Depletion of CD8+ T cells following primary immunization with ovalbumin results in a high and persistent IgE response.
The role of CD8+ T cells in the regulation of IgE was investigated by in vivo CD8+ T-cell depletion. Following intraperitoneal immunization with ovalbumin (OVA), OVA-specific T cell responses were first detected in the draining lymph nodes (LN) and subsequently in the spleen. In vitro depletion of LN CD8+ cells reduced the OVA-specific LN CD4+ T cell response; while depletion of splenic CD8+ cells enhanced the OVA-specific splenic CD4+ T cell response, suggesting an early helper and later suppressor function. CD8+ cell depletion in vivo up to 7 days after immunization failed to enhance IgE production, but depletion of CD8+ T cells between day 12 and day 18 increased IgE levels to over 10 microg/ml. Adoptive transfer of 1 x 10(7) purified CD8+ T cells (> 95% CD8+ > 98% CD3+ < 1% NK, < 1% CD4+) from parallel immunized rats or of 1 x 106 cells of an OVA-specific, MHC class I restricted CD8+ T cell line suppressed the IgE, but not IgG, response by > 95%. These results provide further evidence that CD8+ T cells inhibit IgE production, possibly by preventing the generation of adequate amounts of appropriate CD4+ T cell help.
Holmes
B J
BJ
Department of Immunology, King's College School of Medicine and Dentistry, London, UK.
MacAry
P A
PA
Kemeny
D M
DM
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology*; D005260:Female; D007114:Immunization; D007073:Immunoglobulin E / Q000096:biosynthesis*; D008212:Lymphocyte Depletion; D008297:Male; D010047:Ovalbumin / Q000276:immunology; D051381:Rats
D007073:Immunoglobulin E; D010047:Ovalbumin