Melvin H. Kaplan

Specificity of C-Reactive Protein for Choline Phosphate Residues of Pneumococcal C-Polysaccharide

C-reactive protein (CRP) is an acute phase protein appearing in the serum of man during various pathological conditions, and frequently employed as a clinical index of acute inflammation. It is precipitated from the serum by pneumococcal C-polysaccharide in the presence of Ca ions. Although this precipitation reaction, which led to the discovery of CRP, has been known for many years, there is little information about the active site(s) in the molecule of C-polysaccharide participating in the reaction with CRP. It has been recently reported that choline phosphate is a unit of the macro-molecular structure of C-polysaccharide (1, 2). In an attempt to determine the specificity of CRP for choline phosphate residues of C-polysaccharide, we conducted quantitative inhibition studies of CRP-C-polysaccharide precipitation. The substances tested for inhibitory effect included choline phosphate and a series of organic phosphate menoesters. The results of these experiments indicated that choline phosphate is the most active inhibitor of CRP-C-polysaccharide precipitation yet described, and suggested that this compound might provide the major reacting site of C-polysaccharide. A single lot of CRP-positive serum (no. 9 E.M.), obtained 2 days following surgery from a patient with an intertrochanteric fracture of the femur, was used for all the inhibition experiments described below. Tested by capillary precipitation against a commercial antiserum (Hyland Labs, Los Angeles, California), this serum gave a 4+ reaction for CRP. The results with this serum were representative of data obtained also with other CRP-positive sera. C-polysaccharide was prepared by the method of Anderson and McCarty (3) from a III R strain of pneumococcus. The following substances obtained from commerical sources were tested for inhibitory effect without further purification: Choline phosphate chloride, o-phosphoryl-ethanol-amine, DL-α-glycerophosphate, β-glycerophosphate, L-α-glycerophosphorylcholine, choline base, uridine-5′-monophosphate (UMP), adenosine-5′-monophosphate (AMP), and cytidine-5′-monophosphate (CMP).

Immunopathologic Studies of Systemic Lupus Erythematosus. II. Antinuclear Reaction of γ-Globulin Eluted from Homogenates and Isolated Glomeruli of Kidneys from Patients with Lupus Nephritis

The gammaG-globulin eluted at acid pH from kidney cortex homogenates and isolated glomeruli of five of six patients with lupus nephritis was found to exhibit antinuclear activity, which was not dependent on presence of fresh human serum. Specificity, as demonstrated by absorption of antinuclear activity, was related to nucleoprotein in three glomerular acid eluates and to DNA in two acid eluates as well as in a deoxyribonuclease digest of disrupted glomeruli in one patient. Antinuclear activity was not found in acid eluates of kidneys from two patients with chronic liver disease and chronic discoid lupus, respectively, and one with lupus nephritis. These patients had a low titer of serum antinuclear factor and lesser amounts of kidney bound immunoglobulins. The presence of antinuclear activity in eluates of kidneys appeared to correlate with the amount of glomerular bound immunoglobulin and the level of antinuclear antibodies in serum. These findings suggest that in lupus nephritis, part of the glomerular bound immunoglobulin is derived from serum antinuclear factors possibly deposited as immune complexes.

Autoimmunity to the Heart in Cardiac Disease Current Concepts of the Relation of Autoimmunity to Rheumatic Fever, Postcardiotomy and Postinfarction Syndromes and Cardiomyopathies*

Abstract Current information on the role of immune mechanisms in rheumatic fever, postcardiotomy and postinfarction syndromes, cardiomyopathies and other cardiac disorders is reviewed. The possible role of autoimmunity is emphasized in view of the evidence that serum autoantibodies to diverse constituents of heart tissue frequently may be detected in these cardiac disorders. In rheumatic fever, experimental and clinical data indicate that autoimmunity to heart tissue may be induced in response to a constituent of group A streptococci, antigenically cross-reactive with heart tissue. Populations of autoantibodies with divergent specificities are present in the sera of patients with rheumatic disease. Certain of these autoantibodies exhibit correlation with the severity of disease and with the presence of carditis. The differentiation of those autoantibodies reactive with streptococcal crossreactive antigen seems essential for further understanding of the possible role of autoimmunity in pathogenesis. Evidence for such a role is provided by immunopathologic findings of bound gamma globulin and complement in postmortem rheumatic hearts and in biopsy specimens of atrial appendage. Circulating autoantibodies to heart tissue occur frequently after cardiotomy and myocardial infarction and are commonly associated with postcardiotomy and postmyocardial infarction syndromes. They may reappear during symptomatic recurrent episodes but are not present in quiescent intervals between attacks. Further efforts should be directed to definition of the specific antigens stimulating such autoantibodies, to the biologic and physicochemical properties of the autoantibodies related to clinical symptoms, as well as to immunopathologic observations in these syndromes. In recurrent acute benign pericarditis and in primary cardiomyopathies, viral infection, complicated by hypersensitivity or autoimmunity, or both, has been proposed as a pathogenetic mechanism. Autoimmune bodies have been described in varying frequency in these conditions, and their possible role in pathogenesis should be investigated further, using combined immunologie, virologie and immunopathologic approaches in the early phases of disease. Abnormal immune mechanisms are strongly suspect in the pathogenesis of the cardiac involvement of rheumatoid arthritis, systemic lupus and polyarteritis, but progress must await further understanding of the cause of the primary lesions in these conditions. In tropical endomyocardial fibrosis, an abnormal autoimmunologic diathesis, presumptively related to malarial infection, has been implicated. Animal models of autoimmune myocarditis have been explored. The available data suggest that experimental cardiac lesions of a focal nature may be produced in a variety of animal species. Their relevance as a model for human cardiac disease is under current study.

Nature and Role of the Lytic Factor in Hemolytic Streptococcal Fibrinolysis.

Summary The lytic factor of Milstone and the globulin substance may both be activated by certain organic solvents to yield a true proteolytic enzyme. Both lytic factor and globulin substance are comparable in their quantitative content of the proteinase. Fibrinolysin was found to activate the serum tryptase from an inert precursor.

Immunopathologic Studies of Systemic Lupus Erythematosus (SLE). I. Tissue-bound Immunoglobulins in Relation to Serum Antinuclear Immunoglobulins in Systemic Lupus and in Chronic Liver Disease with LE Cell Factor

We studied the composition of tissue-bound immunoglobulins and of antinuclear factors by immunofluorescent techniques in five patients with systemic lupus and two with chronic liver disease associated with positive LE cell tests. Renal glomeruli in all seven demonstrated deposits of bound gammaG-globulin and complement, although the presence of gammaA- and gammaM-immunoglobulins was variable. Blood vessel walls contained primarily gammaG-globulin and complement in the systemic lupus patients, but such deposits were absent from vessels in the two with chronic liver disease. We observed antinuclear factors, demonstrated by immunofluorescence, in all three immunoglobulin classes. In six of the seven patients, evidence was obtained of a correspondence between the classes of bound immunoglobulins in glomeruli and vessels and the serum titers of antinuclear immunoglobulins. These observations are consistent with the concept that immunoglobulin deposits in tissues may be derived at least in part from antinuclear factors. Neither bound immunoglobulins nor complement was observed in liver parenchyma of the two patients with chronic liver disease or in two patients with systemic lupus and liver pathology. It thus seems doubtful that serum antibodies play a primary role in the pathogenesis of forms of chronic liver disease associated with positive LE cell tests.

Antigenic composition of heart tissue

Abstract Analysis of the antigenic composition of heart tissue is essential for assessing the role of immune mechanisms in cardiac disease, and, in addition, provides an approach to the further definition of the structural properties of heart tissue. Immunologic procedures for differentiation of cardiac antigens have depended on the use of (1) antisera prepared in animals to extractable and insoluble components of heart, (2) autoimmune sera derived from patients with cardiac disease, and (3) antisera to the group A streptococcus which are cross-reactive with myocardial tissue. Technical methods have included complement fixation, tanned cell hemagglutination, antiglobulin consumption, immunofluorescence and precipitin reaction. In addition to the antigens common to all organs, heart tissue contains antigens with distribution either limited to heart alone or limited to the heart and a few other tissues. These include: (1) heart-specific antigens, including a particulate antigen localized to sites between myofibrils, and two or three saline-soluble constituents; (2) antigens found only in heart and skeletal muscle, including insoluble components of sarcolemma extractable in acid, antigens of cross-striations of myofibers and at least one saline-soluble component, identified as myoglobin; (3) insoluble antigens common to cardiac, skeletal and smooth muscle; and (4) a soluble antigen which has been found in heart and kidney and possibly liver tissues. The cardiac antigen crossreactive with the group A streptococcus has been identified in sarcolemma and is extractable in acid. Further progress in the definition of these antigens and in evaluating their possible relation to cardiac disease will depend on their isolation and chemical characterization.

Immunological Similarity of Streptococcal Antifibrinolysins.

Conclusions It was concluded, therefore, that the use of a single fibrinolysin preparation is satisfactory for the serological determination of antifibrinolysin in human infections.

Auto-immunity and rheumatic fever. Some immunopathologic and epidemiologic considerations.

Immunopathologic studies of tissues and serum of patients with rheumatic fever and rheumatic heart disease have indicated that immunoglobulin deposits in heart tissue may derive from auto-immunity. Serologic studies demonstrating a streptococcal antigen cross-reactive specifically with heart tissue suggest that streptococcal infection may serve for induction of autoantibodies to heart in susceptible persons.