys infected with low doses (10(-1)-10(2) pfu) of R. rickettsii died after two to four days of illness. With the onset of fever and rickettsemia, animals developed hyperfibrinogenemia, mild thrombocytopenia, prolonged prothrombin and activated thromboplastin times, and increased serum fibrin/fibrinogen degradation products (FDP). Rickettsemia, thrombocytopenia, and FDP were greater in fatally ill monkeys than in survivors. Hemolytic titers of the second and third components of complement were not depressed except in a single surviving monkey that developed peripheral gangrenous ecchymoses at a time when both rickettsemia and agglutinating antibody were present. Thus, although activation and consumption of complement may occur during Rocky Mountain spotted fever, the hemostatic disturbances in fulminant infections seem to be a direct effect of the infectious vasculitis.

Animals↗

PubMed1977

Comparison of ethyleneglycoltetraacetic acid and its magnesium salt as reagents for studying alternative complement pathway function.

The divalent cation chelators, ethyleneglycoltetraacetic acid (EGTA) and its magnesium salt, MgEGTA, were compared in studies of alternative complement pathway function. EGTA (0.01 M) inhibited both the rate and the amount of complement activation by zymosan whether compared to nonchelated serum or to serum chelated with MgEGTA (0.01 M). The rate of alternative pathway activation by zymosan was slightly slower in MgEGTA-chelated serum than in nonchelated serum, but the overall amount of complement consumed by a given amount of zymosan was not decreased. MgEGTA chelation spontaneously activated the alternative pathway, as reflected by lysis of erythrocytes from a patient with paroxysmal nocturnal hemoglobinuria. No evidence could be found that MgEGTA either spontaneously activated C2 or facilitated zymosan activation of C2. Suggested guidelines for the use of these chelators are advanced.

Adult↗

PubMed1977

Disseminated intravascular coagulopathy during experimental pneumococcal sepsis: studies in normal and asplenic rhesus monkeys.

Disseminated intravascular coagulation (DIC) was induced in both normal and asplenic rhesus monkeys by intravenous challenge with Streptococcus pneumoniae. Our observations in the infected monkeys have led us to conclude that (1) pneumococcal capsular polysaccharide (PCP), immune complexes and complement may not have primary roles in the initiation of DIC; (2) intact pneumococci may be catalysts for the development of DIC; (3) the initial event in DIC may be activation of Hageman factor; and (4) evidence of activation of Hageman factor-dependent systems is present regardless of severity of infection.

Animals↗

PubMed1976

Functional and morphologic changes during experimental Rocky Mountain spotted fever in guinea pigs.

Experimental Rocky Mountain spotted fever was studied in guinea pigs following intraperitoneal inoculation of 10(7) Rickettsia rickettsii. After a 2-day incubation period, animals developed fever, progressive emaciation, and scrotal swelling with necrosis. Vasculitis, with increased small vessel permeability for colloidal carbon, was evident in cremaster muscles as early as 1 day after inoculation. Inflammatory changes in vessels became progressively more severe as numbers of circulating rickettsiae increased. Thrombosis and vascular occlusion were first evident on day 4. Mild thrombocytopenia developed, coinciding with the development of vasculitis, and preceding the appearance of either fibrin-split products in blood or thrombi in vessels. Rickettsiae were first detected in blood on day 2; peak rickettsemia occurred on days 5 to 8. Rickettsiae were demonstrated in inflamed vessels on day 5 and later, but not at earlier stages. Serum lysozyme concentration was moderately elevated and hemolytic complement was moderately depressed throughout the illness. Agglutinating antibody was present in low titers on days 3 to 10. Antibody titers increased on days 12 to 16 after the rickettsiae were cleared from blood. These studies indicate that vasculitis seen early in the course of Rocky Mountain spotted fever is the result of rickettsial infection, but is not dependent on the presence of rickettsiae in endothelial cells or other blood vessel components.

Agglutination Tests↗

PubMed1975

Pneumococcal type-associated variability in alternate complement pathway activation.

Opsonization of Streptococcus pneumoniae may be mediated by the alternate complement pathway. To study the importance of this interaction to human disease, complement consumption by pneumococci of various serotypes was measured in humwn serum chelated with ethyleneglycoltraacetic acid, a substance that blocks the classic but not the alternate complement pathwway. Serotype I, in contrast to all other types studied, lacked ability to consume complement in this system. The ability for serotypes III, IV, and VIII to activate the alternate pathway could be eliminated by prior serum absorption at O C with they type in question, a condition that would remove antibody but not complement. Types VII, XII, XIV, and XXV readily activated the alternate pathway in unabsorbed and absorbed sera. Differences could not be related to properties of the capsules. It was concluded that types I, III, IV, and VIII lack intrinsic ability to activate and thus be opsonized by the alternate complement pathway, although types III, IV, and VIII can do so in concert with specific antibody. The fact that these same types are especially prominent in human disease suggests that the ability to evade opsonization by the alternate complement pathway in pre-antibody phases of infection may be a virulence factor in pneumococci.

Antigen-Antibody Complex↗