ABSTRACT
The mechanisms of immune response generation and regulation at the intestinal level are not well known, mainly due to the lack of suitable and reproducible methods to measure local immune responses. The Cunningham direct and indirect hemolytic plaque assay for the quantification of antibody producing cells against Salmonella in Peyer's patches of mice orally infected with Salmonella typhimurium was used. After infection IgM and IgG producing cells were determined on days 6, 9, 12 and 19. Specific antibody producing cells appeared after bacterial invasion of Peyer's patches, nine days after infection. At this time, there were more antibody producing cells in the distal part of the intestine, which correlated with a higher infection of these Peyer's patches as detected by bacterial culture. After day nine, the number of plaque forming cells was similar in both parts of the intestine. The peak of response was on day 12 and diminished on day 19. The number of IgM and IgG producing cells was similar in all days analyzed. Histological analysis of Peyer's patches of infected mice showed inflammation with disorganization and tumefaction.
Subject(s)
Antibodies, Bacterial/biosynthesis , Immunoglobulin G/biosynthesis , Immunoglobulin M/biosynthesis , Peyer's Patches/immunology , Salmonella typhimurium/immunology , Administration, Oral , Animals , Antibodies, Bacterial/immunology , Antibody-Producing Cells/immunology , Hemolytic Plaque Technique , Immunization , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Intestine, Small/immunology , Mice , Mice, Inbred BALB C , Peyer's Patches/ultrastructure , Time FactorsABSTRACT
It is well known that Entamoeba histolytica can cause damage to its host by means of enzymes, cytotoxins and perforins that affect different types of cells. In this work we investigated the effect of different Entamoeba histolytica trophozoites products over the secretion of antibodies by mice Peyer's patches using a reverse hemolytic assay. Results showed that amoebic glycoproteins inhibited the secretion of antibodies by lymphocytes from mice Peyer's patches. In all cases the decrease in antibody secretion was not due to cell death. The molecules responsible for this effect were shown to be high molecular weight immunogenic glycoproteins without enzymatic activity. The fact that amoebic glycoproteins interfere with plasmatic cells function could be another mechanism of evasion of the immune response by Entamoeba histolytica, although we still do not know how these amoebic products cause the inhibition.
Subject(s)
Antibody-Producing Cells/drug effects , Entamoeba histolytica/chemistry , Glycoproteins/pharmacology , Peyer's Patches/cytology , Protozoan Proteins/pharmacology , Animals , Antibody Formation/drug effects , Antibody-Producing Cells/immunology , Glycoproteins/chemistry , Glycoproteins/isolation & purification , Hemolytic Plaque Technique , Mice , Mice, Inbred BALB C , Molecular Weight , Protozoan Proteins/chemistry , Protozoan Proteins/isolation & purificationABSTRACT
In the course of tissue invasion by the amoeba, cellular immune responses are generated with the production of lymphokines by T lymphocytes that could induce activation of B cells. Therefore, it is possible that besides the induction of B lymphocytes specific for amoebic antigens, there could be activation of B cells with different specificities, that is, polyclonal in nature. IgM antibodies against some natural and synthetic antigens were quantified in both sera from amoebic hepatic abscess (AHA) patients and healthy controls by means of an ELISA. Titers in each case analyzed were significantly higher in AHA patients than in controls. Results indicate that there is polyclonal activation of B lymphocytes in this disease.
