Specific immunoglobulin response in mice immunized with porins and challenged with Salmonella typhi

Specific antiporin antibody (IgG, IgM, and IgA) response was studied in control, infected, immunized-infected, and immunized mice. The activity of specific IgG immunoglobulins was found to be the highest in immunized and immunized-infected groups in which 87.5% protection had been observed by laboratory potency test in mice; the next-highest activities were those of IgM and IgA immunoglobulins. However, in the infected group the activity of specific IgM and IgG immunoglobulins was almost similar.     

Analysis of paraprotein transport into the saliva by using anti-idiotype antibodies

To determine the extent of clonal involvement of the secretory immune system and the origin of salivary immunoglobulins (Ig) in monoclonal gammopathy patients, saliva and serum samples were collected from five affected individuals (two IgA myelomas, one IgG myeloma, one IgG benign monoclonal gammopathy, and one IgM lymphoma) and were assayed for the presence of monoclonal Ig. Purified polyclonal or monoclonal anti-idiotype (Id) antibodies were prepared against each of the isolated serum paraproteins. In all five individuals, the patient saliva samples inhibited the binding of 125I-labeled homologous Ig to the corresponding anti-Id antibodies, but normal saliva did not. The concentration of Id in patients' saliva varied from 1 to 400 micrograms/ml; i.e., 0.004 to 1.0% of the corresponding serum values. Saliva of a lymphoma patient whose IgM kappa protein exhibited rheumatoid factor (RF) activity also contained RF. The salivary Id-bearing molecules were found to have the same Ig isotype as the serum paraproteins. The myeloma IgA represented a minor component (0.4 and 3.9%) of the total salivary IgA. The salivary IgA myeloma proteins were associated at least in part with secretory component, but the salivary IgG paraproteins were not. In an IgA myeloma patient, a minority (17%) of the IgA+ plasma cells found in the lacrymal gland biopsy specimen were Id+, whereas the great majority (98%) of bone marrow IgA plasma cells were Id+. The results suggest active transport rather than passive transudation of myeloma IgA into the patients' saliva, and the integrity of the secretory immune system was not compromised by the neoplastic process.     

Bound class M, A and G immunoglobulins in the thymus of myasthenia gravis patients]

Deposits of granular material containing IgM, IgA, and IgG were revealed in the thymus of patients with myasthenia by direct immunofluorescence. Treatment of the thymus sections by unlabeled preparations against individual classes of human immunoglobulins inhibited the reaction of the granular material with the homologous labeled preparations. Disappearance of fluorescence of these deposits was also seen in treatment of the sections with glycine-HCl-buffer, pH 2.8. These data permitted a suggestion that granular material represented immune complexes where IgM, IgA, and IgG served as antibody, and thymus tissue components--as an antigen. The presence of bound immunoglobulin in the thymus indicated that an autoimmune process directed against the tissues of this organ occurred in myasthenia.     

Protein kinase activity of immunoglobulins in human blood plasma

Protein kinase activity of the immunoglobulins (Ig) fractions from blood plasma of clinically healthy humans has been studied. IgA, IgG and IgM preparations have been obtained using column chromatography on sorbents with rabbit antibody to H-chains of human Ig. The level of 32P incorporation in casein in the presence of [gamma-32P]ATP was used to determine protein kinase activity of the Ig-fractions. The protein kinase activity of the preparation of IgA (but not IgG or IgM) was defined. The high-purified preparation of IgA for studing the protein kinase activity has been obtained. Three stages of purifications were used--the separation of plasma proteins by polyethylenglycol 6000, gel-filtration on the column with Toyopearl HW-60 Fine and affinity chromatography on the column containing rabbit antibody to H-chains of human IgA. It was revealed that the fraction of IgA possesses the casein phosphorylation activity. Heparin and trifluoperazine completely and partially inhibited protein kinase activity of IgA while spermidine did not render essential influence. On the basis of the obtained results the conclusion is made that the blood of clinical by healthy humans contains IgA possessing the protein kinase activity.     

Mouse Ig coded by VH families S107 or J606 bind to protein A

Twenty-five monoclonal mouse Ig (5 IgA, 7 IgM, and 13 IgG1) were tested for binding to staphylococcal protein A. They were allowed to attach to protein A Sepharose column at pH 8.0 and were then eluted with a pH gradient from approximately 7.5 to 3.0. Five of them (IgM or IgA) did not bind. Ten came off with pH approximately 6. They were all IgG1, and were probably bound (weakly) via the Fc portion. The remaining 10 (3 IgA, 4 IgM, and 3 IgG1) were more firmly bound; they came off with pH-values ranging from 5.0 to 3.5. They all expressed VH genes of families J606 or S107, whereas all the 15 Ig that were not firmly bound expressed VH genes of six other families. The VL domains seem to be unimportant for protein A binding inasmuch as a firmly binding and a weakly binding IgG1 antibody share identical VK domains. VH sequences of protein A-binding and nonbinding Ig were compared. No likely peptide sequences were found that might make the ligand for protein A.     

Evidence for an IgD homologue on chicken lymphocytes

Chicken lymphocyte membrane immunoglobulins (Ig), were precipitated with mouse monoclonal antibodies specific for heavy and light chain isotypes and analyzed by polyacrylamide gel electrophoresis. Very little or no membrane-bound IgG and IgA was detected. After sequential precipitation and removal of IgM reactive with any of three monoclonal anti-mu antibodies, anti-light chain antibody precipitated residual Ig with a relative electrophoretic mobility similar to that of IgM. Under reducing conditions, these surface Ig molecules had a heavy chain that appeared slightly larger (approximately 81,000 daltons) than mu-chain (approximately 79,000 daltons), and light chains of approximately 25,000 daltons. Complete clearance of membrane-bound IgM reactive with an anti-mu allotype antiserum left similar molecules precipitate by monoclonal anti-light chain antibody. These non-IgM molecules could be detected on the surface of lymphocytes from blood, spleen, bursa and the B cell line RAV-1, but not from thymus or blood from an agammaglobulinemic chicken. After capping of B cell surface IgM with anti-mu, immunofluorescent staining with anti-light chain antibody revealed residual Ig molecules disturbed across the surface of more than 90% of the IgM-bearing cells. The data suggest the existence of an avian homologue of mammalian IgD. Affinity-purified goat anti-mu antibodies and a fourth monoclonal anti-mu antibody reacted with both IgM and the putative IgD molecules, which suggests that the IgD homologue shares at least one common determinant with chicken IgM.     

Biochemical studies on the interaction of fibronectin with Ig

We have previously biochemically characterized three separate sites on the fibronectin (Fn) molecule that interact with IgG. These studies have been extended to examine the interaction of Fn with other classes and subclasses of Ig. By ELISA, a preferential quantitative binding order of Fn to the major Ig classes and subclasses was obtained as follows: IgG greater than IgM greater than IgA, IgG1 greater than IgG3 = IgG4 greater than IgG2, and IgA1 = IgA2. Using fragments of Fn obtained by subtilisin digestion followed by IgM and IgA affinity chromatography, immunoblot analysis using monospecific antisera to separate regions of the Fn molecule, and amino acid sequence analysis, these studies indicate that polyclonal IgA and IgM interact with Fn in the same three regions and under the same ionic conditions as previously described for IgG. Site 1 is a 22-kDa fragment that commences at residue 1 of the Fn molecule. Sites 2 (16 kDa) and 3 (26-29 kDa) begin at residues 588 and 1597, respectively. Under physiological conditions a monoclonal antibody that recognizes site 1 completely inhibited the interaction of intact Fn with IgG, IgM, and IgA. Therefore, this is the only physiologically active site in the intact molecule. Aggregated but not monomeric IgG competitively inhibited the binding of Fn to IgG-coated microtiter ELISA plates; thus, this interaction can take place in a fluid-phase system. These results indicate that Fn can potentially interact with immune complexes and aggregates of all Ig in the circulation and thus may play a significant role in both their clearance and deposition in Fn-containing tissues, such as occurs in immune-complex-related disorders.     

Idiotypic analysis of a B cell clone with anti-intermediate filament specificity in a patient with Sj?gren's syndrome: involvement of five subpopulations producing different immunoglobulin isotypes

An IgM paraprotein from patient LP with Sj?gren's syndrome exhibited an antibody activity to intermediate filaments (IMF) of cells from all vertebrates examined, and appeared to recognize several classes of IMF (i.e., vimentin, desmin, and keratin). A mouse monoclonal anti-idiotype (Id) antibody, K4A, was prepared against the IgMk (LP) and used as a specific probe in two-color immunofluorescence to examine the extent of clonal involvement in the patient's blood and bone marrow mononuclear cells (MNC). Twenty to 30% of MNC in her blood samples were IgMk+ plasmablasts with morphologic similarity to Waldenstr?m's macroglobulinemia cells. IgG+ and IgA+ plasmablasts were demonstrated in lower frequencies (approximately 2%). Almost all of the IgM+ cells and approximately 80% of the IgG+ cells and IgA+ cells in the blood were reactive with the K4A anti-Id antibody. Immunoglobulin (Ig) subclass analysis revealed that the K4A Id was expressed by IgG1+, IgG3+, IgA1+ and IgA2+ plasmablasts. Similar observations were obtained with bone marrow samples, although the proportion of Id+ cells among IgG+ or IgA+ cells was lower in marrow than in blood. IgG and IgA fractions isolated from the patient's serum were also shown to contain anti-IMF activity. Ig biosynthetic analysis of blood MNC revealed that the K4A anti-Id antibody precipitated not only IgM but also IgG and IgA. Because cells simultaneously producing two different Ig isotypes were not detected, these results indicate the presence of five separate subpopulations of the K4A Id+ neoplastic clone. The data thus suggest the occurrence of a neoplastic or pre-neoplastic transformation event before the switching of Ig heavy chain isotypes, and imply a role for the IMF antigen in the exaggerated proliferation and differentiation along five of the nine potential intraclonal pathways.     

Ordering of antibodies, that react with cardiac muscle fiber and interstitial connective tissue antigens, in different immunoglobulin classes

Sera of patients suffering from rheumatic diseases and myocarditis were examined on the sections of human and bovine myocardial tissue by indirect immunofluorescence with the use of pure IgG antibodies or monospecific sera against IgG, IgA and IgM. It was shown that antibodies reacting with different myofibers and interstitial connective tissue of the heart belong to the main immunoglobulin classes (IgG, IgA and IgM). There was a significant predominance of IgG antibodies as shown by the frequency of their detection and by the titer height. The predominance of antibodies to certain classes of immunoglobulins did not correlate with a specific disease entity. The frequency of detecting antibodies to a certain immunoglobulin class was in good agreement with the time of the disease onset. Moreover, the frequency of positive reactions due to IgG, IgA, and IgM antibodies correlated with the level of the appropriate immunoglobulins in the test sera.     

Comparison of two methods for measuring human serum immunoglobulins (laser-nephelometry and radial immunodiffusion)

The AA. have tested 50 serum samples for immunoglobulins (IgG, IgA, IgM) with two different methods: laser-nephelometry (LN) and radial immunodiffusion (RID). Mean values of IgG and IgA are almost the same in the two tested methods and there is a good correlation between LN and RID (IgG: r = 0,98; IgA: = 0,96). Also IgM have showed a good correlation (r = 0,987) but mean values obtained with LN are just a few lower than those obtained with RID. Regression lines, calculated for all the Ig, confirm these conclusions. The AA. conclude affirming that the obtained difference for IgM is due to the different standards used for LN and RID determinations.     

Human IgA and IgG F(ab')2 that bind to staphylococcal protein A belong to the VHIII subgroup

Staphylococcal protein A (SPA) is a bacterial membrane protein that possesses, in addition to its Fc gamma-binding activity, a distinct specificity for the Fab region of some IgM, IgA, IgG, and IgE. The Fab site that binds to SPA has been localized to the V region of the Ig H chain. In a previous study of human monoclonal and polyclonal IgM, we demonstrated that binding to SPA was highly restricted to molecules of the VHIII subgroup, and that nearly all VHIII IgM were able to bind SPA. The present study examines the VH composition of SPA-binding and SPA-nonbinding fractions of purified human polyclonal IgA, and IgG F(ab')2 fragments. We found that 22% of the IgA and 15% of the IgG F(ab')2 bound to SPA-agarose. Analysis with VH subgroup-specific antisera indicated that the SPA-binding fraction of IgA was dominated by the VHIII subgroup, and the SPA-binding fraction of IgG F(ab')2 contained only VHIII molecules. Furthermore, substantial portions of the total VHIII protein in IgA and in IgG F(ab')2 bound to SPA. We conclude that Fab binding to SPA is both restricted to and highly prevalent among human VHIII molecules, regardless of Ig class. These results suggest that protein A is an Ig superantigen.     

Secretory IgA specific for Toxoplasma gondii

Secretory IgA specific for Toxoplasma gondii was identified in intestinal secretions of mice infected perorally with bradyzoites (encysted in brain) of the Me49 strain of T. gondii by using immunofluorescence microscopy and an ELISA. This activity was absorbed with tachyzoites of T. gondii but not mouse brain. To determine whether increased total amount of intestinal IgA might cause a nonspecific reaction in the ELISA for T. gondii-specific IgA, mice were immunized perorally with cholera toxin. This immunization produced intestinal IgA antibody to cholera toxin and increased the total amount of intestinal IgA, but there was no reactivity of intestinal secretions in the ELISA for T. gondii-specific IgA. Experiments in which ELISA were performed with monoclonal IgA, IgG, or IgM and antisera to IgA, IgG, or IgM demonstrated that the ELISA was specific for each Ig class. In addition, monoclonal IgA competed with the anti-Toxoplasma IgA activity of intestinal secretions obtained from mice infected with T. gondii.     

Detection of anti-sperm antibodies on the surface of live spermatozoa by the method of flow cytometry

Detection of antisperm antibodies is an important step of the diagnosis of infertility. In present study we conducted comparative studies with the detection of antisperm antibodies in IgG, IgA and IgM classes on the surface of living spermatozoa by flow cytometry and with Mixed Agglutination Reaction and Sperm immobilization. Our data show that flow cytometry may be used to verify that immunoglobulins are on the surface of living spermatozoa, either retrieved directly from an ejaculate or following exposure to cervical mucus or serum and to determine their isotype, proportion of sperm which bound antibody and quantity of immunoglobulins bound to cell surface.     

Development of monoclonal IgA and an apparent IgG in a patient with macroglobulinemia: sharing of individually specific antigenic determinants among IgM, IgA, and IgG.

Patient CM, who initially was diagnosed as having macroglobulinemia (IgM, kappa) was subsequently found to develop a monoclonal IgA(kappa) protein. Rabbit antisera directed against the patient's IgAm and IgM were rendered specific for individual antigenic (ind) determinants. The anti-IgAm and IgM ind sera reacted with both 131I labeled monoclonal proteins in a double antibody radioimmunoassay (RIA). In addition, both monoclonal immunoglobulins inhibited the reaction between labeled immunoglobulin and both ind antisera, and statistical analysis of the data suggested that the shared ind determinants were identical. The IgG fraction of patient CM's serum also contained a component which competed with both monoclonal IgA (CM) and IgM (CM) in the RIA specific for ind determinants. Analysis of serum samples taken over a 2-year period revealed that, in addition to IgM, both the IgA and IgG components possessing the shared ind determinant(s) were present in low concentrations in the earliest sample, although not detected by conventional techniques. The monoclonal IgA and the IgG component were found to increase in concentration over this time interval with a concomitant decrease in IgM. The regulation of immunoglobulin expression with respect to the proposed models of gene organization in antibody-producing cells was discussed.     

Composition of immunoglobulins in brucellosis patients using DEAE-cellulose column chromatography.

The composition of immunoglobulins in patients with brucellosis was studied. The method of ion-exchange chromatography on DEAE-cellulose columns was used to define more precisely the physico-chemical character of cysteine-resistant antibodies. The study of IgM, IgA and IgG fractions obtained from the patients sera showed the IgG fraction to possess the greatest serological activity in the agglutination reaction, in the passive haemagglutination reaction and in Coomb's test. Specific antibodies in the remaining 2 fractions (IgA and IgM) were found only in single patients in low titres, mainly in Coomb's test (incomplete antibodies). The study of IgM, IgA and IgG serum fractions before and after cysteine treatment revealed cysteine-resistant antibodies to be usually IgG globulins. The presence of specific IgG antibodies in the sera of patients was found to correlate with active clinical manifestations of brucellosis.     

Anaphylactic properties of mouse monoclonal IgG2a antibodies

Mouse monoclonal antibodies (10 hybridoma antibodies specific for soluble antigens, 8 hybridoma antibodies specific for H-2 $\text{K}\text{D}$ antigens, and 9 myeloma immunoglobulins, among which 5 had a known specificity) of the IgG1, IgG2a, IgG2b, IgG3, IgA, and IgM isotypes were studied for their ability to induce mouse mast cell degranulation in vitro, in the presence of specific antigen or after heat aggregation. Monoclonal IgG1 antibodies, as well as IgG2b, IgG3, IgA, and IgM behaved as polyclonal antibodies of corresponding classes: all IgG1 induced mast cell degranulation with typical characteristics of IgG-mediated anaphylactic reactions, whereas IgG2b, IgG3, IgA, and IgM did not. By contrast, 2 hybridoma IgG2a and 3 myeloma IgG2a induced intense mast cell degranulation that could not be explained by a contamination with IgG1 or IgG1-IgG2a hybrid molecules. IgG2a-mediated reactions were observed in four different situations: soluble antigen-hybridoma IgG2a complexes, specific H-2 antigen-bearing mast cells challenged with hybridoma IgG2a anti-H-2, heat-aggregated myeloma IgG2a, and soluble antigen-myeloma IgG2a complexes. The conclusion was reached that mouse mast cells could be activated by mouse monoclonal IgG2a antibodies through a noncytotoxic, complement-independent mechanism involving mast cell Fcγ receptors.     

Release of leukotrienes C4 and B4 and prostaglandin E2 from human monocytes stimulated with aggregated IgG, IgA, and IgE

Purified human peripheral blood monocytes were stimulated with aggregated human myeloma proteins of different classes or the calcium ionophore A23187 and the release of leukotrienes C4 and B4 (LTC4, LTB4), and prostaglandin E2 (PGE2) into the supernatant was determined. The ionophore induced release of 10 +/- 5 ng LTC4/10(6) cells and 25 +/- 8 ng LTB4/10(6) cells. Aggregated IgG, IgA, and IgE, but not IgM or monomeric immunoglobulins (Ig), induced release of LTC4 and LTB4 that was approximately 10 to 20% of that induced by ionophore. In addition, IgG, IgA, and IgE, but not IgM, induced release of PGE2 (range 0.015 to 0.22 ng/10(6) cells). Aggregated Ig induced LTC4, LTB4, and PGE2 release in a dose-dependent manner; maximal leukotriene (LT) release was observed by 30 min, in contrast to PG release, which continued to increase up to 2.5 hr. Both ionophore- and Ig-induced LTC4 and LTB4 release were completely inhibited by removal of calcium from the media and by preincubation of cells with nordihydroguaiaretic acid. Indomethacin inhibited Ig-induced PGE2 release by 80%. Phagocytosis of the Ig aggregates was not required for LT or PGE2 release, since release was not inhibited by cytochalasin B. Release of LTC4, LTB4, and PGE2 induced by IgG, IgA, and IgE, but not IgM, correlated with the presence or absence of monocyte Fc receptors (FcR) as determined by rosette assays. The data suggest that IgG, IgA, and IgE immune complexes mostly likely induce monocyte arachidonic acid metabolism via cross-linking of FcR. The ability of monocytes to release eicosanoids in the absence of phagocytosis suggests that interaction of monocytes with immobilized immune complexes, such as those deposited in blood vessel walls or glomerular basement membranes, could initiate metabolism of arachidonic acid by monocytes. Such a mechanism could contribute to inflammatory reactions characterized by mononuclear cell infiltrates.     

Changes in serum immunoglobulins in subjects with acute myocardial infarct and essential hypertension

20 (12 men and 8 women) acute myocardial infarction (AMI) patients and 17 (14 men and 3 women) patients with arterial hypertension (II degrees stage according to OMS) in comparison to controls age and sex matched, were studied, serum IgA, IgG, IgM were evaluated with radial immunodiffusion and serum IgE with RIA. Ho significant changes ef immunoglobulins were observed between hypertensive patients and controls; whereas a significant increase of IgM, IgG and IgE, with out changes of IgA, were shown in AMI patients. Serum Ig and IgM were significantly augmented in AMI patients in comparison to hypertensive patients.     

CEA-containing immune complexes in sera of patients with colorectal and breast cancer — analysis of complexed immunoglobulin classes

Summary A sandwich enzyme immunoassay was developed to detect circulating immune complexes containing carcinoembryonic antigen (CEA) and immunoglobulin (Ig) G, IgA, or IgM using a nitrocellulose-bound anti-CEA antibody as the solid phase reagent. Elevated levels of CEA-containing circulating immune complexes (CEA-IC) were found in 15.4% of 117 sera from patients with colorectal cancer in a postsurgery follow-up study. Also in 24.5% of 102 sera from patients with breast cancer in different states of disease CEA-IC were found. The predominant Ig determined in CEA-IC of colorectal cancer patients was IgA, followed by IgG and IgM, whereas IgG and IgM were the most frequent Igs in CEA-IC of breast cancer patients. Elevated CEA levels were found in 12.0% of the colorectal cancer patients and in 25.4% of sera from breast cancer patients. No significance for the coincidence of elevated CEA levels and CEA-IC was recorded in all patients sera tested. In sera of patients with disease recurrence, however, both parameters were shown to be elevated (CEA 80.7% and CEA-IC 42.3%). The data presented indicate the detection of CEA-IC as an additional parameter for the identification of patients at increased risk for disease recurrence.     

Shifts in immunoglobulin (IgG,IgM and IgA) levels in the milk of southern elephant seals,at Potter Peninsula,King George Island,Antarctica

We quantified immunoglobulins (Ig) in mammary secretions of 12 female southern elephant seals ( Mirounga leonina) at King George Island, Antarctica, using single radial immunodiffusion on agarose plates. Seals were chemically immobilized for milk sample collection at four time points during the 3- to 4-week suckling period. All three major mammalian immunoglobulins (IgG, IgM, IgA) were detected in southern-elephant seal milk. Total immunoglobulin levels and the ratio of Ig subclasses varied throughout the suckling period. Total immunoglobulin levels were highest on the 1st day of lactation, when they represented over 57% of the mean total protein concentration of the milk, and declined steadily throughout lactation, representing approximately 40% of the mean total protein concentration at the end of the suckling period. IgG was the most abundant immunoglobulin class (85.93-93.78% of total milk immunoglobulins), followed by IgM (6.06-13.93%), and IgA (0.14-0.23%). There was no significant difference in IgA levels throughout the suckling period. IgG levels were significantly lower during the second stage (3-6 days post-parturition) than during the first, third or fourth stages (1, 13-15, and 19-25 days post-parturition, respectively). IgM levels were highest during the first stage of lactation; these values were significantly higher than levels measured during the second, third and fourth stages of lactation. Transfer of passive immunity from female to offspring in other mammalian species is correlated with the subclass of immunoglobulin secreted in the milk; species acquiring passive immunity in utero, via the placenta, secrete a preponderance of IgA, whereas species acquiring immunity post-partum, via lacteal secretions and gut resorption, secrete a preponderance of IgG. The Ig patterns and concentrations observed in our study of southern elephant seals are consistent with an important role of post-partum transmission of passive immunity during the pinniped lactation period.