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G Perdigón

Publications and source records attributed to G Perdigón.

31 records · Page 2Linked to original sources
PubMed1982

[Production of coprecipitating antibody in rabbits immunized repeatedly with ovalbumin in different physical states].

A comparative study has been made of rabbit precipitating and coprecipitating anti-egg albumin antibody in rabbits repeatedly injected with soluble and particulate antigens. Four different antigens were used. a) Soluble egg albumin. b) Polymerized egg albumin. c) Egg albumin linked Brucella abortus 19 strain. d) Brucella abortus 19 strain. Rabbits were subcutaneously injected every 2 weeks during 29 weeks. Before each inoculation they were bled and the concentration of serum precipitating and coprecipitating antibodies was determined. In animals inoculated with the soluble antigen, coprecipitating antibodies were present during the whole course of the immune response and they constituted 10% of the total antibody population. In rabbits injected with particulate antigen (egg albumin linked Brucella abortus) coprecipitating antibodies were also present during the whole course of the immune response but their serum concentration was not the same in different periods of time. An increase in coprecipitating antibodies began at the 13th week reaching 50% of the total antibodies at the 28th week. Similar results had been obtained in rabbits injected with Brucella s. p. In animals inoculated with polymerized egg albumin, coprecipitating antibodies increased to high levels from the 1st to the 23rd week; during this period it constituted 50% of the total antibody population, after which, the animals became tolerogenic. On the basis of these results, the increase in coprecipitating antibodies in rabbit sera would be related to: 1) antigen physicochemical characteristics (soluble o particulate); 2) the number of epitopes in the particle, and 3) the size of the antigen particles.

Animals↗
PubMed1980

Immunobiological behaviour of rabbit precipitating and non-precipitating (co-precipitating) antibodies.

Complement fixing capacity, antibody-dependent cell cytotoxicity and in vivo opsonic function of rabbit anti-DNP precipitating and co-precipitating antibodies were analysed. Precipitating antibody activated the complement system, but co-precipitating antibody did not. Both antibody preparations behaved similarly in antibody-dependent cytotoxicity reactions. When chicken erythrocytes were employed as target cells, both antibodies were inactive with homologous (rabbit) lymphocytes as effector cells but were active with heterologous lymphoid effector cells (human, guinea-pig). Clearance of antigen from the blood of mice was accelerated following injection of an optimal dose of precipitating antibody but co-precipitating antibody was ineffective even at different doses. Competition between precipitating and co-precipitating antibodies in complement fixation and antigen elimination following interaction with antigen successively or at the same time was investigated. In these tests, both antibodies competed with antigen by mass but not by affinity. The possibility exists that co-precipitating antibody has one high and one low affinity binding site and thus acts as an univalent blocking antibody and is therefore not able to form active complexes with antigen. The possible role of co-precipitating antibody in some humoral and cellular immune mechanisms is discussed.

Animals↗
PubMedDate not supplied

Humoral response to blastospores and mycelium in mice injected with different doses of Candida albicans.

An indirect immunofluorescence assay was carry out to determine the IgM and IgG antibody responses to yeast and mycelial forms of Candida albicans in mice injected with a 5 x 5(5) and 5 x 10(7) live cells suspensions. Prior adsorption of the serum samples with heat-killed blastospores enabled us to follow the specific antimycelial response which were detected considerably later than expected. Slow level of antibodies were obtained within an infection of 5 x 10(5) cell for both antibody classes and for yeast and mycelial forms. When a 5 x 10(7) cell dose was used for inoculation, maximum titers of antibodies to blastospores and mycelium in non-adsorbed sera appeared almost simultaneously (days 15 and 13, respectively). When serum samples from mice infected with the same dose were previously adsorbed with blastospores, the antimycelium antibodies for both types of Igs, were detected delayed during the infection course. In this case the higher titer for IgG appeared on day 33 and on day 23 for IgM. We suggest that the high titer obtained with the blastospore forms for the 5 x 10(7) cell dose may be due to a major immunogenicity of this forms, for to induce an immune response in the host, or that the delay in the antimycelium antibodies detection could be due to that a blastospore form is the predominant in the infection early stages. Implications of this fact for pathogenesis are discussed.

Animals↗
PubMedDate not supplied

[Adjuvant activity of lactic bacteria: perspectives for its use in oral vaccines].

The effect of the oral and subcutaneous administration of Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus on humoral antibody production and delayed type hypersensitivity response against sheep red blood cells (SRBC) was studied. The species of the genus Lactobacillus proved to be more effective in both cases, effects being stronger when working with viable bacteria than with non-viable cells. The stimulation of primary cellular and humoral immune responses reached optimal activity with a dose of 6 x 10(9) cells. The plaque-forming cells (PFC) and the circulating antibody titers to the SRBC antigen obtained in the groups treated with lactobacilli were 2 to 3 times higher than those of the non-treated control group. In mice fed with the different lactic acid bacteria circulating antibody against these microorganisms failed to be detected, but when they were administered by subcutaneous route a strong response to antilactic acid bacteria was stimulated. S. thermophilus was not effective in increasing the immune response. These results suggest that the lactobacilli by oral route, exert a strong adjuvant activity which is responsible for the enhanced host immune responses obtained. In this respect, lactobacilli could be considered as the most promising oral adjuvant.

Adjuvants, Immunologic↗