title: Mechanism of protection during the early phase of a generalized viral infection. I. Contribution of phagocytes to protection against ectromelia virus.
abstract: Effects of carrageenan and gamma-irradiation on virus titre in the liver were observed after intravenous inoculation of 8 X 10(3) p.f.u. of ectromelia virus which was not lethal for untreated mice. Trapping of virus by the liver within 30 min and an initial transient reduction in titre by day 1 were not affected by gamma-irradiation but were inhibited by pretreatment with carrageenan. An increase from day 1 to day 3 was not affected by gamma-irradiation but was augmented by pretreatment with carrageenan. Therefore, protection within 3 days may depend principally upon carrageenan-sensitive and irradiation-resistant cells, namely, fixed macrophages. Elimination of virus from day 4 to day 7 depended upon cell-mediated immunity. When carrageenan was given 3 days after virus inoculation, the titre of virus increased progressively from day 4 ultimately to kill the hosts. The cytotoxic activity of spleen cells against infected target cells was raised in carrageenan-treated mice as well as in untreated mice. Immune elimination of virus may be mediated by a mechanism requiring the cooperation of sensitized T lymphocytes and blood monocytes.
mesh_terms: D000818:Animals; D002351:Carrageenan / Q000494:pharmacology; D002478:Cells, Cultured; D003601:Cytotoxicity Tests, Immunologic; D004481:Ectromelia virus / Q000187:drug effects / Q000528:radiation effects; D004482:Ectromelia, Infectious / Q000276:immunology* / Q000382:microbiology; D005720:Gamma Rays; D008099:Liver / Q000382:microbiology; D051379:Mice; D008808:Mice, Inbred CBA; D010586:Phagocytes / Q000276:immunology*; D011213:Poxviridae Infections / Q000276:immunology*; D013154:Spleen / Q000382:microbiology; D013997:Time Factors; D014779:Virus Replication / Q000187:drug effects / Q000528:radiation effects
chemical_list: D002351:Carrageenan