The αβ complexes of ATP synthase: the α3β3 oligomer and α1β1 protomer

The basic structures of the catalytic portion (F₁, ₃₃) of ATP synthase are the ₃₃ hexamer (oligomer with cooperativity) and ₁₁ heterodimer (protomer). These were reconstituted from the and subunits of thermophilic F₁ (TF₁), and the ₃₃ hexamer was crystallized. On electrophoresis, both the dimer and hexamer showed bands with ATPase activity. Using the dimer and hexamer, we studied the nucleotide-dependent rapid molecular dynamics. The formation of the hexamer required neither nucleotide nor Mg. The hexamer was dissociated into the dimer in the presence of MgADP, while the dimer was associated into the hexamer in the presence of MgATP. The hexamer, like mitochondrial F₁ and TF₁, showed two kinds of ATPase activity: one was cooperative and was inhibited by only one BzADP per hexamer, and the other was inhibited by three BzADP per hexamer.     

A model of associative memory in the brain

A model of associative memory for time varying spatial patterns is proposed and simulated on a digital computer. This is a network composed of many neuron-like elements, and shows an ability for associative memory similar to that of the brain.Suppose a number of sequences of spatial patterns are presented to this network, for example, 12345, ABC, and so on. Then, these patterns are memorized in the network. After that, if any part of one of these sequences, say 23, is presented to the circuit, the rest of the sequence, 45, is recalled following to it. It resembles to such a situation — if we hear a part of a melody which we have memorized in the past, the rest of the melody is recalled even after it is stopped half-way. Although the recalled patterns are not always 100% correct, they are not completely destroyed even if the presented patterns are imperfect.     

Evaluation of hydrophobicity versus chaperonelike activity of bovine alphaA- and alphaB-crystallin

Calf lens A-crystallin isolated by reversed-phase HPLC demonstrates a slightly more hydrophobic profile than B-crystallin. Fluorescent probes in addition to bis-ANS, like cis-parinaric acid (PA) and pyrene, show higher quantum yields or Ham ratios when bound to A-crystallin than to B-crystallin at room temperature. Bis-ANS binding to both A- and B-crystallin decreases with increase in temperature. At room temperature, the chaperone-like activity of A-crystallin is lower than that of B-crystallin whereas at higher temperatures, A-crystallin shows significantly higher protection against aggregation of substrate proteins compared to B-crystallin. Therefore, calf lens A-crystallin is more hydrophobic than B-crystallin and chaperone-like activity of -crystallin subunits is not quantitatively related to their hydrophobicity.     

On age morphological changes of males of Chydoridae (Cladocera)

Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.     

Partial mispairing and crossing-over between β0 and δ genes as the origin of the δ β0 thalassemia gene

Summary Two double heterozygous ⁰/⁰ thalassemic sibs of Mexican descent were studied. The father had a ⁰/⁰ genotype, while the mother, one sib and several maternal relatives were ⁰/⁰ heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both ⁰ and ⁰ genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between ⁰ and genes followed by a crossing-over which would results in a ⁰ recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed.     

The frequency of the γ chain variant AγT in different populations,and its use in evaluating γ gene expression in association with thalassemia

Summary The occurrence of the ^AT chain (i.e. ^A75 Ile Thr) in different populations was evaluated through a study of 4250 cord blood samples and blood samples from more than 350 SS¹ patients. High frequencies were observed in Italy, Yugoslavia, Turkey, Holland, but also in Japan, Vietnam, and India. The chain is (nearly) absent in the Black population of Ghana and Kenya, and low frequencies were observed in China and Australian aborigines. Only a few adult SS patients (18 out of 357) were ^AT heterozygotes. The chromosomes with the ^AT globin gene were mapped through an evaluation of the presence of 10 different restriction sites. The ^AT chromosomes from different populations were closely related and had the same subhaplotypes of [--++-+] (Hinc II 5 to ; Xmn I 5 to ^G; Hind III in ^G and ^A; Hinc II in and 3 to ), quite different from the subhaplotypes seen for ^AT negative chromosomes.² This suggests a common ancestor which may have originated in Southern Europe. An evaluation of the chain production by both chromosomes in SS patients and -thalassemia heterozygotes was possible for subjects with an ^AT heterozygosity. It was concluded that in -thalassemia trait, the chain synthesis is directed for about two-thirds by the thalassemic chromosome and for about onethird by the normal chromosome; the contribution by the normal chromosome decreases with a decrease in total chain production.This is contribution #0890 of the Department of Cell and Molecular Biology, Medical College of Georgia, Augusta, GA 30912, USA     

Parameters involved in the enhancement of monoclonal antibody targeting in vivo with recombinant interferon

Summary The effects of recombinant human leukocyte (clone A) interferon (rHu-IFN-A) were investigated on the expression of monoclonal antibody (MAb)-defined tumor antigens expressed on human mammary and colon carcinomas. The rHu-IFN-A treatment substantially increased the localization of radiolabeled MAb B6.2-F(ab)₂ to the transplantable Clouser human mammary carcinoma, as well as to the moderately differentiated human colon xenograft WiDr, when grown as s.c. tumors in athymic mice. In contrast, human tumor cell lines (i.e., LS174T, A375, etc.) that were unresponsive to the antigen-augmenting ability of rHu-IFN-A in vitro were also unresponsive in vivo, indicating a possible method of screening carcinoma cell populations for subsequent rHu-IFN-A adjuvant therapy prior to MAb administration. The method of delivery of rHu-IFN-A was also studied. The i.m. route resulted in a 3–4 h plasma half-life for rHu-IFN-A. The administration of rHu-IFN-A via an osmotic pump resulted in a stable circulating plasma titer of 400–800 antiviral units/ml for 7 days. Utilizing delivery of rHu-IFN-A by the constant infusion route, it was found that the increase in localization of ¹²⁵I-B6.2-F(ab)₂ was dependent on (1) the length of time of treatment and (2) the circulating plasma rHu-IFN-A levels. These results thus provide information useful for subsequent studies to determine the potential efficacy of adjuvant rHu-IFN-A treatment for MAb-targeted tumor diagnosis and treatment.     

Ultrastructure of four types of striated muscle fibers in the atlantic hagfish (Myxine glutinosa,L.)

Summary Four types of striated muscle fibers with distinctive ultrastructure were defined in the Atlantic hagfish (Myxine glutinosa, L.): white, intermediate, and red fibers of m. parietalis, and red fibers of m. craniovelaris.White fibers are thick, contain very few mitochondria and fat vacuoles, and possess distinct and separate myofibrils with thin Z-disks and distinct M-lines. Intermediate fibers are thinner, possess largely similar myofibrils that often are even better separated due to a higher content of fat vacuoles and especially mitochondria and glycogen granules. Red fibers of m. parietalis contain large amounts of mitochondria, fat vacuoles, and glycogen granules. Their myofibrils possess M-lines, and although branching more, the myofibrils of red fibers conform with a Fibrillenstruktur pattern like those of white and intermediate fibers. Red fibers of m. craniovelaris are very thin, possess many smaller fat vacuoles, and large amounts of mitochondria and glycogen granules. The myofibrils are significantly thinner than in m. parietalis fibers, run as quite independent well separated units, possess thicker Z-disks, and lack M-lines. Large amounts of myosatellite cells are associated with these red fibers.Triads are located near A/I-junctions in all four fiber types and occur irregularly, the density of triads being different in the various fiber types.We are indebted to Dr. Finn Walvig, Biological Station, University of Oslo, Drøbak, for supply of hagfishes, and we also wish to thank Dr. Jan K. S. Jansen, Institute of Physiology, University of Oslo, for valuable suggestions during this study.     

Lipopolysaccharide Induction of MARCKS-Related Protein and Cytokine Secretion are Differentially Impaired in Microglia from LPS-nonresponsive (C3H/HeJ) Mice

Many events involved in activation of microglia and leukocytes by lipopolysaccharide (LPS) are mediated by protein kinase C (PKC), and we have recently demonstrated that a major PKC substrate, MARCKS-related protein (MRP), is selectively induced by LPS in murine microglia. In microglia from LPS-nonresponsive (C3H/HeJ) mice, induction of MRP and secretion of CSF-1 required much higher LPS concentrations (100 ng/ml) than in normal (C3H/OuJ) microglia (10 ng/ml). By contrast, TNF production was not significantly increased in C3H/HeJ microglia even at 1 g LPS/ml. Microglia expressed PKC isoforms , , , and (but not and ); PKC isoform levels were similar in both normal and C3H/HeJ microglia and no significant change in response to LPS was noted. Our results indicate that LPS alters PKC substrate (rather than kinase) expression, and that the Lps^d mutation in C3H/HeJ mice differentially affects regulation of several gene products implicated in microglial function.     

Hydrogen isotope discrimination in higher plants: Correlations with photosynthetic pathway and environment

Summary The ratio of deuterium to hydrogen (expressed as D) in hydrogen released as water during the combustion of dried plant material was examined. The D value (metabolic hydrogen) determined on plant materials grown under controlled conditions is correlated with pathways of photosynthetic carbon metabolism. C₃ plants show mean D values of-132 for shoots and -117 for roots; C₄ plants show mean D values of -91 for shoots and-77 for roots and CAM plants a D value of-75 for roots and shoots. The difference between the D value of shoot material from C₃ and C₄ plants was confirmed in species growing under a range of glasshouse conditions. This difference in D value between C₃ and C₄ species does not appear to be due to differences in the D value (tissue water) in the plants as a result of physical fractionation of hydrogen isotopes during transpiration. In C₃ and C₄ plants the hydrogen isotope discrimination is in the same direction as the carbon isotope discrimination and factors contributing to the difference in D values are discussed. In CAM plants grown in the laboratory or collected from the field D values range from-75 to +50 and are correlated with ¹³C values. When deprived of water, the D value (metabolic hydrogen) in both soluble and insoluble material in leaves of Kalanchoe daigremontiana Hamet et Perr., becomes less negative. These changes may reflect the deuterium enrichment of tissue water during transpiration, or in field conditions, may reflect the different D value of available water in areas of increasing aridity. Whatever the origin of the variable D value in CAM plants, this parameter may be a useful index of the water relations of these plants under natural conditions.     

α-and β-Glycosidases in maize roots

Four glycosidases were analyzed in 10 mm apical segments prepared from growing roots (15 mm) of Zea mays L. The pH optima were found to be 5.8 for -glucosidase, 4.4 for -galactosidase, 6.4 for -glucosidase and 6.0 for -galactosidase. The -glucosidase showed 4-fold higher activity than the -galactosidase. The distribution of the -glucosidase activity was signifcantly different from that of the -galactosidase, -glucosidase and -galactosidase.Abbreviations -Glu -glucosidase - -Gal -galactosidase - -Glu -glucosidase - -Gal -galactosidase     

The reactions of three species of grasshopper to simple visual stimuli at different temperature-humidity conditions

The effect of the temperature-humidity factor on the reaction of two different visual stimuli has been investigated with Chorthippus brunneus (Thunb.) (= Chorthippus bicolor Charp.), Chorthippus longicornis (Latr.) (= Ch. parallelus Zett.) and Mecostethus grossus (L.). At low and high temperatures (high and low relative humidities), the three species show a greater preference for surroundings with vertical stripes than for white surroundings. At medium temperature and relative humidity, the preference for white surroundings is greater than for surroundings with vertical stripes. In a comparison between the three species at high temperature, they show regarding their intensity of preference for surroundings with vertical stripes a ranking order which is identical with that of their preference for dense grass vegetation in natural environments. In a comparison between and at high temperature, show a greater preference for surroundings with vertical stripes than .

---

zusammenfassung Die Wirkung des Temperatur-Luftfeuchtigkeits-Faktors auf die Reaktion gegenüber zwei optischen Reizen wurde bei Chorthippus brunneus (Thunb.) (= Chorthippus bicolor Charp.). Chorthippus longicornis (Latr.) (= Ch. parallelus Zett.) und Mecostethus grossus (L.) untersucht. Bei niederen und hohen Temperaturen (hoher und niederer relativer Luftfeuchtigkeit) zeigen die drei Arten eine größere Bevorzugung für Umgebungen mit vertikalen Streifen als für weiße Umgebungen. Bei mittlerer Temperatur und relativer Feuchtigkeit ist die Bevorzugung weißer Umgebung größer als für Umgebungen mit vertikalen Streifen. Bei einem Vergleich der drei Arten bei hoher Temperatur ergibt sich hinsichtlich der Stärke ihrer Bevorzugung für vertikal gestreifte Umgebung eine Rangfolge, die mit der ihrer Bevorzugung dichter Grasvegetation in natürlicher Umgebung identisch ist. Bei einem Vergleich zwischen und bei hoher Temperatur zeigen die eine größere Präferenz für Umgebung mit Vertikalstreifung als die .

     

Purification and partial characterisation of and α-tocopherol-binding protein from rabbit heart cytosol

An -tocopherol-binding protein has been isolated and purified from rabbit heart cytosol. The purified protein had an apparent molecular mass of 14,200, as derived from SDS-PAGE. The content of the protein in rabbit heart was around 11.8 g per g of tissue. The binding of -tocopherol to the purified protein was rapid, reversible, and saturable. Neither nor tocopherol could displace the bound -tocopherol from the protein, suggesting a high specificity for -tocopherol. -Tocopherol-binding protein did not bind oleate. Transfer of -tocopherol from liposomes to mitochodria was stimulated 8-fold in the presence of the binding protein, suggesting that this protein may be involved in the intracellular transport of -tocopherol in the heart.     

Viability and activity in readily culturable bacteria: a review and discussion of the practical issues

In microbiology the terms viability and culturability are often equated. However, in recent years the apparently self-contradictory expression viable-but-nonculturable (VBNC) has been applied to cells with various and often poorly defined physiological attributes but which, nonetheless, could not be cultured by methods normally appropriate to the organism concerned. These attributes include apparent cell integrity, the possession of some form of measurable cellular activity and the apparent capacity to regain culturability. We review the evidence relating to putative VBNC cells and stress our view that most of the reports claiming a return to culturability have failed to exclude the regrowth of a limited number of cells which had never lost culturability. We argue that failure to differentiate clearly between use of the terms viability and culturability in an operational versus a conceptual sense is fuelling the current debate, and conclude with a number of proposals that are designed to help clarify the major issues involved. In particular, we suggest an alternative operational terminology that replaces VBNC with expressions that are internally consistent.     

„Kolbenbildungen“ der Muskelfasern des menschlichen Kehlkopfs

Zusammenfassung Fasern der menschlichen Kehlkopfmuskulatur weisen seitliche Aussackungen auf, die unter dem Sarkolemm in lockerer Anordnung Kerne, Lysosomen, Lipofuscingranula und Mitochondrien mit oft konzentrisch angeordneten Cristae enthalten. Sie sind mit den lichtmikroskopisch bekannten End- bzw. Seitenkolben identisch. Diese Aussackungen werden von den gefäßnahen subsarkolemmalen Mitochondrienanhäufungen eines bestimmten, auch in der übrigen Skelettmuskulatur weitverbreiteten Muskelfasertyps abgeleitet. Es wurden keine Verbindungen mit Nervenfasern gefunden. Im Gegensatz zu Goerttler können wir diese Bildungen deshalb nicht als Mechanorezeptoren deuten. Die Endkolben werden als sekantial getroffene Seitenkolben aufgefaßt. Da die Aussackungen der Fasern auch bei gesunden jungen Männern in der Kehlkopfmuskulatur regelmäßig auftreten, handelt es sich hier nicht um eine krankhafte Bildung, wenn auch die Faser im Bereich der Aussackungen einen degenerativen Prozeß durchzumachen scheint.

---

Summary Fibers of human larynx muscles show lateral dilatations of the sarcolemma containing loosely disposed mitochondria, lysosomes and eventually one or more nuclei. The cristae of the mitochondria often are arranged concentrically. Corresponding fiber dilatations have already been described by light microscopists as side- resp. end-bulbs.Our electron-microscopical observations lead to the conclusion that the dilatations are derived from accumulations of mitochondria beneath the sarcolemma which in similar form — but smaller — are characteristic of one type of the different muscle fibers, frequently to be found in other muscles of the body. Both subsarcolemma accumulations of mitochondria are close to the muscle capillaries.The fiber dilatations have no connections with nerve axons, and therefore cannot be interpreted as mechanoreceptors (Goerttler, 1960). The end-bulbs are supposed to be secantially (or obliquely) cut side-bulbs. We do not consider them pathologic since they are regularly found in fibers of healthy young men. On the other hand, they may represent a circumscribed degenerative alteration the origin of which remains to be explored.

     

Quaternary uplifted coral reef terraces on Alor Island,East Indonesia

A flight of six major coral reef terraces, up to 700 m in altitude, occurs along the eastern and northern sides of Kabola Peninsula, Alor Island, Indonesia. Some radiometric dates have been obtained from unrecrystallized coral samples collected in growth position by three different methods (¹⁴C, ²³⁰Th/²³⁴U, ESR). This enabled the identification of the terraces corresponding to the Holocene and to oxygen-isotope stages 5c, 5e and 7. According to the present elevation of the dated terraces, a 1.0–1.2 mm/y mean rate of uplift can be discerned. Extrapolation of this trend to the whole sequence of terraces reveals a good correlation between the development of major terraces and interglacial or interstadial stages corresponding to astronomically calibrated oxygen isotope records, up to stage 13. The relatively rapid uplift rate in this region minimized the possibility of polycyclic sea-level stands at the same levels and contributed to the good preservation of some morphological reef features. Two superimposed marine notches are visible near the present shoreline, with retreat points at about 5.0 m and 8.6 m respectively above the present MLWST level. They can be interpreted as corresponding to a glacial interstadial (the upper notch) and to the Holocene sea-level peak (the lower one). As Holocene emergence has been less than what could be expected from a 1 mm/y rate of uplift, a major coseismic vertical displacement may occur in the future.This work is a contribution to the IGCP Project 367 Late Quaternary coastal records of rapid change and to the activities of the INQUA Commissions Neotectonics and Shorelines, the task group Paleoseismicity of the Late Holocene of the Inter-Union Commission on the Lithosphere, and the UNESCO-IUGS cooperative programme Earth Processes in Global Change (CLIP Pilot Project)     

Effects of supplied cinnamic acids and biosynthetic intermediates on the anthocyanins accumulated by wild carrot suspension cultures

Anthocyanins isolated and characterized from the wild carrot suspension cultures used here were 3-O--D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D<-galactopyranosylcyanidin (1), 3-O-[-D- xylopyranosyl-(12)--D-galactopyranosyl]cyanidin (2), 3-O-(6-O-sinapoyl)--D-glucopyranosyl-(16)-[-D- xylopyranosyl-(12)-]-D-galactopyranos ylcyanidin (3), 3-O-(6-O-feruoyl)--D-glucopyranosyl-(16)-[- D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (4), 3-O-(6-O-coumaroyl)--D-glucopyranosyl-(16)- [-D-xylopyranosyl-(12)-]-D-galactopyrano sylcyanidin (5), 3-O-[6-O-(3,4,5-trimethoxycinnamoyl)]-- D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (6), 3-O-[6-O-(3,4-dime- thoxycinnamoyl)]--D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (7), 3-O-[(6-O-sinapoyl)--D-glucopyranosyl-(16)--D-galactopyranosyl]cyanidin (8), and 3-O-(-D-galactopyranosyl)cyanidin (9). Except when cinnamic acids were provided in the culture medium, the major anthocyanin present in the two clones examined was 2. When the naturally occurring and some non-naturally occurring cinnamic acids were provided individually in the medium, 1 and 2 were minor components and the anthocyanin acylated with the supplied cinnamic acid, namely 3, 4, 5, 6, or 7 was the major anthocyanin present in the tissue. When caffeic acid was provided the major anthocyanin in the tissue was 4, thereby suggesting that the caffeic acid was methylated before its use in anthocyanin biosynthesis. Other cinnamic acids supplied had limited effects on the anthocyanins accumulated and appeared not to result in the accumulation of new anthocyanins by the tissue. Thus the tissue can use some but not all analogues of sinapic acid to acylate anthocyanins. Additional anthocyanins were detected in extracts of the wild carrot tissue cultures using mass spectrometry (both MS/MS and HPLC/MS). The additional compounds detected have also been found in cultures of black carrot, an Afghan cultivar of Daucus carota ssp. sativa and the flowers of wild carrot giving no evidence for qualitative differences in the anthocyanins synthesized by subspecies, cell cultures from subspecies, or clones from cell cultures. There are major differences in the amounts of individual anthocyanins found in cultures from different subspecies and in different clones from cell cultures. Here anthocyanins without acyl groups were usually found in the tissues and their accumulation is discussed. On the basis of the structures of the isolated anthocyanins, a likely pathway from cyanidin to the accumulated anthocyanins is proposed and discussed.Abbreviations Sin sinapoyl - Fer feruoyl - 4-Coum. 4-coumaroyl - 3,4-MeO₂Cin 3,4-dimethoxyeinnamoyl - 3,4,5-MeO₃Cin 3,4,5-trimethoxycinnamoyl - Cya cyanidin     

11 S seed storage proteins fromHelianthus species (Compositae): Biochemical,size and charge heterogeneity

The seeds of 19 sunflower species were compared on the basis of their protein contents and the relative proportions of their protein fractions. The globulin content varied from 50% to about 70% and the albumin content from 18% to 35% according to the species. The level of intermediateMr polypeptides showed a great variability (9.6 to 24.3%). Comparative studies onMr polymorphism were carried out by means of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of non reduced and/or reduced samples using both mono- and bidimensional procedures. Polypeptide constituents of helianthinin were compared including both number and molecular size (cultivatedH. annuus was used as a standard). Studies focused on differences observed between the major two (Mr 38 000), (Mr 32 000) and (Mr 25 500), (21 000) polypeptides families constituting the main A, B, and C subunits. and polypeptides analyses permit to discriminate easilyH. petiolaris from the other species. Charge polymorphism was studied using isoelectric focusing (IEF) and IEF-PAGE in mono and bidimensional procedures in the presence or absence of 2-mercaptoethanol (2-ME). Only a specific ₄ polypeptide enables an easy discrimination betweenH. petiolaris and all the other species. Detailed nomenclature of the , and , polypeptides constituting the different helianthinin globulin subunits is given via the results of pI andMr analyses. Monodimensional IEF patterns of the more basic albumins (pI > 8.0) appear to provide a more valuable approach to identifying specific protein markers.     

Localization of Transforming Growth Factor β in Association with Neuromuscular Junctions in Adult Human Muscle

Transforming growth factors- 1, 2, and 3 are known for their regulatory function in embryogenesis, fibrogenesis, and tissue repair of different cell types. A trophic function of TGF- subclasses for motoneurons has been shown in vitro. TGF- 1 is a potent survival factor for cultured embryonic rat motoneurons. In addition, TGF- 1 stimulates proliferation of rat Schwann cells. Recently, TGF- 2 has been reported to be associated with the subsynaptic nuclei of mature rat neuromuscular junctions. In this study, we investigated the expression of TGF- 1, 2, and 3 at neuromuscular junctions in skeletal muscle of 11 adults without neuromuscular disease. On muscle biopsies, neuromuscular junctions were depicted by acetylcholine esterase reaction and acetylcholine receptor antibodies. TGF- 1, 2, and 3 were stained immunohistochemically with monoclonal antibodies. Some muscle fibers showed low levels of inhomogeneous immunoreactivity for both TGF- 1 and TGF- 3. Intense immunoreactivity of TGF- 1 and 3 was shown at the postsynaptic area of neuromuscular junctions. TGF- 2 was expressed in the same subcellular distribution, but less strongly. In conclusion, the colocalization of TGF- with neuromuscular junctions may suggest a significant function in neuromuscular communication.     

Allospecific T cell recognition of HLA-A2 antigens: Evidence for group-specific and subgroup-specific epitopes

Interleukin 2-dependent alloreactive cytotoxic T cell lines, with activity predominantly directed against the HLA-A2 antigen, have been generated in vitro by stimulating blood mononuclear cells from donors nonimmune to the Epstein-Barr (EB) virus with appropriate numbers of EB virus-transformed B cells from A2-homozygous individuals. Such effector cells were tested against a panel of EB virus-transformed target cell lines all expressing the serologically defined A2 antigen but typed into common A2 and variant A2 subgroups on the basis of their recognition by A2-restricted EB virus-specific cytotoxic T cells. Variant A2 responder cells cocultivated with common A2-bearing stimulators gave rise to effector T cell lines which recognized only the common A2-bearing subgroup of targets. By contrast, responder cells from A2-negative donors stimulated with common A2-bearing cells produced effector T cell lines in which the strong lysis of common A2-bearing targets was accompanied by a lower, but still significant, lysis directed against all targets within the variant A2 subgroup. In both cases, lysis of the target cells was blocked equally well by the anti-A2-specific monoclonal antibody MA2.1 as by the monoclonal antibody W6/32 specific for HLA-A, -B, and -C determinants. This suggests that HLA-A2 molecules possess at least two distinct sets of epitopes capable of inducing alloreactive T cell cytotoxicity: first, epitopes probably associated with T cell-restricting sites, which generate subgroup-specific responses, and second, epitopes shared by all A2 molecules, and perhaps associated with serologically defined sites, which generate pan A2 group-specific responses.Abbreviations used in this paper EB Epstein-Barr - IL-2 Interleukin 2 - UM unfractionated mononuclear - AET aminoethylisothiouroniumbromide hydrobromide