The absence of IL-6 does not affect Th2 cell development in vivo, but does lead to impaired proliferation, IL-2 receptor expression, and B cell responses.
The role of IL-6 in Th2 cell differentiation and response development after the injection of eggs from Schistosoma mansoni was investigated using wild-type (WT) and IL-6-/- mice. IL-6 was induced in the lymph nodes (LN) of WT mice within 24 h of egg injection, and IL-4 production by WT LN cells and CD4 T cells isolated 24 h after egg injection and stimulated in vitro was observed. In the absence of IL-6, this early production of IL-4 by LN cells and purified CD4 T cells was not abolished; although the level of IL-4 produced by IL-6-/- LN cells was similar to WT, IL-4 production by purified IL-6-/- CD4 T cells was reduced compared with WT. Despite the difference in CD4 T cell production of IL-4, the development of egg-specific Th2 cells 7 days after egg injection was not affected by the absence of IL-6. Nevertheless, Ab production was impaired and the in vitro proliferative response of whole LN cell populations, CD4 and CD8 T cells, and B cells from IL-6-/- mice was poor compared with WT. The proliferative defect in the IL-6-/- cells correlated with decreased IL-2R expression, and addition of exogenous IL-6 enhanced IL-2R expression as well as proliferation of LN cells from IL-6-/- mice. These studies demonstrate that Th2 differentiation and response development in vivo is not dependent on IL-6, but that Th-dependent and independent B cell responses are. Our results also emphasize the importance of IL-6 for lymphoproliferation, possibly through induction of IL-2R expression.
La Flamme
A C
AC
Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
Pearce
E J
EJ
D000818:Animals; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D002455:Cell Division; D005260:Female; D015850:Interleukin-6 / Q000172:deficiency* / Q000235:genetics / Q000494:pharmacology; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D010063:Ovum / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis*; D012550:Schistosoma mansoni / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology*
D015850:Interleukin-6; D015375:Receptors, Interleukin-2