Antigenic and structural characterization of multiple subpopulations of H3N2 influenza virus from an individual

Influenza viruses grown in embryonated chicken eggs frequently possess antigenically distinguishable hemagglutinin (HA) compared to virus from the same source grown in mammalian cell culture. To further investigate the extent of variation among viruses from an individual, viruses were isolated from throat washes collected over a 48-hr period during infection with influenza virus designated A/Mem/6/86 (H3N2). Viruses were isolated from limit dilutions in eggs and mammalian Madin-Darby canine kidney (MDCK) cells and the antigenic, structural, and receptor-binding properties of these viruses were determined. Viruses which could be isolated in MDCK cells were present at 10- to 100-fold higher frequency in the original sample than viruses which could be isolated in eggs. The HA of virus clones isolated in MDCK cells were antigenically and structurally identical. In contrast, viruses from the same source, selected at limit dilution in eggs, could be divided into three distinct subpopulations based on the distinguishable antigenic and structural characteristics of their HA molecules. The three groups of egg-grown viruses could be distinguished from each other, and from MDCK cell-grown viruses, not only by a panel of anti-HA monoclonal antibodies, but also by immune ferret sera raised to H3N2 virus strains of recent years and sera raised to the different egg-grown clones themselves. Of these groups, group 1 and group 2 egg-grown viruses each represented a minor subpopulation of viruses which could be isolated in eggs, while viruses of the third antigenic phenotype were the most frequently isolated in eggs. Amino acid substitutions in the HA of egg-grown viruses occurred in antigenic and receptor-binding sites of the molecule. Group 1 viruses each possessed two amino acid substitutions in their HA molecules at residues 193 and 229 in HA1. Group 3 viruses, which displayed altered receptor specificities compared to MDCK cell-grown viruses and other egg-grown viruses, possessed a single amino acid substitution at residue 145 in HA1. The HA of the group 2 egg-grown viruses appeared structurally identical, yet displayed marked differences in antigenic and receptor-binding properties, compared to viruses isolated in MDCK cells. These results demonstrate that multiple, distinct subpopulations of virus can be isolated from a single patient during an infection with influenza and highlights the potential problems in selecting the most appropriate virus for epidemiological and vaccine purposes since selection could result in the use of viruses that are not representative of those which predominate in a human population.     

Induction of delayed-type hypersensitivity responses to PPD: dendritic cells in synergy with 5-hydroxytryptamine can substitute for macrophages.

We describe the use of 5-hydroxytryptamine (5HT) as an adjuvant in the induction of the delayed-type hypersensitivity (DTH) response to purified protein derivative (PPD). Based upon our previous studies with antigen-pulsed macrophages (M phi), we have shown that both the Day 2 early (2 hr) reaction and the Day 3 (24 hr) reaction are augmented if 5HT is incorporated into the priming injection. Furthermore, we have confirmed that in contrast to M phi, antigen-pulsed dendritic cells (DC) fail to prime the early (2 hr) component of DTH. However, DC do prime the early response if injected along with 5HT. A peripheral 5HT antagonist, ICS 205-930, inhibits both the M phi-mediated and the 5HT/DC-primed reactions. These findings support the hypothesis that DTH reactions require a cascade of both inflammatory and immunological signals, and that in mice vascular permeability mediated via 5HT is important in the early phase of the reaction.     

Inhibition of anaphylactic inflammation by the gp49B1 receptor on mast cells

gp49B1 is a member of the immunoglobulin (Ig) superfamily expressed on the surface of mast cells, macrophages, and activated natural killer cells. gp49B1 inhibits FcepsilonRI-induced activation of mast cells in vitro by virtue of two immunoreceptor, tyrosine-based inhibitory motifs that recruit the SHP-1 tyrosine phosphatase to the plasma membrane. We created gp49B1 null mice by targeted gene disruption, and found that IgE-dependent mast cell activation is augmented in these animals. Moreover, the ensuing anaphylactic reactions and inflammation are enhanced in the absence of gp49B1. Thus, gp49B1 innately counter-regulates mast cell activation mediated by Ig generated through the adaptive immune response in vivo.     

Utilization of the 2017 diagnostic criteria for hEDS by the Toronto GoodHope Ehlers–Danlos syndrome clinic: A retrospective review

The new 2017 diagnostic criteria for hypermobile Ehlers–Danlos Syndrome (hEDS) provide a framework for diagnosing hEDS but are more stringent than the previous Villefranche criteria. Our clinical experience at the GoodHope EDS clinic was that the 2017 criteria left many highly symptomatic patients without a diagnosis of hEDS. We conducted a retrospective cohort study to confirm our clinic experience and assess the accuracy of the 2017 diagnostic criteria for hEDS in patients who had a previous hEDS diagnosis based on the Villefranche criteria. Our study found that 15% (n = 20 of 131) of patients with a prior diagnosis of hEDS met the 2017 diagnostic criteria, and many of the traits used to distinguish hEDS were not significantly more frequent in patients who met 2017 criteria versus those who did not. In both groups objective systemic manifestations were found less frequently than subjective systemic manifestations. Beighton score (BS) as assessed by primary care practitioner was found to be higher than assessment by EDS practitioner in 81% (n = 74 of 91) of cases. Generalized joint hypermobility was confirmed in only 46% (n = 51 of 111) of patients who had a previous diagnosis of hEDS. Higher BS did not correlate with increased number of systemic manifestations in our cohort. Common comorbidities of hEDS were found with similar frequency in those who met 2017 criteria and those who did not. Based on our cohort, the 2017 hEDS diagnostic criteria require refinement to improve its diagnostic accuracy.     

Racial differences in the cause-specific prevalence of blindness in east Baltimore

BACKGROUND. Bilateral blindness unrelated to simple refractive error is twice as prevalent among blacks as among whites, although the difference narrows among the elderly. The reasons for this race- and age-related pattern are uncertain. METHODS AND RESULTS. A randomly selected, stratified, multistage cluster sample of 2395 blacks and 2913 whites 40 years of age and older in East Baltimore underwent detailed ophthalmic examinations by a single team. We identified 64 subjects who were blind in both eyes. The leading causes of blindness were unoperated senile cataract (accounting for blindness in 27 of the total of 128 eyes), primary open-angle glaucoma (17 eyes), and age-related macular degeneration (16 eyes). Together, these three disorders accounted for 47 percent of all blindness in this sample. Unoperated cataract accounted for 27 percent of all blindness among blacks, among whom it was four times more common than among whites; whites were almost 50 percent more likely than blacks to have undergone cataract extraction before the age of 80 (P less than 0.002). Primary open-angle glaucoma accounted for 19 percent of all blindness among blacks; it was six times as frequent among blacks as among whites and began 10 years earlier, on average. By contrast, age-related macular degeneration resulting in blindness was limited to whites, among whom it was the leading cause of blindness (prevalence, 2.7 per 1000; 95 percent confidence interval, 1.2 to 5.4); it affected 3 percent of all white subjects 80 years of age or older. CONCLUSIONS. The pattern of blindness in urban Baltimore appears to be different among blacks and whites. Whites are far more likely to have age-related macular degeneration, and blacks to have primary open-angle glaucoma. The high rate of unoperated cataracts among younger blacks and among elderly subjects of both races suggests that health services are underused. Half of all blindness in this urban population is probably preventable or reversible.     

Multi-center, double-blind, placebo-controlled trial of fluocortin butyl in perennial rhinitis

Fluocortin butyl (FCB) is a newly synthesized corticosteroid with a high ratio of topical to systemic activity. FCB was studied in a multi-center, double-blind, placebo-controlled trial of therapy of perennial rhinitis. The study was conducted between January and May 1981. Patients evaluated suffered from either chronic allergic or chronic nonallergic rhinitis or both. A total of 306 patients from 16 investigative centers were evaluated by comparing FCB to placebo. Three separate dosage regimens were employed. Patients received a total daily dose of 2, 4, or 8 mg. FCB was found to be an effective therapeutic agent. It reduced symptoms of nasal congestion, rhinorrhea, postnasal drainage, and sneezing. It also markedly reduced the use of concomitant medications (chlorpheniramine maleate and/or pseudoephedrine). Relief of symptoms was noted as early as the first week of therapy, and the degree of improvement increased progressively during the study. There was little difference between the relief produced by the 4 mg and 8 mg regimens. Both of these were superior to the 2 mg regimen. The drug was well tolerated; no significant side effects were noted.     

Inhibition of vaccinia virus late protein synthesis by isatin-beta-thiosemicarbazone: characterization and in vitro translation of viral mRNA.

Thespecific effect of istin-βthiosemicarbozone (IBT) was manifested after vaccinia virus late protein synthesis had commenced. At 6 hr after infection, viral protein synthesis was inhibited by about 9596. We confirmed that λ portion of the virus-specific RNA appears to be degraded (B. Woodson and W. K. Joklik, 1965, Proc. Nat. Acad. Sci. USA 54,946–953). Nevertheless, the amount of viral RNA that was capped, properly methylated, and polyadenylylated, was reduced by only about 50%. Moreover, RNA from IBT-treated cells stimulated cell-free protein synthesis to one-half the level obtained with RNA from control cells. Polyacrylamide gel electrophoretic analysis further demonstrated that RNA from IBT-treated cells was translated into late viral proteins in vitro. Thus, it seems possible that the inhibition of protein synthesis in IBT-treated cells does not result entirely or directly from either an inhibition of mRNA synthesis or from λ depletion of mRNA caused by accelerated degradation. An alternative possibility, that accelerated degradation is secondary to λ more immediate effect of the drug on protein synthesis, was considered.     

Analysis of antigen specific T cell helper function in first degree relatives of patients with systemic lupus erythematosus (SLE).

Fourteen families with first degree relatives of patients with systemic lupus erythematosus (SLE) were studied for the ability of their members to respond to the synthetic polypeptide antigen (T,G)-A-L. The family members were also tested for their HLA determinants. All SLE patients tested responded to (T,G)-A-L as measured by the production of (T,G)-A-L specific T cell helper factors by their antigen activated T cells, confirming our previous findings that 100% of SLE donors responded to (T,G)-A-L in contrast to 50% responders in a control population of healthy donors. The general defect in the regulation of immune responses in SLE patients was further indicated by the demonstration that an SLE patient who is a daughter of non-responder parents to (T,G)-A-L, responded to this genetically regulated antigen. In contrast to our observations with SLE patients, the genetic regulation of the ability to respond to (T,G)-A-L was shown not to be impaired in healthy first degree family members of SLE patients and the segregation of the immune response potential in these families was as expected from an inherited dominant trait.