HLA-DRB1 shared epitope genotyping using the revised classification and its association with circulating autoantibodies,acute phase reactants,cytokines and clinical indices of disease activity in a cohort of South African rheumatoid arthritis patients

Introduction  

The revised shared epitope (SE) concept in rheumatoid arthritis (RA) is based on the presence (S) or absence (X) of the SE RAA amino acid motif at positions 72 to 74 of the third hypervariable region of the various human leucocyte antigen (HLA)-DRB1 alleles. The purpose of this study was to investigate SE subtypes on the basis of the American College of Rheumatology 1987 revised criteria for the classification of RA in a cohort of South African RA patients (n = 143) and their association with clinical and circulating biomarkers of disease activity (autoantibodies, acute phase reactants and cytokines).     

Estimating individual exposure to malaria using local prevalence of malaria infection in the field

Background

Heterogeneity in malaria exposure complicates survival analyses of vaccine efficacy trials and confounds the association between immune correlates of protection and malaria infection in longitudinal studies. Analysis may be facilitated by taking into account the variability in individual exposure levels, but it is unclear how exposure can be estimated at an individual level.

Method and Findings

We studied three cohorts (Chonyi, Junju and Ngerenya) in Kilifi District, Kenya to assess measures of malaria exposure. Prospective data were available on malaria episodes, geospatial coordinates, proximity to infected and uninfected individuals and residence in predefined malaria hotspots for 2,425 individuals. Antibody levels to the malaria antigens AMA1 and MSP1₁₄₂ were available for 291 children from Junju. We calculated distance-weighted local prevalence of malaria infection within 1 km radius as a marker of individual''s malaria exposure. We used multivariable modified Poisson regression model to assess the discriminatory power of these markers for malaria infection (i.e. asymptomatic parasitaemia or clinical malaria). The area under the receiver operating characteristic (ROC) curve was used to assess the discriminatory power of the models. Local malaria prevalence within 1 km radius and AMA1 and MSP1₁₄₂ antibodies levels were independently associated with malaria infection. Weighted local malaria prevalence had an area under ROC curve of 0.72 (95%CI: 0.66–0.73), 0.71 (95%CI: 0.69–0.73) and 0.82 (95%CI: 0.80–0.83) among cohorts in Chonyi, Junju and Ngerenya respectively. In a small subset of children from Junju, a model incorporating weighted local malaria prevalence with AMA1 and MSP1₁₄₂ antibody levels provided an AUC of 0.83 (95%CI: 0.79–0.88).

Conclusion

We have proposed an approach to estimating the intensity of an individual''s malaria exposure in the field. The weighted local malaria prevalence can be used as individual marker of malaria exposure in malaria vaccine trials and longitudinal studies of natural immunity to malaria.     

Sequence of the chicken delta 2 crystallin gene and its intergenic spacer. Extreme homology with the delta 1 crystallin gene

The chicken delta-crystallin locus consists of 2 nonallelic, tandemly arranged genes (5'-delta 1-delta 2-3'). Only the delta 1 gene is known to be expressed. The nucleotide sequence for the delta 1 gene has been reported recently (Nickerson, J.M., Wawrousek, E.F., Hawkins, J.W., Wakil, A.S., Wistow, G.J., Thomas, G., Norman, B.L., and Piatigorsky, J. (1985) J. Biol. Chem. 260, 9100-9105; Ohno, M., Sakamoto, H., Yasuda, K., Okada, T.S., and Shimura, Y. (1985) Nucleic Acids Res. 13, 1593-1606). We now report the sequence for the delta 2 gene and the 4-kilobase intergenic spacer between the two delta-crystallin genes. The delta 2 gene, like the delta 1 gene, has 17 exons and 16 introns. The homologous exons are remarkably similar: exons 3-17 are identical in size between delta 1 and delta 2, and the sequence homology ranges from 70% (exon 2) to 100% (exons 7, 12, and 15), with the remaining exons having 89-98% identity between the delta 1 and delta 2 genes. Consequently, the encoded delta 2 polypeptide is 91% identical to the delta 1 polypeptide. Considerable similarity also exists between homologous introns of delta 1 and delta 2, with most of the differences accounted for by insertions and/or deletions. The presence of a TATA box, consensus splice junctions (almost identical to the delta 1 gene), lariat branch sequences, and a polyadenylation signal strengthen the possibility that delta 2 is a functional gene.     

Metabolism of prostaglandin endoperoxide by microsomes from human lung parenchyma and comparison with metabolites produced by pig, bovine, rat, mouse and guinea-pig

The metabolism of PGH₂ by human lung parenchymal microsomes was characterized by radiometric high performance liquid chromatography and compared with metabolism by pig, bovine, rat, mouse, and guinea pig lung microsomes. Microsomes from human lung synthesized 0.74 nmoles/mg protein and 0.72 nmoles/mg protein, PGI₂ (6-Keto-PGF_1α) and T×A₂ (T×B₂) respectively, upon incubation with 4.0 nmoles of PGH₂. Pig, bovine, rat, mouse, and guinea pig microsomes respectively synthesized 0.1, 1.0, 0.9, 0.4, and 0.1 nmoles of PGI₂/mg protein, and 0.9, 1.0, 0.7, 0.3, 1.8 nmoles of T×A₂/mg protein, and preparations formed some PGE₂, PGF_2α, and PGD₂. Mouse lung microsomes were unique in synthesizing PGE₂ as the major prostaglandin. The thromboxane synthetase inhibitor 1-benzylimidazole was a specific inhibitor in these six species.     

8-Chloro-cAMP inhibits transforming growth factor alpha transformation of mammary epithelial cells by restoration of the normal mRNA patterns for cAMP-dependent protein kinase regulatory subunit isoforms which show disruption upon transformation.

Differential regulation of the regulatory subunits of cAMP-dependent protein kinase isozymes correlates with the growth inhibitory effect of site-selective 8-Cl-cAMP demonstrated in cancer cell lines (Ally, S., Tortora, G., Clair, T., Grieco, D., Merlo, G., Katsaros, D., Ogreid, D., D?skeland, S.O., Jahnsen, T., and Cho-Chung, Y.S. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 6319-6322). Such selective modulation of protein kinase isozyme regulatory subunits was also found in the 8-Cl-cAMP-induced inhibition of both transformation and transforming growth factor alpha (TGF alpha) production in Ki-ras-transformed rat kidney fibroblasts (Tortora, G., Ciardiello, F., Ally, S., Clair, T., Salomon, D. S., and Cho-Chung, Y. S. (1989) FEBS Lett. 242, 363-367). In this work, we have demonstrated that 8-Cl-cAMP antagonizes the TGF alpha effect in TGF alpha-transformed mouse mammary epithelial cells (NOG-8TFC17) at the level of gene expression for cAMP receptor protein isoforms, RI and RII (the regulatory subunits of protein kinase isozymes). Northern blot analysis demonstrated that in the transformed NOG-8TFC17 cells, compared with the nontransformed counterpart NOG-8 cells, the mRNA levels for the RI alpha cAMP receptor protein markedly increased, whereas the mRNA levels for the RII alpha and RII beta cAMP receptor proteins decreased. 8-Cl-cAMP, which induced growth inhibition and phenotypic reversion in NOG-8TFC17 cells, caused an inverse change in the mRNA patterns of the cAMP receptor proteins; RI alpha cAMP receptor mRNA sharply decreased to levels comparable with that of the nontransformed NOG-8 cells, whereas RII beta mRNA increased to a level even greater than that in the NOG-8 cells. In addition, one mRNA species of RII alpha increased, whereas the other RII alpha mRNA species decreased during the treatment. The mRNA level for the catalytic subunit of protein kinase, however, did not change during 8-Cl-cAMP treatment. In addition, 8-Cl-cAMP brought about a reduction in both TGF alpha mRNA and protein levels. These coordinated changes in the expression of the cAMP receptor proteins and TGF alpha were not observed during cis-hydroxyprolineor TGF beta-induced growth inhibition of the NOG-8TFC17 cells. Thus, the antagonistic effect of 8-Cl-cAMP toward TGF alpha-induced transformation involves modulation of the expression of a specific set of cellular genes.