Distinct Antigenic Components Research Articles

Prior genital tract infection with a murine or human biovar of Chlamydia trachomatis protects mice against heterotypic challenge infection.

We sought to assess the degree of cross-protective immunity in a mouse model of chlamydial genital tract infection. Following resolution of genital infection with the mouse pneumonitis (MoPn) biovar of Chlamydia trachomatis, mice were challenged intravaginally with either MoPn or human serovar E or L2. The majority of animals previously infected with MoPn were solidly immune to challenge with either of the two human biovars. Surprisingly, approximately 50% of animals became reinfected when homologously challenged with MoPn, although the secondary infection yielded significantly lower numbers of the organism isolated over a shorter duration than in the primary infection. Primary infection with serovar E also protected against challenge with MoPn or serovar L2, although the degree of immune protection was lower than that resulting from primary infection with MoPn. Blast transformation and assessment of delayed-type hypersensitivity indicated that mice previously infected with either human or murine biovars produced broadly cross-reactive T cells that recognized epitopes of either murine or human biovars of C. trachomatis. Immunoblotting demonstrated that primary MoPn infection produced immunoglobulin G (IgG) antibody to antigens of MoPn as well as at least three distinct antigenic components of human serovar E, one of which was identical in molecular weight to the major outer membrane protein (MOMP). Primary infection with serovar E produced IgG antibody reactive against serovar E but not MoPn MOMP and against at least one ca. 60-kDa protein of both chlamydial strains. Our results indicate that primary genital infection of mice with murine C. trachomatis induces immunity against challenge with either of two human biovars.

Incidence and reactivity patterns of skeletal and heart (SH) reactive autoantibodies in the sera of patients with myasthenia gravis

Serum from patients with myasthenia gravis (MG) contain antibodies to numerous skeletal muscle components in addition to the acetylcholine receptor (AChR). Certain non-AChR skeletal muscle autoantibodies have been shown by absorption to cross-react with cardiac muscle, leading to the designation of ‘skeletal and heart’ or SH antibodies. This study describes a new procedure for the extraction of human cardiac muscle which allows direct determination of SH antibody reactivity. Serologic evaluation of 17 patients with MG revealed 9 17 (53%) were seropositive for SH antibody to cardiac muscle. Absorption of selected MG serum samples with cardiac muscle extracts, reduced or eliminated reactivity to skeletal muscle in all cases, confirming the presence of cross-reactive antibodies. Immunoblot analysis of cardiac muscle extracts demonstrated several distinct antigenic components, which were unrelated to the acetylcholine receptor or to previously identified striatonal muscle proteins. Serum samples from individual MG patients displayed different immunoblot reactivity patterns to the antigens in cardiac muscle extracts, providing the first evidence of multiple heart-reactive SH antibodies in MG.

Antigenic heterogeneity of an alkali-soluble, water-soluble cell wall extract of Coccidioides immitis.

The antigenic composition of an alkali-soluble, water-soluble cell wall extract of Coccidioides immitis, designated C-ASWS, was assessed by two-dimensional immunoelectrophoresis against goat antisera to C-ASWS and coccidioidin. The results established that C-ASWS from mycelia or spherule cell walls is heterogeneous in composition, containing two distinct antigenic components. One is present as a polymer that is antigenically identical to a polymeric antigen in coccidioidin, designated antigen 2. The other component detected in C-ASWS presented an unusual precipitin pattern in that a cathodal leg was demonstrable in the absence of an anodal leg. This incomplete precipitinogen was also detected in coccidioidin. In addition to the finding that C-ASWS is antigenically heterogeneous, the results provide evidence that the conformational and/or configurational structure of the C-ASWS antigen 2 (or antigen 2-like polymer) is altered during physicochemical extraction. This conclusion is based upon the finding that the immunoelectrophoretic profile of the C-ASWS polymer differs from that of coccidioidin antigen 2. The C-ASWS polymer is characterized by having a small cathodal precipitin peak connected to a large anodal peak, whereas coccidioidin antigen 2 is characterized by a predominant cathodal peak.

Myasthenia Gravis: Identification of Skeletal and Heart Muscle antigens not related to the acetylcholine receptor

Myasthenia gravis (MG) is a neuromuscular disease thought to have an autoimmune etiology. The acetylcholine receptor has been considered the primary site of antibody binding; however, other muscle components may be involved in the pathogenesis of myasthenia gravis. This study describes a hypertonic sucrose extract of skeletal muscle (Muscle-HSE) that reacts with antibodies in myasthenic sera. The active component in Muscle-HSE is not the acetylcholine receptor as demonstrated by the inability of this extract to bind [ 125I]α-bungarotoxin. Muscle-HSE does, however, contain two distinct antigenic components reactive with MG sera. One antigen reacted with 70% ( 14 20 ) of myasthenic sera in the passive hemagglutination assay. This antigen was detected in the HSE of both skeletal muscle and heart, and was unaffected by treatment with Triton X-100. The second antigen reacted with 10% ( 2 20 ) of MG sera in the complement fixation assay, was unique to skeletal muscle, and was inactivated by Triton X-100.

Antigens of PPD, old tuberculin, and autoclaved Mycobacterium bovis BCG studied by crossed immunoelectrophoresis.

The effect of heat on mycobacterial antigens was studied by crossed immunoelectrophoresis in a system permitting identification and analysis of about 30 distinct components in Mycobacterium bovis BCG. By heating BCG concentrated culture fluid and BCG sonicates to 120 degrees C for 15 min, most antigens detectable by reaction with rabbit anti-BCG antibodies were destroyed. The BCG antigens 60, 63, 82, and 89 still gave strong precipitate lines, antigens 1B and 23 gave weak but distinct precipitate lines, whereas BCG antigens 27, 71, and 84 did not precipitate but retained some of their ability to combine with anti-BCG antibodies. Tuberculin PPD preparations showed a varying antigen content, the most prominent component corresponding to BCG antigen 60, and 6 additional components being detected in PPD RT33. The polysaccharide antigen responsible for the prominent peak of BCG antigen 89 was not detected in PPD RT 23 or PPD RT33. Only 5 distinct antigenic components were detected in Old tuberculin. They corresponded to the components remaining in autoclaved BCG, with 60 and 89 being the only prominent peaks in direct precipitation tests. The relevance of these findings concerning purification of mycobacterial antigens and the importance of individual antigenic components for induction of delayed hypersensitivity is discussed.

Lens membranes VI. Some characteristics of the EDTA-extractable protein (EEP) from bovine lens fiber membranes

After urea-treatment of calf lens fiber membranes, a well defined extrinsic membrane protein fraction (EEP) can be extracted by EDTA-solution. It contains polypeptides of mol. wt. 32K and 35K (SDS-gel electrophoresis). Thin-layer gel filtration shows that without detergent no oligomers are formed. It is easily lost by its adsorption characteristics, however, it can be purified from contaminating α crystallin by gel filtration. The 35K fraction comprises components with isoelectric points at 4·6–4·7 (double band) and between 6·2 and 7·2. The 32K fraction shows components at 4·6–4·7 and 6·2 as was found by two-dimensional gel electrophoresis. The method of isolation, the isoelectric focusing pattern, and the amino acid and mol. wt. composition distinguish EEP clearly from the soluble crystallins. EEP comprises two distinct antigenic components with isoelectric points between 6·2 and 7·2. This was revealed by immunoelectrofocusing of EEP vs. anti-EEP antiserum from rabbit. Combining the results of two-dimensional electrophoresis and immunoelectrofocusing it was found that the 32K and 35K polypeptide have different antigenic properties. Traces of crystallins are difficult to remove. However, by means of specific anti-crystallin antisera it has been shown that EEP has a determinant in common with γ crystallin.

Antigenic Analysis of Mycobacterium leprae

About twenty distinct antigenic components have been demonstrated in Mycobacterium leprae (M. leprae) by crossed immunoelectrophoresis against a rabbit antiserum produced by immunization with concentrated M. leprae antigen. This system allows a more detailed analysis of the antigenic relationship between M. leprae and other mycobacteria and a better characterization of the antigenic content of various M leprae preparations than with previously available anstisera of the antigenic content of various M. leprae preparations than with previously available antisera which reacted with far fewer components. The antibody activity in sera of patients with lepromatous leprosy was studied by incorporating the sera into the intermediate gel of the M. leprae reference system. Antibodies were found against only seven of the components. Since those compared are all known to be cross-reacting widely with antigens of other mycobacteria, it is speculated that cross-immunization may influence the antibody response in lepromatous leprosy.

Cross‐reactions between Mycobacteria

Cross-reactions between Mycobacterium bovis BCG and various other mycobacteria, Nocardia asteroides, Corynebacterium pyogenes and Listeria monocytogenes were studied by incorporating antibodies against these bacteria in the intermediate gel of a crossed immunoelectrophoretic system with BCG antigen and anti-BCG antibodies. In the BCG reference system forty-four distinct antigenic components were recorded, of which thiryt-three cross-reacted with Mycobacterium tuberculosis, twenty-five with M. avium, twenty-one with M. suvalii, eighteen with M. smegmatis, Fifteen with M. nonchromogenicum, twelve with M. phlei, eight with N. anteroides and two with C. pyogenes, whereas no cross-reaction was detected with L. monocytogenes. The value of the method for characterization of mycobacterial antigens is discussed. A taxonomic system based on this method appears particularly valuable for studies of non-cultivativable mycobacteria such as M. leprae. A majority of twenty-one patients with lepromatous leprosy had anti-BCG antibodies of restricted specificity, affecting only four or five BCG antigens, although one patient had twelve anti-BCG specificities. Most of these antibodies reacted with those BCG antigens that cross-react extensively with other mycobacteria.

Formation of Antibody Against Mycobacterium Leprae Antigen 7 in Armadillos

A radioimmunoassay developed to measure antibody against Mycobacterium leprae antigen 7 in man was applied to the nine-banded armadillo (Dasypus novemcinctus). Normal armadillo sera had low but significant antibody activity in the test. Fourteen of 17 armadillos with systemic mycobacterial infection after inoculation with M. leprae showed increased antibody activity in the assay, and in some instances the activity was higher than in a pool of sera from patients with lepromatous leprosy. Crossed immunoelectrophoresis with armadillo serum in the intermediate gel revealed antibodies against five distinct antigenic components of M. leprae. Development of systemic mycobacterial infection after inoculation with M. leprae is thus associated with a distinct humoral immune response. The use of radioimmunosassay for selection of animals for inoculation and for following the development of the infection is discussed.

Chido and Rodgers blood groups are distinct antigenic components of human complement C4.

THE HLA complex consists of many closely linked genes which code for a variety of characters, particularly the expression of cell surface antigens found on lymphocytes (HLA-A, B, C, DR antigens) or erythrocytes (Chido and Rodgers blood groups) and polymorphic variation of certain complement components (Bf, C2, C4). We1 have recently suggested that the polymorphism of the fourth component of human complement (C4), detected by immunofixation electrophoresis, is controlled by two genes linked to HLA and not by codominant alleles at a single locus as previously described2,3. One C4 variant, designated F, is controlled by one locus with alleles determining the presence (F+) or absence (f0) of four fast-moving anodal bands of C4 while the second variant, S, is controlled by a second locus with alleles determining the presence (S+) or absence (s0) of four slow-moving cathodal bands. We noted that C4 F individuals homozygous for the s0 allele and lacking the four cathodal bands were always Chido (Cha) negative, whereas individuals homozygous for the f0 allele and lacking the four anodal bands of C4 (C4 S) were always Rodgers (Rga) negative. This intriguing observation led us to study the relationship of Chido and Rodgers red cell antigens, which are also found in serum and C4. We show here that Chido and Rodgers are distinct antigenic components of human C4, a finding which provides a biological explanation as to why these unique red cell antigens are controlled by genes of the HLA complex.

Surface differentiation antigens of human mammary epithelial cells carried on the human milk fat globule.

Rabbit antibodies against components of the human milk fat globule bind specifically to normal human breast epithelial cells and cell lines derived from breast carcinomas, as well as to the outer surface of the human milk fat globule. Variation in indirect immunofluorescence staining in both intensity per cell and percentage of cells stained is observed for the different brest cell lines. Cells derived from other epithelial and other ectodermal tissues, fetal fibroblasts, cells of the blood buffy coat, and even fibroblasts of the breast itself do not bind the antibodies. This suggests that these antibodies are detecting cell-type-specific antigens. These normal breast epithelial cell antigens are on the cell surface and their expression is stable in long-term cultured cell lines, even after much chromosomal variation in a given line. By affinity chromatography, three distinct antigenic components can be isolated from the milk fat globule, one of which contains carbohydrate. These differentiation antigens of the human breast epithelial cell are not only useful as specific cell-type markers, but also can provide a tool to study the role of the cell surface in normal and neoplastic mammary development.

The detection by immunodiffusion of tumour associated antigenic components in extracts of human bronchongenic carcinoma.

Antisera to extracts of a variety of bronchogenic carcinoma were raised in rabbits and extensively absorbed with immunoadsorbents prepared with normal lung extracts cyanogen bromide linked to Sepharose 4B, and glutaraldehyde insolubilized normal lung extracts. The antisera were tested by immunodiffusion against a panel of extracts from a variety of bronchogenic carcinoma, foetal lung extracts and pools of normal lung extracts. The results indicate that two distinct antigenic components are associated with bronchogenic carcinoma; one which is present in a high percentage of the tumour extracts tested and appears to have partial identity with a foetal lung component, and one (or more) which is not foetal and appears to have higher cross-reactivity (but not exclusively) with tumours of the same pathological type. Attempts to detect either antibody or antigens relating to these components in the serum of patients with bronchogenic carcinoma by these techniques were unsuccessful. The foetal cross-reacting component was neither carcinoembryonic antigen and alpha1-foetoprotein.

Basement Membranes: Structural And Biosynthetic Considerations

Basement membranes are extracellular matrices synthesized by a variety of cells including the basal cells of the epidermis; the respiratory, gastrointestinal, and glandular epithelium; the capillary endothelium; the epithelial cells of the glomerulus, the renal tubule, and the lens capsule; and the endothelium of Descemet's membrane. Basement membranes in the mature animal are free of lipids, DNA, and proteoglycans and are composed of dissimilar protein subunits. One of these is a procollagen-like molecule associated with a noncollagenous matrix glycoprotein. The proportion of the latter component varies among basement membranes. These various subunits are stabilized by hydrogen bonds, disulfide bonds, and aldehyde-derived cross-links which are so extensive that they render the basement membranes highly insoluble. Immunochemical studies indicate three distinct antigenic components which correspond to the collagenous moiety, its nonhelical extension, and the matrix glycoprotein. The collagen component of basement membranes, free of the nonhelical extension, is composed of three identical alpha-chains. It is highly rich in hydroxylysine, 3- and 4-hydroxyproline and contains 4 to 8 residues of half-cystine. It contains 38 residues of glucosyl-galactosyl-hydroxylysine per chain and minimal amounts of mannose, glucosamine, and fucose. Newly synthesized basement membrane collagen is secreted in the extracellular space as the precursor molecule "procollagen." This molecule does not undergo conversion to collagen but interacts with the matrix glycoprotein to give rise to the appropriate structure.

Hepatitis B antigen - an incomplete history.

Hepatitis B virus still cannot be grown in an in vitro system; therefore, research into hepatitis B antigen (HB Ag) is limited to laboratory methods such as serology, electron microscopy, and biochemistry. These have established the presence of two distinct antigenic components of HB Ag, that associated with the small forms and the outer covering of the Dane particle (HBs Ag), and that of the Dane particle core (HBc Ag). Current findings make it almost certain that the Dane particle represents the hepatitis B virus (HBV), the smaller forms of the antigen representing excess viral lipoprotein. The group of individuals positive for the antigen are considered and the immunopathology of the disease is discussed. Present understanding of the antigen has made it possible to consider the use of HBs Ag as a means of vaccination. However, further information on the immune mechanisms associated with HB Ag are required before this can be accepted as a general means of protection. Finally, looking at currently available techniques, it would appear that passive hemagglutination and radioimmunoassay are both highly specific and sensitive methods of screening for HB Ag.

Basement membranes: current concepts of structure and synthesis.

Basement membranes are composed of dissimilar protein subunits. The procollagen-like subunit is associated with noncollagenous matrix glycoproteins. The proportion of the latter components varies among basement membranes. The various subunits interact via hydrogen bonds, disulfide bonds and aldehyde-derived cross-links. The extensive degree of cross-linking renders basement membranes highly insoluble. A procollagen-like molecule, extracted from calf anterior lens capsule, exhibits on electron microscopy a filamentous component with a globular portion attached at one end. Treatment of basement membranes with pepsin at low temperature digests the noncollagenous glycoprotein components and allows the collagenous component to come into solution. Purification of the pepsin-solubilized collagen from basement membranes reveals a molecule composed of three identical alpha-chains. Other unique features include 40-50 residues of hydroxylysine, 128-140 residues of 4-hydroxyproline, 12-15 residues of 3-hydroxyproline, 29 residues of arginine, 35 residues alanine, 2-4 residues of half-cystine, 38 residues of glucosyl-galactosyl-hydroxylysine, 3 residues of mannose, 2 residues of glucosamine, and 0.3 residues of fucose. Immunochemical studies indicate the presence of three distinct antigenic components and support the evidence that one is collagenous and the other two are noncollagenous glycoproteins. One of the latter corresponds to the non-helical extension of procollagen. The other is a large-molecular weight highly cross-linked matrix protein.

Two distinct antigenic components in an Epstein-Barr virus-related early product induced by halogenated pyrimidines in non-producing human lymphoblastoid cells.

ACTIVATION of a repressed Epstein-Barr virus (EBV) genome in non-producing human lymphoblastoid cells by halogenated pyrimidines has been described1–3. Our immunofluorescence studies3 showed that at least two distinct antigenic products can be induced by 5-bromodeoxyuridine (BUdR) or 5-iodo-deoxyuridine (IUdR) in NC-37 and Raji cells, which represent EBV-related early antigen (EA)4 and viral capsid antigen (VCA)5, respectively. Here we describe the confirmation and further antigenic characterization of such drug induced EA, concerning the early functional expression of the repressed endogenous EBV genome, compared with EA complex6 recently established in experimental abortive EBV infection.

The significance of gastric antibodies.

Chronic inflammatory disease of the acid‐secretory gastric mucosa in man may be associated with the development of circulating antibodies directed against two distinct antigenic components of the gastric parietal cell. The first can be shown by immunofluorescent techniques to be present in the cytoplasm of this cell (Taylor et al, 1962). Immunoabsorption studies suggest that it is present in the microsomal fraction of gastric mucosal extracts and that it may be a lipoprotein (Baur et al, 1965). Immunolocalization using the electron microscope has recently suggested that it may be a component of the micro‐villi of the canalicular system of the parietal cell (Hoedemaeker & Ito, 1970).The other antigen is Castle's intrinsic factor (IF), a protein of mol. wt 55 000, which is produced by the parietal cell in man and some other mammals (Hoedemaeker et al, 1964; Fisher & Taylor, 1969) and which mediates the absorption of vitamin B12 in the distal small intestine.

Immunological investigation on the origin of myosin of skeletal muscle

Rabbit antiserum against chicken myosin was labeled with fluorescein isothiocyanate and found to react strongly with chicken muscle mitochondria and microsomes. The staining could be inhibited by a KCl extract of myofibrils. Particulate fractions of chicken liver and pancreas did not bind the labeled antimyosin. In agar gel diffusion experiments, three distinct antigenic components were shown to be common for myosin, myofibrils, and muscle mitochondria and microsomes of chickens. One of these antigens was also detected in sub-cellular fractions of pancreas and liver, and in blood plasma. The results support the view that myosin, and probably other myofibrillar fractions, are synthesized in the granules of the muscle cell. It is postulated that they are then released and integrated to constitute the myofibril structure.

THE ANTIBODY RESPONSE TO GRAM NEGATIVE ORGANISMS: AN EXPLANATION OF THE DIFFERENCES BETWEEN BACTERIAL AND HEMAGGLUTINATING ANTIBODY TITERS

1. 0 antigens to one strain each of Klebsiella type 55-97, Paracolon 0, Group 3, and S. Choleraesuis produce antibodies in rabbits which can be measured by the following techniques: bacterial agglutination, indirect hemagglutination using red blood cells sensitized with bacterial suspension, bacterial polysaccharide or Seitz filtrate of broth culture of the bacteria, and the hemolytic modificaion of the hemagglutination test using bacterial suspension or polysaccharide sensitized red blood cells as antigen. 2. The highest absolute titers are recorded with bacterial suspension sensitized red blood cells in either the hemagglutination test or the hemolytic modification of this test. Titer differences between paired sera are measured as well by the bacterial agglutination test as by the indirect hemaglutination test. This is true for any of the three bacterial antigens studies. 3. Cross absorption tests with a Klebsiella antiserum and four forms of the homologous antigen indicate that the Klebsiella organism least two antigenic components giving rise to distinct antibodies. 4. Differences in titer between bacterial and hemagglutinating antibodies for Klebsiella are the result of the existence of two distinct antigenic components in the bacteria which are measured separately by each test.

The Serological Types of Shigella Paradysenteriae (Flexner)

Abstract Shigella paradysenteriae Flexner is antigenically heterogenous as has early been recognized by Kruse (1). Of the several attempts to classify the serological variants of the Flexner bacillus, the work of Andrewes and Inman (2) has found the widest recognition, especially throughout the English-speaking world. They distinguished five races and two subraces. This classification was based upon the differentiation of four distinct antigenic components which were termed “primary agglutinogens.” For these, the symbols V, W, X, and Z were introduced. The fifth “race,” termed Y, was thought to be characterized by the presence of a mixture of the four antigens V, W, X, and Z rather than by an antigen of its own. However, it is difficult to understand how Andrewes and Inman came to this conclusion: The experimental documentation of their paper contains good evidence for the existence of an antigen characteristic for all the strains of their Y race; it shows up clearly in their absorptive tests.