Sensitization of mice with wild-type and cold-adapted influenza virus variants: immune response to two H1N1 and H3N2 viruses

Two A strain influenza viruses, A/Hong Kong/123/77 (A/HK/123/77) (H1N1) and A/Queensland/6/72 (A/Qld/6/72) (H3N2), and the two cold-adapted reassortants which possess the surface antigens of these strains (CR35 and CR6, respectively) were tested for their ability both to induce primary cytotoxic T-cell (Tc cell) responses in mice and to sensitize mice for a second Tc cell response when challenged with a distantly related A strain virus, A/Shearwater/72 (H6N5). After intranasal inoculation, A/Qld/6/72 replicated to higher titers in the lung (1 to 2 log10 50% egg infective doses) than did A/HK/123/77 or either of the reassortants. A/Qld/6/72 induced higher Tc cell responses in the lung than did CR6, and both were more effective than either A/HK/123/77 or CR35 in this respect. When similar doses (10 or 10(3) hemagglutinin units) of each virus were injected intravenously into mice and the spleens were tested for Tc cell activity 6 days later, both A/Qld/6/72 and CR6 were ca. 100-fold better at inducing a primary Tc cell response than A/HK/123/77 or CR35. In contrast, the H1N1 and H3N2 viruses gave rather similar anti-hemagglutinin antibody titers (after intravenous injection) and delayed-type hypersensitivity reactions (after subcutaneous injection). If mice were primed with a low dose of these viruses (10(4) 50% egg infective doses intranasally), A/Qld/6/72 and CR6 were more effective than A/HK/123/77 or CR35 at sensitizing for a secondary Tc cell response when challenged with A/Shearwater/72, but if larger doses were given either intranasally (10(6) 50% egg infective doses) or intravenously (10 to 10(3) hemagglutinin units), all viruses sensitized the mice equally well, despite the fact the A/Shearwater/72 gives a poor primary Tc cell response in mice. Thus, the viral glycoprotein antigens can be important in determining the immunogenicity of the virus and, particularly, the class I antigen-restricted Tc cell response of the host.     

Partial purification and characterization of locust allatotropin I

Methanol extracts of locust brains, corpora cardiaca (CC), and suboesophageal ganglia (SOG) were separated by gradient and/or isocratic reverse-phase high-performance liquid chromatography (HPLC) and allatotropic activity monitored in the eluted fractions. A major peak of activity, separated by isocratic separation with 12% 2-propanol, designated allatotropin I, exhibited identical retention times in the three tissue extracts. Doseresponse curves of allatotropin I indicate similar content in brain and CC-equivalents, whereas optic lobes, similarly separated by isocratic HPLC, contain only one-tenth of this amount of allatotropin. Allatotropin I is resistant to boiling and is susceptible to tryptic and chymotryptic digestion. Methanol extracts of thoracic muscle, Malpighian tubules, fat body or ovaries, similarly prepared and boiled, did not exhibit allatotropic activity at high doses of tissue equivalents.     

Thymostimulin: an immunohistochemical and immunological evaluation

The immunohistochemical and immunological properties of a rabbit serum raised against the calf thymic hormonal factor "Thymostimulin" were studied on mammalian and human thymuses, discussing the problem of species-specificity. The serum was also injected in chick embryos to study the possible interrelationship between avian thymus and Bursa of Fabricius.     

Influenza virus-specific antibody-secreting cells in the murine lung during primary influenza virus infection.

An enzyme-linked immunosorbent plaque assay is described which can reliably enumerate influenza virus-specific antibody-secreting cells and exhibits specificity similar to that of the indirect enzyme-linked immunosorbent assay. The assay was used to characterize the development of specific antibody-secreting cells, principally within lung tissue, during primary murine influenza virus infection after intranasal inoculation. Cells secreting influenza virus-specific immunoglobulin M (IgM), IgG, and IgA were detected in greatest numbers in lung tissue, and the data presented indicated that the cells may have originated from specific B-cell precursors in lung tissue which are demonstratable in vitro. At 11 months after infection, cells secreting IgG and IgA were still present in lung tissue. Influenza virus-specific antibody-secreting cells were also detected in spleen tissue and blood. Antibody-secreting cells appeared earlier in spleen than in lung tissue and declined more rapidly in spleen tissue.     

Studies on Analogues of Succinic Semialdehyde as Substrates for Succinate Semialdehyde Dehydrogenase from Rat Brain

The methyl ester of succinic semialdehyde (SSA) was examined as a substrate for succinate semialdehyde dehydrogenase (SSADH) from rat brain. It was found that the ester can be oxidized by the enzyme. Values of Km for SSA-Me were higher than for those for SSA, and for this substrate the enzyme showed a substrate-dependent inhibition. This finding suggests that the carboxylate group of SSA is not essential in the process of inhibition of SSADH by the substrate. Cyclopropyl analogues of SSA, cis- and trans-1-formyl-cyclopropan-2-carboxylic acids, were also individually tested as substrates of SSADH. Only the trans isomer was found to be oxidized to the corresponding dicarboxylic acid; it inhibited the enzyme in the same range of concentrations as SSA. The above data suggest that, as for gamma-aminobutyric acid, SSA is present in an unfolded, transoid conformation at the active site of SSADH.     

Variations in the middle ear of the Mammalia

The comparative morphology of mammalian middle ear structures has been studied by examining the histological sections of the ears of 144 specimens of mammals which had been collected, with a few exceptions, in two expeditions to the Caribbean area. Fifty-four species of six orders of mammals were represented. Sixteen structural features or relationships were specifically studied and the bearing of taxonomic groupings on the variability was analysed.
A taxonometric analysis using these middle ear features indicated that Microdipodops may lie nearer to Dipodomys than to Perognathus.
A table presenting the detailed results has been deposited with the British Museum (Natural History).     

The β4Integrin Subunit Is Expressed in Mouse Fibroblasts and Modulated by Transforming Growth Factor-β1

Integrin β₄subunit is present in association with α₆chain on both normal and transformed epithelial cells. Recently α₆β₄heterodimer was found on the endothelium of medium-sized blood vessels and on immature thymocytes. In this report we show, by Northern blotting, indirect immunofluorescence, immunoprecipitation, and Western blotting, that β₄subunit is expressed also on cells of mesenchymal origin such as fibroblasts, myoblasts, and myotubes. Increased expression of α₆β₄has been related to the aggressive metastatic phenotype of human and murine carcinomas. The transforming growth factor β₁(TGF-β₁) has been found to modulate the expression of several integrins and intracellular matrix proteins, as well as to stimulate cell invasion and metastatic potential. To evaluate whether α₆β₄expression is modulated by TGF-β₁, we transfected 3T3 fibroblasts with an expression vector carrying the human TGF-β₁cDNA driven by the SV40 early promoter. We observed by indirect immunofluorescence a modification in the subcellular distribution of β₄subunit, which acquires a perinuclear localization. This finding suggests this integrin subunit correlates with the cytoskeletal reorganization induced by TGF-β₁.     

Relationship between radiation induced adaptive response in human fibroblasts and changes in chromatin conformation

Chromatin conformation changes in the normal human fibroblasts VH-10 were studied by the method of anomalous viscosity time dependence (AVTD). Gamma-irradiation of cells in a dose range of 0.1–3 Gy caused an increase in maximal viscosity of cell lysates. Conversely, irradiation of cells with low doses of 0.5 or 2 cGy resulted in a decrease in the AVTD peaks with a maximum effect approximately 40 min after irradiation. The same exposure conditions were used to study a possible adaptive effect of low doses, measured by changes in cell survival. A primary dose of 2 cGy caused significant modification of cell response to a challenge dose. Approximately 20% protection to challenge doses of 0.5 Gy (p < 0.003), 2 Gy (p < 0.02) and 2.5 Gy (p < 0.002) was observed. However, the direction of this effect (adaptation or synergism) was found to be dependent on a challenge dose. The combined effect of 2 cGy and 1 Gy was significantly synergistic, while no modification was observed for 1.5 Gy and 3 Gy. A partial correlation was found between the AVTD changes and cell survival when the combined effect of a primary dose of 2 cGy and challenge dose was examined. The dose of 2 cGy alone increased survival by 16% (p < 0.0003). These results suggest that the low-dose induced effects on survival may be related to chromatin reorganization.     

A recombination outside the BB deletion refines the location of the X linked retinitis pigmentosa locus RP3.

Genetic loci for X-linked retinitis pigmentosa (XLRP) have been mapped between Xp11.22 and Xp22.13 (RP2, RP3, RP6, and RP15). The RP3 gene, which is responsible for the predominant form of XLRP in most Caucasian populations, has been localized to Xp21.1 by linkage analysis and the map positions of chromosomal deletions associated with the disease. Previous linkage studies have suggested that RP3 is flanked by the markers DXS1110 (distal) and OTC (proximal). Patient BB was thought to have RP because of a lesion at the RP3 locus, in addition to chronic granulomatous disease, Duchenne muscular dystrophy (DMD), mild mental retardation, and the McLeod phenotype. This patient carried a deletion extending approximately 3 Mb from DMD in Xp21.3 to Xp21.1, with the proximal breakpoint located approximately 40 kb centromeric to DXS1110. The RP3 gene, therefore, is believed to reside between DXS1110 and the proximal breakpoint of the BB deletion. In order to refine the location of RP3 and to ascertain patients with RP3, we have been analyzing several XLRP families for linkage to Xp markers. Linkage analysis in an American family of 27 individuals demonstrates segregation of XLRP with markers in Xp21.1, consistent with the RP3 subtype. One affected mate shows a recombination event proximal to DXS1110. Additional markers within the DXS1110-OTC interval show that the crossover is between two novel polymorphic markers, DXS8349 and M6, both of which are present in BB DNA and lie centromeric to the proximal breakpoint. This recombination places the XLRP mutation in this family outside the BB deletion and redefines the location of RP3.     

Electron microscope tomography of Balbiani Ring hnRNP substructure

Three-dimensional (3-D) reconstructions, by electron microscope tomography, of selectively stained, contrast enhanced Balbiani Ring (BR) hnRNP granules reveal a complex spatial arrangement of RNA-rich domains. This particulate substructure was examined by volume rendering computer graphics. Modeling the arrangement of RNA-rich domains is made difficult by apparent structural flexibility and/or heterogeneity of composition. Formulation of a consensus 3-D arrangement of RNA-rich domains will require an expanded data base of reconstructed BR granules and the development of new image manipulation and analysis techniques. This study demonstrates the potential for ultra-structural cell biology of combining several new techniques: selective nucleic acid staining, electron spectroscopic imaging to enhance contrast, electron microscope tomography and volume rendering computer graphics.Abbreviations BR Balbiani Ring - EMT electron microscope tomography - ESI electron spectroscopic imaging - hnRNP heterogeneous nuclear ribonucleoprotein - OA-B osmium ammine-B - kb kilobases by P.B. Moens