SECONDARY CYTOTOXIC CELL RESPONSE TO LYMPHOCYTIC CHORIOMENINGITIS VIRUS .3. INVIVO PROTECTIVE ACTIVITY OF EFFECTOR CELLS GENERATED INVITRO

  • 1 January 1978
    • journal article
    • research article
    • Vol. 34  (2) , 291-302
Abstract
Secondary cytotoxic T [thymus derived] cells were generated in vitro by culturing WE3-LCM [viscerotrophic lymphocytic choriomeningitis] virus-specific memory CBA/H spleen cells with WE3-LCM virus-infected syngeneic peritoneal cells at 37.degree. C for 5 days. They were highly potent in reducing virus titers in the visceral organs of syngeneic recipients when transferred 24 h before i.v. virus challenge (e.g., 3.1 .times. 106 cells transferred gave approximately 3 logs reduction of virus titer). Protection was measured by titrating spleens for virus in a plaque assay, usually 2 days post virus-challenge. I.v. administered secondary effectors did not elicit a reduction in brain virus titers by 3 days after intracerebral inoculation of virus. Cells mediating protection were sensitive to treatment with anti-.theta. ascitic fluid plus complement. Protection occurred only when donors of secondary cells, infected stimulator cells and recipients shared H-2K or H-2D. There was a similar genetic restriction for these effectors to efficiently lyse virus-infected targets in vitro. Spleen cells from ectromelia virus-memory mice were cultured with ectromelia virus-infected syngeneic peritoneal stimulator cells and generated secondary effector cells which protected syngeneic recipients from subsequent challenge with ectromelia but not LCM virus. Secondary effector cells derived from in vitro stimulation of spleen cells from WE3-LCM virus-memory mice with WE3-LCM virus-infected syngeneic stimulator cells caused a significant reduction in spleen virus titers in syngeneic recipients challenged with either ectromelia or LCM virus. If WE3-LCM virus-infected stimulator cells were fixed and responder spleen cells were either from very old (6-12 mo. post-priming) WE3-LCM virus-memory mice, or from ARM[Armstrong]-LCM virus-memory mice, this unidirectional cross-protection of ectromelia virus-challenged mice was less pronounced. One explanation for the unidirectional cross-protection was that the transferred secondary effectors contained and released infectious LCM virus (or defective virions) which adsorbed to recipients'' spleen cells; these latter cells displayed LCM and ectromelia virus-specific antigenic patterns after ectromelia virus challenge, rendering them susceptible to specific T-cell mediated lysis. Clear specificity of effector cells was demonstrated at the effector: target level in vitro between LCM virus and ectromelia virus. (Experiments to compare the in vivo activity of secondary effectors with primary effector T cells raised in vivo or in vitro were hampered because of the large amounts of infectious virus in the latter 2 populations.) Secondary effectors reduced spleen, lung and liver virus titers when transferred 24 h after virus challenge, but were less efficient in protecting recipients than when given before virus.