乙型肝炎病毒表面抗原的微团化及其免疫刺激复合物抗原的理化特性和免疫原性

本文用哺乳动物细胞系表达的乙型肝炎病毒表面抗原(HBsAg),制备了HBsAg的微团化(Micelle)和免疫剂激复合物(Immune-stimulating Complexes,简称ISCOMS)两种形式的抗原。在电镜下观察,微团化抗原是由球形亚单位颗粒组成直径100～150nm的较原颗粒大得多的大颗粒,在蔗糖中的浮力密度为1.24g/ml;而ISCOMS在电镜下为直径30～40nm左右稍大于原颗粒的多面体形态颗粒。SDS-PAGE分析表明,这两种形式的颗粒都是由HBsAg的P23和GP27蛋白所组成。 小鼠免疫接种结果显示,ISCOMS的免疫原性优于微团化抗原,后者又优于原22nm HBsAg颗粒。在抗体产生的速度和强度上,ISCOMS组显著优于微团化抗原组,而微团化抗原组略优于22nm HBsAg组。 ISCOMS的免疫性强,抗体产生早,强度高,又易于制备,而且不需要使用氢氧化铝胶佐剂,有可能发展成为一种新一代的乙型肝炎疫苗。     

Production and characterization of alloantisera specific for bovine class II major histocompatibility complex antigens

Ten alloantisera defining five major histocompatibility complex (MHC) class II specificities of the bovine lymphocyte antigen (BoLA) complex were produced and characterized. Eight antisera defining four of the specificities were generated by immunizing cattle with class I compatible-class II incompatible lymphocytes. The alloantiserum defining the fifth class II specificity was produced by skin implant immunization. A pregnancy serum specific for one of the class II specificities was also identified. The class II antigens recognized by these antisera were designated 'Dx' antigens to indicate that they are BoLA-D region antigens encoded by one or more undetermined class II loci. The molecules identified by the alloantisera are heterodimers composed of a 34-kd alpha and a 26- to 28-kd beta chain, and are expressed on B-lymphocytes but not on resting T-lymphocytes. In family studies the BoLA-Dx antigens segregated in linkage with the BoLA-A locus alleles. Most of the BoLA-A alleles present in the Cornell Holstein herd at a high frequency were found to exist in gametic association with two or more serologically defined class II haplotypes. On the basis of a population study it was determined that three pairs of class I and class II alleles (w10-Dx4, w31-Dx5, and c3-Dx2) were present in the Cornell herd at significantly increased frequencies.     

"Metallothionein-like" metal complexes in angiosperms; their structure and function

Evidence for the presence of the metal-binding protein metallothionein, MT, in higher plants is equivocal. Although a number of MT-like metal complexes have been isolated from plants, the chemical structures of most of these compounds have not been fully elucidated. Recently a novel class of plant peptides, poly (γ-glutamylcysteinyl) glycines, (γEC)_nG, have been discovered. These peptides bind metal ions, and in the presence of such ions the amount of (γEC), G in plant cells increases. The presence of peptide bonds through the γ-carboxyl group of glutamate, rather than the α-carboxyl group, suggests that these peptides are not encoded by structural genes but are the products of biosynthetic pathways. Cells which are resistant to supra-optimal concentrations of certain metal ions over-produce (γEC)_n G. (γEC)_n G. may be functional analogues of MT. Whether or not some plants also produce MT is an important question which remains to be answered.     

The antenna system of Rhodospirillum rubrum. Detection of macromolecular constituents not stainable by Coomassie brilliant blue in solubilized preparations of the B880 complex

A solubilized preparation of the major Rhodospirillum rubrum antenna complex (B880) was obtained by a described procedure and its polypeptide composition was analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Only two polypeptides of molecular weights close to 7000 were detected after staining the gels with Coomassie brilliant blue. However, several other constituents could be visualized by silver staining or by an immunochemical method. When the preparation was chromatographed on Sephacryl, some of the resulting fractions exhibited the characteristic B880 absorption spectrum and contained only the two proteins that were detectable with Coomassie brilliant blue. In those fractions the A ₂₈₀/A ₈₈₀ratio was 0.4, which indicated a significant improvement of the bacteriochlorophyll to protein ratio over the unchromatographed preparation (A ₂₈₀/A ₈₈₀=0.7). Other chromatography fractions lacked bacteriochlorophyll and contained a carotenoid which seemed to be bound to protein. The macromolecular constituents present in these latter fractions differed from those associated to the purified B880 complex in their electrophoretic moblities and/or in their staining properties. That suggested the possible existence of a carotenoprotein that did not result from the B880 complex upon loss of bacteriochlorophyll.     

Diversity in the immune system: “Preconceived ideas” or ideas preconceived?

Two concepts of the evolution and regulation of expression of the combining site repertoire of the immune system, are compared. One view is based on the Associative Recognition Theory as formulated by the author and the other is based on the Idiotype Network Idea as conceived by Jerne. The two concepts are analyzed from the point of view of their logic, internal consistency and factual support.     

Complexes prepared from protein A and human serum,IgG, or Fcγ fragments: characterization by immunochemical analysis of ultracentrifugation fractions and studies on their interconversion

Summary Protein A of Staphylococcus aureus is an Fc receptor for IgG that has been used as a therapeutic reagent to treat cancer in humans and experimental animals. We used ultracentrifugation combined with analysis of isolated fractions by radioimmunoprecipitation and competitive radioimmunoassay with chicken antibodies that bind free protein A or protein A in complexes but do bind free immunoglobulin reagents to localize and characterize the types of complexes formed with different molar ratios of ¹²⁵I-protein A and human ¹³¹I-IgG alone or in serum, and ¹³¹1-Fc fragments. This approach offers a distinct advantage over direct counting of radioactivity in the fractions because resolution of complexes and free reagents is much improved. With excess ¹³¹I-IgG or ¹³¹1-Fc, all the ¹²⁵I-protein A is present only in complexes that contained 4 molecules of immunoglobulin reagent and 2 molecules of protein A (4:2 complexes), whereas with excess ¹²⁵I-protein A the stoichiometry of the complexes was 1:1. We have also shown the preformed 4:2 and 1:1 complexes will interconvert in the presence of added excess protein A or IgG, respectively, and that fresh IgG will exchange with IgG or Fc in preformed complexes. Because protein A has been found to elute from an immobilized reagent used in serotherapy of human cancer and is present in a large excess of IgG, the 4:2 complexes may play an active role in the tumoricidal or toxic reactions observed.Abbreviations SpA protein A of Staphyloccus aureus - VBS EDTA gel, 0.0055 M veronal buffered saline containing 0.01 M EDTA and 0.1% gelatin, pH 7.4 - PBS 0.01 M phosphate buffered saline, pH 7.4     

Chlorophyll-protein and polypeptide composition of Mn-deficient sugar beet thylakoids

The chlorophyll-protein and polypeptide composition of manganese deficient and control sugar beet thylakoids was examined using three different detergent-electrophoresis systems. On a per chlorophyll basis, manganese deficiency reduced the amounts of CPa complex (separated by sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis), and CP 47 and CP 43 complexes (separated by octylglucoside/SDS-polyacrylamide gel electrophoresis) without decreasing the amounts of light harvesting complexes. Lithium dodecylsulfate/Triton X-100 polyacrylamide gel electrophoresis showed that manganese deficiency decreased several thylakoid polypeptides, including a chlorophyll b containing 30 kilodalton chlorophyll-protein complex, but did not decrease the amounts of 28 and 29 kilodalton light-harvesting chlorophyll b-containing polypeptides.     

Pigment protein complexes and functional properties of tetratype resulting from crosses between CP1 and CP2 less Chlamydomonas mutants

A chlorophyll b-less mutant of Chlamydomonas reinhardtii (Pg ₂₇) was isolated after UV irradiation of the wild type cells. This photosynthetically competent mutant totally lacks chlorophyll b and the CP₂ chlorophyll-protein complex. However, SDS-PAGE, proteolytic digestions and immunodetections demonstrated that the 24–25 Kd apoproteins of the lacking CP₂ complex are still present in thylakoids of the Pg₂₇ mutant. It is concluded that this CP₂-less mutant is affected in the biosynthesis pathway of chlorophyll b.This CP₂-less mutant was crossed with a CP₁-less mutant (Fl₅) Fluorescence emission spectra and fluorescence inductions in the presence of DCMU were analysed in the resulting (cp ₂ ^– , cp ₁ ⁺ ), (cp ₂ ⁺ , cp ₁ ^– ), (cp ₂ ⁺ , cp ₁ ⁺ ), cp ₂ ^– , cp ₁ ^– )tetratype. Differences in PS 2 optical cross section and in the relative amplitude or localisation of fluorescence emission peaks fit well with a quadripartite model where PS1 and PS2 would each correspond to a reaction centre core complex (CP₁ and CP₂ respectively) associated to a light harvesting antenna (LHC1 and LHC2 respectively). The occurrence of energy transfers from PS1 peripheral antenna to PS2 in the Fl ₅ mutant shows that, in absence of CP₁, at least a part of its associated PS1 light harvesting antenna migrates in the PS2 containing appressed thylakoids.Abbreviations Chl Chlorophyll - LHC Light harvesting chl a/b complex - CP₂ Predominant form of LHC or SDS polyacrylamide gels - WT Wild type - DM Double mutant (cp ₁ ^– , cp ₂ ^– ) - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis - DOC-PAGE Deoxycholate polyacrylamide gel electrophoresis     

Plasmodium berghei: a mouse model for the "sudden death" and "malarial lung" syndromes

A mouse model for the "sudden death" and "malarial lung" syndromes is described. Mice of the C3H/z strain succumb suddenly approximately 7 days after an infection with Plasmodium berghei becomes patent, at a time when parasitemia is still moderate (6 to 8%). Death could be shown to be due to anaphylactoid shock, probably induced by soluble immune complexes. Increased vascular permeability caused transudation and leakage of serum proteins into the interstitium and the alveoli. The lungs were found to be edematous, with a fine granular precipitate in the alveoli and adherent to the vascular walls. The precipitates reacted with antiglobulins G and M, and could be shown to also contain malaria antigens and C3/4. A dramatic drop in hematocrit was recorded several hours before death, indicating the sudden release of malaria antigens. The myocardium of animals that had died very suddenly showed a patchy loss of phosphorylase activity. This loss of activity was much more extensive, and sometimes almost total, when there had been an agonal period of several (1 to 3) hours before death. In these cases the irreversibility of the myocardial damage was also indicated by the loss of activity of the dehydrogenases, as well as by typical inflammatory reactions of granulocytic and histiocytic infiltrations. The hearts thus presented a typical picture of the acute and peracute shock syndromes. In acute shock cardiac insufficiency develops so suddenly that death ensues before irreversible damage has occurred, and cardiac insufficiency can only be demonstrated by the most sensitive of enzyme histochemical means. In the present case shock was induced by the anaphylactoid activity of immune complexes with the lung as target organ. The described syndrome appears analogous to human "malarial lung."     

Coxal organs of Lithobius forficatus (Myriapoda,Chilopoda)

Summary In Lithobius forficatus each of the coxae of the four posterior trunk segments bear a pore field with several coxal pores. The surrounding single-layered epithelium is composed of four different cell types: the main epithelial cells having a fine-structural organization of transport cells with deep apical and basal folds of the cell surfaces and plasmalemma-mitochondrial complexes, junctional cells, exocrine glands, and the wall cells of the pore channel. The entire epithelium is separated from the hemolymph by an inner cellular sheath. It is assumed that the coxal organs participate in fluid uptake.