Immunity to Epstein-Barr virus in Hodgkin's disease preceded by infectious mononucleosis

A patient who developed Hodgkin''s disease four years after infectious mononucleosis had elevated serum antibody titres to Epstein-Barr virus and delayed hypersensitivity reactions to membrane antigens prepared from fresh autologous spleen, from spleen cells of another Hodgkin''s patient, and from cell lines known to carry the Epstein-Barr virus genome. Additional studies in more lymphoma patients will be needed to determine the significance of the reactivity against tumour and virus-associated antigens which has been documented in this patient.     

Coreconstitution of bacterial ATP synthase with monomeric bacteriorhodopsin into liposomes. A comparison between the efficiency of monomeric bacteriorhodopsin and purple membrane patches in coreconstitution experiments

The conditions for coreconstitution of a bacterial ATP synthase and bacteriorhodopsin into lecithin liposomes and for light driven ATP synthesis have been optimized. A rate of maximally 280 nmol ATP min-1 mg ATP synthase-1 was achieved with monomerized bacteriorhodopsin compared with a rate of up to 45 nmol ATP min-1 mg-1 found for proteoliposomes containing bacteriorhodopsin in the form of purple membrane patches. The different rates are explained by the finding that monomeric bacteriorhodopsin is more homogeneously distributed among the liposomes than the purple membrane patches. The final activities depended on both the purification method for the two proteins and the coreconstitution procedure. Furthermore, the ratio (lipid to bacteriorhodopsin to ATP synthase) could be optimized. Light-driven ATP synthesis depends also on the type of detergent used. The best result was obtained by deoxycholate. Also the relationship between proton translocation (by bacteriorhodopsin) and ATP synthesis activity was measured. A constant H+/ATP ratio was found at higher light intensities. This ratio increased strongly at lower light intensities.     

The epithelium overlying rabbit bronchus-associated lymphoid tissue does not express the secretory component of immunoglobulin A

Summary The epithelium associated with lymphoid aggregates in the bronchial tract (BALT) was studied in rabbits by immunohistochemistry using monoclonal antibodies against the secretory component (SC) of IgA. The normal bronchus epithelium was intensely labelled. In contrast, epithelium overlying the central parts of the follicles was negative. This specialized epithelium cannot participate in the SC-mediated transport of IgA, which might be a basis for the adherence and transport of microorganisms into the lymphoid tissue, thus initiating immune responses of the BALT.     

Are all lymphoid blasts in the cell cycle?

Labelling index after one or repeated intravenous injections of 3H-thymidine was measured for various subpopulations of lymphatic cells in different canine lymphoid compartments and correlated with cell morphology. High doses of tritiated thymidine were injected and exposure times of up to 211 days were used. The labelling indices of lymphoid blasts were comparable in all tissues investigated. Labelling index varied from 100% in immunoblasts to 4% in small-sized lymphocytes. Approximately 80% of immunoblasts were labelled 1 h after 3H-thymidine application and 100% labelling was obtained after 12 h repetitive 3H-thymidine labelling. In contrast with mediumsized and large lymphocytes, immunoblasts seem to be rapidly proliferating cells in the dog with almost no G_o cells. Supported by the Deutsche Forschungsgemeinschaft DFG Grant SFB 112     

Low incidence of bronchus-associated lymphoid tissue (BALT) in chronically inflamed human lungs

The relevance of bronchus-associated lymphoid tissue (BALT) in man is still under discussion. Animal experiments indicate that the development of BALT is dependent on microbial stimulation. Therefore, the incidence of BALT was investigated retrospectively in specimens removed during surgical procedures on patients with chronic pulmonary inflammation. All these patients had severe chronic bronchitis and bronchiectasis, but BALT was found in only 8%. In patients with BALT and a malignant tumor, occlusion of a bronchus with poststenotic pneumonia was always present and BALT was observed exclusively in areas peripheral to the occlusion. In man other compartments of the lung must be responsible for the immune function of BALT found in animals. Partly presented at the Congress of the Eur. Respir. Soc, 21.- 26.9.1991 in Brussels. (Abstract: Eur Respir J. 4, Suppl. 14:217p)     

"Haemostasis time", a modified bleeding time test and its comparison with the Duke and Ivy/template bleeding times. I. Normal values, application in thrombocytopenic patients and evaluation of heparin and aspirin effects

The occlusion time ("haemostasis time" - HT) of a thin, short cannula inserted into the cubital vein, was compared with the skin bleeding times of the Duke and Ivy/template techniques. 25 male and 25 female volunteers without a history of bleeding were divided into 5 equally large age groups ranging from 10 to over 50 years of age. They exhibited a range of 46 s-6 min 38 s (95% tolerance interval), while the Duke and Ivy/template bleeding times, which were simultaneously determined, corresponded to values given by other authors. HT is different from the skin bleeding times in that endothelium is replaced by a standard foreign surface which allows better standardization of the method. Similar results were obtained with HT compared to the skin bleeding times. These and a similar, non-significant heparin response with all three techniques suggest that HT is not more influenced by clotting factors than the Duke and Ivy/template bleeding times and, indeed, may be regarded as a bleeding time modification. HT, like both of the skin bleeding times, reflected lowered platelet counts and is even more sensitive in this respect. As tested in a group of 20 male and 20 female volunteers, HT showed a significant prolongation two hours after ingestion of 1 g aspirin. While male individuals exhibited longer bleeding times than females with the Ivy/template technique (sex-related difference p = 0.01), no male to female differences were found both with HT and the Duke bleeding time. HT is easy to perform, inexpensive, leaves no scars and is safe even for the patient with severe bleeding. Moreover, compared to the skin bleeding times, it permits a differential evaluation of vessel wall and tissue effects.     

Enhanced release of oxygen metabolites by monocyte-derived macrophages exposed to proteolytic enzymes: activity of neutrophil elastase and cathepsin G

Macrophages at sites of inflammation are exposed to proteolytic enzymes derived from neutrophils, platelets, clotting factors, complement, and damaged tissues. To investigate the possible effect of proteases on the plasma membrane-mediated oxidative metabolic response of macrophages in inflammatory sites, cultured human monocyte-derived macrophages were treated in vitro with proteolytic enzymes and were then assayed for their ability to release superoxide anion (O2-) and hydrogen peroxide (H2O2) in response to stimuli. Macrophages pretreated for 1 to 20 min with trypsin, chymotrypsin, pronase, or papain, 0.1 to 200 micrograms/ml, released up to 3.5-times more O2- and H2O2 than did control (untreated) cells. This enhanced production of oxygen metabolites was observed by using either phorbol myristate acetate or opsonized zymosan as the stimulus. Macrophages were also "primed" for enhanced O2- release (2.3-fold) by pretreatment with a subfraction of granules extracted from human neutrophils. This subfraction contained primarily elastase and cathepsin G. Similar enhancement was observed with 60 ng/ml or purified human neutrophil cathepsin G (2.2-fold) and with 20 micrograms/ml of purified neutrophil elastase (3.3-fold). Priming by these neutrophil proteases could be blocked by specific inhibitors of their proteolytic activity. These results suggest that macrophages involved in an inflammatory response might be rapidly primed by proteases released from degranulating neutrophils. Primed macrophages could mount a more effective oxidative metabolic response to microorganisms or tumor cells, but might also cause greater tissue damage.     

Light-driven proton transport of bacteriorhodopsin incorporated into long-term stable liposomes of a polymerizable sulfolipid

The chromoprotein bacteriorhodopsin from Halobacterium halobium has been incorporated into liposomes made of a fully synthetic, polymerizable lipid. Bacteriorhodopsin is found to be active in these polymer liposomes. The advantage in the use of such polymer systems concerning long-term stability in comparison with liposomes made of natural lipid is demonstrated.     

Localization of sequences regulating ancestral and acquired sites of esterase6 activity in Drosophila melanogaster

We have broadly defined the DNA regions regulating esterase6 activity in several life stages and tissue types of D. melanogaster using P- element-mediated transformation of constructs that contain the esterase6 coding region and deletions or substitutions in 5' or 3' flanking DNA. Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and the primary sequences regulating its activity lie between -171 and -25 bp relative to the translation initiation site: deletion of these sequences decrease activity approximately 20-fold. Hemolymph activity is also modulated by four other DNA regions, three of which lie 5' and one of which lies 3' of the coding region. Of these, two have positive and two have negative effects, each of approximately twofold. Esterase6 activity is present also in two male reproductive tract tissues; the ejaculatory bulb, which is another ancestral activity site, and the ejaculatory duct, which is a recently acquired site within the melanogaster species subgroup. Activities in these tissues are at least in part independently regulated: activity in the ejaculatory bulb is conferred by sequences between -273 and -172 bp (threefold decrease when deleted), while activity in the ejaculatory duct is conferred by more distal sequences between -844 and -614 bp (fourfold decrease when deleted). The reproductive tract activity is further modulated by two additional DNA regions, one in 5' DNA (-613 to -284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to +2731 bp; threefold decrease when deleted) that probably overlaps the adjacent esteraseP gene. Collating these data with previous studies suggests that expression of EST6 in the ancestral sites is mainly regulated by conserved proximal sequences while more variable distal sequences regulate expression in the acquired ejaculatory duct site.      

Phylogenetic diversification of immunoglobulin genes and the antibody repertoire

Immunoglobulins are encoded by a large multigene system that undergoes somatic rearrangement and additional genetic change during the development of immunoglobulin-producing cells. Inducible antibody and antibody-like responses are found in all vertebrates. However, immunoglobulin possessing disulfide-bonded heavy and light chains and domain-type organization has been described only in representatives of the jawed vertebrates. High degrees of nucleotide and predicted amino acid sequence identity are evident when the segmental elements that constitute the immunoglobulin gene loci in phylogenetically divergent vertebrates are compared. However, the organization of gene loci and the manner in which the independent elements recombine (and diversify) vary markedly among different taxa. One striking pattern of gene organization is the "cluster type" that appears to be restricted to the chondrichthyes (cartilaginous fishes) and limits segmental rearrangement to closely linked elements. This type of gene organization is associated with both heavy- and light-chain gene loci. In some cases, the clusters are "joined" or "partially joined" in the germ line, in effect predetermining or partially predetermining, respectively, the encoded specificities (the assumption being that these are expressed) of the individual loci. By relating the sequences of transcribed gene products to their respective germ-line genes, it is evident that, in some cases, joined-type genes are expressed. This raises a question about the existence and/or nature of allelic exclusion in these species. The extensive variation in gene organization found throughout the vertebrate species may relate directly to the role of intersegmental (V<==>D<==>J) distances in the commitment of the individual antibody-producing cell to a particular genetic specificity. Thus, the evolution of this locus, perhaps more so than that of others, may reflect the interrelationships between genetic organization and function.