European Journal of Cardio-Thoracic Surgery, Vol 8, 549-553, Copyright © 1994 by European Association for Cardio-thoracic Surgery
In vitro immunogenicity of allogeneic cardiac valves
N Ketheesan, E Ingham, G Gowland and JN Kearney
Department of Microbiology, University of Leeds, UK.
The immunogenicity of allogeneic cardiac valves (ACV) has not been
previously demonstrated in vitro, though valve failure due to tissue
degeneration has been attributed to adverse immunological reactions. A
novel in vitro assay has been developed in a Brown Norway (BN; RT1n)- Lewis
(RT1; donor-recipient) rat model system that demonstrates the
immunogenicity of ACVs. A single cell suspension of viable cardiac valve
conduit (CVC) cells was obtained by collagenase treatment of BN rat aortic
valve conduits. Brown Norway rat CVC cells (5 x 10(4)) and Lewis responder
lymphocytes (10(5)) were co-cultured in 96 well plates in RPMI 1640 plus
2.5% (v/v) non heat-inactivated Lewis rat serum and supplements with
appropriate controls. Stimulation of responder lymphocytes by CVC cells was
measured by 3H-thymidine incorporation into DNA. The counts obtained
between 96-192 h of co-culture in the CVC cell/responder lymphocyte
reaction were significantly higher (P < 0.05) than those of responder
cell controls as assessed by analysis of variance. These results indicate
the presence of potent immunostimulatory cells in viable ACVs and the
possibility of using a sensitive and reproducible in vitro assay to
evaluate ACV immunogenicity.