THE SPECIFIC POLYSACCHARIDES OF TYPES I, II, AND III PNEUMOCOCCUS : A REVISION OF METHODS AND DATA

THE INFLUENCE OF INFLAMMATION ON THE ABSORPTION OF SUBSTANCES OF VARIED DIFFUSIBILITY

1. Inflammation retards the absorption of horse serum globulin and crystalline egg albumin from the peritoneal cavity and subcutaneous tissue, but retardation of the absorption of crystalline egg albumin is less than that of globulin, which is less diffusible. 2. Inflammation retards the absorption of the specific polysaccharide of pneumococcus Type I from the peritoneal cavity; inflammation may accelerate, but does not hinder, the absorption of glucose from the peritoneal cavity. 3. Inflammation retards the spread of trypan blue in the skin, but accelerates absorption from the skin of the more diffusible dye, brom phenol blue. 4. Phenol red is excreted in the urine with equal rapidity after injection into normal and into inflamed subcutaneous tissue or into normal and into inflamed peritoneal cavities. Direct extractions of phenol red from inflamed subcutaneous sites indicate that inflammation accelerates the absorption of the dye from these areas. 5. Inflammation retards the absorption of the indiffusible proteins, carbohydrates and dyes; it tends to accelerate the absorption of the diffusible carbohydrates and dyes.

THE SPECIFIC POLYSACCHARIDE CONTENT OF PNEUMONIC SPUTA

1. The average specific polysaccharide content of rusty or bloody sputa in Type III was 91 times greater than the average for Types I, II, VII, and VIII pneumonia. 2. Those Type III sputums which were classified as reticulated contained an average S concentration of 1,360 mg. per cent or 170 times more than the amount found in other types. 3. Those Type III sputa which were classified as non-reticulated contained an average S concentration of 45 mg. per cent or 5.5 times more than the amount found in other types. 4. The amount of specific polysaccharide in the sputa of patients with Type III pneumonia furnishes an index to the severity of the disease and an aid in prognosis.

THE MOLECULAR WEIGHT OF ANTIBODIES

1. Highly purified rabbit Type III pneumococcus anticarbohydrate proved to be homogeneous in the ultracentrifuge and its sedimentation constant, 7.0·10^–13, did not differ from that of the principal component of normal rabbit globulin or of immune rabbit globulin containing up to 50 per cent of anti-egg albumin. The molecular weight of antibody in the rabbit is therefore probably very close to that of the principal normal globulin component, namely, 150,000. 2. Highly purified horse Type I pneumococcus anticarbohydrate, on the other hand, was only homogeneous in the ultracentrifuge when prepared from sera stored without preservative. Its sedimentation constant, 18.4·10^–13, coincided with that of the principal globulin component in most of the Felton solutions and purified antibody solutions studied. The molecular weight of pneumococcus anticarbohydrate in the horse is probably three to four times that of the principal normal globulin component. 3. The significance of the differences between pneumococcus anticarbohydrate formed in the rabbit and in the horse is discussed. 4. Results are given of ultracentrifuge studies on the molecular species in solutions of egg albumin-anti-egg albumin specific precipitates dissolved in excess egg albumin. The implications of the results are discussed.

ANTIGEN-ANTIBODY REACTIONS BETWEEN LAYERS ADSORBED ON BUILT UP STEARATE FILMS

By adsorbing antigens and antibodies on barium stearate multilayers immunological reactions at surfaces have been studied. Pneumococcus polysaccharide specific antibody systems using purified antibodies from both horse and rabbit sera were investigated. The polysaccharides failed to show visible adsorption, but by alternate treatment with antibody and polysaccharide several layers of antibody could be specifically deposited. With the diphtheria toxin-antitoxin system antitoxin was found to adsorb to layers of toxin but not conversely. The reaction, however, was not specific. Molecular weights calculated from the thickness of adsorbed protein layers, using dissymmetry factors, roughly correspond to molecular weights calculated from sedimentation and diffusion constants.

A QUANTITATIVE THEORY OF THE PRECIPITIN REACTION : IV. THE REACTION OF PNEUMOCOCCUS SPECIFIC POLYSACCHARIDES WITH HOMOLOGOUS RABBIT ANTISERA

1. The reaction between the specific polysaccharide of Type III pneumococcus and homologous antibody in rabbit sera is quantitatively accounted for by expressions similar to those derived from the mass law for the corresponding horse sera. Preliminary data are also given for the Type I reaction. 2. Differences and similarities of the reaction with antibodies produced by the two animals are discussed. 3. Calculations are made of the equivalent composition of the specific precipitate at various reference points in the reaction range. 4. Certain theoretical and practical implications of the findings are pointed out.

SEROLOGICALLY REACTIVE POLYSACCHARIDES PRODUCED THROUGH THE ACTION OF BACTERIAL ENZYMES : I. DEXTRAN OF LEUCONOSTOC MESENTEROIDES FROM SUCROSE

A serologically reactive polysaccharide of dextran nature was produced from sucrose by the action of some enzyme or similar heat-labile agent contained in sterile filtered extracts derived from sucrose broth cultures of Leuconostoc mesenteroides. Rigorous controls were included to prove that this reaction occurred in the absence of microorganisms. Purified preparations of the dextran formed by the sterile extracts were similar to the dextran elaborated in sucrose broth cultures of the bacteria in respect to both chemical and serological properties. The serological likeness was established not only by tests against leuconostoc antiserums but also by cross reactions with antiserums of Types 2, 20, and 12 pneumococci and by tests against a series of variously absorbed antiserums.

THE GROWTH OF BACTERIOPHAGE

1. An anti-Escherichia coli phage has been isolated and its behavior studied. 2. A plaque counting method for this phage is described, and shown to give a number of plaques which is proportional to the phage concentration. The number of plaques is shown to be independent of agar concentration, temperature of plate incubation, and concentration of the suspension of plating bacteria. 3. The efficiency of plating, i.e. the probability of plaque formation by a phage particle, depends somewhat on the culture of bacteria used for plating, and averages around 0.4. 4. Methods are described to avoid the inactivation of phage by substances in the fresh lysates. 5. The growth of phage can be divided into three periods: adsorption of the phage on the bacterium, growth upon or within the bacterium (latent period), and the release of the phage (burst). 6. The rate of adsorption of phage was found to be proportional to the concentration of phage and to the concentration of bacteria. The rate constant k_a is 1.2 x 10^–9 cm.⁸/min. at 15°C. and 1.9 x 10^–9 cm.⁸/min. at 25°. 7. The average latent period varies with the temperature in the same way as the division period of the bacteria. 8. The latent period before a burst of individual infected bacteria varies under constant conditions between a minimal value and about twice this value. 9. The average latent period and the average burst size are neither increased nor decreased by a fourfold infection of the bacteria with phage. 10. The average burst size is independent of the temperature, and is about 60 phage particles per bacterium. 11. The individual bursts vary in size from a few particles to about 200. The same variability is found when the early bursts are measured separately, and when all the bursts are measured at a late time.

PROPERTIES OF THE TYPE SPECIFIC PROTEINS OF ANTIPNEUMOCOCCUS SERA : I. THE MOUSE PROTECTIVE VALUE OF TYPE I SERA WITH REFERENCE TO THE PRECIPITIN CONTENT

The ability to carry out with some measure of precision mouse protection tests for the estimation of potency of antipneumococcus sera has made possible the correlation of the protective potency with the amount of specifically precipitable protein. With antipneumococcus rabbit sera these protective ratios are relatively constant and higher than those with immune horse serum. Type I antipneumococcus horse sera, on the other hand, show no such constancy but fall into two groups; and there is as yet no simple method for determining to which group a serum belongs.

PREPARATION OF THE TYPE-SPECIFIC POLYSACCHARIDE OF THE TYPE I MENINGOCOCCUS AND A STUDY OF ITS EFFECTIVENESS AS AN ANTIGEN IN HUMAN BEINGS

1. Methods for preparing small amounts of Type I meningococcal polysaccharide which are electrophoretically homogeneous and contain only traces of other immunologically reactive material are given. 2. These polysaccharides are very poor antigens in man but in a small number of instances definite amounts of precipitin and protective antibody were formed. 3. The significance of these findings is discussed.

IMPROVED METHODS FOR THE PREPARATION OF THE SPECIFIC POLYSACCHARIDES OF PNEUMOCOCCUS

The specific polysaccharides of Types I and V pneumococcus give sharp equivalence zones and show maximal precipitation with homologous rabbit antisera only when carefully prepared from cultures which have not been neutralized with alkali. The precipitating power of S V toward homologous rabbit antiserum falls off in 0.1 N NaOH even more rapidly than that of S I, dropping to 7 per cent of the original value in 6 days at room temperature. The alkaline solution develops a large absorption peak at 270 mµ. Directions are given for the preparation of S VII and S XII.

THE PNEUMOCOCCAL CAPSULAR SWELLING REACTION, STUDIED WITH THE AID OF THE ELECTRON MICROSCOPE

Electron micrographs indicate, in harmony with previous findings, that the pneumococcal capsule is a gel of low density outside of and closely applied to the bacterial cell wall. Interaction with homologous immune rabbit serum greatly increases the thickness and density of this capsular gel; the increase in thickness of the specifically swollen pneumococcal capsule may exceed by 25-fold the thickness of the surface deposit caused by rabbit immune serum on the cell walls and flagella of homologous non-capsulated bacteria. Conclusions drawn from these and earlier data are that homologous immune serum permeates the pneumococcal capsular gel; the specific antibody combines with the capsular polysaccharide; non-specific serum components are secondarily adsorbed to or combined with the specific antigen-antibody complex. The relatively low antibacterial titers characteristic of pneumococcal antisera can be explained in part by the permeation of the capsule by antiserum, in part by the high combining capacity of pneumococcal carbohydrate for antibody (17).

A QUANTITATIVE STUDY OF THE CROSS REACTION OF TYPES III AND VIII PNEUMOCOCCI IN HORSE AND RABBIT ANTISERA

1. A preparation of the specific polysaccharide of Type VIII pneumococcus is described in which the use of heat, strong acid, and alkali were avoided. 2. Quantitative estimations are given of the homologous and cross reacting precipitin and agglutinin in Types III and VIII antisera produced in the rabbit and in the horse. Quantitative data are also given on the mechanism of the Type VIII precipitin reaction and the cross reaction between the Type III polysaccharide and Type VIII antipneumococcus horse serum. 3. The significance of the data is discussed.

QUANTITATIVE EXPERIMENTS WITH ANTIBODIES TO SPECIFIC PRECIPITATES. II

1. Antisera have been produced in chickens with specific precipitates from Type II pneumococcus horse and rabbit antisera. 2. Specific precipitates from anti-Types I and II pneumococcus horse sera removed the same amount of antibody from the chicken anti-horse specific precipitate serum. Specific precipitates from horse antisera to diphtheria toxin and to crystalline egg albumin removed about one-half of the antibody. 3. Specific precipitates from anti-egg albumin, antipneumococcus C substance, and anti-Type II pneumococcus rabbit sera removed the same amount of antibody from the chicken anti-rabbit specific precipitate serum. 4. No antibody was removed from the chicken anti-horse specific precipitate serum by rabbit specific precipitates or from the chicken anti-rabbit specific precipitate serum by horse specific precipitates. 5. It is concluded that the antigenic specificities of antibodies from the horse and rabbit are not influenced by their particular antibody functions.

AN ELECTROPHORETIC STUDY OF IMMUNE SERA AND PURIFIED ANTIBODY PREPARATIONS

1. Antibody produced in the horse migrates as a new serum component between the β and γ components, whereas rabbit antibody is electrophoretically identical with the γ globulin component of the serum. 2. In rabbit and monkey antisera the percentage of antibody in the serum and in the γ globulin fraction can be determined by integration of the electrophoresis diagrams of unabsorbed and absorbed sera. Antibody solutions of high purity can be obtained by electrophoretic isolation of the γ globulin of rabbit antisera in which the percentage of antibody to total γ globulin is high. 3. The isoelectric points of pig, cow, horse, and rabbit antibodies have been determined. 4. In horse sera prolonged immunization is accompanied by the formation of another antibody component of lower mobility.

QUANTITATIVE STUDIES ON ANTIBODY PURIFICATION : II. THE DISSOCIATION OF ANTIBODY FROM PNEUMOCOCCUS SPECIFIC PRECIPITATES AND SPECIFICALLY AGGLUTINATED PNEUMOCOCCI

1. The salt dissociation and barium hydroxide-barium chloride methods are extended to the preparation of highly purified antibody solutions from specific precipitates derived from Type III and Type VIII antipneumococcus horse sera and a low grade polyvalent bovine serum. Analytically pure precipitin (agglutinin) was obtained from the last, and Types I, II, and III antibodies were separated. 2. Difficulties connected with the application of the methods to Type I antipneumococcus rabbit sera are described, as is also the purification of antibody from low grade pig and sheep sera. 3. The dissociation of antibody by both methods from Type I pneumococci agglutinated in antisera produced in the horse, rabbit, pig, and sheep, is described and its advantages discussed. 4. Certain theoretical aspects of the work are also discussed.

THE MOLECULAR WEIGHT OF ANTIBODIES

1. Highly purified preparations of homogeneous antibody can be made by the salt dissociation methods (6, 7) without any change in sedimentation due to the method of purification. 2. Antibodies prepared from sera of various animal species fall into two groups as regards molecular weight; in one group cow, horse, and pig, a heavy molecule of molecular weight 990,000 is formed; in human being, rabbit, and monkey, the molecular size is that of the normal gamma serum globulin. Both types of antibody molecules are either not compact or not spherical since the frictional ratios f/f(0) are 2.0 and 1.5 respectively. 3. Horse antibody shows an unchanged activity and sedimentation diagram between pH 3.44-9.06, although there is some aggregation at the more acid and some dissociation at the more alkaline pH. At pH 1.44 the antibody activity is unchanged but some breakdown of the molecule takes place. At pH 12.4 activity is destroyed and the molecule is completely broken down. 4. Some horse antibody preparations show evidence of breakdown of the antibody into inhomogeneous material on continued immunization over a long period.

THE ISOLATION OF THE BLOOD GROUP A SPECIFIC SUBSTANCE FROM COMMERCIAL PEPTONE

The isolation of the blood group A specific substance from commercial peptone has been described. The chemical and serological properties of the material from that source have been defined.

STUDIES ON PHOTO-OXIDATION OF ANTIGEN AND ANTIBODIES

1. Quantitative precipitin studies indicate that progressive photo-oxidation progressively destroys the antigenic function of egg albumin. 2. Quantitative precipitin reactions of antisera (anti-egg albumin rabbit serum and antipneumococcus Type I horse serum) demonstrate that progressive photo-oxidation causes progressive lowering of the potency of the sera. 3. Quantitative precipitin reactions of the photo-oxidized globulin gamma fraction of anti-egg albumin rabbit serum and of Felton solution of antipneumococcus Type I horse serum show that these specific antibody fractions behave similarly to antibodies in whole sera. 4. Egg albumin whose precipitin reaction is destroyed by photo-oxidation no longer causes anaphylaxis in guinea pigs and does not produce precipitins in rabbits. 5. Chemical studies of progressively photo-oxidized egg albumin show a progressive destruction of tryptophane and histidine while tyrosine remains intact and cystine is reversibly oxidized. Sulfhydryl groups can no longer be demonstrated in photo-oxidized egg albumin whose antigenic characteristics are greatly weakened. 6. Similar studies on the globulin gamma fraction of anti-egg albumin rabbit serum and on Felton solution show no diminution of these amino acids in photo-oxidized material whose antigenic properties are destroyed. 7. The non-coagulable nitrogen and the amino nitrogen of egg albumin, antisera, and their specific antibody fractions show but an insignificant increase during photo-oxidation, indicating that the loss of the precipitin reaction is not due to splitting of the respective protein molecules. 8. Electrophoretic studies of egg albumin, antisera, and their specific antibody fractions show that photo-oxidation causes a marked alteration of the pattern of these substrates. 9. Photo-oxidation of proteins causes the formation of aggregates, indicating denaturation. 10. Hematoporphyrin migrates with the albumin fraction of unaltered as well as the photo-oxidized anti-egg albumin rabbit serum and pneumococcus Type I horse serum; in isolated proteins such as egg albumin, globulin gamma, or Felton solution, etc., the dye moves independently of the protein; after progressive photo-oxidation Hp becomes progressively fixed to the protein. Eosin behaves similarly to hematoporphyrin.

QUANTITATIVE EXPERIMENTS WITH ANTIBODIES TO A SPECIFIC PRECIPITATE. I

1. Rabbits were injected with the washed specific precipitate from Type II antipneumococcus horse serum. Antibody in the resulting antiserum was determined by the quantitative agglutinin method using various specific precipitates as antigens. 2. Suspensions of Types I and II antipneumococcus horse specific precipitates, as well as the specific precipitates derived from Type VIII Pn (anti-C portion), and H. influenzae horse antisera were found to remove the same amount of antibody from the immune rabbit serum. 3. Purified antibody solutions prepared by dissociation methods from Types I and II antipneumococcus horse sera were found to remove the same quantity of antibody as did the homologous specific precipitates. 4. Specific precipitates from anti-crystalline egg albumin and anti-diphtheria horse sera were found to remove only a fraction of the antibody. The reasons for this are discussed. 5. A specific precipitate prepared from pepsin-digested Type I anti-pneumococcus horse serum removed all of the antibody to the homologous antigen from the rabbit anti-precipitate serum, but followed a different quantitative course. 6. From the quantitative course of these reactions and from experiments with specific precipitates from anti-Pn rabbit and pig sera it is concluded that the only antigenic specificity demonstrable for the antibodies investigated was that due to their common origin, and that the groupings responsible for their antibody function constitute either a small part of the total protein molecule or else are non-antigenic.

QUANTITATIVE EXPERIMENTS WITH ANTIBODIES TO A SPECIFIC PRECIPITATE : III. ANTIGENIC PROPERTIES OF HORSE SERUM FRACTIONS ISOLATED BY ELECTROPHORESIS AND BY ULTRACENTRIFUGATION

1. Rabbit antisera to a Type II pneumococcus specific precipitate from horse serum were tested with fractions prepared by ultracentrifugation and electrophoresis of normal and immune horse serum. 2. In one instance a rapidly sedimenting protein from normal horse serum had nearly the same quantitative antigenic properties toward the anti-antibody rabbit serum as did the purified pneumococcus antibody solutions previously reported. In another instance a comparable fraction removed only a part of the rabbit antibody. 3. Electrophoretic γ-globulin from an immune horse serum had quantitatively the same antigenic properties as did antibody solutions prepared by salt-dissociation of specific precipitates. 4. Electrophoretic γ-globulin from normal horse serum differed in its antigenic behavior from γ-globulin containing antibody. The data are compared with the antigenic properties of acid and alkali treated pneumococcus specific polysaccharides toward antipneumococcus horse sera. An interpretation in terms of polymers is suggested. 5. The cross-reaction of goat serum γ-globulin against the anti-antibody serum is reported and the extent of the reaction compared with those of goat and horse serum albumins against a rabbit antiserum to the latter.

A FURTHER STUDY OF THE CROSS REACTION BETWEEN THE SPECIFIC POLYSACCHARIDES OF TYPES III AND VIII PNEUMOCOCCI IN HORSE ANTISERA

1. The cross reaction of the specific polysaccharide of Type VIII pneumococcus with Type III antipneumococcus horse serum has been studied quantitatively and found similar to the S III-anti-S VIII reaction. 2. Contrasted with the general similarity of the two-segment reaction curves were distinct qualitative and quantitative differences in the course and character of the reciprocal reactions with respect to each segment. 3. These differences could be interpreted in terms of the known chemical differences between the specific polysaccharides of the two types. A minimum molecular weight of 62,000 was calculated for S III and 140,000 for S VIII. 4. It was also found possible to fractionate the Type VIII antibody into portions characteristic of each segment of the cross reaction curve. At least three different kinds of Type III and Type VIII anticarbohydrates were identified.

CHEMO-IMMUNOLOGICAL STUDIES ON CONJUGATED CARBOHYDRATE-PROTEINS : XI. THE SPECIFICITY OF AZOPROTEIN ANTIGENS CONTAINING GLUCURONIC AND GALACTURONIC ACIDS

1. Azoprotein antigens containing glucuronic and galacturonic acids give rise in rabbits to specific antibodies. The immune sera show no serological crossing with antigens containing glucose or galactose. 2. The galacturonic acid antigen reacts in antipneumococcus horse serum Type I in high dilutions. 3. Azoprotein antigens containing galacturonic acid, benzene sulfonic and carboxylic acids precipitate in antipneumococcus horse sera of various types but not in normal horse serum. The mechanism underlying these cross reactions is discussed.

CHEMICAL STUDIES ON BACTERIAL AGGLUTINATION : V. AGGLUTININ AND PRECIPITIN CONTENT OF ANTISERA TO HAEMOPHILUS INFLUENZA, TYPE B

1. The quantitative, absolute methods of agglutinin and precipitin analysis previously developed for antipneumococcus sera have been shown to be applicable to horse and rabbit anti-influenza type B sera and plasmas. 2. With the aid of these methods and improved immunization schedules the antibody content of the rabbit sera has been increased five to ten times. 3. The method recommended for the purification of rabbit antipneumococcus antibody has also been found applicable to rabbit anti-influenza type B sera.

The inhibition of surface phagocytosis by the capsular slime layer of pneumococcus type III

Five strains of type III pneumococcus have been shown to possess wide capsular slime layers during the logarithmic phase of growth in serum broth. The slime layer stains metachromatically with methylene blue and can be visualized under the electron microscope as a fuzzy halo which extends well beyond the surace of the capsule proper and causes centrifugates of the organism to be of extremely large volume. This outer capsular structure is most readily demonstrated in vivo and in nutrient broth containing glucose and serum. It disappears from the surface of the cell with aging of the culture, and is easily removed by dilute alkali, alcohol, and heat. Exposure of slime-covered type III pneumococci to homologous antibody and to type III polysaccharidase reveals that the slime layer contains the same type-specific polysaccharide that is present in the rest of the capsule. From a type III strain producing a prominent slime layer an intermediate mutant has been isolated which forms small non-mucoid colonies on blood agar and possesses a relatively small capsule with a barely discernible slime layer. The wide slime layer protects virulent type III pneumococci from surface phagocytosis. Whenever the type III cells lose their broad slime layer, whether from aging of the culture, from mutation, from exposure to injurious chemicals, or from the action of type III polysaccharidase, they become susceptible to phagocytosis by the surface mechanism. Once phagocyted the type III pneumococci are promptly destroyed, even in the absence of antibodies.

Host-parasite relationships in experimental pneumonia due to pneumococcus type III

Experimental pneumonia was produced with a highly virulent strain of type III pneumococcus which synthesizes, during rapid growth, large amounts of capsular polysaccharide. The type III pneumonia differed from that caused by pneumococcus I in that (a) death occurred more promptly in the type III infection, (b) the local pulmonary lesion became more heavily infected, and (c) frank suppuration was common even after otherwise effective chemotherapy. The greater pathogenicity of the type III organism was shown by special histologic techniques to be due primarily to its capsular slime layer which interferes with surface phagocytosis. Capsular polysaccharide shed from the organism during growth was also demonstrated in high concentration in certain parts of the pneumonic lesion. Removal of the excess polysaccharide from the alveoli resulted from (a) lymphatic drainage to regional lymph nodes and (b) phagocytosis, particularly by macrophages. The possible relationship of the free carbohydrate to the malignancy and the characteristically viscous exudate of type III pneumonia was discussed. The lung abscesses which resulted from type III infection were observed to occur in those areas in which the maximum number of organisms had accumulated. Evidence was obtained that suppuration was due, not to necrotoxic products peculiar to the type III pneumococcus, but rather to the survival of large numbers of bacteria in the tissues, brought about primarily by the antiphagocytic effect of the slime layer. When pneumonia was produced with an intermediate type III mutant lacking the protective slime layer, back mutation to the mucoid parent occurred during the course of the infection, and the mucoid form eventually predominated in the lung as a result of selective phagocytosis of the intermediate organisms. Similar mutation to the maximally virulent type III form was noted with a transformed intermediate type III strain grown from single cell preparations.

Absence of a prosthetic group in a type-specific polysaccharide of pneumococcus

The specific polysaccharide of Type III pneumococcus, with only 0.05 per cent of N and 0.01 per cent of P, still shows almost maximal precipitation of a Type III antipneumococcus rabbit serum and the expected antigenicity in man. There is therefore no evidence that a prosthetic group is involved in these characteristic activities.

A comparison of the peptides released from related rabbit antibodies by enzymatic hydrolysis

Rabbit antibodies against pneumococcus capsular polysaccharides of Types II, III, VI, VII, and XII were isolated from type-specific antisera by precipitation with homologous antigen and hydrolyzed with either subtilisin, chymotrypsin or trypsin. Purified antibodies were also hydrolyzed with papain; the two polypeptides with active antibody sites and the crystallizable polypeptide were separated, studied in the ultracentrifuge and hydrolyzed with either subtilisin or chymotrypsin. The resulting peptides were separated on filter paper by electrophoresis and chromatography. 1. The two polypeptides with antigen-combining activity, fractions I and II, each constituted about 25 per cent of the original antibody molecule; the crystallizable polypeptide did not combine with antigen, fraction III, and represented about 35 per cent of the original antibody molecule. About 10 to 15 per cent of the original antibody molecule was hydrolyzed by papain into about 35 peptides. 2. The peptide patterns obtained for hydrolyzates of fraction I were almost identical with those obtained for fraction II obtained from the same antibody and were quite different for those obtained for fraction III. 3. Many of the peptide spots in the patterns obtained with whole antibody hydrolysates contained at least two peptides derived from different parts of the antibody molecule. 4. Differences were observed in the peptide patterns for different antibodies that suggested the existence of differences in both primary and tertiary structures among these antibodies.

Immunochemistry of pneumococcal types II, V, and VI. II. Inhibition tests in the type VI precipitating system

Rebers, Paul A. (Rutgers University, New Brunswick, N. J.), Esther Hurwitz, and Michael Heidelberger. Immunochemistry of pneumococcal types II, V, and VI. II. Inhibition tests in the type VI precipitating system. J. Bacteriol. 82:920-926. 1961.-As in other immune systems involving polysaccharides, rabbit antibodies but not those engendered in the horse were found sensitive to degradation of type VI pneumococcal (Pn) polysaccharide (SVI), and were readily inhibited by fragments of SVI. Large amounts, 30 to 111 mumoles, of most sugars gave up to 15% inhibition, while sugar and polyol phosphates inhibited as much as 25%, with little relation to their presence or absence in SVI. The phosphate-free repeating unit of SVI was a good inhibitor, its phosphate monoester was better, and the "trimer" still better. The "trimer" precipitated most of the antibodies from horse anti-Pn VI.Although inhibition of precipitation of SVI anti-Pn horse sera could not be demonstrated with fragments of SVI, cross-reactions of antibodies in the horse sera could be inhibited. Precipitation of SII was inhibited by low concentrations of l-rhamnose, while even high concentrations of the other sugar components of SII and SVI were ineffective. Precipitation by guar gum was inhibited by galactose and alpha- and beta-methyl-galactopyranosides, also by rhamnose, although guar gum does not contain this sugar, while SVI, the antigenic determinant, does.

Simultaneous production of two capsular polysaccharides by pneumococcus. II. The genetic and biochemical bases of binary capsulation

Study of the capsular genome of pneumococcus has shown that it controls a multiplicity of biochemical reactions essential to the synthesis of capsular polysaccharide. Mutation affecting any one of several biochemical reactions concerned with capsular synthesis may result in loss of capsulation without alteration of other biochemical functions similarly concerned. Mutations affecting the synthesis of uronic acids are an important cause of loss of capsulation and of virulence by strains of pneumococcus Type I and Type III. The capsular genome appears to have a specific location in the total genome of the cell, this locus being occupied by the capsular genome of whatever capsular type is expressed by the cell. Transformation of capsulated or of non-capsulated pneumococci to heterologous capsular type results probably from a genetic exchange followed by the development of a new biosynthetic pathway in the transformed cell. The new capsular genome is transferred to the transformed cell as a single particle of DNA. Binary capsulation results from the simultaneous presence within the pneumococcal cell of two capsular genomes, one mutated, the other normal. Interaction between the biochemical pathways controlled by the two capsular genomes leads to augmentation of the phenotypic expression of the product controlled by one and to partial suppression of the product determined by the other. Knowledge of the biochemical basis of binary capsulation can be used to indicate the presence of uronic acid in the capsular polysaccharide of a pneurnococcal type the composition of the capsule of which is unknown.

Antigenic structure and serological relationships of Mycobacterium, Actinomyces, Streptococcus, and Diplococcus

Kwapinski, Jerzy B. (South African Institute for Medical Research, Johannesburg), and Marshall L. Snyder. Antigenic structure and serological relationships of Mycobacterium, Actinomyces, Streptococcus, and Diplococcus. J. Bacteriol. 82:632-639. 1961.-Chemical fractions, 72 in all, from four strains of Mycobacterium, four strains of Actinomyces, and four strains of Streptococceae, were tested in homologous and heterologous antisera prepared against intact cells and chemical fractions of Mycobacterium tuberculosis. Antigens isolated from the cytoplasm of these bacteria proved to be serologically related to each other. In contrast, most of the cell-wall antigens, except those extracted with either 30% sodium hydroxide or formamide at 100 to 130 C, were species specific. Sera prepared against the individual fractions of Mycobacterium reacted only with the strain of Mycobacterium from which they were isolated.

STUDIES ON THE RELATIONSHIP OF ALLOTYPIC SPECIFICITIES TO ANTIBODY SPECIFICITIES IN THE RABBIT

Purified antibodies against three different antigens and haptens (ovalbumin, dinitrophenol, and Type II pneumococcal polysaccharide) were prepared from specific precipitates from the antisera of several rabbits. The reactions of these preparations with antisera against the allotypic specificities carried by each of the animals forming the antibodies were used to compare the relative concentrations of molecules bearing each specificity in the different solutions of antibodies from each rabbit. These relative concentrations appeared to vary greatly from one preparation to another, although all the allotypic specificities carried by each animal were found in all the preparations of antibodies from that animal. The interpretation of these results is discussed.

An immunoregulatory factor associated with spleen cells from tumor-bearing animals. III. Characterization of the factor's target cells

An immunoregulatory factor associated with spleen cells from tumor-bearing mice was found to potentiate the generation of antibody-producing cells (APC). In an attempt to characterize the target cell of this enhancing factor (EF), its activity in mice devoid of mature T lymphocytes was tested. Levels of anti-SRBC APC were augmented when EF was injected together with SRBC to nude mice and "B" mice. In addition, EF potentiated the antibody response against the IgM-inducing T-independent pneumococcal plysacchardide SIII antigen. These results suggest that EF most probably exerts its enhancing influence directly on B lymphocytes. In a different line of experiments adoptive secondary responses were performed. Mice were immunized with SRBC as carrier or with the NIP-chicken erythrocytes (as a source of NIP-specific primed B cells) in the presence or absence of EF. Various combinations of spleen cells from the donor immunized mice were transferred in a mixture with NIP-SRBC to lethally irradiated recipient mice, EF did not exert any potentiation effect on helper function, except when primed B cells were used. In contrast, a clear activation or clone expansion of hapten-specific B cells was observed. These findings indicate that the enhancing factor from tumor-bearing animals directly affected the antigenic triggering of B lymphocytes and their subsequent proliferation and differentiation to antibody-producing cells.

Polysaccharide capsule of Escherichia coli: microscope study of its size, structure, and sites of synthesis

This report describes the structure, size, and shape of the uncollapsed polysaccharide capsule of Escherichia coli strain Bi 161/42 [O9:K29(A):H-], its ultrastructural preservation as well as the filamentous components of the isolated capsular material. In a temperature-sensitive mutant, sites were localized at which capsular polysaccharide is "exported" to the cell surface. The highly hydrated capsule of the wild-type cells was visible in the uncollapsed state after freeze-etching, whereas dehydration in greater than or equal to 50% acetone or alcohol caused the capsule to collapse into thick bundles. This was prevented by pretreatment of the cell with capsule-specific immunoglobulin G; the capsule appeared as a homogeneous layer of 250- to 300-nm thickness. The structural preservation depended on the concentration of the anti-capsular immunoglobulin G. Temperature-sensitive mutants, unable to produce capsular antigen at elevated temperatures, showed, 10 to 15 min after shift down to permissive temperature, polysaccharide strands with K29 specificity appearing at the cell surface at roughly 20 sites per cell; concomitantly, capsule-directed antibody started to agglutinate the bacteria. The sites at which the new antigen emerged were found in random distribution over the entire surface of the organism. Spreading of purified polysaccharide was achieved on air-water interfaces; after subsequent shadow casting with heavy metal, filamentous elements were observed with a smallest class of filaments measuring 250 nm in length and 3 to 6 nm in width. At one end these fibers revealed a knoblike structure of about 10-nm diameter. The slimelike polysaccharides from mutants produced filamentous bundles of greater than 100-microns length, with antigenic and phage-receptor properties indistinguishable from those of the wild-type K29 capsule antigen.

Mechanisms by which hapten conjugates of pneumococcal polysaccharide interfere with the challenge of anti-hapten memory cells

Incubation of trinitrophenylated hemocyanin (TNP-KLH)-primed spleen cells with microgram amounts of 2,4-dinitrophenyl (DNP) or 2,4,6-trinitrophenyl (TNP) conjugates of pneumococcal polysaccharide type 3 (SIII) for as little as 5 min at 4 degrees C results in a specific "block" of the 19 S and 7 S adoptive memory response to TNP-KLH. This hapten-SIII-induced block of anti-hapten memory B cell responsiveness seems to be an example of specific receptor blockade. The block is specific and can be prevented by simultaneous incubation of the primed cells with hapten-protein conjugates which presumably compete with the hapten-polysaccharide for attachment to the B cell surface via anti-hapten Ig receptors. Removal via capping of these Ig receptors by exposure of TNP-KLH-primed memory cells to rabbit anti-mouse Fab serum for 45 min at 37 degrees C renders these cells refractory to the blocking effect of hapten-SIII. Once the hapten-SIII has attached to the memory cells, these blocked cells can be "rescued" (i.e. returned to a state of responsiveness) by incubating these cells with either mouse anti-SIII at 37 degrees C or rabbit anti-DNP serum at 4 degrees C. Since a papain digest of the IgG fraction of rabbit anti-DNP did not rescue the cells while the intact IgG did, a capping off of the TNP-SIII was proposed as the mechanims for this return to responsiveness of the hitherto blocked cells. A rescue was not seen by treatment of recipient mice with such B cell mitogens as dextran sulfate, endotoxin or purified protein derivative of tuberculin.