Antigenic Analysis of Human Trophoblast Membrane: Detection of a Lymphocyte Cross-Reactive Antigen

ABSTRACT: The antigenicity of human syncytiotrophoblast membrane (TM) was analyzed using rabbit antiserum raised against TM. From immunoblot analysis, about ten protein bands in TM were recognized by the anti-TM. These included placental alkaline phosphatase and TM-bound albumin. From limited antigenic specificity studies, these antigens, with the exception of albumin, were not detectable in membranes of liver, kidney, heart, and erythrocyte, or in human normal serum. Therefore, these antigens appear to be placental membrane specific. Analysis of lymphocyte membrane by Immunoelectrophoresis, crossed Immunoelectrophoresis, and immunoblot techniques revealed that a single protein band, designated “40 kDa,” was cross-reactive with the anti-TM antiserum, indicating that this antigen is shared commonly between placenta and lymphocyte membranes. Experimental evidence suggesting that the 40-kDa membrane antigen is probably a unique trophoblast-Iymphocyte cross-reactive antigen is based on the following observations: 1) the 40-kDa antigen was not detectable in liver, heart, and kidney membrane; 2) γ₂-microglobulin (12,000 daltons) was not detectable in our TM preparation; and 3) the lymphocyte membrane showed only a single protein band at 40,000 daltons, not at 12,000 for γ-microglobulin.     

Protein Phosphorylation Pattern and Role of Products of c-erbB-1 and c-abl Proto-oncogenes in Murine Preimplantation Embryonic Development

PROBLEM: To investigate the protein phosphorylation pattern and role of products of c-erbB-1 and c-abl proto-oncogenes with known tyrosine kinase activity in preimplantation embryonic development in mice. METHOD: The protein phosphorylation pattern was studied by in vitro ³²P metabolic labeling of murine ova/embryos as well as by in vitro kinase assay performed directly on various ova/embryos extracts. The role of products of c-erbB-1 (170 kDa, receptor for epidermal growth factor [EGF]) and c-abl proto-oncogenes (150 kDa) was examined by in vitro culturing murine embryos in the presence of monoclonal antibodies to respective protein products and by co-culturing with EGF, the ligand for EGF receptor (EGF-R). RESULTS: In vitro metabolic labeling of murine ova/embryos showed ³²P incorporation into at least two protein bands of murine ova (M_r 81 and 36 kDa), six protein bands of two-cell (M_r 81, 36; and 97, 52, 22 and 19 kDa, respectively), six protein bands of morula (M_r 81, 36; 97, 22, and 19; and 33 kDa, respectively), and eight protein bands of blastocyst (81, 36; 97, 22, 19; and 115, 58, and 15 kDa, respectively), stage embryos; there were some specific bands in each stage. Prolonged labeling from 2 to 4 h not only resulted in a relative increase in ³²P incorporation into these proteins but also revealed additional bands in morula (M_r 133 and 115 kD) and blastocyst (M_r 49, 33, and 31 kD) stage embryos. In vitro kinase assays performed directly on various ova/embryos extracts revealed at least three phosphoproteins (M_r 58, 36 and 33, respectively) that were common to ova, two-cell, morula, and early/late blastocyst stage embryos. Additionally, three protein bands each in murine ova and two-cell embryos (M_r 108, 81, 73 kDa, respectively), and four protein bands of late blastocyst (M_r 108, 73; 133 and 18 kDa, respectively) stage embryos were also revealed. Culture of two-cell embryos in the presence of EGF, the ligand for EGF-receptor, resulted in a concentration dependent increase (P< .001) in the number of cells per blastocyst. Monoclonal antibody to c-erbB-1 170 kDa protein (receptor for EGF) did not affect development of in vitro cultured murine embryos from two-cell to morula, but significantly (P<.001) inhibited the in vitro development of morula to late blastocyst stage. Monoclonal antibody to c-abl protein inhibited the development of murine embryos from two-cell to morula (P<.017), as well as, from morula to late blastocyst stage (P<.002 to .01). CONCLUSIONS: These results suggest that the stage-specific protein phosphorylation pattern and specific products of c-erbB-1 and c-abl proto-oncogenes may have a role in preimplantation embryonic development in mice.     

Identification of carmine allergens among three carmine allergy patients

BACKGROUND: There have been several reports of carmine allergy; however, identification of the responsible carmine allergens has not been widely documented. METHODS: Three female patients presented with a history of anaphylaxis and/or urticaria/angioedema after ingestion of carmine-containing foods. All three patients had 4+ skin prick tests to carmine. Among them, two patients were confirmed to have carmine allergy by blinded, placebo-controlled food challenges to carmine. SDS-PAGE of cochineal insects and carmine, immunoblotting for IgE antibody with sera from all three patients, and immunoblotting inhibition with carmine were performed. RESULTS: SDS PAGE of minced cochineal insects revealed several protein bands of 23-88 kDa. Several of these bands were variably recognized by our three patients' sera, and this reactivity was inhibited by carmine. Although no protein bands could be visualized on SDS-PAGE of carmine in Coomassie brilliant blue staining, three protein bands were recognized by two of the three patients' serum. CONCLUSIONS: These results suggest that commercial carmine retains protein-aceous material from the source insects. These insect-derived proteins (possibly complexed with carminic acid) are responsible for IgE-mediated carmine allergy. Patient reactivity to these proteins may vary.     

Differentiation of the epidermis in turtle: an immunocytochemical, autoradiographic and electrophoretic analysis

Proteins involved in the process of cornification of turtle epidermis are not well known. The present immunocytochemical, electrophoretic and autoradiographic study reports on the localization patterns and molecular weights of keratins, which are cornification proteins, and of tritiated histidine in turtle epidermis. Alpha-keratins with a molecular weight of 40-62 kDa are present in the epidermis. Beta-keratin is mainly detectable in the stratum corneum of the carapace and plastron, but is rarely present or even absent in the corneous layer of limb, tail and neck epidermis. After electrophoresis and immunoblotting with an antibody against chicken scale beta-keratin, bands at 15-17, 22-24, and 36-38 kDa appeared. This antibody recognized weaker bands at 38-40 and 58-60 kDa in the soft epidermis. After reduction and carboxymethylation of proteins extracted from carapace and plastron, but not of proteins from the soft epidermis, protein bands at 15-17 and 35-37 kDa were found when using the anti-beta 1-keratin antibody. Loricrin-, filaggrin-, sciellin-, and transglutaminase-like immunostaining was detectable only in the transitional and lowermost corneous layers of the soft epidermis. Vesicular bodies in the transitional layer were immunolabeled by the anti-loricrin antibody, and weakly by the anti-filaggrin and anti-transglutaminase antibodies. In immunoblots, the anti-loricrin antibody reacted with a major band at 50-54 kDa in both carapace-plastron and soft epidermis. The anti-sciellin antibody detected major bands at 38-40 and 50 kDa in hard epidermis, and at 50 and 54-56 kDa in soft epidermis. Filaggrin-like immunostained bands were observed at 50-55 and 62-64 kDa. This immunostaining was probably due to a common epitope in filaggrin and some keratins. Histidine was evenly incorporated in the epidermis, and the ultrastructural study showed random labeling, often associated with keratin bundles of alpha and beta-keratinocytes. Histidine-labeled protein bands were not found in the carapace-plastron. In the soft epidermis, weakly labeled bands at 15-20, 25, and 45-60 kDa were found occasionally. The latter bands probably represented neo-synthesized keratins as was also indicated by the ultrastructural autoradiographic analysis. In conclusion, our study suggests that proteins with epitopes that they have in common with cornification proteins of mammalian epidermis are also present in the epidermis of turtle.     

Characterization of Anti-Mesangial Cell Antibodies and Their Target Antigens in Patients with Lupus Nephritis

The pathogenetic mechanisms of lupus nephritis (LN) remain to be elucidated. In our previous study, autoantibodies against human glomerular mesangial cells (HMC) were identified in sera of most patients with lupus nephritis. The current study is to investigate the binding characteristics of anti-mesangial cell antibodies to human mesangial cell membrane. Serum samples were collected from 54 patients with renal biopsy proven lupus nephritis, 12 patients with systemic lupus erythematosus without clinical renal involvement, and 15 healthy subjects. Membrane proteins were obtained from in vitro cultured HMC by sonication and sequential centrifugation. DNase I were employed to remove DNA fragments in sera and membrane protein preperation and IgG F(ab′)₂ was obtained by pepsin digestion. Western Blot analysis was used to characterize the antibody and antigen interaction. In results, 25 of 54 (46.3%) sera from patients with lupus nephritis had anti-mesangial cell antibodies targeted at 74 kDa, 63 kDa, 52 kDa and 42 kDa protein bands of HMC membrane. Only four of 12 (33.3%) sera from patients without renal involovement recognized the protein bands at 74 kDa and 63 kDa, but not 52 kDa and 42 kDa. DNase treatment of the HMC membrane and the sera did not affect the binding. IgG F(ab′)₂ from sera of 10 patients with positive anti-mesangial cell antibodies could still bind the 63 kDa protein. In conclusion, anti-mesangial cell antibodies from sera of patients with lupus nephritis could bind membrane proteins of HMC directly without a DNA bridge and the binding was through antigen–antibody interation. Anti-mesangial cell antibodies might play some role in the pathogenesis of lupus nephritis(LN).     

Monoclonal antibody stains oligodendrocytes and Schwann cells in zebrafish (Danio rerio)

We prepared a monoclonal antibody that recognizes oligodendrocytes and Schwann cells in zebrafish. On immunoblots, the antibody mainly recognized three protein bands of 34 kDa in a membrane fraction from adult zebrafish brain. Medaka fish (Oryzias latipes) also possessed the same protein bands in a membrane fraction. The antibody did not stain neurons, but stained cells in fiber tracts and cranial and spinal nerves. In order to determine the nature of these cells, the staining pattern of the monoclonal antibody was compared with that of a myelin basic protein antiserum. Both antibodies stained oligodendrocytes and Schwann cells in fixed sections from the adult zebrafish. Both antigens were also co-localized in cultured glial cells. Taken together, these results indicate that the new monoclonal antibody recognizes myelinating glial cells in zebrafish and will be useful for the analysis of piscine glia. Accepted: 18 October 1999     

Biosynthesis and secretion of enamel proteins in the rat incisor

The synthesis and secretion of enamel proteins (EPs) in rat incisors was examined using cytochemical and biochemical methods. Radioautography after injection of 3H-methionine showed that ameloblasts in the presecretory, secretory, and maturation stages of amelogenesis actively synthesized and secreted proteins. Immunocytochemistry with an antibody to mouse amelogenins revealed the presence of EPs in the protein synthetic and secretory organelles of these cells at all three stages. Labeling was also found in elements of the endosomal/lysosomal compartment. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining of proteins extracted from enamel and enamel organ showed several protein bands. However, transfer to nitrocellulose paper and immunoblotting revealed that most of the proteins recognized by the antibody were situated between approximately 14 and 32 kDa. EPs were further characterized by using lectins to examine their carbohydrate content. Lectin-gold cytochemistry on sections showed the binding of wheat germ agglutinin and Helix pomatia lectin to secretory stage enamel. Lectin blotting indicated that the amelogenins were heterogeneously glycosylated and contained the sugars N-acetyl-glucosamine/N-acetyl-neuraminic acid and N-acetyl-D-galactosamine. Fluorography at 6 and 10 min and 1 h after injection of 35S-methionine revealed four labeled bands in the main amelogenin group near 22, 28, 30, and 32 kDa. A short-lived protein of approximately 58 kDa was also observed primarily in cells. The appearance of labeled proteins in enamel was paralleled by their disappearance from cells and the intensity of the radiolabeled protein bands, both, in enamel and in cells, decreased towards the maturation stage. These data are consistent with the concept that ameloblasts produce multiple amelogenins throughout amelogenesis.     

Serodiagnosis of Lyme borreliosis by western immunoblot: reactivity of various significant antibodies against Borrelia burgdorferi.

The significance of various antibodies against Borrelia burgdorferi was studied by Western blot (immunoblot) by using 578 human serum samples. The proteins regularly detected by using samples from patients with Lyme borreliosis were those with bands with molecular masses of 94, 83, 75, 66, 60, 55, 46, 41, 39, 34, 31, 29, 22, and 17 kDa. The detectable frequencies of most of these proteins appeared to be significantly different between the sera from patients with Lyme borreliosis and those from normal control individuals as well as from the group with syphilis. The 39-kDa protein band recognized by polyvalent antibody was found to be the most significant marker for Lyme borreliosis. Furthermore, an anti-39-kDa immunoglobulin M response was detected in the samples from patients with early-stage Lyme borreliosis. Results from the use of monoclonal antibodies and patient sera revealed that the 39- and 41-kDa proteins may be structurally related but are immunologically distinct antigens. The significance of antibody reactivities to the 41-, 94-, 22-, 31-, and 34-kDa protein bands is also discussed.     

A recombinant surface protein of Babesia bovis elicits bovine antibodies that react with live merozoites

Ten monoclonal antibodies (MoAbs) were generated against five surface-exposed proteins (16 kDa, 42 kDa, 44 kDa, 60 kDa, 225 kDa) on merozoites of Babesia bovis. A genomic library constructed in the lambda gt11 expression vector was screened with MoAbs in a plaque immunoassay for identification of clones expressing recombinant surface proteins. Two recombinant clones were identified (lambda Bo44-15 and lambda Bo44-16) that encoded a protein recognized by a MoAb specific for an epitope on the native 44-kDa surface protein. Southern blot analysis using radiolabeled Bo44-15 DNA (1.25 kb) against merozoite DNA and bovine leukocyte DNA confirmed the parasite-specificity of the cloned insert and revealed multiple bands of hybridization with merozoite DNA. Western blot analyses of lambda Bo44-15 lysogen preparations demonstrated that recombinant protein production in this clone was IPTG-induced and that the recombinant molecule was a beta-galactosidase fusion protein. Additionally, recombinant 44-kDa protein, purified by immunoaffinity chromatography, reacted with specific MoAb in Western blot assay indicating that the integrity of the epitope was retained during purification. Immune sera from calves immunized with purified recombinant Bo44-15 protein immunoprecipitated metabolically radiolabeled merozoite protein of 44 kDa indicating that antibody induced by recombinant Bo44-15 protein recognized native 44-kDa protein. Also, these sera reacted with the surface of live merozoites as evidenced by indirect immunofluorescence assay. Serum antibody titers determined by this assay had a wide range.     

Serum antibody response to the superficial and released components of Helicobacter pylori.

Superficial and released components were extracted from six selected Helicobacter pylori strains. The protein and antigenic profiles of these extracts were representative of the profiles found most frequently among the clinical strains and included major peptidic fractions at 19, 23.5, 57, 68, 76, 118, and 132 kDa and major antigens at 68, 57, and 23.5 kDa. Immuno-cross-reactions were seen with a hyperimmune rabbit serum to Campylobacter fetus but not with sera to Campylobacter jejuni or Salmonella spp. An antigenic preparation was obtained by pooling equivalent quantities of each extract, and the antigenic preparation was used to study the antibody responses of sera from 65 French patients and 127 Tunisian patients. By enzyme-linked immunosorbent assay, we observed that the sera from French and Tunisian patients clustered into two populations, defined as antibody positive (72 patients) and antibody negative (120 patients). The antibody-positive patients were more frequently infected with H. pylori (P < 0.01) and were more frequently affected with gastritis (P = 0.05). However, no correlation between antibody levels and clinical signs of dyspepsia was noticed. The proportions of antibody-positive patients were similar in France and Tunisia. Antibody-positive and antibody-negative sera were studied by western blot (immunoblot) analysis. The antibody-positive sera revealed an average of 7.7 antigenic bands, whereas the antibody-negative sera revealed an average of 2.4 antigenic bands (P < 0.01). The antigens between 15 and 40 kDa and greater than 66 kDa were specifically recognized by the antibody-positive sera, although in this molecular size range the antibody profiles of these sera exhibited a fairly high degree of diversity. We conclude that the superficial and released components from H. pylori contain a variety of bacterial immunogens and may be useful in antigenic preparations for the serodiagnosis of H. pylori infections. Moreover, a group of antigens in combination appears to be useful for discriminating antibody-positive and antibody-negative patients.     

日本血吸虫成虫及虫卵可溶性抗原的早期诊断分子筛选

为获取有效的日本血吸虫病早期诊断靶抗原分子。以感染前和感染后2周、4周、6周兔混合血清以及急性、慢性日本血吸虫病人和正常人血清,用Westernblot对日本血吸虫成虫可溶性抗原(AWA)和虫卵可溶性抗原(SEA)进行了全面的分析与筛选。SEA140kDa和AWA54kDa、21kDa、20kDa分子出现最早,能被感染后2周兔血清所识别;SEA69kDa、50kDa、45kDa、38kDa和AWA72kDa、45kDa、34kDa、15kDa相继能被感染后4周兔血清所识别;其中SEA140kDa、50kDa、45kDa、38kDa和AWA34kDa、21kDa、54kDa、15kDa与病人血清反应同6周兔血清反应效果相仿,均为免疫反应主带,且在SDS-PAGE上有对应的蛋白主带,具有潜在的早期诊断价值。进一步对SEA进行抗体类型的分析,发现SEA能刺激机体产生IgG、IgM和IgA反应,其中SEA50kDa、45kDa、38kDa三个抗原分子均能被IgG、IgM、IgA三种抗体所识别,且均为反应主带;SEA140kDa以IgM反应带最深;SEA100kDa反应带仅出现于病人血清,以IgM反应最强,且其与IgM反应带在急性病人血清明显深于慢性病人血清,表明针对IgM的SEA100kDa分子也具有一定的早期诊断和区分病程的价值。SEA140kDa、50kDa、45kDa、38kDa和AWA34kDa、21kDa、54kDa、15kDa和针对IgM的SEA100kDa分子是具有潜在早期诊断价值的优势靶抗原分子。     

Partial characterization of two serologically related DNA-binding proteins specified by the cottontail rabbit herpesvirus CTHV

Summary We have previously described two serologically related DNA-binding phosphoproteins of different apparent molecular mass (75 kDa and 35 kDa) produced in cottontail rabbit herpesvirus (CTHV)-infected cells. The 75 kDa protein appeared before the 35 kDa protein in the infectious cycle. Here, we extend the characterization of these proteins. Protease V8 fingerprints of methionine-labelled 35 kDa protein showed four major peptide products, three of which comigrated with major peptides from digests of the 75 kDa protein. The fourth peptide, with an estimated mass of 10 kDa, reacted with an antiserum recognizing both proteins. In vitro translation of total or poly A-containing RNA isolated from infected cells at 24 h to 72 h post-infection produced only the 75 kDa protein as measured by immunoprecipitation with anti-75/35 kDa serum, suggesting that the 35 kDa protein is derived from the 75 kDa protein by proteolytic cleavage. Virus-specific RNA obtained by prehybridization to CTHV DNA also produced the 75 kDA protein, confirming its viral origin. The putative gene for the 75 kDa protein was localized to a region on the CTHV DNA restricted byPvuII.     

Matrix metalloproteinases activity demonstrated in the infective stage of the nematodes, Angiostrongylus cantonensis

Ingestion of the larval nematode Angiostrongylus cantonensis can cause the human eosinophilic meningitis known as angiostrongyliasis. Analysis of the extracts and excretory-secretory (ES) products of A. cantonensis larvae and adult stages on gelatin substrate zymography demonstrated the presence of distinct gelatinolytic enzymes. In worm extracts, inhibitor studies showed that the metalloproteinases revealed in L₁ (23 kDa), L₃ (66, 42 and 30 kDa), young adult worm (72 and 94 kDa) and adult worm (72 and 94 kDa). In ES products, the L₁ revealed one low (42 kDa) and two high (105 and 94 kDa) molecular weight proteolytic bands that degraded gelatin in substrate gels. The L₃ revealed three low (66, 50, and 30 kDa) and one high (105 kDa) molecular weight proteolytic bands. Inhibitor studies confirmed that the 105 and 94 proteolytic bands of the L₁, and the 50 and 30 kDa proteolytic bands of the L₃ classification were metalloproteinases. These metalloproteinases secreted in the infective larvae may be associated with the parasite dissemination or pathogenesis.     

MHC- and non-MHC-encoded surface antigens of chicken lymphoid cells and erythrocytes recognized by polyclonal xeno-, allo- and monoclonal antibodies

Surface antigens on chicken thymus and bursa cells were analyzed by immunoprecipitation using polyclonal and monoclonal antisera raised against (and specific for) thymus (ATS) or bursa (ABS) cells, respectively. The antigens identified were compared with those governed by the B-F, B-L and B-G regions of the chicken major histocompatibility complex (B complex). Four proteins were precipitated from thymus cells by 2 polyclonal ATS: both antisera recognized molecules of apparent molecular mass of 172–182, 132–135, 75–76 kDa, and one antiserum in addition recognized a protein of 102 kDa. The 172–182 and 102-kDa peaks were still demonstrable under reducing conditions indicating that they are composed of a single polypeptide chain, the other 2 were lost under reducing conditions, therefore, must be composed of smaller subunits. Of the 2 monoclonal ATS tested, one identified a single protein of 186 kDa and the other a 135-kDa protein (in addition to 2 smaller molecules); whether these are the same as those precipitated by the polyclonal antisera remains to be determined as they behaved differently under reducing conditions. Proteins of 162 and 78–84 kDa were revealed by 2 polyclonal ABS under nonreducing conditions but the former may in one case be a polymer (it disappeared under reducing conditions) and in the other a single molecule. In addition molecules of 182 kDa were identified by one antiserum and of 84 and 60 kDa by the other under nonreducing conditions. Of the 4 monoclonal ABS only one identified a 200-kDa protein: molecules of 115–125, 90–100, 48–52 and 40–43 kDa were also precipitated, all of which were reduced to smaller molecules. With 2 specific anti-B-F alloantisera we were able to precipitate the “conventional” B-F antigen from red blood cell lysates of CB-strain chickens resolving into a 40-kDa peak and a light chain of about 12 kDa corresponding to β₂ microglobulin. Precipitates from peripheral blood lymphocytes, bursa and thymus cells revealed an additional protein of 22 kDa. With 2 specific B-L alloantisera two peaks of 33 kDa and 31 kDa were obtained from peripheral blood lymphocytes. Using anti-B-G alloantisera a double band corresponding to 47 and 42 kDa was seen under reducing conditions. There is no evidence from these data to indicate that the polyclonal and monoclonal antibodies are directed towards major histocompatibility complex antigens.     

A western blot characterization of Mycobacterium bovis antigens recognized by cattle sera

The immune response to Mycobacterium bovis in cattle was assessed by Western blot. The antibody recognition pattern to M. bovis whole cell extracts and culture supernatant antigens was studied by using sera from M. bovis-infected (n=62) and healthy (n=38) cattle. Although the recognition patterns were highly variable, some proteins were regularly detected, mainly those with molecular masses of 17, 23, 28, 42, 66, 71 and 80 kDa in cellular extracts, and with molecular masses of 23 and 33 kDa in supernatants. Whole cell extract antigens were more frequently recognized than culture supernatant antigens. Healthy controls produced only a week antibody response.The antibody response was variable, depending on tuberculosis stage. In early stages very few antibodies were detected. A response against the 66-kDa stress protein was mounted in intermediate tuberculosis and remained stable in more advanced disease. In late diseases, the preferentially recognized antigens were a 28-kDa cellular protein and supernatant antigens.The 28-kDa protein was studied in some detail. As determined by using monoclonal antibodies, the 28-kDa protein is different from superoxide dismutase. This protein aggregated in stored cell extracts and was not totally transferred to nitrocellulose.The principal conclusions of this work are: (i) whole cell extract proteins are more frequently recognized than the secreted proteins and (ii) a 28-kDa protein is a major antigen in late disease.     

Bovine helper T cell clones recognize five distinct epitopes on Babesia bovis merozoite antigens.

Helper T cell clones from two Babesia bovis-immune cattle were characterized for use in identification of potentially protective immunogens of B. bovis merozoites. Proliferation assays with 11 CD4+ clones revealed a differential pattern of response to soluble cytosolic antigen, membrane-enriched antigen, detergent extracts of the membrane-enriched antigen, soluble culture supernatant exoantigen, and different geographical isolates of B. bovis as well as Babesia bigemina parasites. When the data were combined, the clones could be grouped according to five different patterns of response. One group recognized only the membrane-enriched fraction of New World and Australian parasites. Four remaining groups recognized antigens found in the cytosolic as well as the membrane-enriched fraction, and clones representative of each group were used to identify cytosolic antigens fractionated by anion-exchange chromatography with the use of fast-performance liquid chromatography. One clone (C97.3C3), which responded to all B. bovis isolates and to B. bigemina, recognized a single peak of activity that eluted with 0.25 M NaCl and contained protein bands of 70 and 75 kDa. The remaining clones were stimulated by a second antigenic peak that eluted between 0.35 and 0.45 M NaCl and contained protein bands of 42, 47, 56, and 84 kDa. The majority of the clones produced interferon, whereas tumor necrosis factor alpha/tumor necrosis factor beta production was less frequent. These studies provide the basis for using helper T cell clones to identify potentially protective immunogens of B. bovis and delineate a minimum of five helper T cell epitopes recognized by two immune cattle.     

Hypersensitivity to Forcipomyia taiwana (biting midge): clinical analysis and identification of major For t 1, For t 2 and For t 3 allergens

BACKGROUND: Forcipomyia taiwana is a tiny, blood-sucking midge that cause intense pruritis and swelling in sensitive individuals. It is distributed island-wide in rural Taiwan and Southern China. Objective: This study aimed to study the allergic immune responses and identify F. taiwana allergens. METHODS: Crude whole body F. taiwana extracts were prepared with phosphate-buffered saline. The specific IgE antibody was determined by enzyme-linked immunoassay and immunoblotting. Protein was analyzed by electrospray ionization tandem mass spectrometry. RESULTS: Among the 372 subjects that were exposed to F. taiwana bites, 179 (48%) reported an immediate skin reaction with/without delay reaction and 41(11.1%) reported a solely delay reaction. The skin of 21 subjects was tested with F. taiwana extract. Of these 21 subjects, 12 (57.1%) produced immediate skin reactions and contained high levels of specific IgE antibody against F. taiwana. Immunoblotting revealed that 11 allergenic components are able to bind specific IgE. Allergens of 22, 24, 35, 36, and 64 kDa bound 50, 50, 75, 66.7, and 75% of IgE-containing sera tested, respectively. Tryptic fragments of the 24, 35, 36, and 64 kDa allergens were analyzed by ESI-MS/MS. Selected tryptic peptides of 24, 35, and 36, and 64 kDa allergens exhibited significant sequence identity with triosephosphate isomerase of Anopheles merus,Tenebrio molitor,Ochlerotatus togoi, and Chrysops vittatus, fructose 1,6-bisphosphate aldolase of Antheraea yamamai and Homalodisca coagulata, and a slow muscle myosin S1 heavy chain of Homarusamericanus and a protein with unknown function from A. gambiae, respectively. The 35 and 36 kDa proteins may represent different isoforms of the fructose 1,6-bisphosphate aldolase. CONCLUSION: We conclude that immediate reaction to F. taiwana bites is IgE mediated and the 24 (For t 1), 35 (For t 2), and 64 kDa (For t 3) proteins are candidates for major F. taiwana allergens. Further studies are needed to confirm these allergens.     

Changes of sialomolecules during the dimethylsulfoxide-induced differentiation of Herpetomonas samuelpessoai

The expression of sialoglycoconjugates during the dimethylsulfoxide (DMSO)-induced differentiation of Herpetomonas samuelpessoai was analyzed by flow cytometry and Western blotting using sialic acid-specific lectins. Parasites reacted strongly with Limax flavus (LFA) and Sambucus nigra (SNA) agglutinins, and only weakly with Maackia amurensis (MAA) lectin. However, analysis of crude protein extracts by Western blotting revealed that bands with molecular masses corresponding to 15 and 40 kDa are recognized by MAA, and that treatment with DMSO induced the expression of two additional polypeptides with molecular masses of 65 and 90 kDa. Profiles of binding to LFA were indistinguishable when protein extracts from control or differentiated cells were analyzed. SNA recognized a major molecule with 25 kDa in extracts from non-differentiated forms and two low-molecular-weight bands from differentiated cells. These results indicate that molecules containing alpha2,6 and alpha2,3 sialyl-galactosyl sequences are present in H. samuelpessoai, and that their biosynthesis and expression are influenced by DMSO-induced differentiation.     

Monospecific antibodies to Marek's disease virus antigen B dimer (200 kDa) and monomer (130 and 60 kDa) glycoproteins neutralize virus infectivity and detect the antigen B proteins in infected cell membranes

Summary Monospecific antibodies were prepared by nitrocellulose blot immunoaffinity to 3 polypeptide components of the host-membrane associated B antigen of Marek's disease herpesvirus (MDV) and to its soluble A antigen. The B antigen comprised a 200 kDa dimer which is 2-mercaptoethanol (2-ME) labile, a monomer of 130 kDa and a 60 kDa protein, both of which are 2-ME resistant. Cross-immunoblotting studies showed that the anti-dimer antibody recognized the dimer protein as well as the 130 and 60 kDa components. In contrast, the anti-130 kDa antibody gave the strongest signal on blots of reducing gels indicating that the monomer is largely formed by in vitro reduction with 2-ME. All four antibodies recognized membrane antigens on chicken embryo fibroblasts infected with MDV vaccine viruses representative of the three serotypes and in addition, neutralized the homologous MDV isolate. The anti-dimer antibody was greatest, the anti-monomer antibody was the weakest and the anti-60 kDa antibody intermediate in neutralizing efficacy to all four viruses. We conclude from these studies that the B antigen presents at least two classes of neutralizing epitopes: one is discontinuous and of broad specificity on the intact dimer molecule and the other, on the 130 and 60 kDa proteins, is continuous and of lower avidity.