Immune Netw.  2002 Dec;2(4):195-201. 10.4110/in.2002.2.4.195.

Identification of Functionally Different Rat IgE in RBL-2H3 Exocytosis

• Kim JS
• Cho S
• Joo KH
• Lee JS
• Conrad DH
• Cho SW

• KMID: 1974517
• DOI: http://doi.org/10.4110/in.2002.2.4.195

Abstract

BACKGROUND: IgE is closely related to the development of allergies. However, the poor relationship between the specific IgE level and the severity of allergic diseases suggests the possibility of functionally different IgE isoforms. With this in mind, rat basophilic leukemia (RBL)-2H3 activation was analyzed with each type of rat IgE for two parameters, exocytosis and IL-4 mRNA production. RBL-2H3 has been well documented in the rat mucosal mast cell line.
METHODS
RBL-2H3 cells sensitized with each kind of rat IgE was activated by cross-linking FcRI with B5 (monoclonal anti-rat IgE mouse IgG antibodies). The RBL-2H3 exocytosis was measured by analyzing the beta-hexosaminidase level, and the level of IL-4 mRNA synthesis was analyzed using semi- quantitative RT-PCR. Rat IgE, which was produced by a parasite infection (REP), was prepared using either Paragonimus westermani metacercariae (REP-PW) or Anisakis simplex third stage larvae (REP-AS). A rat IgE prototype of IR162 was prepared by a peritoneal injection of immunocytoma.
RESULTS
The level of exocytosis showed a linear relationship with the rat IgE concentration when REP-PW or REP-AS was applied. However, it exhibited a biphasic response with IR162. In addition, the time course of heating at 56oC illustrated the similarity between REP-PW and REP-AS, which differed from that of IR162. In contrast, the level of IL-4 mRNA synthesis in the RBL-2H3 cells with IR162 was comparable to that of either REP-PW or REP-AS.
CONCLUSION
These results suggest that functionally different rat IgE isoforms exists in RBL-2H3 exocytosis.

Keyword

Rat; IgE; mast cells; parasites; RT-PCR

MeSH Terms

Animals
Anisakis
Basophils
beta-N-Acetylhexosaminidases
Exocytosis*
Heating
Hot Temperature
Hypersensitivity
Immunoglobulin E*
Immunoglobulin G
Interleukin-4
Larva
Leukemia
Mast Cells
Metacercariae
Mice
Paragonimus westermani
Parasites
Protein Isoforms
Rats*
RNA, Messenger
Immunoglobulin E
Immunoglobulin G
Interleukin-4
Protein Isoforms
RNA, Messenger
beta-N-Acetylhexosaminidases