ACTIVATION OF INFLUENZA-SPECIFIC MEMORY CYTOTOXIC T-LYMPHOCYTES BY CONCANAVALIN-A STIMULATION

Traditionally, the in vitro activation of virus-specific memory cytoto xic T lymphocytes (CTLs) has been achieved by stimulating the CTLs wit h antigen-presenting cells (APCs) infected with an appropriate virus o r pulsed with virus-specific antigenic peptides. Here, we describe the utilization of the polyclonal activator Concanavalin A (ConA) for in vitro restimulation of memory CTLs from virus-primed mice. Using this simple method, the activation of splenocytes with ConA for 3 days (i) eliminates the need to stimulate with virus-pulsed APCs and (ii) gener ates CD8(+) CTLs that exhibit virus specificity and MHC-restricted lyt ic activity similar to CTLs obtained by conventional viral restimulati on. In vitro ConA stimulation of splenocytes from BALB/c mice primed w ith the A/Texas/77 or A/Japanese/57 strain of influenza virus and from C57L/J mice infected with the A/Texas strain, generated CTLs with spe cific lytic activity. Hence reactivation of memory CTLs by this method is a general phenomenon rather than a mouse or viral strain-specific one. The ConA stimulation method used here had a recall of long-term ( 1 year) memory CTLs that effectively lysed virally infected targets. F urther ConA-stimulated effector lymphocytes from virally primed animal s have been shown to recognize and subsequently lyse target cells puls ed with virus or virus-derived peptides. The ConA reactivation of spec ific anti-viral CTLs may facilitate (i) studying anti-viral CTL respon ses and (ii) identifying of viral epitopes when unknown or when approp riate viral stimulation is impossible. (C) 1998 Elsevier Science B.V. All rights reserved.