ABSTRACT
Human IgE is useful for immunological assays, such as sensitization of FcεRI-positive cells and IgE measurement. In this study, we report the development of a recombinant Ig fragment, designated IgCw-γεκ, as an alternative reagent to human IgE. IgCw-γεκ (â¼130 kDa) comprises two hybrid constant H chain regions (Cγ1-Cε2-4, each â¼53 kDa) and two constant κ L chains (Cκ, each â¼12 kDa) and lacks a V domain. The presence of Cγ1 instead of Cε1 within the H chain increased the production yield and facilitated assembly of the H and L chains. IgCw-γεκ was produced in cultured human embryonic kidney 293F cells, with a yield of â¼27 mg/l. IgCw-γεκ bound to human FcεRIαRs expressed on the surface of rat basophilic leukemia-2H3 cells. A ß-hexosaminidase release assay revealed that the biological activity of IgCw-γεκ was comparable with that of IgE. The IgE concentration measured using IgCw-γεκ as a standard was similar to that measured using IgE as a standard. These results suggest that the IgCw-γεκ molecule retains the basic characteristics of IgE, but does not cross-react with Ags, making it an alternative to the IgE isotype references used in a variety of immunological assays.
Subject(s)
Immunoglobulin E/immunology , Immunoglobulin Fragments/genetics , Immunoglobulin Fragments/immunology , Immunoglobulin Heavy Chains/immunology , Immunoglobulin kappa-Chains/immunology , Animals , Cell Line , HEK293 Cells , Humans , Immunoglobulin Heavy Chains/genetics , Immunoglobulin kappa-Chains/genetics , Indicators and Reagents , Rats , Recombinant Proteins/genetics , Recombinant Proteins/immunologyABSTRACT
A previous study reported lateral habenula (LHb) lesions decelerated appetitive extinction. Therefore, we examined whether LHb activation accelerated appetitive extinction. In this study, rats received appetitive Pavlovian conditioning, pairing a conditioned stimulus (CS, light) with an unconditioned stimulus (food pellets), followed by CS-alone presentations. Chemogenetic LHb activation accelerated the decline in conditioned food-cup responses during extinction. The present results and the reports of previous LHb lesion studies suggest that LHb mediates appetitive extinction. (PsycInfo Database Record (c) 2023 APA, all rights reserved).