Background: In vitro, various cytokines can modulate the level of expression of major histocompatibility complex (MHC) Class II antigens. Major histocompatibility complex Class II hyperexpression occurs in many immunologic disorders in vivo, but the cytokines that affect this are difficult to analyze because they are produced in small amounts, they act locally, and their mRNAs have short half-lives. Methods: We studied the expression of cytokines known to up-regulate MHC Class II genes in heart allografts in mice from B10.BR donors to B10.D2 recipients by reverse transcription of mRNA and polymerase chain reaction amplification. The I-Aβk gene expression was also studied in the same fully MHC incompatible strain combination. Results: Messenger RNA for interferon (INF)-γ, interleukin (IL)-4, and tumor necrosis factor (TNF)-α, known inducers of MHC Class II expression in vitro, could be detected in allografts either 24 hours before or simultaneously with massive induction of graft specific I-Aβ mRNA. Interleukin-6 mRNA could be detected as early as 1 day after grafting. Conclusions: These data suggest that known cytokine up-regulators of MHC Class II genes, i.e., IFN-γ, IL-4, and TNF-α may contribute to the upregulation of graft-specific MHC Class II antigens during an allograft reaction. Also, IL-6 expression in allografts may result from the stress of the grafting procedure, as it is evident very early after grafting.
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Cardiology and Cardiovascular Medicine