[Comparison of various methods for the measurement of the humoral immune response in mice vaccinated with aphthous fever virus]. / Comparación de distintos métodos para la medición de la respuesta inmune humoral de ratones vacunados con el virus de la fiebre aftosa.

Kinetics of the humoral immune primary response and seven-day secondary response of adult CF1 mice to FMDV O1 Campos adjuvanted in aluminium hydroxide-saponin (AHS) or in oil emulsion (OE) were evaluated by means of ELISA and passive hemagglutination (PH). Analysis of the response to AHS vaccine showed that ELISA measured maximal titres of primary response at 23 days post-vaccination (dpv), and at day 17 of secondary response, while PH detected maximal titres for primary as well as secondary response around day 60 pv. Mice immunized with OE vaccine studied by ELISA presented a plateau of primary response around 40 dpv, while secondary response was maximal around 80 dpv. The same sera tested by PH showed the highest titres for primary response on day 50 pv and secondary response was maximal on day 40 pv. A criterion for the evaluation of vaccination efficiency in the murine model is proposed based on the methods employed in the determination of antibody level.

Comparación de distintos métodos para la medición de la respuesta inmune humoral de ratones vacunados con el virus de la fiebre aftosa / [Comparison of various methods for the measurement of the humoral immune response in mice vaccinated with aphthous fever virus]

Kinetics of the humoral immune primary response and seven-day secondary response of adult CF1 mice to FMDV O1 Campos adjuvanted in aluminium hydroxide-saponin (AHS) or in oil emulsion (OE) were evaluated by means of ELISA and passive hemagglutination (PH). Analysis of the response to AHS vaccine showed that ELISA measured maximal titres of primary response at 23 days post-vaccination (dpv), and at day 17 of secondary response, while PH detected maximal titres for primary as well as secondary response around day 60 pv. Mice immunized with OE vaccine studied by ELISA presented a plateau of primary response around 40 dpv, while secondary response was maximal around 80 dpv. The same sera tested by PH showed the highest titres for primary response on day 50 pv and secondary response was maximal on day 40 pv. A criterion for the evaluation of vaccination efficiency in the murine model is proposed based on the methods employed in the determination of antibody level.

Comparación de distintos métodos para la medición de la respuesta inmune humoral de ratones vacunados con el virus de la fiebre aftosa / [Comparison of various methods for the measurement of the humoral immune response in mice vaccinated with aphthous fever virus]

Kinetics of the humoral immune primary response and seven-day secondary response of adult CF1 mice to FMDV O1 Campos adjuvanted in aluminium hydroxide-saponin (AHS) or in oil emulsion (OE) were evaluated by means of ELISA and passive hemagglutination (PH). Analysis of the response to AHS vaccine showed that ELISA measured maximal titres of primary response at 23 days post-vaccination (dpv), and at day 17 of secondary response, while PH detected maximal titres for primary as well as secondary response around day 60 pv. Mice immunized with OE vaccine studied by ELISA presented a plateau of primary response around 40 dpv, while secondary response was maximal around 80 dpv. The same sera tested by PH showed the highest titres for primary response on day 50 pv and secondary response was maximal on day 40 pv. A criterion for the evaluation of vaccination efficiency in the murine model is proposed based on the methods employed in the determination of antibody level.

Coupling of foot-and-mouth disease virus to sheep red blood cells using tannic acid for immunological assays.

A technique for coupling foot-and-mouth disease virus (FMDV) to tanned sheep red blood cells (SRBC) is reported. Different parameters influencing the procedure were studied. Subtypes C2, C3, O1 and A24 were used as antigens, and guinea pig hyperimmune sera obtained were tested for specific antibody in passive hemagglutination (PH), passive hemagglutination inhibition (PHI) and passive immune hemolysis (PIL) assays. Fresh and SRBC stored in Alsever's solution showed similar behavior when used as indicator cells. Optimal sensitization of erythrocytes was achieved using tannic acid 1:20,000 and 20 micrograms of purified virus/ml at pH 7.6. Specificity of the reaction was confirmed by PH and PHI in homologous and heterologous systems. The coupled antigen-antibody complex was sensitive to complement mediated lysis in a PIL test.

Inhibitory effect of 1-beta-D-arabinofuranosylcytosine on the synthesis of phosphatidyl-dCMP.

The synthesis of phosphatidyl-dCMP in mouse thymocytes is inhibited by the antineoplastic agent 1-beta-D-arabinofuranosyl cytosine (AraCyt) 50% inhibition (ID50) being reached at an AraCyt concentration of 0.18 mM. In the same cells, ID50 for DNA synthesis is 0.03 mM. This inhibition is probably mediated by the phosphorylated derivative of AraCyt (aCTP) since the synthesis of phosphatidyl-dCMP from dCTP using permeabilized thymocytes is inhibited by aCTP (ID50 = 0.11 mM). The incorporation of [3H]AraCyt into the organic phase could also be detected, suggesting that this drug may act as a substrate for the enzyme that catalyzes the transfer of dCTP into phosphatidic acid.

Separation of newborn BALB/c thymocytes by a density gradient method.

The recognition of T-lymphocyte subpopulations has led to a search for methods to separate lymphoid subsets on the basis of physical, biochemical and biological differences. The analysis of these properties of thymic cells made it possible to distinguish two main subsets: a major population of immunologically inactive cells, and a minor subpopulation of immunocompetent T cells. In the present paper a method for the separation of thymic lymphoid cell subpopulations in mice aged 5 to 10 days is reported. The cells resulting from this procedure were analyzed according to different criteria. From a morphological point of view, the existence of a large blast-like cell (termed I) and a smaller cell (termed III) was evident. These two cell subclasses were investigated in order to characterize their division rate, in vitro sensitivity to dexamethasone and peanut lectin agglutination pattern. It was found that subpopulation I had a faster division rate than subpopulation III, as measured in vitro by [3H]thymidine (dThd) incorporation and mitotic index with colchicine. When these different cells were incubated in the presence of dexamethasone at different concentrations, no significant difference was seen in [3H]dThd incorporation at the age of 5 days, while on the tenth day subpopulation I became more resistant to the hormone than subpopulation III. When incubated with peanut lectin, it was evident that subpopulation I was mainly constituted by PNA-unagglutinable cells. On the other hand, subpopulation III consisted mostly of PNA-agglutinable cells.