A comparison of bovine lymphocyte antigens

In Canberra, 31 antigens have been described on the surface of bovine lymphocytes. Seven antigens are subgroups of other antigens. Eleven antigens are similar to the eleven antigens which have been described in Melbourne. Fourteen antigens are similar to twelve international-workshop antigens and two European-workshop antigens.     

A comparison of bovine lymphocyte antigens

In Canberra, 31 antigens have been described on the surface of bovine lymphocytes. Seven antigens are subgroups of other antigens. Eleven antigens are similar to the eleven antigens which have been described in Melbourne. Fourteen antigens are similar to twelve international-workshop antigens and two European-workshop antigens.     

Ontogeny of human Ia antigens

Indirect immunofluorescence (IIP) staining of tissues from human fetuses (ages ranging from 8 to 32 weeks of intrauterine life) with monoclonal antibodies (MoAb) to monomorphic determinants of Ia antigens and HLA-A,B,C antigens has shown that both types of antigens are already detectable in tissues of 8-week-old fetuses. Ia antigens and HLA-A,B,C antigens reach their almost-complete tissue distribution after 32 and 24 weeks of intrauterine life, respectively. The structure of Ia antigens synthesized by fetal thymus cells is similar to that of B-lymphoid cell-derived Ia antigens. Ia antigen-bearing thymic fetal cells can stimulate allogeneic lymphocytes in mixed lymphocyte reactions (MLRs). These reactions are blocked by monoclonal antibodies to monomorphic determinants of human Ia antigens and of HLA-A,B, antigens.     

Alternative antigens reduce cross-reactions in an ELISA for the detection of Salmonella enteritidis in poultry

Two alternative antigens for the use in detection of antibodies to salmonellas were investigated: firstly, lipopolysaccharide (LPS) from members of the D2 group, having antigens O : 9, 46, and flagella antigens. Whereas LPS from the D2 group did not discriminate sufficiently with control sera, flagella antigens reacted specifically with antibodies directed to serotype specific H antigens. When flagella antigens were used to screen sera from birds of commercial flocks, however, cross-reactivity between flagella antigens was observed. When both LPS and flagella antigens were used to screen sera from chickens infected with Salmonella, enteritidis, the sera gave higher titres with flagella antigens during the early stages of infection, and titres with flagella antigens dropped earlier after infection had ended than titres with lipopolysaccharide.     

Immunodiffusion analysis of water-soluble rat bone marrow antigens

Antisera were obtained against six electrophoretic fractions of the rat bone marrow extract. With their help, 18 tissular antigens and 11 antigens immunologically similar to the blood serum proteins were revealed in the rat bone marrow. All tissular antigens are divided in five groups by the degree of organ specificity: 1) bone marrow organospecific antigens (4 antigens), 2) antigens present in the bone marrow, spleen and lung extracts (2), 3) "granulocytic" antigens (4), 4) antigens common for many rat organs, but not found in the extracts of blood formed elements, skeletal muscle, heart, brain, eyes (3), 5) antigens present in all the organs studied (5). The bone marrow organospecific antigens may be specific antigens of hemopoietic cell precursors. The possibility of utilization of antisera against the bone marrow water soluble proteins for labelling hemopoietic cells of different lines of differentiation is discussed.     

The reverse proteomics for identification of tumor antigens

The identification of tumor antigens is essential for the development of anticancer therapeutic vaccines and clinical diagnosis of cancer. SEREX (serological analysis of recombinant cDNA expression libraries) has been used to identify such tumor antigens by screening sera of patients with cDNA expression libraries. SEREX-defined antigens provide markers for the diagnosis of cancers. Potential diagnostic values of these SEREX-defined antigens have been evaluated. SEREX is also a powerful method for the development of anticancer therapeutics. The development of anticancer vaccines requires that tumor antigens can elicit antigen-specific antibodies or T lymphocytes. More than 2000 antigens have been discovered by SEREX. Peptides derived from some of these antigens have been evaluated in clinical trials. This review provides information on the application of SEREX for identification of tumor-associated antigens (TAA) for the development of cancer diagnostics and anticancer therapeutics.     

Partial characterization of Ia antigens from murine lymphoid cells

Congenic anti-Ia antisera were used to bind radiolabelled Ia antigens from cells of various strains of mice of knownH-2 haplotype. The results indicate that Ia antigens are proteins of molecular weight 30,000 to 35,000 daltons. The Ia antigens are distinct from known H-2 antigens as judged by independent immunoprecipitation as well as by molecular weight. Ia antigens are synthesized by, and are present on the surface of lymphoid cells as evidenced by incorporation studies using³H-leucine and enzymatic radioiodination of cells, respectively. Tissue distribution of cell surface Ia suggests that Ia antigens are on B cells. Ia antigens were detected in the incubation media of³H-leucine labeled splenocytes suggesting that antigens may be secreted.     

Partial purification and characterization of mold antigens commonly found in foods.

Rapid methods are needed for detection of molds in foods; therefore, an enzyme-linked immunosorbent assay was developed. The extracellular and mycelial antigens for Mucor, Aspergillus, Cladosporium, and Geotrichum species were partially purified and characterized. The molecular masses of the mycelial and extracellular antigens, as determined by size exclusion chromatography, ranged from 4.5 x 10(5) to 6.7 x 10(5) Da. There was only one main antigenic peak separated by Sepharose CL-4B and concanavalin A-Sepharose columns for Mucor, Cladosporium, and Geotrichum mycelial and extracellular antigens, but there were two for Aspergillus mycelial antigens and three for Aspergillus extracellular antigens. These antigens contained 10 to 50% protein which was part of the active site since protease digestion significantly decreased antigenic activity. Neutral sugars, ranging from 13 to 75%, made up the rest of the active site, and < 1% phosphate was detected in mycelial antigens. Geotrichum, Cladosporium, and Aspergillus antigens contained mainly glucose, galactose, and mannose. Mucor antigens contained these sugars plus fucose. The percentage of sugars differed between the mycelia and extracellular antigens. Enzymatic digestion and competitive inhibition tests using different sugar derivatives showed that galactosyl residues with beta linkages were immunodominant for Aspergillus, Geotrichum, and Cladosporium antigens and mannosyl residues with alpha linkages were immunodominant for Mucor antigens.     

Independence of H-2 and viral antigens on the cell surface and absence of H-2 antigens on murine leukemia virus and mouse mammary tumor virus particles

By indirect immunoelectron microscopy we tested for the presence of H-2 antigens on murine mammary tumor virus (MMTV) and murine leukemia virus (MuLV) particles. The association of H-2 antigens and viral antigens on the virus-infected cell surface was investigated with antibody-induced redistribution. Mammary tumor cells and leukemia cell lines with different H-2 genotypes and carrying different MuMTV or MuLV were used. No H-2 antigens could be demonstrated on the envelope of MMTV and MuLV particles, even after the permeabilization of their envelopes with saponin. On the surface of virus-infected cells antibody-induced patching or capping of the viral antigens did not result in copatching or cocapping of the H-2 antigens. In the reciprocal tests no co-redistribution of viral antigens with H-2 antigens was seen. Our experiments failed to show any physical association between H-2 antigens and MMTV or MuLV antigens on the cell surface.Abbreviations used in this paper MMTV mammary tumor virus - MuLV murine leukemia virus - MHC major histocompatibility complex - IEM immunelectron microscopy     

Association of mouse adenovirus-induced cell surface antigen(s) with histocompatibility antigens

The topological relationship on the mouse adenovirus (M-Ad)-infected cell surface between virus-induced specific cell surface(s) antigens and serologically defined major histocompatibility antigens (H-2) was analyzed by the cap formation technique. Rhodamine-isothiocyanate (RITC)-labeled anti-S serum failed to stain the surface of virus-infected lymphoid cells which were pretreated with anti-H-2 serum and fluorescein isothiocyanate (FITC)-labeled anti-mouse immunoglobulin serum (anti-M-Ig) to cap the appropriate H-2 antigens. Conversely, the capping of the S antigens by pretreatment with anti-S followed by FITC anti-M-Ig serum induced cocapping of H-2 antigens. The β₂ microglobulins (β₂m) were also shown to be cocapped with S antigens by anti-β₂m or by anti-S serum. The S antigens, however, did not cocap with mouse-immunoglobulins or Thyl. 2 antigens on virus-infected B or T lymphocytes, respectively. To further elucidate the molecular relationship between S and H-2 antigens, radio-iodinated virus-infected cells were solubilized with Nonidet P40 (NP40) and S antigens were precipitated with anti-S serum. When the precipitates were analysed with sodium dodecyl sulfate Polyacrylamide gel electrophoresis, two major peaks were seen at positions of molecules of about 45,000 and 12,000 daltons both of which corresponded with molecules which were observed when NP40 extracts of virus-infected or uninfected cells were precipitated with anti-H-2 serum. Sequential immunoprecipitation analysis of infected cell extracts showed that S antigens were coprecipitated with either H-2K or H-2D antigens. These results suggest that the S antigens are somehow associated with H-2K or H-2D antigens separately.     

Water-soluble proteins in early amphibian embryos. III. Immunoelectrophoretic analysis of the antigenic changes in the ectoderm of the early gastrula and neural plate during development

20 water-soluble antigen have been identified with the help of rabbit antisera to extracts of the early gastrula ectoderm and neural plate in Rana temporaria. All of them were also found in the early blastula embryos and unfertilized eggs. The identified antigens are characterized by a definite embryospecificity. As the development proceeds, the concentration of these antigens in the embryonic tissues decreases until the complete disappearance of corresponding immunoelectrophoretic reactions. By this characteristic all antigens under study are subdivided into four groups: I--five antigens identified at the early developmental stages only (until hatching, stage 29); II--nine antigens present up to stages 33--35; III--three antigens followed up to stages 39--40 (well formed tadpole); IV--three antigens were found at all developmental stages under study up to stages 45--47. 11 out of 20 identified antigens have antigenic similarity with the proteins of blood serum of adult amphibians. Besides, the early gastrula ectoderm contains antigens similar with those of the brain of adult amphibians.     

New serotypes of Morganella morganii.

On the basis of 8 new O and 11 new H antigens determined in 22 strains, the Morganella morganii antigenic schema was supplemented with 8 serogroups (O35-O42) and 13 serotypes. Four strains belonged to O groups described earlier and 2 strains contained new O antigens in combination with known O antigens. Known H antigens were present in one strain as a single factor and in one strain as combination of two factors. New H antigens were demonstrated in 5 serotypes in combination with known H antigens. Six out of the 22 isolates were classified into O group 35. Two isolates contained different B-type surface antigens; these factors were not related to Escherichia coli B antigens and, unlike the latter, their living suspension gave a higher titre agglutination in OK serum as compared to the boild culture.     

Tumor antigens discovery: perspectives for cancer therapy.

The adoptive transfer of cytotoxic T lymphocytes (CTLs) derived from tumor-infiltrating lymphocytes (TIL) along with interleukin 2 (IL-2) into autologous patients with cancer resulted in the objective regression of tumor, indicating that these CTLs recognized cancer rejection antigens on tumor cells. To understand the molecular basis of T cell-mediated antitumor immunity, several groups started to search for such tumor antigens in melanoma as well as in other types of cancers. This led to the subject I will review in this article. A number of tumor antigens were isolated by the use of cDNA expression systems and biochemical approaches. These tumor antigens could be classified into several categories: tissue-specific differentiation antigens, tumor-specific shared antigens, and tumor-specific unique antigens. However, the majority of tumor antigens identified to date are nonmutated, self proteins. This raises important questions regarding the mechanism of antitumor activity and autoimmune disease. The identification of human tumor rejection antigens provides new opportunities for the development of therapeutic strategies against cancer. This review will summarize the current status and progress toward identifying human tumor antigens and their potential applications to cancer treatment.     

Dirofilaria immitis: identification and partial characterization of parasite antigens in the serum of infected dogs

We have recently developed a sensitive and specific immunodiagnostic test for canine Dirofilaria immitis infection based on detection of soluble parasite antigens in dog sera by monoclonal antibody-based enzyme immunoassay. In addition to their importance as markers of infection, these antigens may contribute to the pathogenesis of heartworm disease in dogs. In the present study, a variety of methods were used to identify and characterize circulating D. immitis antigens. Two antigens were identified in infected dog sera that formed lines of identity in rocket-line immunoelectrophoresis with soluble antigens extracted from adult D. immitis. Circulating D. immitis antigens were also demonstrated in infected dog sera by immunoblot analysis with polyclonal and monoclonal antibodies. These antigens had apparent molecular weights that ranged from 50 to 250 kDa. Most of the circulating D. immitis antigens contained the epitope defined by monoclonal antibody 1418BF2.1 which is used in our enzyme immunoassay for circulating D. immitis antigen. Studies of parasite antigens released during in vitro culture indicated that the circulating D. immitis antigens in dog sera that are detected by our enzyme immunoassay are primarily derived from adult female worms.     

Schistosome surface antigens: developmental expression and immunological function

It has long been held as axiomatic that antigens exposed on the surfaces of parasitic organisms are primary targets of protective immune responses. It is becoming apparent that not all protective schistosome antigens are surface antigens and that not all surface antigens are necessarily targets of protective immunity. Andy Simpson suggests that one of the factors that determines the immunological function of surface antigens may be developmental expression.     

Purification and characterization of precipitating antigens from Theileria parva.

Precipitating antigens from Theileria parva have been partially purified. Two antigens from each of the schizont and piroplasm stages of the parasite were identified; the major antigens from the two stages shared the same specificity. The antigens showed considerable molecular heterogeneity, almost certainly a result of the preparative method, and they always contained large amounts of DNA. The piroplasm antigens were of parasite nuclear origin and the schizont antigens were probably of the same origin. The antigens were weakly antigenic, and the activity against them of humoral antibody from cattle immune to East Coast fever was low. These antigens do not appear to induce protection against East Coast fever.     

Immunochemical and functional analysis of HLA class II antigens induced by recombinant immune interferon on normal epidermal melanocytes

The effect of recombinant immune interferon (IFN-gamma) on the expression and shedding of HLA antigens and of melanoma-associated antigens (MAA) by epidermal melanocytes was investigated by using serologic and immunochemical techniques. IFN-gamma enhances the expression and/or shedding of HLA class I antigens and of the cytoplasmic MAA defined by monoclonal antibody (MoAb) 465.12S and induces a slight reduction in the expression of the high m.w. melanoma-associated antigen (HMW-MAA). In agreement with the data in the literature, melanocytes incubated with IFN-gamma acquire HLA-DR, -DQ, and -DP antigens. Contrary to previous information in the literature, the effect is not restricted to HLA class II antigens, since IFN-gamma also induces the expression of the 96-kDa MAA recognized by MoAb CL203. The effect of IFN-gamma on HLA class II antigens and 96-kDa MAA is dose and time dependent and is specific, because recombinant leukocyte interferon affects the expression of neither type of antigen. In spite of the expression of HLA class II antigens, IFN-gamma-treated melanocytes do not acquire the ability to stimulate the proliferation of allogeneic lymphocytes. HLA-DR antigens are more susceptible to induction by IFN-gamma than HLA-DQ and -DP antigens, since the percentage of melanocytes acquiring HLA-DQ and -DP antigens is lower than that acquiring HLA-DR antigens. Furthermore, the dose of IFN-gamma is higher and the time of incubation is longer to induce HLA-DQ and -DP antigens than to induce HLA-DR antigens. The differential susceptibility of HLA-DR, -DQ, and -DP antigens as well as of melanocytes from various donors to the modulating effect of IFN-gamma may provide an explanation for the more frequent detection of HLA-DR than of HLA-DQ and -DP antigens in melanoma lesions and for the expression of HLA class II antigens by some, but not all, melanoma lesions.     

The growth of B cell receptor microcluster is a universal response of B cells encountering antigens with different motion features

B lymphocyte cell senses and acquires foreign antigens through clonal distributed B cell receptors (BCRs) expressed on the surface of plasma membrane. The presentation formats of antigens are quite diverse. Based on their Brownian diffusion mobility, there are three forms: free mobile soluble antigens, lateral mobile membrane bound antigens, and fixed immobile antigens. Here, using high resolution high speed live cell imaging approaches, we provide evidence that BCR microclusters are formed on the surface of B cells shortly after B cell’s encountering of antigens with each format of motion features. Through high speed live cell imaging, we determine that these BCR microclusters show dynamic growth feature and by doing so function as the basic platforms for B cells to acquire the antigens. We propose that the formation and dynamic growth of BCR microcluster is a universal mechanism for B cell to response to antigens with diverse motion features.     

A serologic comparison of Moloney lymphoma cell surface and Moloney oncornavirus antigens.

Moloney lymphomas and Moloney sarcomas share strong tumor antigens. In this report we analyze the cell-surface antigens on a Balb/c Moloney lymphoma, LSTRA, using hyperimmune sarcoma regressor sera (alphaMo) as a primary reagent. We also use heterologous anti-viral p30 and gp70 sera for a direct analysis of virion protein antigens on the LSTRA surface. Using radiolabeled alphaMo-binding assays, we demonstrate that LSTRA tumor antigens detected by these sera are all Moloney viral antigens; approximately 1/3 of these antigenic determinants are expressed on the intact virus, and the other determinants are revealed by detergent lysis of the virus. The major viral antigens expressed on the LSTRA cell surface are viral env gene products, whereas gag gene products are only sparsely represented. We conclude that alphaMo sera detect almost exclusively viral antigens on LSTRA cells, and these antigens are almost exclusively virion env gene products.     

Antigens and Antigenic Variability of the African Trypanosomes*†

SYNOPSIS. The recent literature on the physical, chemical and biological characterization of antigens from the African trypanosomes is reviewed. The antigens are divided into three major groups: a) variant-specific antigens, b) common antigens, and c) host-like antigens. The variant-specific antigen(s) are relatively small molecular weight proteins located on the surface of the trypanosome, and are involved in protection and agglutination. It is suggested that there is more than a single variant-specific antigen on the cell surface. In contrast, the common antigens are internal or somatic antigens which are believed to have structural or enzymatic functions but are not involved in either protection or agglutination. In addition, evidence is also presented which suggests that there are host-like antigens within the surface coat and/or membranes of the trypanosomes. The importance of these three groups of antigens, and the mechanis(s) of antigenic variation are discussed in relationship to the immune response of the host to the African trypanosomes. Several possible approaches for future investigations are described.