IN-VITRO IMMUNOGENICITY OF ALLOGENEIC CARDIAC VALVES

The immunogenicity of allogeneic cardiac valves (ACV) has not been pre viously demonstrated in vitro, though valve failure due to tissue dege neration has been attributed to adverse immunological reactions. A nov el in vitro assay has been developed in a Brown Norway (BN; RT1n) - Le wis (RT1(1); donor-recipient) rat model system that demonstrates the i mmunogenicity of ACVs. A single cell suspension of viable cardiac valv e conduit (CVC) cells was obtained by collagenase treatment of BN rat aortic valve conduits. Brown Norway rat CVC cells (5 x 10(4)) and Lewi s 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 sup plements with appropriate controls. Stimulation of responder lymphocyt es by CVC cells was measured by H-3-thymidine incorporation into DNA. The counts obtained between 96-192 h of co-culture in the CVC cell/res ponder lymphocyte reaction were significantly higher (P < 0.05) than t hose of responder cell controls as assessed by analysis of variance. T hese results indicate the presence of potent immunostimulatory cells i n viable ACVs and the possibility of using a sensitive and reproducibl e in vitro assay to evaluate ACV immunogenicity.