Selective expression of the interleukin-2 gene discriminates between the auto- and allo-mixed lymphocyte reaction.
The in vitro mixed lymphocyte reaction (MLR) is a useful model to study alloresponsiveness to histocompatibility antigens. Secretion of different cytokine proteins in the supernatant of allo-MLR cultures has been reported in a few studies with no reference to results in auto-MLR. Since most cytokines are autocrine factors, their levels in the supernatant may not reflect the actual intracellular production. Therefore, we studied cytokine gene expression in auto- and allo-MLR by Northern dot blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. mRNA for IL-beta and IL-8 was detected in both auto- and allo-MLR by Northern dot blotting. mRNA for IL-2, gamma-IFN, TNF-alpha, IL-4, IL-10 and IL-2 receptor (IL-2R) was not found by Northern dot blotting and could only be detected by RT-PCR. Expression of mRNA for IL-4, IL-10, TNF-alpha, gamma-IFN and IL-2R by RT-PCR analysis was seen in both auto- and allo-MLR. There was slightly increased expression of gamma-IFN, IL-2R and TNF-alpha in allo-MLR in comparison to auto-MLR. However, IL-2 was exclusively expressed in allo-MLR and was detected as early as 5 h of initiation of culture. These results indicate that mRNA expression for a number of cytokines can be seen in both auto- and allo-MLR using RT-PCR analysis. However, the consistent expression of IL-2 in the allo-MLR indicates that it is an important cytokine which discriminates an allo- from an autoresponse. These findings suggest that detection of IL-2 gene expression by RT-PCR may be useful for immune monitoring of allograft rejection.
Moudgil
A
A
Ahmanson Department of Pediatrics, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
Toyoda
M
M
Galfayan
K
K
Jordan
S C
SC
D015152:Blotting, Northern; D015870:Gene Expression / Q000276:immunology; D006801:Humans; D007376:Interleukin-2 / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D016133:Polymerase Chain Reaction / Q000379:methods; D012194:RNA-Directed DNA Polymerase
D007376:Interleukin-2; D012194:RNA-Directed DNA Polymerase