Activated human B lymphocytes express cyclooxygenase-2 and cyclooxygenase inhibitors attenuate antibody production

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of inflammatory diseases and target cyclooxygenases 1 and 2 (Cox-1, Cox-2) that are responsible for PG production. Newer Cox-2-selective drugs have been heavily prescribed to quench inflammation. Little is known about whether or not these drugs influence human B lymphocytes and their ability to produce Ab. We report herein that activated human B cells not only highly express Cox-2 and produce PGs, but that the NSAID indomethacin and Cox-2-selective drugs profoundly inhibit the ability of human B cells to produce IgG and IgM in vitro. Human blood B cells highly express Cox-2 mRNA and protein and produce PGs after activation with CD40L, pansorbin, or CD40L plus BCR engagement. Cox-2 is also highly expressed by human tonsil B cells, as shown by immunohistochemistry. Cox-inhibiting drugs modestly affect purified B cell proliferation but profoundly reduce Ab production. The ability of whole blood to produce IgM and IgG following stimulation is also strongly inhibited. In support that Cox-2 plays a seminal role in B lymphocyte Ab production, Cox-2 knockout mice have 64% less IgM and 35% less IgG than normal littermate controls. These findings support that NSAIDs and the new Cox-2-selective drugs have an unsuspected target, the B cell, and attenuate Ab production in humans. Use of NSAIDs may therefore influence autoantibody production in autoimmune diseases and may dampen humoral immunity in response to antigenic challenge/vaccination.     

Protection against malaria induced by chirally modified Plasmodium falciparum's MSP-1 42 pseudopeptides

The C-terminal portion of the Plasmodium falciparum blood stage MSP-1 antigen plays a key role in invasion of human erythrocytes. The MSP-1(1282-1301) non-polymorphic 1585 peptide, from the processed MSP-1(42) fragment, is poorly immunogenic and highly alpha-helical [Angew. Chem. Int. Ed. 40 (2001) 4654]. Assessing the alpha-carbon asymmetry and its implication in the host immune response is proposed in this work to overcome the 1585 peptide's immunological properties. Accordingly, the effect of incorporating single D-amino acids and psi-[CH(2)-NH] isoster bonds into the 1585 peptide was examined both at the immunogenic and 3D-structure levels. Therefore, specific binding to RBCs is promoted by site-directed chiral modifications on the native peptide as well as by simultaneously combining specific D-substitutions with psi-[CH(2)-NH] isoster bonds transforming this molecule into a high specific HLAbeta1*1101 allele binder. D-analog pseudopeptide immunized animals induced antibodies selectively recognizing a recombinant as well as native MSP-1(42) and MSP-1(33) fragments. Protection and low parasitemia levels were induced in Aotus monkeys immunized with the EVLYL(dK)PLAGVYRSLKKQLE analog. Peptide alpha-carbon chiral transformation is therefore an important target for structural modulation and, consequently, represents a novel approach towards designing multi-component subunit-based malarial vaccines.     

On averaging power for genetic association and linkage studies

A power calculation is crucial in planning genetic studies. In genetic association studies, the power is often calculated using the expected number of individuals with each genotype calculated from an assumed allele frequency under Hardy-Weinberg equilibrium. Since the allele frequency is often unknown, the number of individuals with each genotype is random and so a power calculation assuming a known allele frequency may be incorrect. Ambrosius et al. recently showed that the power ignoring this randomness may lead to studies with insufficient power and proposed averaging the power due to the randomness. We extend the method of averaging power in two directions. First, for testing association in case-control studies, we use the Cochran-Armitage trend test and find that the time needed for calculating the averaged power is much reduced compared to the chi-square test with two degrees of freedom studied by Ambrosius et al. A real study is used for illustration of the method. Second, we extend the method to linkage analysis, where the number of identical-by-descent alleles shared by siblings is random. The distribution of identical-by-descent numbers depends on the underlying genetic model rather than the allele frequency. The robust test for linkage analysis is also examined using the averaged powers. We also recommend a sensitivity analysis when the true allele frequency or the number of identical-by-descent alleles is unknown.     

Genetic evidence for a distinct subtype of schizophrenia characterized by pervasive cognitive deficit

A novel phenotyping strategy in schizophrenia, targeting different neurocognitive domains, neurobehavioral features, and selected personality traits, has allowed us to identify a homogeneous familial subtype of the disease, characterized by pervasive neurocognitive deficit. Our genome scan data indicate that this subtype, which accounts for up to 50% of our sample, has a distinct genetic basis and explains linkage to chromosome 6p24 reported previously. If representative of other populations, the ratio of schizophrenia subtypes observed in our families could have a profound impact on sample heterogeneity and on the power of genetic studies to detect linkage and association. Our proposed abbreviated battery of tests should facilitate phenotype characterization for future genetic analyses and allow a focus on a crisply defined schizophrenia subtype, thus promoting a more informed search for susceptibility genes.     

A systematics for discovering the fundamental units of bacterial diversity

Bacterial systematists face unique challenges when trying to identify ecologically meaningful units of biological diversity. Whereas plant and animal systematists are guided by a theory-based concept of species, microbiologists have yet to agree upon a set of ecological and evolutionary properties that will serve to define a bacterial species. Advances in molecular techniques have given us a glimpse of the tremendous diversity present within the microbial world, but significant work remains to be done in order to understand the ecological and evolutionary dynamics that can account for the origin, maintenance, and distribution of that diversity. We have developed a conceptual framework that uses ecological and evolutionary theory to identify the DNA sequence clusters most likely corresponding to the fundamental units of bacterial diversity. Taking into account diverse models of bacterial evolution, we argue that bacterial systematics should seek to identify ecologically distinct groups with evidence of a history of coexistence, as based on interpretation of sequence clusters. This would establish a theory-based species unit that holds the dynamic properties broadly attributed to species outside of microbiology.     

Class-specific interaction of profilin and ADF isovariants with actin in the regulation of plant development

Two ancient and highly divergent actin-based cytoskeletal systems have evolved in angiosperms. Plant genomes encode complex actin and actin binding protein (ABP) gene families, most of which are phylogenetically grouped into gene classes with distinct vegetative or constitutive and reproductive expression patterns. In Arabidopsis thaliana, ectopic expression of high levels of a reproductive class actin, ACT1, in vegetative tissues causes severe dwarfing of plants with aberrant organization of most plant organs and cell types due to a severely altered actin cytoskeletal architecture. Overexpression of the vegetative class actin ACT2 to similar levels, however, produces insignificant phenotypic changes. We proposed that the misexpression of the pollen-specific ACT1 in vegetative cell types affects the dynamics of actin due to its inappropriate interaction with endogenous vegetative ABPs. To examine the functionally distinct interactions among the major classes of actins and ABPs, we ectopically coexpressed reproductive profilin (PRF4) or actin-depolymerizing factor (ADF) isovariants (e.g., ADF7) with ACT1. Our results demonstrated that the coexpression of these reproductive, but not vegetative, ABP isovariants suppressed the ectopic ACT1 expression phenotypes and restored wild-type stature and normal actin cytoskeletal architecture to the double transgenic plants. Thus, the actins and ABPs appear to have evolved class-specific, protein-protein interactions that are essential to the normal regulation of plant growth and development.     

Automated Assay of Telomere Length Measurement and Informatics for 100,000 Subjects in the Genetic Epidemiology Research on Adult Health and Aging (GERA) Cohort

The Kaiser Permanente Research Program on Genes, Environment, and Health (RPGEH) Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort includes DNA specimens extracted from saliva samples of 110,266 individuals. Because of its relationship to aging, telomere length measurement was considered an important biomarker to develop on these subjects. To assay relative telomere length (TL) on this large cohort over a short time period, we created a novel high throughput robotic system for TL analysis and informatics. Samples were run in triplicate, along with control samples, in a randomized design. As part of quality control, we determined the within-sample variability and employed thresholds for the elimination of outlying measurements. Of 106,902 samples assayed, 105,539 (98.7%) passed all quality control (QC) measures. As expected, TL in general showed a decline with age and a sex difference. While telomeres showed a negative correlation with age up to 75 years, in those older than 75 years, age positively correlated with longer telomeres, indicative of an association of longer telomeres with more years of survival in those older than 75. Furthermore, while females in general had longer telomeres than males, this difference was significant only for those older than age 50. An additional novel finding was that the variance of TL between individuals increased with age. This study establishes reliable assay and analysis methodologies for measurement of TL in large, population-based human studies. The GERA cohort represents the largest currently available such resource, linked to comprehensive electronic health and genotype data for analysis.