Cellular Immune Response in Turkeys Inoculated with Two Antigenically Indistinguishable Avian Influenza-A Viruses

Abstract

SUMMARY Peripheral blood lymphocytes from two groups of turkeys, each inoculated with one of two antigenically indistinguishable (Hav6 Nav2) strains of avian influenza virus (A/Ty/Ca/6750/73 or A/Ty/ Mass/65), were incubated in vitro with homologous and heterologous strains of AI virus. LaSota Newcastle disease virus and phytohemagglutinin were used as control mitogens. The degree of lymphocyte transformation was determined by measuring the incorporation of (3H)-thymidine. Lymphocytes from turkeys inoculated with AI strain A/Ty/Ca/ 6750/73 showed a greater blastogenesis when treated with the homologous virus than lymphocytes sensitized to A/Ty/Mass/65 and treated in vitro with its homolog. However, lymphocytes from turkeys inoculated with A/Ty/Mass/65 showed considerable blastogenesis when treated in vitro with the heterologous AI virus (A/Ty/ Ca/7650/73), whereas lymphocytes from turkeys inoculated with A/ Ty/Ca/7650/73 showed less stimulation when treated with the heterologous AI virus (A/Ty/Mass/65). The A/Ty/Mass/65 strain of AI was antigenically superior in producing an HI antibody response, suggesting that the humoral and cell immunity are separate immunologic events. The property of an AI strain of virus to stimulate blastogenesis and tissue immunity may become an important factor in selecting a virus for use in vaccine production.