Effects of Anti-Thymocyte Serum on Lymphocytic Choriomeningitis (LCM) Virus Infection in Mice

Abstract

Several studies ( 1,2,3) have suggested that lethality in acute lymphocytic choriomeningitis (LCM) virus infection of mice is a result of host immunologic response, rather than a direct effect of virus multiplication. Mice inoculated neonatally are protected from lethal effects of the virus, while adult morbidity and mortality can be reduced or delayed by various immunosuppressive methods, including X-irradiation, antimetabolite therapy, and neonatal thymectomy ( 1,2). In the present study, the role of cellular immunity in LCM palthogenesis was further examined, using rablbi t anti-mouse thymo-cyte (RAMT) serum to inhibit host response.Materials and methods. Three-to fourweek-old ICR mice of both sexes were used in all experiments. RAMT serum was prepared as described previously (4), by immunizing rabbits over a several-week period with dispersed suspensions of viable mouse thymus cells. Serum effectiveness was assayed by its ability to (a) diminish peripheral blood lymphocyte counts by 50% within a 4-hour period, and to (b) double the mean survival time of AKR skin grafts on C3H mice. All RAMT sera were shown to be free of anti-LCM activity as assayed by mouse neuat RYERSON UNIV on June 18, 2015 ebm.sagepub.com Downloaded from

Mechanism of Recovery From Systemic Vaccinia Virus Infection

“…Cytoxan has been highly effective in preventing rejection of immunologically foreign lymphocytes by mice, even when the donor and recipient differ across the H-2 locus (13). A single dose of Cytoxan protected mice against acute LCM disease (9), which is thought to be a cell-mediated immunopathological disease (10,11). We have confirmed, under the conditions of the present experiments, the effect of Cytoxan on experimental infection with LCM virus.…”

Immunosuppression-induced susceptibility of inbred hamsters (Mesocricetus auratus) to lethal-disease by lymphocytic choriomeningitis virus infection

“…Whereas immunosuppressivc treatment protected susceptible murine hosts from immunopathogenetic disease by LCMV-infection [6,13,14,[38][39][40], such measures had an opposite efi~ct on the susceptibility of hamsters to WE-induced mortality. By treatment with either irradiation or cyclophosphamide all hamsters, regardless of pedigree, died of WEinfection and exhibited diarrheal wasting-disease that charcterized lethal WE-infections of susceptible inbred MHA and PD4 hamsters [10].…”

“…Under conditions of compromised thymus-dependent immune functions LCMV-infectcd murine hosts survive and remain actively infected as life-long virus carriers. This latter condition may develop after congenital or neonatal infection [7,23,26], by infection of genetically athymic mice [7, 27,], or in immunocompetent adults by immunosuppressive treatment [7,13,14,[38][39][40]. In LCMV-carrier mice chronic immune-complex disease occurs [7], and the extent to which pathology and disease develop may be due to thymus-dependent LCMV-antibody responses [7,37].…”

Further Studies of Antiviral Activity of Natural Products on Lymphocytic Choriomeningitis Infection

“…This hypothesis is supported by the following ev idence: (1) Newborn mice acquire immunological tolerance against LCM infection. (2) Thymectomy, X-ray, methotrexate and anti-thymocyte serum [5] protect adult mice against the manifestation of disease, but do not suppress virus growth in brain. (3) No CPE of LCM virus in tissue culture cells (except KB cells) is reported in spite of the propagation of virus in the cells [9,1].…”