C1.7 monoclonal antibody designates high-avidity CD4+ cytotoxic T lymphocytes involved in clinical heart rejection.
BACKGROUND
It is assumed that not all donor-specific cytotoxic T lymphocytes (CTLs), but only those with a high avidity for donor antigens, can function as terminal effector cells in transplant rejection.


METHODS
In the present study, we searched for markers that would exclusively designate these high-avidity CTL.


RESULTS
FACS analysis of donor-specific CTL clones obtained from heart transplant patients revealed that high- and low-avidity CTL varied in their expression of p38, a surface molecule involved in signal transduction, which is stained by the antibody C1.7. High- and low-avidity CD8+ CTL and high-avidity CD4+ CTL expressed p38, whereas low-avidity CD4+ CTL did not. Noncytotoxic and naive CD4+ lymphocytes also lacked p38 surface expression.


CONCLUSIONS
Therefore, we conclude that p38 is a marker for CD4+ lymphocytes with the potency to damage the transplanted heart. Accordingly, p38 might be used to analyze the contribution of CD4+ CTL in immune responses, such as transplant rejection.
Department of Internal Medicine I and Thorax Centre, University Hospital Rotterdam-Dijkzigt and Erasmus University Rotterdam, The Netherlands.
N E
NE
van Emmerik
C J
CJ
Knoop
L M
LM
Vaessen
A H
AH
Balk
B
B
Mochtar
F H
FH
Claas
W
W
Weimar
D000911:Antibodies, Monoclonal / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002469:Cell Separation; D002999:Clone Cells; D005434:Flow Cytometry; D006084:Graft Rejection / Q000276:immunology*; D016027:Heart Transplantation; D006801:Humans; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000911:Antibodies, Monoclonal