PLATELET-DEPENDENT GENERATION OF CHEMOTACTIC ACTIVITY IN SERUM

A protein fraction extracted from the lysosomal granules of human platelets generated chemotactic activity for polymorphonuclear leukocytes when incubated with fresh serum. The platelet factor was also released during platelet aggregation with collagen or epinephrine and appeared to be released during blood clotting. Heated serum did not support the platelet-dependent generation of chemotactic activity. Treatment of fresh serum with antibody to the fifth component of complement also prevented development of activity. Purified human C5 but not C3 yielded chemotactic activity upon incubation with the platelet factor. Thus, human platelets are capable of stimulating chemotaxis via complement activation in a manner similar to leukocytes, and may therefore participate in the early stages of inflammation.     

Does cytomegalovirus play a role in community-acquired pneumonia?

Cytomegalovirus (CMV) is recognized as an important pathogen in the immuno-suppressed patient. Sporadic case reports of cytomegalovirus community-acquired pneumonia have appeared. We studied 443 patients with community-acquired pneumonia requiring hospitalization to define the role of cytomegalovirus in this illness. Four patients (0.9%) had good evidence that cytomegalovirus caused their pneumonia: 2 had the virus isolated from pulmonary tissue and 2 had cytomegalovirus inclusion bodies visualized in this tissue. An additional 14 patients had serologic evidence (a fourfold rise in the complement fixation tests) of cytomegalovirus infection. Analysis of these 18 patients suggest, that cytomegalovirus plays a role in community-acquired pneumonia. Six (33%) of the patients were immunosuppressed. Six others had concomitant infections: Chlamydia trachomatis (3); Epstein-Barr virus and M. pneumoniae (1); and bacteremia with Group B streptococcus and Bacteroides fragilis plus Eubacterium lentum (1 each). Seven patients (39%) required assisted ventilation, four of whom developed secondary bacterial pneumonia. Five (28%) died. Only two patients had a clinical and radiographic picture suggestive of a viral illness as a cause of the pneumonia. Three patients had atypical lymphocytes in their peripheral blood film. We found that the prevalence of complement fixing antibody to cytomegalovirus increased with age. Such antibody was lacking among those in the 16-20 year group while it peaked at 65% for males and at 78% for females ages 91-100 years. Despite the fact that 42.2% of the adults lacked antibody to cytomegalovirus, community-acquired pneumonia due to this virus is uncommon and does not justify routine serological testing for such infection among patients with community-acquired pneumonia.     

STUDIES ON A NON-HEMOLYTIC STREPTOCOCCUS ISOLATED FROM THE RESPIRATORY TRACT OF HUMAN BEINGS : I. BIOLOGICAL CHARACTERISTICS OF STREPTOCOCCUS MG

A single serological type of non-hemolytic streptococcus, designated streptococcus MG, has been isolated from the lungs of fatal cases of primary atypical pneumonia, from the sputa of patients with this disease, and occasionally from the respiratory tracts of normal human beings. Certain biological characteristics of this microorganism have been studied. All of the 59 strains isolated have been shown to belong to a homogeneous bacteriological group with characteristics which serve to distinguish it from any other well defined species of streptococcus. It has been suggested that this microorganism probably represents a distinct and hitherto undifferentiated species of streptococcus.     

STUDIES ON THE ETIOLOGY OF PRIMARY ATYPICAL PNEUMONIA : III. SPECIFIC NEUTRALIZATION OF THE VIRUS BY HUMAN SERUM

Significant increases in neutralizing antibodies were demonstrated in 42 of a total of 69 persons with a clinical diagnosis of primary atypical pneumonia. Detailed titrations of virus-neutralizing antibodies in a representative group of 28 patients are presented. Increases of four- to 64-fold were demonstrated. Acute-phase titers were 4 or less in 83 per cent and convalescent titers were 16 or over in 86 per cent of these cases. Only about half of the number of patients having increases in neutralizing antibodies also developed cold agglutinins and agglutinins for the indifferent streptococcus No. 344. Patients from the Eastern United States as well as those from the Pacific Coast were shown to develop virus-neutralizing antibodies. Patients with pneumococcal pneumonia and pneumonias caused by influenza virus type A or viruses of the psittacosis group did not have significant increases in neutralizing antibodies for the virus of atypical pneumonia. Cold agglutinins appeared in 3 cases of type A influenzal pneumonia. Sera from persons with atypical pneumonia, when tested against the 3 most prevalent respiratory viruses isolated from cotton rats and hamsters, failed to neutralize these agents or showed no significant change in neutralization titer.     

EXPERIMENTAL GLOMERULONEPHRITIS : II. IMMUNOLOGIC EVENTS IN THE PATHOGENESIS OF NEPHROTOXIC SERUM NEPHRITIS IN THE RAT

The primary phase of nephrotoxic serum nephritis produced by rabbit nephrotoxic serum appears to be dependent to a great extent, but not completely, upon the participation of serum complement. On the other hand, duck nephrotoxic serum produces its primary renal injury without detectable utilization of or dependence upon serum complement. The secondary phase of nephrotoxic serum nephritis appears to be largely or entirely dependent upon the host's antibody response to the heterologous gamma globulin fixed in the glomeruli. No evidence could be obtained for the existence of an autoimmune antikidney response by the host in this experimental model.     

PRIMARY SERUM TOXICITY AS DEMONSTRATED BY THE CHICKEN EMBRYO

1. The 3 day old chicken embryo removed from its shell is a suitable test object for the demonstration of primary serum toxicity. Addition of normal rabbit type sera as well as Forssman antiserum causes the vascular network to contract and the embryo sinks in the yolk and dies. 2. Only sera of animals of the so called rabbit type produce this phenomenon. Sera of the guinea pig type are ineffective. 3. Heating to 51°C. destroys the complement content of normal human serum as also its effectiveness to produce the vascular phenomenon. 4. Up to the present it has not been possible to reactivate heat-inactivated normal serum by the addition of complement, while inactivated Forssman antiserum can be easily reactivated. 5. The vascular phenomenon of the chicken embryo is produced not only by the addition of a mixture of Forssman antiserum and complement but also by separate addition of both components. 6. Guinea pig type sera, containing dissolved Forssman antigen, are not only ineffective but actually exert an inhibitory influence on effective rabbit type sera as well as on Forssman antiserum.     

Studies on primary atypical pneumonia. II. Observations concerning the development and immunological characteristics of antibody in patients

By using the indirect method of fluorescent staining to study the antibody response in patients with primary atypical pneumonai associated with the development of cold agglutinin, it was found that the PAP antibody developed during the 2nd and 3rd week of the illness, and persisted for over a year, and is not related to the cold and streptococcus MG agglutinins. The development of the PAP fluorescent staining antibody paralleled the neutralizing antibody for the PAP virus as tested in cotton rats. The sensitivity of this specific serological test was indicated by the observation that 67 to 92 per cent of the patients in several outbreaks of PAP showed a rise of antibody titer during convalescence. Absorption of the sera with various tissue powders did not affect the PAP antibody detected by this method.     

REDUCTION OF SERUM COMPLEMENT IN RABBITS AFTER INJECTION OF ENDOTOXIN

Injection into rabbits of a consistently lethal dose of endotoxin regularly produced a rapid and sustained fall of complement levels and lowered the titers of antibody to endotoxin. Doses of endotoxin below the LD₅₀ lowered complement levels sporadically but not the titers of antibody to endotoxin. The possibility is discussed that complement may be involved in the mechanisms responsible for the lethal action of endotoxin.     

Multicenter surveillance of adult atypical pneumonia in Japan: its clinical features,and efficacy and safety of clarithromycin

A prospective multicenter study involving 156 Japanese medical institutions was conducted to clarify the clinical features of adult atypical pneumonia and the efficacy and safety of clarithromycin. Atypical pneumonia was suspected in 730 patients according to the Japanese Respiratory Society’s Guidelines for the Management of Community-Acquired Pneumonia in Adults, and clarithromycin was administered. On the basis of bacteriological and serological tests, 465 patients were diagnosed with atypical pneumonia. Mycoplasma pneumonia was common among younger patients and chlamydia pneumonia among older patients. Underlying respiratory disease was uncommon among mycoplasma patients but prevalent among chlamydia patients. According to the severity classification given in the abovementioned guidelines, most mycoplasma patients had mild infection, whereas a high percentage of chlamydia patients had moderate infections. Body temperature was higher and coughing more severe in the mycoplasma patients than in the chlamydia patients. On the other hand, intergroup differences were not observed regarding extent of lung shadowing on plain radiographs, peripheral white blood cell count, or C-reactive protein (CRP). The effectiveness of clarithromycin was 96.8% in mycoplasma patients (153/158), 92.9% in chlamydia patients (78/84), and 96.0% in the group comprising all atypical pneumonia patients, including those with superinfection (288/300). The incidence of adverse drug reactions was 3.4% (24/698). Macrolide resistance in Mycoplasma pneumoniae has been reported in Japan, but the results of this surveillance study showed that clarithromycin is effective in treating adult atypical pneumonia.     

STUDIES ON THE ETIOLOGY OF PRIMARY ATYPICAL PNEUMONIA : A FILTERABLE AGENT TRANSMISSIBLE TO COTTON RATS,HAMSTERS, AND CHICK EMBRYOS

1. A filterable virus from certain cases of primary atypical pneumonia was transmitted to chick embryos by inoculation into the amnion of suspensions of bacteriologically sterile lung tissue or filtered sputum, and three strains were adapted by passage. 2. After intranasal inoculation into cotton rats or hamsters, suspensions of the infected chick embryo tissues produced pulmonary lesions which were similar to those seen after instillation of infective human material. 3. The agent propagated in chick embryos was specifically neutralizable by serum from patients recovered from primary atypical pneumonia and was not neutralized by the acute-phase specimens. 4. Passages of the virus in cotton rats and hamsters gave confusing results because of contamination with latent respiratory agents already present in the animals.     

Influence of the Escherichia coli capsule on complement fixation and on phagocytosis and killing by human phagocytes.

To define mechanisms by which polysaccharide capsules confer enhanced virulence on gram-negative bacteria, we examined the effect of the Escherichia coli capsule on complement fixation to the bacterial surface and on phagocytosis and killing of these bacteria by mouse macrophages and human polymorphonuclear leukocytes (PMN) and monocytes. When E. coli were attached to mouse macrophages with concanavalin A, the macrophages readily phagocytosed unencapsulated but not encapsulated bacteria even in the presence of fresh mouse serum; macrophages did not phagocytose encapsulated E. coli unless antibacterial or anti-Con A antibody was added. Similarly, when these bacteria were attached to human PMN with Con A, PMN ingested unencapsulated but not encapsulated E. coli. PMN phagocytosed and killed encapsulated serum-resistant E. coli only in the presence of both complement and antibacterial antibody; PMN phagocytosed and killed unencapsulated E. coli of the same strain in the presence of complement alone. Fluorescence microscopy showed that antibody had to be present for encapsulated but not unencapsulated E. coli to fix complement to its surface. To examine the role of the complement receptors of human PMN and monocytes in phagocytosis and killing of encapsulated E. coli, we used human and rabbit antibacterial immunoglobulin (Ig)M to fix complement to the bacteria. PMN and monocytes phagocytosed and killed encapsulated E. coli in the presence of both IgM and complement, but not in the presence of either serum opsonin alone. In the presence of antibacterial IgG, PMN and monocytes required complement to effectively phagocytose and kill the E. coli. We conclude that (a) attachment by itself results in ingestion of unencapsulated but not encapsulated E. coli; (b) under physiologic conditions, E. coli are not phagocytosed or killed the absence of antibody, the E. coli capsule blocks complement fixation to the bacterial surface probably by masking surface components, such as lipopolysaccharide, capable of activating the complement pathway; (d) the E. coli capsule imposes a requirement for specific antibacterial antibody for complement fixation; and (e) the complement receptor of human PMN and monocytes mediates phagocytoses of complement-coated encapsulated bacteria and is the primary mediator of phagocytosis and killing of these bacteria.     

THE ROLE OF SERUM COMPLEMENT IN CHEMOTAXIS OF LEUKOCYTES IN VITRO

By the use of chambers containing two compartments with an interposed micropore filter, chemotaxis of polymorphonuclear leukocytes (PMN's) in vitro was studied employing various agents that fixed serum complement (C'). Antigen-antibody complexes, zymosan, and aggregated human gamma globulin, in the presence of fresh rabbit, guinea pig, or mouse serum resulted in the migration of PMN's through the micropore filter. Pepsin-degraded rabbit antibody or unaltered duck serum containing antibody did not exhibit such activity after addition of antigen. Heating of the serum before treatment or the presence of EDTA prevented the generation of the chemotactic factor. The chemotactic factor could not be generated in whole serum from rabbits genetically deficient in C'. However, the defect in this rabbit serum could be corrected by addition of rabbit or human C'6. Serum of B10·D2 mice deficient in hemolytic C' also yielded poor chemotactic activity. Interaction of the first four reacting components of guinea pig C' did not result in significant chemotactic activity unless guinea pig euglobulin with heat labile components was also present. In rabbit serum, C'5 and C'6, when "activated" by interaction with the first four reacting components, behaved like a protein-protein complex and exhibited marked chemotactic activity. By employing conditions favoring dissociation of the complex, the individual components were isolated and shown to be chemotactically inactive. Upon recombination of the two components, however, activity reappeared. Using another approach, the C'5–C'6 complex was isolated intact, and shown to be chemotactically active while other fractions not containing these components were not active. It is postulated that the C'5–C'6 complex is the active chemotactic factor generated in serum after the addition of C'-fixing agents.     

Effect of complement binding on a solid-phase immunometric TSH assay

The binding of serum thyrotropin (TSH) to plastic beads coated with a monoclonal antibody to human TSH was inhibited unless EDTA was present during the incubation. The inhibitory factor in serum was heat labile, and its effect could be abrogated by the addition of human albumin-anti-albumin immune complexes. Subsequently it was shown that the antibody-coated beads were able to bind the first component of complement, C1q, and that this binding was inhibited by addition of albumin-anti-albumin complexes. The results show that a surface coated with a monoclonal murine antibody is able to bind complement, and that binding of complement may interfere in solid-phase immunometric assays.     

THE ENHANCEMENT OF BACTERIAL PHAGOCYTOSIS BY SERUM : THE ROLE OF COMPLEMENT COMPONENTS AND TWO COFACTORS

The role of serum factors in the phagocytosis of pneumococci was studied employing a spectrophotometric assay which measures reduced nitro blue tetrazolium (NBT) dye. Dye reduction occurs within the phagocyte shortly after bacterial ingestion as measured by the phagocytic index technique and by the uptake of ¹²⁵I-pneumococci. Bacteria prepared with γG antibody were not phagocytosed unless a small volume of fresh normal serum was added. Using fresh sera deficient in single complement components, it was demonstrated that the first four components are necessary for optimal bacterial phagocytosis. When highly purified complement components were added to the antibody-coated pneumococci, enhancement of phagocytosis was achieved only with the sequential addition of C1, C4, C2, and C3. Evidence has been presented that human C3 bound to an immune complex exhibits peptidase activity and that this activity is essential for phagocytosis. A heat-labile, dialyzable serum cofactor which enhances C3 peptidase activity enhanced the phagocytosis of pneumococci prepared with purified complement components. A second phagocytosis-promoting cofactor, which is not a complement component, was found to be a heat-labile, 5–6S, beta pseudoglobulin. This protein may stabilize C3 peptidase activity or inhibit enzymatic inactivation of C3.     

非典型肺炎25例临床分析

目的 探讨非典型肺炎的临床特点及其有效防治措施。方法 对25例非典型肺炎患者临床资料进行回顾性分析。结果 社区感染3例；22例院内感染者均有该病接触史，潜伏期约为1-11天。临床表现均有高热、头痛、咳嗽和气促；10例(4_0％)有严重呼吸困难；12例(4-8％)关节肌肉剧痛；仅4例(16％)有少量湿罗音；25例(100％)血白细胞总数不高，血培养、衣原体抗体阴性；X线检查3例(12％)呈双肺间质性改变；22例(88％)呈斑片状浸润影。结论 非典型肺炎具有较强的传染性．综合治疗其于预后良好．     

Drugs that inhibit complement

The complement system is an important part of the innate immune system. Complement plays a crucial role in the pathophysiology of many disorders.Despite the pivotal role of the complement system, an approved targeted inhibitor of a complement factor became available only recently. Eculizumab is a humanized monoclonal antibody that inhibits complement factor C5. It is a targeted, disease modifying, treatment of paroxysmal nocturnal hemoglobinuria (PNH). It was approved be the US FDA and the European Commission in 2007. In this review we will update the experience with eculizumab in PNH and discuss potential use of eculizumab in other disorders (e.g. cold agglutinin disease; atypical HUS) and new approaches to complement inhibition with drugs other than eculizumab.     

SURFACE TENSION OF SERUM OF THE SENSITIZED GUINEA PIG : I. SURFACE TENSION CHANGES INCIDENT TO THE PROCESS OF SENSITIZATION.

The change in surface tension behavior in the serum of sensitized guinea pigs is, as du Noüy has concluded for immunized rabbit serum, not referable to an antibody content, since we know that the capacity for transfer of sensitization remains in the serum indefinitely, while the increased time-drop phenomenon is a transitory manifestation. That this phenomenon cannot be invoked by a new antigen capable of calling out its specific antibody would seem to make this response one due to some basic stable alteration of a tissue active in the general process of sensitization: That this alteration is not one called out by such a simple toxic injury as a uranium nitrate nephritis is contributory evidence that the primary toxicity of the horse serum is not the specific factor involved.     

Immunoreactions involving platelets. III. Quantitative aspects of platelet agglutination,inhibition of clot retraction,and other reactions caused by the antibody of quinidine purpura

Quantitative aspects of platelet agglutination and inhibition of clot retraction by the antibody of quinidine purpura were described. The reactions appeared to depend on formation of types of antibody-quinidine-platelet complexes which could fix complement but complement was not necessary for these reactions. Complement fixation was at least 10 times more sensitive than platelet agglutination or inhibition of clot retraction for measurement and detection of antibody activity. Although it has been considered that antibodies of drug purpura act as platelet lysins in the presence of complement and that direct lysis of platelets accounts for development of thrombocytopenia in drug purpura, the present study suggests that attachment of antibody produces a change in platelets which is manifested in vitro only by increased susceptibility to non-specific factors which can alter the stability of platelets in the absence of antibody. The attachment of antibody to platelets in vivo may only indirectly affect platelet survival. In contrast to human platelets, dog, rabbit, and guinea pig platelets, and normal or trypsin-treated human red cells did not agglutinate, fix complement, or adsorb antibody; and intact human endothelial cells did not fix complement or adsorb antibody. Rhesus monkey platelets were not agglutinated by the antibody but did adsorb antibody and fix complement although their activity in these reactions differed quantitatively from that of human platelets. Cinchonine could be substituted for quinidine in agglutination and inhibition of clot retraction reactions but quinine and cinchonidine could not. Attempts to cause passive anaphylaxis in guinea pigs with the antibody of quinidine purpura were not successful.     

THE PATHOLOGIC EFFECTS OF INTRAVENOUSLY ADMINISTERED SOLUBLE ANTIGEN-ANTIBODY COMPLEXES : I. PASSIVE SERUM SICKNESS IN MICE

The intravenous administration to mice of soluble antigen-antibody complexes in antigen excess resulted in a high incidence of glomerulonephritis and less frequently in endocarditis or arteritis. These lesions are present within 48 hours of the first of 3 injections and disappear within 2 weeks. The same pathological changes were produced with complexes prepared from either rabbit or chicken antibody. In the case of rabbit antibody, the severity of the glomerulonephritis was greater with the ovalbumin antiovalbumin system than with the BSA system. Anaphylaxis regularly occurred in mice given complexes prepared from rabbit antibody, but was not seen following administration of complexes prepared from chicken antibody. Pretreatment with cortisone diminished the severity of the glomerulo-nephritis and resulted in accumulation of amorphous, eosinophilic material within glomerular capillaries in mice injected with antigen-antibody complexes. The rabbit antibody used in these experiments failed to sensitize guinea pig skin to passive cutaneous anaphylaxis when injected in the form of soluble complexes. This indicates that these complexes do not dissociate to a detectable extent in vivo and thus favors the interpretation that complexes localize as such in the sites where tissue damage occurs. Chicken anti-mouse erythrocyte antibody produced hemolysis of mouse red cells in the presence of mouse complement. In contrast to a similar rabbit anti-serum, the hemolytic activity of the chicken antibody with mouse complement was very slight. This suggests that complement does not play an important role in the pathogenesis of these experimental lesions.     

THE LOCALIZATION OF IN VIVO BOUND COMPLEMENT IN TISSUE SECTIONS

A technique has been described for the demonstration of a human complement component by an immunofluorescent method. The component detected is β_1C-globulin, a moiety of the third complement component, which has previously been obtained in pure form and to which a specific antiserum has been prepared. It has been shown in a model system that the binding of β_1C-globulin as shown by immunofluorescence is strictly equivalent to complement fixation as assessed by standard serological methods. This technique has been applied to the detection of in vivo bound complement in pathological human tissues. It was found that in vivo complement binding occurs in the lesions of several human diseases, but not elsewhere in the same tissues. In a rather limited survey of diseases that has been carried out, in vivo complement binding was found particularly in systemic L.E., various nephritides, and amyloidosis, as well as in single cases of some other diseases. The spectrum of in vivo complement binding has been compared with that of γ-globulin binding (7S and 19S types) and with the demonstration of in vitro complement fixation and rheumatoid factor fixation. It was distinct from each of these. Rheumatoid factor fixation, detected by anti-19S antiserum showed promise as a method for the detection of antigen-antibody complexes and aggregated γ-globulin in tissue sections. The interpretation of these findings in regard to the nature of the binding sites, and their possible significance in regard to pathogenic mechanisms have been discussed.