PubMed · 32470
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V G Bristow. 1978-12-02. Allergic rhinitis.. https://doi.org/10.5694/j.1326-5377.1978.tb77398.x
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The region of the promoter of the pollen-specific maize gene, ZM13, from -119 to -37 was analyzed by a linker-scanning type of substitution mutagenesis and two areas were shown to be responsible for pollen expression: a proximal region delineated by mutations from -84 to -53 that conferred pollen specificity, and an upstream region delineated by a mutation from -107 to -102 (Q-element) that could increase the expression of the proximal region but showed no ability to cause expression in pollen on its own. Replacement of both of these areas with other sequences including the CaMV 35S promoter failed to replace activity.
Avocado, the fruit of the tropical tree Persea americana, is a source of allergens that can elicit diverse IgE-mediated reactions including anaphylaxis in sensitized individuals. We characterized a 32-kDa major avocado allergen, Prs a 1, which is recognized by 15 out of 20 avocado- and/or latex-allergic patients. Natural Prs a 1 was purified, and its N-terminal and two tryptic peptide sequences were determined. We isolated the Prs a 1 encoding cDNA by PCR using degenerate primers and 5'-rapid amplification of cDNA ends. The Prs a 1 cDNA coded for an endochitinase of 326 amino acids with a leader peptide of 25 amino acids. We expressed Prs a 1 in the yeast Pichia pastoris at 50 mg/liter of culture medium. The recombinant Prs a 1 showed endochitinase activity, inhibited growth and branching of Fusarium oxysporum hyphae, and possessed IgE binding capacity. IgE cross-reactivity with latex proteins including a 20-kDa allergen, most likely prohevein, was demonstrated, providing an explanation for the commonly observed cross-sensitization between avocado and latex proteins. Sequence comparison showed that Prs a 1 and prohevein had 70% similarity in their chitin-binding domains. Characterization of chitinases as allergens has implications for engineering transgenic crops with increased levels of chitinases.
While a differential sensitivity to cyclic AMP (cAMP)-mediated signaling between Th1 and Th2 cells has been hypothesized, differential activity of downstream signaling through cAMP-dependent protein kinase (cAK) isoforms remains unexplored. We herein report the effects of type 1- and type 2-specific cAK agonists and antagonists on proliferative responses and cytokine generation from ragweed-driven peripheral blood mononuclear cells (PBMCs) and Amb a 1-specific Th1 and Th2 clones. Rp-8-Cl- and Rp-8-CPT-cAMP were utilized as single agent antagonists of cAKI and cAKII, respectively; 8-AHA-cAMP, with and without 8-PIP-cAMP, and 8-CPT-cAMP, with and without 6-Bnz-cAMP, were used as synergistic agonist pairs specific for the cAKI and cAKII, respectively. Activation of either cAKI or cAKII individually was ineffective in down-regulating proliferative responses of PBMCs or T cell clones; concentration-response curves for the Th1 and Th2 clones were identical. Moreover, inhibition of either cAKI or cAKII individually was ineffective in overcoming the down-regulatory effects of phosphodiesterase inhibition. Activation of either cAKI or cAKII individually was ineffective in down-regulating proinflammatory cytokine generation from T cell clones (interleukin-4 from Th2; interferon-gamma from Th1). However, concurrent activation of both cAKI and cAKII produced down-regulatory effects equivalent to those of the phosphodiesterase inhibitor on both proliferation and cytokine generation. These data suggest a critical role for concurrent activation of cAKI and cAKII in the functional efficacy of antigen-driven downstream signaling due to elevations of intracellular cAMP and argue against differential regulation of Th1 and Th2 responses by cAK subtypes.