Laryngotracheitis herpesvirus infection in the chicken. II. The adoptive transfer of resistance with immune spleen cells.

Protection against virulent infectious laryngotracheitis (ILT) virus was successfully transferred between inbred white leghorn chickens with spleen cells or peripheral blood leukocytes from immune cock birds. Resistance to infection could be demonstrated 7 to 8 days, but not 2 days after cell-transfer. Both hyperimmune spleen cells and memory spleen cells conferred resistance to infection, while the transfer of non-immune spleen cells failed to protect the chickens. Thymocytes or bursal cells from immune donors also failed to confer protection. The majority of cyclophosphamide pretreated recipients of immune spleen cells survived the challenge with ILT virus without synthesising detectable levels of humoral antibody. These findings indicate that cell-mediated immune mechanisms are involved in vaccine-induced immunity to acute ILT infections.