FIG. 5.

Equivalent lysis of targets infected with either the plasmid-cured (avirulent) or the plasmid-bearing (virulent) strain. PBMC effectors were stimulated in vitro for 5 days with live virulent R. equi. (A) Autologous and (B) ELA-A mismatched targets were infected with either virulent or avirulent (PC) R. equi. Uninfected PBACs served as controls. Representative data from one animal (H44) are presented in the figure. Similar results were obtained from H81. ELA-A-unrestricted lysis of PBAC targets infected with either plasmid-bearing R. equi 33701 or the PC derivative were not significantly different. However, in all cases, the lysis of infected targets was significantly different from that of uninfected targets at the same E:T ratio.