Image-plate sensitivity to x rays at 2 to 60 keV.

The sensitivity of Fuji SR and MS image plates (IPs) used in x-ray spectrometers on OMEGA and the National Ignition Facility has been measured using two techniques. A set of radioisotopes has been used to constrain image-plate sensitivity between 6 and 60 keV, while a Manson source has been used to expose image plates to x rays at energies between 1.5 and 8 keV. These data have shown variation in sensitivity on the order of 5% for a given IP type and scanner settings. The radioisotope technique has also been used to assess IP fading properties for MS-type plates over long times. IP sensitivity as a function of scanner settings and pixel size has been systematically examined, showing variations of up to a factor of 2 depending on the IP type. Cross-calibration of IP scanners at different facilities is necessary to produce a consistent absolute sensitivity curve spanning the energy range of 2-60 keV.

Pertussis toxin is required for pertussis vaccine encephalopathy.

A mouse model for encephalopathy induced by pertussis immunization has been described; it has features that closely resemble some of the severe reactions, including seizures and a shock-like state leading to death, occasionally seen after administration of Bordetella pertussis (whooping cough) vaccine. Susceptibility to encephalopathy maps to genes of the major histocompatibility complex and correlates as well with the genetic regulation of the level of antibody response to bovine serum albumin. In this study we have investigated which bacterial determinant is responsible for the encephalopathy. Two lines of evidence implicate pertussis toxin as the active bacterial component. Single-site mutants of B. pertussis with single affected virulence factors were tested. A mutant that produces a defective pertussis toxin had greatly diminished capacity to induce encephalopathy, whereas a hemolysin- and adenylate-cyclase-deficient avirulent mutant had the same activity in the mouse model as a virulent strain. Purified pertussis toxin plus bovine serum albumin was tested and found to induce the lethal encephalopathy, demonstrating that the toxin was the critical constituent of B. pertussis responsible for encephalopathy.

Murine model for pertussis vaccine encephalopathy: role of the major histocompatibility complex; antibody to albumin and to Bordetella pertussis and pertussis toxin.

A mouse model for pertussis immunization encephalopathy has been described with features that closely resemble the severe adverse reactions occasionally seen after pertussis vaccine administration,m including seizures and a shock-like state leading to death. These reactions are produced with nearly one hundred percent efficiency provided that the mice immunized with Bordetella pertussis have 1) the appropriate major histocompatibility (H-2) genotype, 2) have been sensitized to bovine serum albumin (BSA), and 3) that the injected B. pertussis contained sufficient amounts of pertussis toxin. Antibody titres were measured in mice with haplotypes H-2d.s.k. that are highly susceptible to encephalopathy as well as in H-2b mice, that are totally resistant. Mice with H-2d.s.k. haplotypes were high responders to BSA, while H-2b (B10) mice were non-responders to BSA. Both H-2d and H-2b mice responded well to B. pertussis. Encephalopathy was induced in resistant H-2b mice with B. pertussis and passively administered anti-BSA antiserum, but not with B. pertussis and anti-(T,G)-A--L antibody. This indicated that B. pertussis and anti-BSA were absolutely required for development of encephalopathy. Encephalopathy could be induced in mice decomplemented with cobra venom factor and given BSA and B. pertussis. Several single-site mutants of B. pertussis affecting single virulence factors were induced with transposon Tn5. One of these mutants, BP357, deficient in pertussis toxin production, had a greatly reduced encephalopathic potential in the mouse model compared to the virulent strain BP 338, or to BP348, an adenylate cyclase and hemolysin double mutant, or to BP 349, a hemolysin mutant.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of (NZB x NZW)F1 disease with anti-I-A monoclonal antibodies.

(NZB x NZW)F1 mice spontaneously develop an autoimmune syndrome characterized by a fatal immune complex glomerulonephritis. Administration of monoclonal antibodies specific for an I region gene product (I-Az) of the H-2 haplotype associated with susceptibility to glomerulonephritis in these animals produced a remission in female mice with established renal disease. The results demonstrated that anti-I-A therapy stabilized the level of proteinuria and increased the 1-yr survival rate from 10% to greater than 90% in treated animals relative to control mice. These findings may ultimately have therapeutic potential for the treatment of systemic lupus erythematosus.

In vivo effects of antibodies to immune response gene products. I. Haplotype-specific suppression of humoral immune responses with a monoclonal anti-I-A.

Immune response (Ir) gene products control immunologic function at several critical sites. We administered in vivo a monoclonal antibody reactive with I-Ak to F1 mice with the genotype H-2k/b. These treated mnice made a markedly reduced antibody response to antigen (H,G)-A--L, under the control of I-Ak, but not to antigen (T,G)-A--L, under the control of I-Ab. This relative specificity was lost if the antigen was given in complete Freund's adjuvant rather than aqueous solution. The monoclonal antibody reduced the antibody titer in an ongoing, secondary response as well. Several potential mechanisms can be postulated for this effect. This haplotypic specificity might ultimately be relevant to human disease.

Correlation between agarose microdroplet and capillary tube procedures as assays for migration inhibition of target cells.

We have compared the capillary tube assay for migration inhibition studies with our modification of the agarose microdroplet technique, using several sources of factors with inhibitory activity (lymphokines, bacterial factors) and a variety of cell types (inflammatory exudate cells, tumor cells). In all circumstances both procedures gave quantitatively similar results, and high statistical correlation was found. These results suggest that the two procedures are measuring similar properties, and in any case may be used interchangeably as assays.