An immunosuppressed Syrian golden hamster model for SARS-CoV infection

Virology
Volume 380, Issue 2, 25 October 2008, Pages 312-321

Scott R. Schaecher, Jennifer Stabenow, Christina Oberle, Jill Schriewer, R. Mark Buller, John E. Sagartz, Andrew Pekosz.

Abstract

Several small animal models have been developed for the study of severe acute respiratory syndrome coronavirus (SARS-CoV) replication and pathogenesis. Syrian golden hamsters are among the best small animal models, though little clinical illness and no mortality are observed after virus infection. Cyclophosphamide was used to immunosuppress hamsters leading to a prolonged disease course and higher mortality after SARS-CoV infection. In addition, there was a significant weight loss, expanded tissue tropism, and increased viral pathology in the lung, heart, kidney, and nasal turbinate tissues. Infection with recombinant SARS-CoV viruses bearing disruptions in the gene 7 coding region showed no significant change in replication kinetics, tissue tropism, morbidity, or mortality suggesting that the ORF7a (7a) and ORF7b (7b) proteins are not required for virus replication in immunosuppressed hamsters. This modified hamster model may provide a useful tool for SARS-CoV pathogenesis studies, evaluation of antiviral therapy, and analysis of additional SARS-CoV mutants.

Keywords

SARS-CoV, Coronavirus, Cyclophosphamide, ORF7a, ORF7b, Hamster, Accessory gene, Pathogenesis

The effect of immunosuppression on protective immunity of turkey poults against infection with turkey coronavirus

Comparative Immunology, Microbiology and Infectious Diseases
Volume 25, Issue 2, March 2002, Pages 127-138

Chien Chang Loa, Tsang Long Lin, Ching Ching Wu, Thomas Bryan, Tom Hooper, Donna Schrader

Abstract

The objective of the present study was to evaluate the protective effect of humoral and cellular immunities on turkeys infected with turkey coronavirus (TCV). Two trials were conducted with two separate hatches of turkey poults. Turkeys were experimentally immunosuppressed with cyclosporin A (CsA) or cyclophosphamide (CY) and infected with TCV. Prior to infection, treatment with CsA selectively suppressed T cell activity as revealed by 2–3 fold decreased (p<0.1) lymphocyte proliferation responses to a T cell mitogen, concanavalin A (Con A). Treatment with CY mainly induced B cell deficiency as indicated by significant reductions (p<0.05) in antibody responses to sheep erythrocytes 7 days after injection. Body weight gain of turkeys treated with CY was significantly lower (p<0.05) than that of untreated turkeys at 9 days post-infection (PI). Turkeys treated with CY had 1–2 fold higher immunofluorescent antibody assay (IFA) scores for TCV antigens (p<0.05) in the intestine than untreated turkeys at 9 or 14 days PI. These results suggested that humoral immunity against TCV infection may be important in turkeys.

Keywords

Cyclophosphamide, Cyclosporin A, Enteritis, Immunity, Immunosuppression, Turkey coronavirus