Akesson, A. and Ingvarsson, S. and Brady, K. and Moynagh, Paul N. and Borrebaeck, C.A.K.
(2000)
Rapid polarization of Th2 cells during induction of
antigen-specific IgE antibodies in vitro.
Clinical and Experimental Allergy, 30 (9).
pp. 1298-1306.
ISSN 0954-7894
Abstract
Background: Type 2 T-helper cells (Th2) are involved in the regulation of the humoral
immune response against antigens and allergens and directly affect which isotype will be
produced. The mechanism that regulates antigen-specific IgE secretion and immune
deviation is still not known.
Objectives: To delineate mechanisms behind antigen-specific IgE secretion we have used
in vitro immunization and focused on T-cell phenotype and the activation status of the
transcription factor NFkB.
Methods: Peripheral blood lymphocytes (PBMC) from seronegative donors were immunized
in vitro with a peptide consisting of both a T-cell and a B-cell epitope.
Results Antigen-specific IgE antibodies could be detected after a primary immunization,
during which T-helper cells secreted type 2 cytokines. Specific IgE was also detected in the
secondary immunization, but due to a rapid polarization from Th2 to Th1 phenotype,
exogenous IL-4 was required for the specific IgE secretion. Analysis of NFkB activation in
B and T cells during primary and secondary immunization showed that NFkB could be
detected in both B and T cells during primary immunization, but was dependent on
exogenous IL-4 in the secondary immunization.
Conclusion: This is the first evidence of antigen-specific IgE induction in vitro using naive
B cells, demonstrating the involvement of T-helper cell phenotype and NFkB and
demonstrates the usefulness of in vitro cultures to study the effect of antigens on human
immunocytes.
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