RESUMO
The immune response of the Buffalo/Sim rat to heterologous sheep red blood cells (SRBC) was studied here. The earliest time of response to 10(9) SRBC, the most suitable inoculation route and the behavior to challenge were determined. The intraperitoneal (ip) proved more effective than the subcutaneous (sc) route, since serum agglutinins became detectable in low titers in animals inoculated at 6-7 days of life by the former route and at 12 days by the latter. No splenic plaque-forming cells (PFC) were found in rats immunized ip at 2 days of age, and strong inhibition developed on challenge at day 14 post-inoculation (pi) (agglutinin titers at day 7 pi: 0.71 +/- 0.47 vs 4.6 +/- 0.51 in unprimed controls; PFC/10(7) cells at day 5: 122.21 +/- 36.17 vs 3,977.38 +/- 777.5 in unprimed controls). Serum agglutinin formation was also decreased, though to a lesser degree, when: a) animals were challenged at 30 or 60 days of age; b) both priming and challenge took place by sc route; or c) antigen dose was lowered to 10(7) or 10(5) SRBC. Mechanisms interpreting observed behavior are discussed.
Assuntos
Formação de Anticorpos , Transfusão de Eritrócitos , Hemaglutinação , Ratos Endogâmicos BUF/imunologia , Ratos Endogâmicos/imunologia , Envelhecimento , Animais , Animais Recém-Nascidos , Testes de Inibição da Hemaglutinação , Cinética , Ratos , OvinosAssuntos
Eritrócitos/imunologia , Hipersensibilidade Tardia/imunologia , Tolerância Imunológica , Animais , Células Apresentadoras de Antígenos/imunologia , Ciclofosfamida/farmacologia , Imunidade Celular/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C/imunologia , Ovinos , Linfócitos T Reguladores/imunologiaRESUMO
The object of this paper was to determine the influence of cyclophosphamide immunosuppression on the mortality of 40-45 day old Balb/c mice infected intracerebrally with a pathogenic strain of Junin virus, using different administration schedules. Up to 200 mg/kg of cyclophosphamide were not toxic. Results show that, unlike in other experimental models, three or four 50 mg/kg cyclophosphamide doses given both before and after viral infection were required to break-down resistance to Junin virus (90-96.5% mortality vs. 8% in controls). Taking into account the effect of cyclophosphamide on the cell populations involved in the immune response, causes likely to lead to the greater susceptibility of the suppressed adult mouse to Junin virus are discussed.
Assuntos
Ciclofosfamida/administração & dosagem , Febre Hemorrágica Americana/imunologia , Imunossupressores/administração & dosagem , Animais , Arenavirus do Novo Mundo , Ciclofosfamida/toxicidade , Esquema de Medicação , Febre Hemorrágica Americana/mortalidade , Imunidade Inata/efeitos dos fármacos , Imunossupressores/toxicidade , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Delayed-type-hypersensitivity (DTH) response "in vivo" is commonly evaluated by the footpad swelling test (FPST). High doses of Sheep Red Blood Cells (SRBC) are known to produce negligible DTH, while low doses lead to optimal sensitization. As expected FPST values obtained in Balb/c mice using 10(6) or 10(8) SRBC as sensitizing doses, showed that in 9 out of 10 batches from individual rams, the former dose resulted in higher values than the latter. However, only 3 out of the above 9 exhibited statistically significant differences between immunizing doses (Table 1). Therefore, in our hands, the accuracy of FPST is highly dependent on the SRBC source. We suggest the need of testing individual SRBC batches at both dilutions before use.
Assuntos
Eritrócitos/imunologia , Hipersensibilidade Tardia/imunologia , Imunidade Celular , Animais , Feminino , Hipersensibilidade Tardia/etiologia , Imunização , Masculino , Camundongos , Camundongos Endogâmicos BALB C/imunologia , Ovinos/sangueRESUMO
Delayed-type-hypersensitivity (DTH) response [quot ]in vivo[quot ] is commonly evaluated by the footpad swelling test (FPST). High doses of Sheep Red Blood Cells (SRBC) are known to produce negligible DTH, while low doses lead to optimal sensitization. As expected FPST values obtained in Balb/c mice using 10(6) or 10(8) SRBC as sensitizing doses, showed that in 9 out of 10 batches from individual rams, the former dose resulted in higher values than the latter. However, only 3 out of the above 9 exhibited statistically significant differences between immunizing doses (Table 1). Therefore, in our hands, the accuracy of FPST is highly dependent on the SRBC source. We suggest the need of testing individual SRBC batches at both dilutions before use.
RESUMO
The object of this paper was to determine the influence of cyclophosphamide immunosuppression on the mortality of 40-45 day old Balb/c mice infected intracerebrally with a pathogenic strain of Junin virus, using different administration schedules. Up to 200 mg/kg of cyclophosphamide were not toxic. Results show that, unlike in other experimental models, three or four 50 mg/kg cyclophosphamide doses given both before and after viral infection were required to break-down resistance to Junin virus (90-96.5
mortality vs. 8
in controls). Taking into account the effect of cyclophosphamide on the cell populations involved in the immune response, causes likely to lead to the greater susceptibility of the suppressed adult mouse to Junin virus are discussed.
RESUMO
The object of this paper was to determine the influence of cyclophosphamide immunosuppression on the mortality of 40-45 day old Balb/c mice infected intracerebrally with a pathogenic strain of Junin virus, using different administration schedules. Up to 200 mg/kg of cyclophosphamide were not toxic. Results show that, unlike in other experimental models, three or four 50 mg/kg cyclophosphamide doses given both before and after viral infection were required to break-down resistance to Junin virus (90-96.5
in controls). Taking into account the effect of cyclophosphamide on the cell populations involved in the immune response, causes likely to lead to the greater susceptibility of the suppressed adult mouse to Junin virus are discussed.
Assuntos
Animais , Camundongos , Formação de Anticorpos , Ciclofosfamida , Imunidade Celular , Soros ImunesAssuntos
Animais , Camundongos , Ciclofosfamida , Formação de Anticorpos , Imunidade Celular , Soros ImunesRESUMO
Tacaribe virus is the member most closely related to Junín virus within the Tacaribe complex. It has been demonstrated that both viruses are indistinguishable by complement-fixation, due to the high cross-reactivity. However, adult guinea pigs are highly sensitive to infection with the XJ pathogenic strain of Junín virus whereas Tacaribe virus is nonpathogenic for this species. Furthermore this last virus protects them against Junín virus. The XJ strain reduces the immune response of guinea pigs to many antigens. Both the humoral response and the hypersensitivity of the Arthus type have been reduced in infected animals. Considering that Tacaribe virus could be used as vaccine antigen, the purpose of the present study was to investigate the effect of Tacaribe infection on the immune system of guinea pigs. The data reported here supports earlier findings showing that the XJ strain of Junín virus suppresses humoral immune response as indicated by lower precipitating antibody titers to ovoalbumin (which contributed to milder Arthus cutaneous reactivity) and a significant depression of plaque-forming cells to sheep erythrocytes. In contrast, Tacaribe-infected guinea pigs did not show detectable immunosuppression employing the same models. Similar results were found when the cell-mediated immunity was investigated. Tacaribe-infected guinea pigs had a normal immune response to contact sensitivity to 2-4 dinitro-1-fluorobenzene as demonstrated by measuring ear swelling and unmodified tuberculin reaction, after injection with complete Freund's adjuvant. Our results and those of previous investigations justify the consideration of Tacaribe immunization as an approach to the prophylaxis of Argentine Hemorrhagic Fever.